src/libGLESv2/Context.cpp

//
// Copyright (c) 2002-2012 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// Context.cpp: Implements the gl::Context class, managing all GL state and performing
// rendering operations. It is the GLES2 specific implementation of EGLContext.

#include "libGLESv2/Context.h"

#include <algorithm>

#include "libEGL/Display.h"

#include "libGLESv2/main.h"
#include "libGLESv2/mathutil.h"
#include "libGLESv2/utilities.h"
#include "libGLESv2/Blit.h"
#include "libGLESv2/ResourceManager.h"
#include "libGLESv2/Buffer.h"
#include "libGLESv2/Fence.h"
#include "libGLESv2/FrameBuffer.h"
#include "libGLESv2/Program.h"
#include "libGLESv2/Query.h"
#include "libGLESv2/RenderBuffer.h"
#include "libGLESv2/Shader.h"
#include "libGLESv2/Texture.h"
#include "libGLESv2/VertexDataManager.h"
#include "libGLESv2/IndexDataManager.h"

#undef near
#undef far

namespace gl
{
Context::Context(const egl::Config *config, const gl::Context *shareContext, bool notifyResets, bool robustAccess) : mConfig(config)
{
    ASSERT(robustAccess == false);   // Unimplemented

    mDisplay = NULL;
    mDevice = NULL;

    mFenceHandleAllocator.setBaseHandle(0);

    setClearColor(0.0f, 0.0f, 0.0f, 0.0f);

    mState.depthClearValue = 1.0f;
    mState.stencilClearValue = 0;

    mState.cullFace = false;
    mState.cullMode = GL_BACK;
    mState.frontFace = GL_CCW;
    mState.depthTest = false;
    mState.depthFunc = GL_LESS;
    mState.blend = false;
    mState.sourceBlendRGB = GL_ONE;
    mState.sourceBlendAlpha = GL_ONE;
    mState.destBlendRGB = GL_ZERO;
    mState.destBlendAlpha = GL_ZERO;
    mState.blendEquationRGB = GL_FUNC_ADD;
    mState.blendEquationAlpha = GL_FUNC_ADD;
    mState.blendColor.red = 0;
    mState.blendColor.green = 0;
    mState.blendColor.blue = 0;
    mState.blendColor.alpha = 0;
    mState.stencilTest = false;
    mState.stencilFunc = GL_ALWAYS;
    mState.stencilRef = 0;
    mState.stencilMask = -1;
    mState.stencilWritemask = -1;
    mState.stencilBackFunc = GL_ALWAYS;
    mState.stencilBackRef = 0;
    mState.stencilBackMask = - 1;
    mState.stencilBackWritemask = -1;
    mState.stencilFail = GL_KEEP;
    mState.stencilPassDepthFail = GL_KEEP;
    mState.stencilPassDepthPass = GL_KEEP;
    mState.stencilBackFail = GL_KEEP;
    mState.stencilBackPassDepthFail = GL_KEEP;
    mState.stencilBackPassDepthPass = GL_KEEP;
    mState.polygonOffsetFill = false;
    mState.polygonOffsetFactor = 0.0f;
    mState.polygonOffsetUnits = 0.0f;
    mState.sampleAlphaToCoverage = false;
    mState.sampleCoverage = false;
    mState.sampleCoverageValue = 1.0f;
    mState.sampleCoverageInvert = false;
    mState.scissorTest = false;
    mState.dither = true;
    mState.generateMipmapHint = GL_DONT_CARE;
    mState.fragmentShaderDerivativeHint = GL_DONT_CARE;

    mState.lineWidth = 1.0f;

    mState.viewportX = 0;
    mState.viewportY = 0;
    mState.viewportWidth = config->mDisplayMode.Width;
    mState.viewportHeight = config->mDisplayMode.Height;
    mState.zNear = 0.0f;
    mState.zFar = 1.0f;

    mState.scissorX = 0;
    mState.scissorY = 0;
    mState.scissorWidth = config->mDisplayMode.Width;
    mState.scissorHeight = config->mDisplayMode.Height;

    mState.colorMaskRed = true;
    mState.colorMaskGreen = true;
    mState.colorMaskBlue = true;
    mState.colorMaskAlpha = true;
    mState.depthMask = true;

    if (shareContext != NULL)
    {
        mResourceManager = shareContext->mResourceManager;
        mResourceManager->addRef();
    }
    else
    {
        mResourceManager = new ResourceManager();
    }

    // [OpenGL ES 2.0.24] section 3.7 page 83:
    // In the initial state, TEXTURE_2D and TEXTURE_CUBE_MAP have twodimensional
    // and cube map texture state vectors respectively associated with them.
    // In order that access to these initial textures not be lost, they are treated as texture
    // objects all of whose names are 0.

    mTexture2DZero.set(new Texture2D(0));
    mTextureCubeMapZero.set(new TextureCubeMap(0));

    mState.activeSampler = 0;
    bindArrayBuffer(0);
    bindElementArrayBuffer(0);
    bindTextureCubeMap(0);
    bindTexture2D(0);
    bindReadFramebuffer(0);
    bindDrawFramebuffer(0);
    bindRenderbuffer(0);

    mState.currentProgram = 0;

    mState.packAlignment = 4;
    mState.unpackAlignment = 4;
    mState.packReverseRowOrder = false;

    mVertexDataManager = NULL;
    mIndexDataManager = NULL;
    mBlit = NULL;
    mLineLoopIB = NULL;

    mInvalidEnum = false;
    mInvalidValue = false;
    mInvalidOperation = false;
    mOutOfMemory = false;
    mInvalidFramebufferOperation = false;

    mHasBeenCurrent = false;
    mContextLost = false;
    mResetStatus = GL_NO_ERROR;
    mResetStrategy = (notifyResets ? GL_LOSE_CONTEXT_ON_RESET_EXT : GL_NO_RESET_NOTIFICATION_EXT);
    mRobustAccess = robustAccess;

    mSupportsDXT1Textures = false;
    mSupportsDXT3Textures = false;
    mSupportsDXT5Textures = false;
    mSupportsEventQueries = false;
    mSupportsOcclusionQueries = false;
    mNumCompressedTextureFormats = 0;
    mMaxSupportedSamples = 0;
    mMaskedClearSavedState = NULL;
    markAllStateDirty();
}

Context::~Context()
{
    if (mState.currentProgram != 0)
    {
        Program *programObject = mResourceManager->getProgram(mState.currentProgram);
        if (programObject)
        {
            programObject->release();
        }
        mState.currentProgram = 0;
    }

    while (!mFramebufferMap.empty())
    {
        deleteFramebuffer(mFramebufferMap.begin()->first);
    }

    while (!mFenceMap.empty())
    {
        deleteFence(mFenceMap.begin()->first);
    }

    while (!mQueryMap.empty())
    {
        deleteQuery(mQueryMap.begin()->first);
    }

    while (!mMultiSampleSupport.empty())
    {
        delete [] mMultiSampleSupport.begin()->second;
        mMultiSampleSupport.erase(mMultiSampleSupport.begin());
    }

    for (int type = 0; type < TEXTURE_TYPE_COUNT; type++)
    {
        for (int sampler = 0; sampler < MAX_COMBINED_TEXTURE_IMAGE_UNITS_VTF; sampler++)
        {
            mState.samplerTexture[type][sampler].set(NULL);
        }
    }

    for (int type = 0; type < TEXTURE_TYPE_COUNT; type++)
    {
        mIncompleteTextures[type].set(NULL);
    }

    for (int i = 0; i < MAX_VERTEX_ATTRIBS; i++)
    {
        mState.vertexAttribute[i].mBoundBuffer.set(NULL);
    }

    for (int i = 0; i < QUERY_TYPE_COUNT; i++)
    {
        mState.activeQuery[i].set(NULL);
    }

    mState.arrayBuffer.set(NULL);
    mState.elementArrayBuffer.set(NULL);
    mState.renderbuffer.set(NULL);

    mTexture2DZero.set(NULL);
    mTextureCubeMapZero.set(NULL);

    delete mVertexDataManager;
    delete mIndexDataManager;
    delete mBlit;
    delete mLineLoopIB;

    if (mMaskedClearSavedState)
    {
        mMaskedClearSavedState->Release();
    }

    mResourceManager->release();
}

void Context::makeCurrent(egl::Display *display, egl::Surface *surface)
{
    mDisplay = display;
    mDevice = mDisplay->getDevice();

    if (!mHasBeenCurrent)
    {
        mDeviceCaps = mDisplay->getDeviceCaps();

        mVertexDataManager = new VertexDataManager(this, mDevice);
        mIndexDataManager = new IndexDataManager(this, mDevice);
        mBlit = new Blit(this);

        mSupportsShaderModel3 = mDeviceCaps.PixelShaderVersion >= D3DPS_VERSION(3, 0);
        mSupportsVertexTexture = mDisplay->getVertexTextureSupport();
        mSupportsNonPower2Texture = mDisplay->getNonPower2TextureSupport();
        mSupportsInstancing = mDisplay->getInstancingSupport();

        mMaxTextureDimension = std::min(std::min((int)mDeviceCaps.MaxTextureWidth, (int)mDeviceCaps.MaxTextureHeight),
                                        (int)gl::IMPLEMENTATION_MAX_TEXTURE_SIZE);
        mMaxCubeTextureDimension = std::min(mMaxTextureDimension, (int)gl::IMPLEMENTATION_MAX_CUBE_MAP_TEXTURE_SIZE);
        mMaxRenderbufferDimension = mMaxTextureDimension;
        mMaxTextureLevel = log2(mMaxTextureDimension) + 1;
        TRACE("MaxTextureDimension=%d, MaxCubeTextureDimension=%d, MaxRenderbufferDimension=%d, MaxTextureLevel=%d",
              mMaxTextureDimension, mMaxCubeTextureDimension, mMaxRenderbufferDimension, mMaxTextureLevel);

        const D3DFORMAT renderBufferFormats[] =
        {
            D3DFMT_A8R8G8B8,
            D3DFMT_X8R8G8B8,
            D3DFMT_R5G6B5,
            D3DFMT_D24S8
        };

        int max = 0;
        for (int i = 0; i < sizeof(renderBufferFormats) / sizeof(D3DFORMAT); ++i)
        {
            bool *multisampleArray = new bool[D3DMULTISAMPLE_16_SAMPLES + 1];
            mDisplay->getMultiSampleSupport(renderBufferFormats[i], multisampleArray);
            mMultiSampleSupport[renderBufferFormats[i]] = multisampleArray;

            for (int j = D3DMULTISAMPLE_16_SAMPLES; j >= 0; --j)
            {
                if (multisampleArray[j] && j != D3DMULTISAMPLE_NONMASKABLE && j > max)
                {
                    max = j;
                }
            }
        }

        mMaxSupportedSamples = max;

        mSupportsEventQueries = mDisplay->getEventQuerySupport();
        mSupportsOcclusionQueries = mDisplay->getOcclusionQuerySupport();
        mSupportsDXT1Textures = mDisplay->getDXT1TextureSupport();
        mSupportsDXT3Textures = mDisplay->getDXT3TextureSupport();
        mSupportsDXT5Textures = mDisplay->getDXT5TextureSupport();
        mSupportsFloat32Textures = mDisplay->getFloat32TextureSupport(&mSupportsFloat32LinearFilter, &mSupportsFloat32RenderableTextures);
        mSupportsFloat16Textures = mDisplay->getFloat16TextureSupport(&mSupportsFloat16LinearFilter, &mSupportsFloat16RenderableTextures);
        mSupportsLuminanceTextures = mDisplay->getLuminanceTextureSupport();
        mSupportsLuminanceAlphaTextures = mDisplay->getLuminanceAlphaTextureSupport();

        mSupports32bitIndices = mDeviceCaps.MaxVertexIndex >= (1 << 16);

        mNumCompressedTextureFormats = 0;
        if (supportsDXT1Textures())
        {
            mNumCompressedTextureFormats += 2;
        }
        if (supportsDXT3Textures())
        {
            mNumCompressedTextureFormats += 1;
        }
        if (supportsDXT5Textures())
        {
            mNumCompressedTextureFormats += 1;
        }

        initExtensionString();
        initRendererString();

        mState.viewportX = 0;
        mState.viewportY = 0;
        mState.viewportWidth = surface->getWidth();
        mState.viewportHeight = surface->getHeight();

        mState.scissorX = 0;
        mState.scissorY = 0;
        mState.scissorWidth = surface->getWidth();
        mState.scissorHeight = surface->getHeight();

        mHasBeenCurrent = true;
    }

    // Wrap the existing Direct3D 9 resources into GL objects and assign them to the '0' names
    IDirect3DSurface9 *defaultRenderTarget = surface->getRenderTarget();
    IDirect3DSurface9 *depthStencil = surface->getDepthStencil();

    Colorbuffer *colorbufferZero = new Colorbuffer(defaultRenderTarget);
    DepthStencilbuffer *depthStencilbufferZero = new DepthStencilbuffer(depthStencil);
    Framebuffer *framebufferZero = new DefaultFramebuffer(colorbufferZero, depthStencilbufferZero);

    setFramebufferZero(framebufferZero);

    if (defaultRenderTarget)
    {
        defaultRenderTarget->Release();
    }

    if (depthStencil)
    {
        depthStencil->Release();
    }
    
    markAllStateDirty();
}

// This function will set all of the state-related dirty flags, so that all state is set during next pre-draw.
void Context::markAllStateDirty()
{
    for (int t = 0; t < MAX_TEXTURE_IMAGE_UNITS; t++)
    {
        mAppliedTextureSerialPS[t] = 0;
    }

    for (int t = 0; t < MAX_VERTEX_TEXTURE_IMAGE_UNITS_VTF; t++)
    {
        mAppliedTextureSerialVS[t] = 0;
    }

    mAppliedProgramSerial = 0;
    mAppliedRenderTargetSerial = 0;
    mAppliedDepthbufferSerial = 0;
    mAppliedStencilbufferSerial = 0;
    mAppliedIBSerial = 0;
    mDepthStencilInitialized = false;
    mViewportInitialized = false;
    mRenderTargetDescInitialized = false;

    mVertexDeclarationCache.markStateDirty();

    mClearStateDirty = true;
    mCullStateDirty = true;
    mDepthStateDirty = true;
    mMaskStateDirty = true;
    mBlendStateDirty = true;
    mStencilStateDirty = true;
    mPolygonOffsetStateDirty = true;
    mScissorStateDirty = true;
    mSampleStateDirty = true;
    mDitherStateDirty = true;
    mFrontFaceDirty = true;
    mDxUniformsDirty = true;
    mCachedCurrentProgram = NULL;
}

void Context::markDxUniformsDirty()
{
    mDxUniformsDirty = true;
}

void Context::markContextLost()
{
    if (mResetStrategy == GL_LOSE_CONTEXT_ON_RESET_EXT)
        mResetStatus = GL_UNKNOWN_CONTEXT_RESET_EXT;
    mContextLost = true;
}

bool Context::isContextLost()
{
    return mContextLost;
}

void Context::setClearColor(float red, float green, float blue, float alpha)
{
    mState.colorClearValue.red = red;
    mState.colorClearValue.green = green;
    mState.colorClearValue.blue = blue;
    mState.colorClearValue.alpha = alpha;
}

void Context::setClearDepth(float depth)
{
    mState.depthClearValue = depth;
}

void Context::setClearStencil(int stencil)
{
    mState.stencilClearValue = stencil;
}

void Context::setCullFace(bool enabled)
{
    if (mState.cullFace != enabled)
    {
        mState.cullFace = enabled;
        mCullStateDirty = true;
    }
}

bool Context::isCullFaceEnabled() const
{
    return mState.cullFace;
}

void Context::setCullMode(GLenum mode)
{
    if (mState.cullMode != mode)
    {
        mState.cullMode = mode;
        mCullStateDirty = true;
    }
}

void Context::setFrontFace(GLenum front)
{
    if (mState.frontFace != front)
    {
        mState.frontFace = front;
        mFrontFaceDirty = true;
    }
}

void Context::setDepthTest(bool enabled)
{
    if (mState.depthTest != enabled)
    {
        mState.depthTest = enabled;
        mDepthStateDirty = true;
    }
}

bool Context::isDepthTestEnabled() const
{
    return mState.depthTest;
}

void Context::setDepthFunc(GLenum depthFunc)
{
    if (mState.depthFunc != depthFunc)
    {
        mState.depthFunc = depthFunc;
        mDepthStateDirty = true;
    }
}

void Context::setDepthRange(float zNear, float zFar)
{
    mState.zNear = zNear;
    mState.zFar = zFar;
}

void Context::setBlend(bool enabled)
{
    if (mState.blend != enabled)
    {
        mState.blend = enabled;
        mBlendStateDirty = true;
    }
}

bool Context::isBlendEnabled() const
{
    return mState.blend;
}

void Context::setBlendFactors(GLenum sourceRGB, GLenum destRGB, GLenum sourceAlpha, GLenum destAlpha)
{
    if (mState.sourceBlendRGB != sourceRGB ||
        mState.sourceBlendAlpha != sourceAlpha ||
        mState.destBlendRGB != destRGB ||
        mState.destBlendAlpha != destAlpha)
    {
        mState.sourceBlendRGB = sourceRGB;
        mState.destBlendRGB = destRGB;
        mState.sourceBlendAlpha = sourceAlpha;
        mState.destBlendAlpha = destAlpha;
        mBlendStateDirty = true;
    }
}

void Context::setBlendColor(float red, float green, float blue, float alpha)
{
    if (mState.blendColor.red != red ||
        mState.blendColor.green != green ||
        mState.blendColor.blue != blue ||
        mState.blendColor.alpha != alpha)
    {
        mState.blendColor.red = red;
        mState.blendColor.green = green;
        mState.blendColor.blue = blue;
        mState.blendColor.alpha = alpha;
        mBlendStateDirty = true;
    }
}

void Context::setBlendEquation(GLenum rgbEquation, GLenum alphaEquation)
{
    if (mState.blendEquationRGB != rgbEquation ||
        mState.blendEquationAlpha != alphaEquation)
    {
        mState.blendEquationRGB = rgbEquation;
        mState.blendEquationAlpha = alphaEquation;
        mBlendStateDirty = true;
    }
}

void Context::setStencilTest(bool enabled)
{
    if (mState.stencilTest != enabled)
    {
        mState.stencilTest = enabled;
        mStencilStateDirty = true;
    }
}

bool Context::isStencilTestEnabled() const
{
    return mState.stencilTest;
}

void Context::setStencilParams(GLenum stencilFunc, GLint stencilRef, GLuint stencilMask)
{
    if (mState.stencilFunc != stencilFunc ||
        mState.stencilRef != stencilRef ||
        mState.stencilMask != stencilMask)
    {
        mState.stencilFunc = stencilFunc;
        mState.stencilRef = (stencilRef > 0) ? stencilRef : 0;
        mState.stencilMask = stencilMask;
        mStencilStateDirty = true;
    }
}

void Context::setStencilBackParams(GLenum stencilBackFunc, GLint stencilBackRef, GLuint stencilBackMask)
{
    if (mState.stencilBackFunc != stencilBackFunc ||
        mState.stencilBackRef != stencilBackRef ||
        mState.stencilBackMask != stencilBackMask)
    {
        mState.stencilBackFunc = stencilBackFunc;
        mState.stencilBackRef = (stencilBackRef > 0) ? stencilBackRef : 0;
        mState.stencilBackMask = stencilBackMask;
        mStencilStateDirty = true;
    }
}

void Context::setStencilWritemask(GLuint stencilWritemask)
{
    if (mState.stencilWritemask != stencilWritemask)
    {
        mState.stencilWritemask = stencilWritemask;
        mStencilStateDirty = true;
    }
}

void Context::setStencilBackWritemask(GLuint stencilBackWritemask)
{
    if (mState.stencilBackWritemask != stencilBackWritemask)
    {
        mState.stencilBackWritemask = stencilBackWritemask;
        mStencilStateDirty = true;
    }
}

void Context::setStencilOperations(GLenum stencilFail, GLenum stencilPassDepthFail, GLenum stencilPassDepthPass)
{
    if (mState.stencilFail != stencilFail ||
        mState.stencilPassDepthFail != stencilPassDepthFail ||
        mState.stencilPassDepthPass != stencilPassDepthPass)
    {
        mState.stencilFail = stencilFail;
        mState.stencilPassDepthFail = stencilPassDepthFail;
        mState.stencilPassDepthPass = stencilPassDepthPass;
        mStencilStateDirty = true;
    }
}

void Context::setStencilBackOperations(GLenum stencilBackFail, GLenum stencilBackPassDepthFail, GLenum stencilBackPassDepthPass)
{
    if (mState.stencilBackFail != stencilBackFail ||
        mState.stencilBackPassDepthFail != stencilBackPassDepthFail ||
        mState.stencilBackPassDepthPass != stencilBackPassDepthPass)
    {
        mState.stencilBackFail = stencilBackFail;
        mState.stencilBackPassDepthFail = stencilBackPassDepthFail;
        mState.stencilBackPassDepthPass = stencilBackPassDepthPass;
        mStencilStateDirty = true;
    }
}

void Context::setPolygonOffsetFill(bool enabled)
{
    if (mState.polygonOffsetFill != enabled)
    {
        mState.polygonOffsetFill = enabled;
        mPolygonOffsetStateDirty = true;
    }
}

bool Context::isPolygonOffsetFillEnabled() const
{
    return mState.polygonOffsetFill;

}

void Context::setPolygonOffsetParams(GLfloat factor, GLfloat units)
{
    if (mState.polygonOffsetFactor != factor ||
        mState.polygonOffsetUnits != units)
    {
        mState.polygonOffsetFactor = factor;
        mState.polygonOffsetUnits = units;
        mPolygonOffsetStateDirty = true;
    }
}

void Context::setSampleAlphaToCoverage(bool enabled)
{
    if (mState.sampleAlphaToCoverage != enabled)
    {
        mState.sampleAlphaToCoverage = enabled;
        mSampleStateDirty = true;
    }
}

bool Context::isSampleAlphaToCoverageEnabled() const
{
    return mState.sampleAlphaToCoverage;
}

void Context::setSampleCoverage(bool enabled)
{
    if (mState.sampleCoverage != enabled)
    {
        mState.sampleCoverage = enabled;
        mSampleStateDirty = true;
    }
}

bool Context::isSampleCoverageEnabled() const
{
    return mState.sampleCoverage;
}

void Context::setSampleCoverageParams(GLclampf value, bool invert)
{
    if (mState.sampleCoverageValue != value ||
        mState.sampleCoverageInvert != invert)
    {
        mState.sampleCoverageValue = value;
        mState.sampleCoverageInvert = invert;
        mSampleStateDirty = true;
    }
}

void Context::setScissorTest(bool enabled)
{
    if (mState.scissorTest != enabled)
    {
        mState.scissorTest = enabled;
        mScissorStateDirty = true;
    }
}

bool Context::isScissorTestEnabled() const
{
    return mState.scissorTest;
}

void Context::setDither(bool enabled)
{
    if (mState.dither != enabled)
    {
        mState.dither = enabled;
        mDitherStateDirty = true;
    }
}

bool Context::isDitherEnabled() const
{
    return mState.dither;
}

void Context::setLineWidth(GLfloat width)
{
    mState.lineWidth = width;
}

void Context::setGenerateMipmapHint(GLenum hint)
{
    mState.generateMipmapHint = hint;
}

void Context::setFragmentShaderDerivativeHint(GLenum hint)
{
    mState.fragmentShaderDerivativeHint = hint;
    // TODO: Propagate the hint to shader translator so we can write
    // ddx, ddx_coarse, or ddx_fine depending on the hint.
    // Ignore for now. It is valid for implementations to ignore hint.
}

void Context::setViewportParams(GLint x, GLint y, GLsizei width, GLsizei height)
{
    mState.viewportX = x;
    mState.viewportY = y;
    mState.viewportWidth = width;
    mState.viewportHeight = height;
}

void Context::setScissorParams(GLint x, GLint y, GLsizei width, GLsizei height)
{
    if (mState.scissorX != x || mState.scissorY != y || 
        mState.scissorWidth != width || mState.scissorHeight != height)
    {
        mState.scissorX = x;
        mState.scissorY = y;
        mState.scissorWidth = width;
        mState.scissorHeight = height;
        mScissorStateDirty = true;
    }
}

void Context::setColorMask(bool red, bool green, bool blue, bool alpha)
{
    if (mState.colorMaskRed != red || mState.colorMaskGreen != green ||
        mState.colorMaskBlue != blue || mState.colorMaskAlpha != alpha)
    {
        mState.colorMaskRed = red;
        mState.colorMaskGreen = green;
        mState.colorMaskBlue = blue;
        mState.colorMaskAlpha = alpha;
        mMaskStateDirty = true;
    }
}

void Context::setDepthMask(bool mask)
{
    if (mState.depthMask != mask)
    {
        mState.depthMask = mask;
        mMaskStateDirty = true;
    }
}

void Context::setActiveSampler(unsigned int active)
{
    mState.activeSampler = active;
}

GLuint Context::getReadFramebufferHandle() const
{
    return mState.readFramebuffer;
}

GLuint Context::getDrawFramebufferHandle() const
{
    return mState.drawFramebuffer;
}

GLuint Context::getRenderbufferHandle() const
{
    return mState.renderbuffer.id();
}

GLuint Context::getArrayBufferHandle() const
{
    return mState.arrayBuffer.id();
}

GLuint Context::getActiveQuery(GLenum target) const
{
    Query *queryObject = NULL;
    
    switch (target)
    {
      case GL_ANY_SAMPLES_PASSED_EXT:
        queryObject = mState.activeQuery[QUERY_ANY_SAMPLES_PASSED].get();
        break;
      case GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT:
        queryObject = mState.activeQuery[QUERY_ANY_SAMPLES_PASSED_CONSERVATIVE].get();
        break;
      default:
        ASSERT(false);
    }

    if (queryObject)
    {
        return queryObject->id();
    }
    else
    {
        return 0;
    }
}

void Context::setEnableVertexAttribArray(unsigned int attribNum, bool enabled)
{
    mState.vertexAttribute[attribNum].mArrayEnabled = enabled;
}

const VertexAttribute &Context::getVertexAttribState(unsigned int attribNum)
{
    return mState.vertexAttribute[attribNum];
}

void Context::setVertexAttribState(unsigned int attribNum, Buffer *boundBuffer, GLint size, GLenum type, bool normalized,
                                   GLsizei stride, const void *pointer)
{
    mState.vertexAttribute[attribNum].mBoundBuffer.set(boundBuffer);
    mState.vertexAttribute[attribNum].mSize = size;
    mState.vertexAttribute[attribNum].mType = type;
    mState.vertexAttribute[attribNum].mNormalized = normalized;
    mState.vertexAttribute[attribNum].mStride = stride;
    mState.vertexAttribute[attribNum].mPointer = pointer;
}

const void *Context::getVertexAttribPointer(unsigned int attribNum) const
{
    return mState.vertexAttribute[attribNum].mPointer;
}

const VertexAttributeArray &Context::getVertexAttributes()
{
    return mState.vertexAttribute;
}

void Context::setPackAlignment(GLint alignment)
{
    mState.packAlignment = alignment;
}

GLint Context::getPackAlignment() const
{
    return mState.packAlignment;
}

void Context::setUnpackAlignment(GLint alignment)
{
    mState.unpackAlignment = alignment;
}

GLint Context::getUnpackAlignment() const
{
    return mState.unpackAlignment;
}

void Context::setPackReverseRowOrder(bool reverseRowOrder)
{
    mState.packReverseRowOrder = reverseRowOrder;
}

bool Context::getPackReverseRowOrder() const
{
    return mState.packReverseRowOrder;
}

GLuint Context::createBuffer()
{
    return mResourceManager->createBuffer();
}

GLuint Context::createProgram()
{
    return mResourceManager->createProgram();
}

GLuint Context::createShader(GLenum type)
{
    return mResourceManager->createShader(type);
}

GLuint Context::createTexture()
{
    return mResourceManager->createTexture();
}

GLuint Context::createRenderbuffer()
{
    return mResourceManager->createRenderbuffer();
}

// Returns an unused framebuffer name
GLuint Context::createFramebuffer()
{
    GLuint handle = mFramebufferHandleAllocator.allocate();

    mFramebufferMap[handle] = NULL;

    return handle;
}

GLuint Context::createFence()
{
    GLuint handle = mFenceHandleAllocator.allocate();

    mFenceMap[handle] = new Fence(mDisplay);

    return handle;
}

// Returns an unused query name
GLuint Context::createQuery()
{
    GLuint handle = mQueryHandleAllocator.allocate();

    mQueryMap[handle] = NULL;

    return handle;
}

void Context::deleteBuffer(GLuint buffer)
{
    if (mResourceManager->getBuffer(buffer))
    {
        detachBuffer(buffer);
    }
    
    mResourceManager->deleteBuffer(buffer);
}

void Context::deleteShader(GLuint shader)
{
    mResourceManager->deleteShader(shader);
}

void Context::deleteProgram(GLuint program)
{
    mResourceManager->deleteProgram(program);
    mCachedCurrentProgram = NULL;
}

void Context::deleteTexture(GLuint texture)
{
    if (mResourceManager->getTexture(texture))
    {
        detachTexture(texture);
    }

    mResourceManager->deleteTexture(texture);
}

void Context::deleteRenderbuffer(GLuint renderbuffer)
{
    if (mResourceManager->getRenderbuffer(renderbuffer))
    {
        detachRenderbuffer(renderbuffer);
    }
    
    mResourceManager->deleteRenderbuffer(renderbuffer);
}

void Context::deleteFramebuffer(GLuint framebuffer)
{
    FramebufferMap::iterator framebufferObject = mFramebufferMap.find(framebuffer);

    if (framebufferObject != mFramebufferMap.end())
    {
        detachFramebuffer(framebuffer);

        mFramebufferHandleAllocator.release(framebufferObject->first);
        delete framebufferObject->second;
        mFramebufferMap.erase(framebufferObject);
    }
}

void Context::deleteFence(GLuint fence)
{
    FenceMap::iterator fenceObject = mFenceMap.find(fence);

    if (fenceObject != mFenceMap.end())
    {
        mFenceHandleAllocator.release(fenceObject->first);
        delete fenceObject->second;
        mFenceMap.erase(fenceObject);
    }
}

void Context::deleteQuery(GLuint query)
{
    QueryMap::iterator queryObject = mQueryMap.find(query);
    if (queryObject != mQueryMap.end())
    {
        mQueryHandleAllocator.release(queryObject->first);
        if (queryObject->second)
        {
            queryObject->second->release();
        }
        mQueryMap.erase(queryObject);
    }
}

Buffer *Context::getBuffer(GLuint handle)
{
    return mResourceManager->getBuffer(handle);
}

Shader *Context::getShader(GLuint handle)
{
    return mResourceManager->getShader(handle);
}

Program *Context::getProgram(GLuint handle)
{
    return mResourceManager->getProgram(handle);
}

Texture *Context::getTexture(GLuint handle)
{
    return mResourceManager->getTexture(handle);
}

Renderbuffer *Context::getRenderbuffer(GLuint handle)
{
    return mResourceManager->getRenderbuffer(handle);
}

Framebuffer *Context::getReadFramebuffer()
{
    return getFramebuffer(mState.readFramebuffer);
}

Framebuffer *Context::getDrawFramebuffer()
{
    return mBoundDrawFramebuffer;
}

void Context::bindArrayBuffer(unsigned int buffer)
{
    mResourceManager->checkBufferAllocation(buffer);

    mState.arrayBuffer.set(getBuffer(buffer));
}

void Context::bindElementArrayBuffer(unsigned int buffer)
{
    mResourceManager->checkBufferAllocation(buffer);

    mState.elementArrayBuffer.set(getBuffer(buffer));
}

void Context::bindTexture2D(GLuint texture)
{
    mResourceManager->checkTextureAllocation(texture, TEXTURE_2D);

    mState.samplerTexture[TEXTURE_2D][mState.activeSampler].set(getTexture(texture));
}

void Context::bindTextureCubeMap(GLuint texture)
{
    mResourceManager->checkTextureAllocation(texture, TEXTURE_CUBE);

    mState.samplerTexture[TEXTURE_CUBE][mState.activeSampler].set(getTexture(texture));
}

void Context::bindReadFramebuffer(GLuint framebuffer)
{
    if (!getFramebuffer(framebuffer))
    {
        mFramebufferMap[framebuffer] = new Framebuffer();
    }

    mState.readFramebuffer = framebuffer;
}

void Context::bindDrawFramebuffer(GLuint framebuffer)
{
    if (!getFramebuffer(framebuffer))
    {
        mFramebufferMap[framebuffer] = new Framebuffer();
    }

    mState.drawFramebuffer = framebuffer;

    mBoundDrawFramebuffer = getFramebuffer(framebuffer);
}

void Context::bindRenderbuffer(GLuint renderbuffer)
{
    mResourceManager->checkRenderbufferAllocation(renderbuffer);

    mState.renderbuffer.set(getRenderbuffer(renderbuffer));
}

void Context::useProgram(GLuint program)
{
    GLuint priorProgram = mState.currentProgram;
    mState.currentProgram = program;               // Must switch before trying to delete, otherwise it only gets flagged.

    if (priorProgram != program)
    {
        Program *newProgram = mResourceManager->getProgram(program);
        Program *oldProgram = mResourceManager->getProgram(priorProgram);
        mCachedCurrentProgram = NULL;
        mDxUniformsDirty = true;

        if (newProgram)
        {
            newProgram->addRef();
        }
        
        if (oldProgram)
        {
            oldProgram->release();
        }
    }
}

void Context::beginQuery(GLenum target, GLuint query)
{
    // From EXT_occlusion_query_boolean: If BeginQueryEXT is called with an <id>  
    // of zero, if the active query object name for <target> is non-zero (for the  
    // targets ANY_SAMPLES_PASSED_EXT and ANY_SAMPLES_PASSED_CONSERVATIVE_EXT, if  
    // the active query for either target is non-zero), if <id> is the name of an 
    // existing query object whose type does not match <target>, or if <id> is the
    // active query object name for any query type, the error INVALID_OPERATION is
    // generated.

    // Ensure no other queries are active
    // NOTE: If other queries than occlusion are supported, we will need to check
    // separately that:
    //    a) The query ID passed is not the current active query for any target/type
    //    b) There are no active queries for the requested target (and in the case
    //       of GL_ANY_SAMPLES_PASSED_EXT and GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT,
    //       no query may be active for either if glBeginQuery targets either.
    for (int i = 0; i < QUERY_TYPE_COUNT; i++)
    {
        if (mState.activeQuery[i].get() != NULL)
        {
            return error(GL_INVALID_OPERATION);
        }
    }

    QueryType qType;
    switch (target)
    {
      case GL_ANY_SAMPLES_PASSED_EXT: 
        qType = QUERY_ANY_SAMPLES_PASSED; 
        break;
      case GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT: 
        qType = QUERY_ANY_SAMPLES_PASSED_CONSERVATIVE; 
        break;
      default: 
        ASSERT(false);
        return;
    }

    Query *queryObject = getQuery(query, true, target);

    // check that name was obtained with glGenQueries
    if (!queryObject)
    {
        return error(GL_INVALID_OPERATION);
    }

    // check for type mismatch
    if (queryObject->getType() != target)
    {
        return error(GL_INVALID_OPERATION);
    }

    // set query as active for specified target
    mState.activeQuery[qType].set(queryObject);

    // begin query
    queryObject->begin();
}

void Context::endQuery(GLenum target)
{
    QueryType qType;

    switch (target)
    {
      case GL_ANY_SAMPLES_PASSED_EXT: 
        qType = QUERY_ANY_SAMPLES_PASSED; 
        break;
      case GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT: 
        qType = QUERY_ANY_SAMPLES_PASSED_CONSERVATIVE; 
        break;
      default: 
        ASSERT(false);
        return;
    }

    Query *queryObject = mState.activeQuery[qType].get();

    if (queryObject == NULL)
    {
        return error(GL_INVALID_OPERATION);
    }

    queryObject->end();

    mState.activeQuery[qType].set(NULL);
}

void Context::setFramebufferZero(Framebuffer *buffer)
{
    delete mFramebufferMap[0];
    mFramebufferMap[0] = buffer;
    if (mState.drawFramebuffer == 0)
    {
        mBoundDrawFramebuffer = buffer;
    }
}

void Context::setRenderbufferStorage(RenderbufferStorage *renderbuffer)
{
    Renderbuffer *renderbufferObject = mState.renderbuffer.get();
    renderbufferObject->setStorage(renderbuffer);
}

Framebuffer *Context::getFramebuffer(unsigned int handle)
{
    FramebufferMap::iterator framebuffer = mFramebufferMap.find(handle);

    if (framebuffer == mFramebufferMap.end())
    {
        return NULL;
    }
    else
    {
        return framebuffer->second;
    }
}

Fence *Context::getFence(unsigned int handle)
{
    FenceMap::iterator fence = mFenceMap.find(handle);

    if (fence == mFenceMap.end())
    {
        return NULL;
    }
    else
    {
        return fence->second;
    }
}

Query *Context::getQuery(unsigned int handle, bool create, GLenum type)
{
    QueryMap::iterator query = mQueryMap.find(handle);

    if (query == mQueryMap.end())
    {
        return NULL;
    }
    else
    {
        if (!query->second && create)
        {
            query->second = new Query(handle, type);
            query->second->addRef();
        }
        return query->second;
    }
}

Buffer *Context::getArrayBuffer()
{
    return mState.arrayBuffer.get();
}

Buffer *Context::getElementArrayBuffer()
{
    return mState.elementArrayBuffer.get();
}

Program *Context::getCurrentProgram()
{
    if (!mCachedCurrentProgram)
    {
        mCachedCurrentProgram = mResourceManager->getProgram(mState.currentProgram);
    }
    return mCachedCurrentProgram;
}

Texture2D *Context::getTexture2D()
{
    return static_cast<Texture2D*>(getSamplerTexture(mState.activeSampler, TEXTURE_2D));
}

TextureCubeMap *Context::getTextureCubeMap()
{
    return static_cast<TextureCubeMap*>(getSamplerTexture(mState.activeSampler, TEXTURE_CUBE));
}

Texture *Context::getSamplerTexture(unsigned int sampler, TextureType type)
{
    GLuint texid = mState.samplerTexture[type][sampler].id();

    if (texid == 0)   // Special case: 0 refers to different initial textures based on the target
    {
        switch (type)
        {
          default: UNREACHABLE();
          case TEXTURE_2D: return mTexture2DZero.get();
          case TEXTURE_CUBE: return mTextureCubeMapZero.get();
        }
    }

    return mState.samplerTexture[type][sampler].get();
}

bool Context::getBooleanv(GLenum pname, GLboolean *params)
{
    switch (pname)
    {
      case GL_SHADER_COMPILER:           *params = GL_TRUE;                            break;
      case GL_SAMPLE_COVERAGE_INVERT:    *params = mState.sampleCoverageInvert;        break;
      case GL_DEPTH_WRITEMASK:           *params = mState.depthMask;                   break;
      case GL_COLOR_WRITEMASK:
        params[0] = mState.colorMaskRed;
        params[1] = mState.colorMaskGreen;
        params[2] = mState.colorMaskBlue;
        params[3] = mState.colorMaskAlpha;
        break;
      case GL_CULL_FACE:                 *params = mState.cullFace;                    break;
      case GL_POLYGON_OFFSET_FILL:       *params = mState.polygonOffsetFill;           break;
      case GL_SAMPLE_ALPHA_TO_COVERAGE:  *params = mState.sampleAlphaToCoverage;       break;
      case GL_SAMPLE_COVERAGE:           *params = mState.sampleCoverage;              break;
      case GL_SCISSOR_TEST:              *params = mState.scissorTest;                 break;
      case GL_STENCIL_TEST:              *params = mState.stencilTest;                 break;
      case GL_DEPTH_TEST:                *params = mState.depthTest;                   break;
      case GL_BLEND:                     *params = mState.blend;                       break;
      case GL_DITHER:                    *params = mState.dither;                      break;
      case GL_CONTEXT_ROBUST_ACCESS_EXT: *params = mRobustAccess ? GL_TRUE : GL_FALSE; break;
      default:
        return false;
    }

    return true;
}

bool Context::getFloatv(GLenum pname, GLfloat *params)
{
    // Please note: DEPTH_CLEAR_VALUE is included in our internal getFloatv implementation
    // because it is stored as a float, despite the fact that the GL ES 2.0 spec names
    // GetIntegerv as its native query function. As it would require conversion in any
    // case, this should make no difference to the calling application.
    switch (pname)
    {
      case GL_LINE_WIDTH:               *params = mState.lineWidth;            break;
      case GL_SAMPLE_COVERAGE_VALUE:    *params = mState.sampleCoverageValue;  break;
      case GL_DEPTH_CLEAR_VALUE:        *params = mState.depthClearValue;      break;
      case GL_POLYGON_OFFSET_FACTOR:    *params = mState.polygonOffsetFactor;  break;
      case GL_POLYGON_OFFSET_UNITS:     *params = mState.polygonOffsetUnits;   break;
      case GL_ALIASED_LINE_WIDTH_RANGE:
        params[0] = gl::ALIASED_LINE_WIDTH_RANGE_MIN;
        params[1] = gl::ALIASED_LINE_WIDTH_RANGE_MAX;
        break;
      case GL_ALIASED_POINT_SIZE_RANGE:
        params[0] = gl::ALIASED_POINT_SIZE_RANGE_MIN;
        params[1] = supportsShaderModel3() ? gl::ALIASED_POINT_SIZE_RANGE_MAX_SM3 : gl::ALIASED_POINT_SIZE_RANGE_MAX_SM2;
        break;
      case GL_DEPTH_RANGE:
        params[0] = mState.zNear;
        params[1] = mState.zFar;
        break;
      case GL_COLOR_CLEAR_VALUE:
        params[0] = mState.colorClearValue.red;
        params[1] = mState.colorClearValue.green;
        params[2] = mState.colorClearValue.blue;
        params[3] = mState.colorClearValue.alpha;
        break;
      case GL_BLEND_COLOR:
        params[0] = mState.blendColor.red;
        params[1] = mState.blendColor.green;
        params[2] = mState.blendColor.blue;
        params[3] = mState.blendColor.alpha;
        break;
      default:
        return false;
    }

    return true;
}

bool Context::getIntegerv(GLenum pname, GLint *params)
{
    // Please note: DEPTH_CLEAR_VALUE is not included in our internal getIntegerv implementation
    // because it is stored as a float, despite the fact that the GL ES 2.0 spec names
    // GetIntegerv as its native query function. As it would require conversion in any
    // case, this should make no difference to the calling application. You may find it in 
    // Context::getFloatv.
    switch (pname)
    {
      case GL_MAX_VERTEX_ATTRIBS:               *params = gl::MAX_VERTEX_ATTRIBS;               break;
      case GL_MAX_VERTEX_UNIFORM_VECTORS:       *params = gl::MAX_VERTEX_UNIFORM_VECTORS;       break;
      case GL_MAX_VARYING_VECTORS:              *params = getMaximumVaryingVectors();           break;
      case GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS: *params = getMaximumCombinedTextureImageUnits(); break;
      case GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS:   *params = getMaximumVertexTextureImageUnits();  break;
      case GL_MAX_TEXTURE_IMAGE_UNITS:          *params = gl::MAX_TEXTURE_IMAGE_UNITS;          break;
      case GL_MAX_FRAGMENT_UNIFORM_VECTORS:     *params = getMaximumFragmentUniformVectors();   break;
      case GL_MAX_RENDERBUFFER_SIZE:            *params = getMaximumRenderbufferDimension();    break;
      case GL_NUM_SHADER_BINARY_FORMATS:        *params = 0;                                    break;
      case GL_SHADER_BINARY_FORMATS:      /* no shader binary formats are supported */          break;
      case GL_ARRAY_BUFFER_BINDING:             *params = mState.arrayBuffer.id();              break;
      case GL_ELEMENT_ARRAY_BUFFER_BINDING:     *params = mState.elementArrayBuffer.id();       break;
      //case GL_FRAMEBUFFER_BINDING:            // now equivalent to GL_DRAW_FRAMEBUFFER_BINDING_ANGLE
      case GL_DRAW_FRAMEBUFFER_BINDING_ANGLE:   *params = mState.drawFramebuffer;               break;
      case GL_READ_FRAMEBUFFER_BINDING_ANGLE:   *params = mState.readFramebuffer;               break;
      case GL_RENDERBUFFER_BINDING:             *params = mState.renderbuffer.id();             break;
      case GL_CURRENT_PROGRAM:                  *params = mState.currentProgram;                break;
      case GL_PACK_ALIGNMENT:                   *params = mState.packAlignment;                 break;
      case GL_PACK_REVERSE_ROW_ORDER_ANGLE:     *params = mState.packReverseRowOrder;           break;
      case GL_UNPACK_ALIGNMENT:                 *params = mState.unpackAlignment;               break;
      case GL_GENERATE_MIPMAP_HINT:             *params = mState.generateMipmapHint;            break;
      case GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES: *params = mState.fragmentShaderDerivativeHint; break;
      case GL_ACTIVE_TEXTURE:                   *params = (mState.activeSampler + GL_TEXTURE0); break;
      case GL_STENCIL_FUNC:                     *params = mState.stencilFunc;                   break;
      case GL_STENCIL_REF:                      *params = mState.stencilRef;                    break;
      case GL_STENCIL_VALUE_MASK:               *params = mState.stencilMask;                   break;
      case GL_STENCIL_BACK_FUNC:                *params = mState.stencilBackFunc;               break;
      case GL_STENCIL_BACK_REF:                 *params = mState.stencilBackRef;                break;
      case GL_STENCIL_BACK_VALUE_MASK:          *params = mState.stencilBackMask;               break;
      case GL_STENCIL_FAIL:                     *params = mState.stencilFail;                   break;
      case GL_STENCIL_PASS_DEPTH_FAIL:          *params = mState.stencilPassDepthFail;          break;
      case GL_STENCIL_PASS_DEPTH_PASS:          *params = mState.stencilPassDepthPass;          break;
      case GL_STENCIL_BACK_FAIL:                *params = mState.stencilBackFail;               break;
      case GL_STENCIL_BACK_PASS_DEPTH_FAIL:     *params = mState.stencilBackPassDepthFail;      break;
      case GL_STENCIL_BACK_PASS_DEPTH_PASS:     *params = mState.stencilBackPassDepthPass;      break;
      case GL_DEPTH_FUNC:                       *params = mState.depthFunc;                     break;
      case GL_BLEND_SRC_RGB:                    *params = mState.sourceBlendRGB;                break;
      case GL_BLEND_SRC_ALPHA:                  *params = mState.sourceBlendAlpha;              break;
      case GL_BLEND_DST_RGB:                    *params = mState.destBlendRGB;                  break;
      case GL_BLEND_DST_ALPHA:                  *params = mState.destBlendAlpha;                break;
      case GL_BLEND_EQUATION_RGB:               *params = mState.blendEquationRGB;              break;
      case GL_BLEND_EQUATION_ALPHA:             *params = mState.blendEquationAlpha;            break;
      case GL_STENCIL_WRITEMASK:                *params = mState.stencilWritemask;              break;
      case GL_STENCIL_BACK_WRITEMASK:           *params = mState.stencilBackWritemask;          break;
      case GL_STENCIL_CLEAR_VALUE:              *params = mState.stencilClearValue;             break;
      case GL_SUBPIXEL_BITS:                    *params = 4;                                    break;
      case GL_MAX_TEXTURE_SIZE:                 *params = getMaximumTextureDimension();         break;
      case GL_MAX_CUBE_MAP_TEXTURE_SIZE:        *params = getMaximumCubeTextureDimension();     break;
      case GL_NUM_COMPRESSED_TEXTURE_FORMATS:   
        params[0] = mNumCompressedTextureFormats;
        break;
      case GL_MAX_SAMPLES_ANGLE:
        {
            GLsizei maxSamples = getMaxSupportedSamples();
            if (maxSamples != 0)
            {
                *params = maxSamples;
            }
            else
            {
                return false;
            }

            break;
        }
      case GL_SAMPLE_BUFFERS:                   
      case GL_SAMPLES:
        {
            gl::Framebuffer *framebuffer = getDrawFramebuffer();
            if (framebuffer->completeness() == GL_FRAMEBUFFER_COMPLETE)
            {
                switch (pname)
                {
                  case GL_SAMPLE_BUFFERS:
                    if (framebuffer->getSamples() != 0)
                    {
                        *params = 1;
                    }
                    else
                    {
                        *params = 0;
                    }
                    break;
                  case GL_SAMPLES:
                    *params = framebuffer->getSamples();
                    break;
                }
            }
            else 
            {
                *params = 0;
            }
        }
        break;
      case GL_IMPLEMENTATION_COLOR_READ_TYPE:   *params = gl::IMPLEMENTATION_COLOR_READ_TYPE;   break;
      case GL_IMPLEMENTATION_COLOR_READ_FORMAT: *params = gl::IMPLEMENTATION_COLOR_READ_FORMAT; break;
      case GL_MAX_VIEWPORT_DIMS:
        {
            int maxDimension = std::max(getMaximumRenderbufferDimension(), getMaximumTextureDimension());
            params[0] = maxDimension;
            params[1] = maxDimension;
        }
        break;
      case GL_COMPRESSED_TEXTURE_FORMATS:
        {
            if (supportsDXT1Textures())
            {
                *params++ = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
                *params++ = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
            }
            if (supportsDXT3Textures())
            {
                *params++ = GL_COMPRESSED_RGBA_S3TC_DXT3_ANGLE;
            }
            if (supportsDXT5Textures())
            {
                *params++ = GL_COMPRESSED_RGBA_S3TC_DXT5_ANGLE;
            }
        }
        break;
      case GL_VIEWPORT:
        params[0] = mState.viewportX;
        params[1] = mState.viewportY;
        params[2] = mState.viewportWidth;
        params[3] = mState.viewportHeight;
        break;
      case GL_SCISSOR_BOX:
        params[0] = mState.scissorX;
        params[1] = mState.scissorY;
        params[2] = mState.scissorWidth;
        params[3] = mState.scissorHeight;
        break;
      case GL_CULL_FACE_MODE:                   *params = mState.cullMode;                 break;
      case GL_FRONT_FACE:                       *params = mState.frontFace;                break;
      case GL_RED_BITS:
      case GL_GREEN_BITS:
      case GL_BLUE_BITS:
      case GL_ALPHA_BITS:
        {
            gl::Framebuffer *framebuffer = getDrawFramebuffer();
            gl::Renderbuffer *colorbuffer = framebuffer->getColorbuffer();

            if (colorbuffer)
            {
                switch (pname)
                {
                  case GL_RED_BITS:   *params = colorbuffer->getRedSize();   break;
                  case GL_GREEN_BITS: *params = colorbuffer->getGreenSize(); break;
                  case GL_BLUE_BITS:  *params = colorbuffer->getBlueSize();  break;
                  case GL_ALPHA_BITS: *params = colorbuffer->getAlphaSize(); break;
                }
            }
            else
            {
                *params = 0;
            }
        }
        break;
      case GL_DEPTH_BITS:
        {
            gl::Framebuffer *framebuffer = getDrawFramebuffer();
            gl::Renderbuffer *depthbuffer = framebuffer->getDepthbuffer();

            if (depthbuffer)
            {
                *params = depthbuffer->getDepthSize();
            }
            else
            {
                *params = 0;
            }
        }
        break;
      case GL_STENCIL_BITS:
        {
            gl::Framebuffer *framebuffer = getDrawFramebuffer();
            gl::Renderbuffer *stencilbuffer = framebuffer->getStencilbuffer();

            if (stencilbuffer)
            {
                *params = stencilbuffer->getStencilSize();
            }
            else
            {
                *params = 0;
            }
        }
        break;
      case GL_TEXTURE_BINDING_2D:
        {
            if (mState.activeSampler < 0 || mState.activeSampler > getMaximumCombinedTextureImageUnits() - 1)
            {
                error(GL_INVALID_OPERATION);
                return false;
            }

            *params = mState.samplerTexture[TEXTURE_2D][mState.activeSampler].id();
        }
        break;
      case GL_TEXTURE_BINDING_CUBE_MAP:
        {
            if (mState.activeSampler < 0 || mState.activeSampler > getMaximumCombinedTextureImageUnits() - 1)
            {
                error(GL_INVALID_OPERATION);
                return false;
            }

            *params = mState.samplerTexture[TEXTURE_CUBE][mState.activeSampler].id();
        }
        break;
      case GL_RESET_NOTIFICATION_STRATEGY_EXT:
        *params = mResetStrategy;
        break;
      default:
        return false;
    }

    return true;
}

bool Context::getQueryParameterInfo(GLenum pname, GLenum *type, unsigned int *numParams)
{
    // Please note: the query type returned for DEPTH_CLEAR_VALUE in this implementation
    // is FLOAT rather than INT, as would be suggested by the GL ES 2.0 spec. This is due
    // to the fact that it is stored internally as a float, and so would require conversion
    // if returned from Context::getIntegerv. Since this conversion is already implemented 
    // in the case that one calls glGetIntegerv to retrieve a float-typed state variable, we
    // place DEPTH_CLEAR_VALUE with the floats. This should make no difference to the calling
    // application.
    switch (pname)
    {
      case GL_COMPRESSED_TEXTURE_FORMATS:
        {
            *type = GL_INT;
            *numParams = mNumCompressedTextureFormats;
        }
        break;
      case GL_SHADER_BINARY_FORMATS:
        {
            *type = GL_INT;
            *numParams = 0;
        }
        break;
      case GL_MAX_VERTEX_ATTRIBS:
      case GL_MAX_VERTEX_UNIFORM_VECTORS:
      case GL_MAX_VARYING_VECTORS:
      case GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS:
      case GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS:
      case GL_MAX_TEXTURE_IMAGE_UNITS:
      case GL_MAX_FRAGMENT_UNIFORM_VECTORS:
      case GL_MAX_RENDERBUFFER_SIZE:
      case GL_NUM_SHADER_BINARY_FORMATS:
      case GL_NUM_COMPRESSED_TEXTURE_FORMATS:
      case GL_ARRAY_BUFFER_BINDING:
      case GL_FRAMEBUFFER_BINDING:
      case GL_RENDERBUFFER_BINDING:
      case GL_CURRENT_PROGRAM:
      case GL_PACK_ALIGNMENT:
      case GL_PACK_REVERSE_ROW_ORDER_ANGLE:
      case GL_UNPACK_ALIGNMENT:
      case GL_GENERATE_MIPMAP_HINT:
      case GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES:
      case GL_RED_BITS:
      case GL_GREEN_BITS:
      case GL_BLUE_BITS:
      case GL_ALPHA_BITS:
      case GL_DEPTH_BITS:
      case GL_STENCIL_BITS:
      case GL_ELEMENT_ARRAY_BUFFER_BINDING:
      case GL_CULL_FACE_MODE:
      case GL_FRONT_FACE:
      case GL_ACTIVE_TEXTURE:
      case GL_STENCIL_FUNC:
      case GL_STENCIL_VALUE_MASK:
      case GL_STENCIL_REF:
      case GL_STENCIL_FAIL:
      case GL_STENCIL_PASS_DEPTH_FAIL:
      case GL_STENCIL_PASS_DEPTH_PASS:
      case GL_STENCIL_BACK_FUNC:
      case GL_STENCIL_BACK_VALUE_MASK:
      case GL_STENCIL_BACK_REF:
      case GL_STENCIL_BACK_FAIL:
      case GL_STENCIL_BACK_PASS_DEPTH_FAIL:
      case GL_STENCIL_BACK_PASS_DEPTH_PASS:
      case GL_DEPTH_FUNC:
      case GL_BLEND_SRC_RGB:
      case GL_BLEND_SRC_ALPHA:
      case GL_BLEND_DST_RGB:
      case GL_BLEND_DST_ALPHA:
      case GL_BLEND_EQUATION_RGB:
      case GL_BLEND_EQUATION_ALPHA:
      case GL_STENCIL_WRITEMASK:
      case GL_STENCIL_BACK_WRITEMASK:
      case GL_STENCIL_CLEAR_VALUE:
      case GL_SUBPIXEL_BITS:
      case GL_MAX_TEXTURE_SIZE:
      case GL_MAX_CUBE_MAP_TEXTURE_SIZE:
      case GL_SAMPLE_BUFFERS:
      case GL_SAMPLES:
      case GL_IMPLEMENTATION_COLOR_READ_TYPE:
      case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
      case GL_TEXTURE_BINDING_2D:
      case GL_TEXTURE_BINDING_CUBE_MAP:
      case GL_RESET_NOTIFICATION_STRATEGY_EXT:
        {
            *type = GL_INT;
            *numParams = 1;
        }
        break;
      case GL_MAX_SAMPLES_ANGLE:
        {
            if (getMaxSupportedSamples() != 0)
            {
                *type = GL_INT;
                *numParams = 1;
            }
            else
            {
                return false;
            }
        }
        break;
      case GL_MAX_VIEWPORT_DIMS:
        {
            *type = GL_INT;
            *numParams = 2;
        }
        break;
      case GL_VIEWPORT:
      case GL_SCISSOR_BOX:
        {
            *type = GL_INT;
            *numParams = 4;
        }
        break;
      case GL_SHADER_COMPILER:
      case GL_SAMPLE_COVERAGE_INVERT:
      case GL_DEPTH_WRITEMASK:
      case GL_CULL_FACE:                // CULL_FACE through DITHER are natural to IsEnabled,
      case GL_POLYGON_OFFSET_FILL:      // but can be retrieved through the Get{Type}v queries.
      case GL_SAMPLE_ALPHA_TO_COVERAGE: // For this purpose, they are treated here as bool-natural
      case GL_SAMPLE_COVERAGE:
      case GL_SCISSOR_TEST:
      case GL_STENCIL_TEST:
      case GL_DEPTH_TEST:
      case GL_BLEND:
      case GL_DITHER:
      case GL_CONTEXT_ROBUST_ACCESS_EXT:
        {
            *type = GL_BOOL;
            *numParams = 1;
        }
        break;
      case GL_COLOR_WRITEMASK:
        {
            *type = GL_BOOL;
            *numParams = 4;
        }
        break;
      case GL_POLYGON_OFFSET_FACTOR:
      case GL_POLYGON_OFFSET_UNITS:
      case GL_SAMPLE_COVERAGE_VALUE:
      case GL_DEPTH_CLEAR_VALUE:
      case GL_LINE_WIDTH:
        {
            *type = GL_FLOAT;
            *numParams = 1;
        }
        break;
      case GL_ALIASED_LINE_WIDTH_RANGE:
      case GL_ALIASED_POINT_SIZE_RANGE:
      case GL_DEPTH_RANGE:
        {
            *type = GL_FLOAT;
            *numParams = 2;
        }
        break;
      case GL_COLOR_CLEAR_VALUE:
      case GL_BLEND_COLOR:
        {
            *type = GL_FLOAT;
            *numParams = 4;
        }
        break;
      default:
        return false;
    }

    return true;
}

// Applies the render target surface, depth stencil surface, viewport rectangle and
// scissor rectangle to the Direct3D 9 device
bool Context::applyRenderTarget(bool ignoreViewport)
{
    Framebuffer *framebufferObject = getDrawFramebuffer();

    if (!framebufferObject || framebufferObject->completeness() != GL_FRAMEBUFFER_COMPLETE)
    {
        return error(GL_INVALID_FRAMEBUFFER_OPERATION, false);
    }

    bool renderTargetChanged = false;
    unsigned int renderTargetSerial = framebufferObject->getRenderTargetSerial();
    if (renderTargetSerial != mAppliedRenderTargetSerial)
    {
        IDirect3DSurface9 *renderTarget = framebufferObject->getRenderTarget();
        if (!renderTarget)
        {
            return false;   // Context must be lost
        }
        mDevice->SetRenderTarget(0, renderTarget);
        mAppliedRenderTargetSerial = renderTargetSerial;
        mScissorStateDirty = true; // Scissor area must be clamped to render target's size-- this is different for different render targets.
        renderTargetChanged = true;
        renderTarget->Release();
    }

    IDirect3DSurface9 *depthStencil = NULL;
    unsigned int depthbufferSerial = 0;
    unsigned int stencilbufferSerial = 0;
    if (framebufferObject->getDepthbufferType() != GL_NONE)
    {
        depthStencil = framebufferObject->getDepthbuffer()->getDepthStencil();
        if (!depthStencil)
        {
            ERR("Depth stencil pointer unexpectedly null.");
            return false;
        }
        
        depthbufferSerial = framebufferObject->getDepthbuffer()->getSerial();
    }
    else if (framebufferObject->getStencilbufferType() != GL_NONE)
    {
        depthStencil = framebufferObject->getStencilbuffer()->getDepthStencil();
        if (!depthStencil)
        {
            ERR("Depth stencil pointer unexpectedly null.");
            return false;
        }
        
        stencilbufferSerial = framebufferObject->getStencilbuffer()->getSerial();
    }

    if (depthbufferSerial != mAppliedDepthbufferSerial ||
        stencilbufferSerial != mAppliedStencilbufferSerial ||
        !mDepthStencilInitialized)
    {
        mDevice->SetDepthStencilSurface(depthStencil);
        mAppliedDepthbufferSerial = depthbufferSerial;
        mAppliedStencilbufferSerial = stencilbufferSerial;
        mDepthStencilInitialized = true;
    }

    if (!mRenderTargetDescInitialized || renderTargetChanged)
    {
        IDirect3DSurface9 *renderTarget = framebufferObject->getRenderTarget();
        if (!renderTarget)
        {
            return false;   // Context must be lost
        }
        renderTarget->GetDesc(&mRenderTargetDesc);
        mRenderTargetDescInitialized = true;
        renderTarget->Release();
    }

    D3DVIEWPORT9 viewport;

    float zNear = clamp01(mState.zNear);
    float zFar = clamp01(mState.zFar);

    if (ignoreViewport)
    {
        viewport.X = 0;
        viewport.Y = 0;
        viewport.Width = mRenderTargetDesc.Width;
        viewport.Height = mRenderTargetDesc.Height;
        viewport.MinZ = 0.0f;
        viewport.MaxZ = 1.0f;
    }
    else
    {
        RECT rect = transformPixelRect(mState.viewportX, mState.viewportY, mState.viewportWidth, mState.viewportHeight, mRenderTargetDesc.Height);
        viewport.X = clamp(rect.left, 0L, static_cast<LONG>(mRenderTargetDesc.Width));
        viewport.Y = clamp(rect.top, 0L, static_cast<LONG>(mRenderTargetDesc.Height));
        viewport.Width = clamp(rect.right - rect.left, 0L, static_cast<LONG>(mRenderTargetDesc.Width) - static_cast<LONG>(viewport.X));
        viewport.Height = clamp(rect.bottom - rect.top, 0L, static_cast<LONG>(mRenderTargetDesc.Height) - static_cast<LONG>(viewport.Y));
        viewport.MinZ = zNear;
        viewport.MaxZ = zFar;
    }

    if (viewport.Width <= 0 || viewport.Height <= 0)
    {
        return false;   // Nothing to render
    }

    if (renderTargetChanged || !mViewportInitialized || memcmp(&viewport, &mSetViewport, sizeof mSetViewport) != 0)
    {
        mDevice->SetViewport(&viewport);
        mSetViewport = viewport;
        mViewportInitialized = true;
        mDxUniformsDirty = true;
    }

    if (mScissorStateDirty)
    {
        if (mState.scissorTest)
        {
            RECT rect = transformPixelRect(mState.scissorX, mState.scissorY, mState.scissorWidth, mState.scissorHeight, mRenderTargetDesc.Height);
            rect.left = clamp(rect.left, 0L, static_cast<LONG>(mRenderTargetDesc.Width));
            rect.top = clamp(rect.top, 0L, static_cast<LONG>(mRenderTargetDesc.Height));
            rect.right = clamp(rect.right, 0L, static_cast<LONG>(mRenderTargetDesc.Width));
            rect.bottom = clamp(rect.bottom, 0L, static_cast<LONG>(mRenderTargetDesc.Height));
            mDevice->SetScissorRect(&rect);
            mDevice->SetRenderState(D3DRS_SCISSORTESTENABLE, TRUE);
        }
        else
        {
            mDevice->SetRenderState(D3DRS_SCISSORTESTENABLE, FALSE);
        }

        mScissorStateDirty = false;
    }

    if (mState.currentProgram && mDxUniformsDirty)
    {
        Program *programObject = getCurrentProgram();

        GLint halfPixelSize = programObject->getDxHalfPixelSizeLocation();
        GLfloat xy[2] = {1.0f / viewport.Width, -1.0f / viewport.Height};
        programObject->setUniform2fv(halfPixelSize, 1, xy);

        // These values are used for computing gl_FragCoord in Program::linkVaryings(). The approach depends on Shader Model 3.0 support.
        GLint coord = programObject->getDxCoordLocation();
        float h = mSupportsShaderModel3 ? mRenderTargetDesc.Height : mState.viewportHeight / 2.0f;
        GLfloat whxy[4] = {mState.viewportWidth / 2.0f, h, 
                          (float)mState.viewportX + mState.viewportWidth / 2.0f, 
                          (float)mState.viewportY + mState.viewportHeight / 2.0f};
        programObject->setUniform4fv(coord, 1, whxy);

        GLint depth = programObject->getDxDepthLocation();
        GLfloat dz[2] = {(zFar - zNear) / 2.0f, (zNear + zFar) / 2.0f};
        programObject->setUniform2fv(depth, 1, dz);

        GLint depthRange = programObject->getDxDepthRangeLocation();
        GLfloat nearFarDiff[3] = {zNear, zFar, zFar - zNear};
        programObject->setUniform3fv(depthRange, 1, nearFarDiff);
        mDxUniformsDirty = false;
    }

    return true;
}

// Applies the fixed-function state (culling, depth test, alpha blending, stenciling, etc) to the Direct3D 9 device
void Context::applyState(GLenum drawMode)
{
    Program *programObject = getCurrentProgram();

    Framebuffer *framebufferObject = getDrawFramebuffer();

    GLenum adjustedFrontFace = adjustWinding(mState.frontFace);

    GLint frontCCW = programObject->getDxFrontCCWLocation();
    GLint ccw = (adjustedFrontFace == GL_CCW);
    programObject->setUniform1iv(frontCCW, 1, &ccw);

    GLint pointsOrLines = programObject->getDxPointsOrLinesLocation();
    GLint alwaysFront = !isTriangleMode(drawMode);
    programObject->setUniform1iv(pointsOrLines, 1, &alwaysFront);

    D3DADAPTER_IDENTIFIER9 *identifier = mDisplay->getAdapterIdentifier();
    bool zeroColorMaskAllowed = identifier->VendorId != 0x1002;
    // Apparently some ATI cards have a bug where a draw with a zero color
    // write mask can cause later draws to have incorrect results. Instead,
    // set a nonzero color write mask but modify the blend state so that no
    // drawing is done.
    // http://code.google.com/p/angleproject/issues/detail?id=169

    if (mCullStateDirty || mFrontFaceDirty)
    {
        if (mState.cullFace)
        {
            mDevice->SetRenderState(D3DRS_CULLMODE, es2dx::ConvertCullMode(mState.cullMode, adjustedFrontFace));
        }
        else
        {
            mDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
        }

        mCullStateDirty = false;
    }

    if (mDepthStateDirty)
    {
        if (mState.depthTest)
        {
            mDevice->SetRenderState(D3DRS_ZENABLE, D3DZB_TRUE);
            mDevice->SetRenderState(D3DRS_ZFUNC, es2dx::ConvertComparison(mState.depthFunc));
        }
        else
        {
            mDevice->SetRenderState(D3DRS_ZENABLE, D3DZB_FALSE);
        }

        mDepthStateDirty = false;
    }

    if (!zeroColorMaskAllowed && (mMaskStateDirty || mBlendStateDirty))
    {
        mBlendStateDirty = true;
        mMaskStateDirty = true;
    }

    if (mBlendStateDirty)
    {
        if (mState.blend)
        {
            mDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);

            if (mState.sourceBlendRGB != GL_CONSTANT_ALPHA && mState.sourceBlendRGB != GL_ONE_MINUS_CONSTANT_ALPHA &&
                mState.destBlendRGB != GL_CONSTANT_ALPHA && mState.destBlendRGB != GL_ONE_MINUS_CONSTANT_ALPHA)
            {
                mDevice->SetRenderState(D3DRS_BLENDFACTOR, es2dx::ConvertColor(mState.blendColor));
            }
            else
            {
                mDevice->SetRenderState(D3DRS_BLENDFACTOR, D3DCOLOR_RGBA(unorm<8>(mState.blendColor.alpha),
                                                                        unorm<8>(mState.blendColor.alpha),
                                                                        unorm<8>(mState.blendColor.alpha),
                                                                        unorm<8>(mState.blendColor.alpha)));
            }

            mDevice->SetRenderState(D3DRS_SRCBLEND, es2dx::ConvertBlendFunc(mState.sourceBlendRGB));
            mDevice->SetRenderState(D3DRS_DESTBLEND, es2dx::ConvertBlendFunc(mState.destBlendRGB));
            mDevice->SetRenderState(D3DRS_BLENDOP, es2dx::ConvertBlendOp(mState.blendEquationRGB));

            if (mState.sourceBlendRGB != mState.sourceBlendAlpha || 
                mState.destBlendRGB != mState.destBlendAlpha || 
                mState.blendEquationRGB != mState.blendEquationAlpha)
            {
                mDevice->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, TRUE);

                mDevice->SetRenderState(D3DRS_SRCBLENDALPHA, es2dx::ConvertBlendFunc(mState.sourceBlendAlpha));
                mDevice->SetRenderState(D3DRS_DESTBLENDALPHA, es2dx::ConvertBlendFunc(mState.destBlendAlpha));
                mDevice->SetRenderState(D3DRS_BLENDOPALPHA, es2dx::ConvertBlendOp(mState.blendEquationAlpha));
            }
            else
            {
                mDevice->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, FALSE);
            }
        }
        else
        {
            mDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
        }

        mBlendStateDirty = false;
    }

    if (mStencilStateDirty || mFrontFaceDirty)
    {
        if (mState.stencilTest && framebufferObject->hasStencil())
        {
            mDevice->SetRenderState(D3DRS_STENCILENABLE, TRUE);
            mDevice->SetRenderState(D3DRS_TWOSIDEDSTENCILMODE, TRUE);

            // FIXME: Unsupported by D3D9
            const D3DRENDERSTATETYPE D3DRS_CCW_STENCILREF = D3DRS_STENCILREF;
            const D3DRENDERSTATETYPE D3DRS_CCW_STENCILMASK = D3DRS_STENCILMASK;
            const D3DRENDERSTATETYPE D3DRS_CCW_STENCILWRITEMASK = D3DRS_STENCILWRITEMASK;
            if (mState.stencilWritemask != mState.stencilBackWritemask || 
                mState.stencilRef != mState.stencilBackRef || 
                mState.stencilMask != mState.stencilBackMask)
            {
                ERR("Separate front/back stencil writemasks, reference values, or stencil mask values are invalid under WebGL.");
                return error(GL_INVALID_OPERATION);
            }

            // get the maximum size of the stencil ref
            gl::Renderbuffer *stencilbuffer = framebufferObject->getStencilbuffer();
            GLuint maxStencil = (1 << stencilbuffer->getStencilSize()) - 1;

            mDevice->SetRenderState(adjustedFrontFace == GL_CCW ? D3DRS_STENCILWRITEMASK : D3DRS_CCW_STENCILWRITEMASK, mState.stencilWritemask);
            mDevice->SetRenderState(adjustedFrontFace == GL_CCW ? D3DRS_STENCILFUNC : D3DRS_CCW_STENCILFUNC, 
                                   es2dx::ConvertComparison(mState.stencilFunc));

            mDevice->SetRenderState(adjustedFrontFace == GL_CCW ? D3DRS_STENCILREF : D3DRS_CCW_STENCILREF, (mState.stencilRef < (GLint)maxStencil) ? mState.stencilRef : maxStencil);
            mDevice->SetRenderState(adjustedFrontFace == GL_CCW ? D3DRS_STENCILMASK : D3DRS_CCW_STENCILMASK, mState.stencilMask);

            mDevice->SetRenderState(adjustedFrontFace == GL_CCW ? D3DRS_STENCILFAIL : D3DRS_CCW_STENCILFAIL, 
                                   es2dx::ConvertStencilOp(mState.stencilFail));
            mDevice->SetRenderState(adjustedFrontFace == GL_CCW ? D3DRS_STENCILZFAIL : D3DRS_CCW_STENCILZFAIL, 
                                   es2dx::ConvertStencilOp(mState.stencilPassDepthFail));
            mDevice->SetRenderState(adjustedFrontFace == GL_CCW ? D3DRS_STENCILPASS : D3DRS_CCW_STENCILPASS, 
                                   es2dx::ConvertStencilOp(mState.stencilPassDepthPass));

            mDevice->SetRenderState(adjustedFrontFace == GL_CW ? D3DRS_STENCILWRITEMASK : D3DRS_CCW_STENCILWRITEMASK, mState.stencilBackWritemask);
            mDevice->SetRenderState(adjustedFrontFace == GL_CW ? D3DRS_STENCILFUNC : D3DRS_CCW_STENCILFUNC, 
                                   es2dx::ConvertComparison(mState.stencilBackFunc));

            mDevice->SetRenderState(adjustedFrontFace == GL_CW ? D3DRS_STENCILREF : D3DRS_CCW_STENCILREF, (mState.stencilBackRef < (GLint)maxStencil) ? mState.stencilBackRef : maxStencil);
            mDevice->SetRenderState(adjustedFrontFace == GL_CW ? D3DRS_STENCILMASK : D3DRS_CCW_STENCILMASK, mState.stencilBackMask);

            mDevice->SetRenderState(adjustedFrontFace == GL_CW ? D3DRS_STENCILFAIL : D3DRS_CCW_STENCILFAIL, 
                                   es2dx::ConvertStencilOp(mState.stencilBackFail));
            mDevice->SetRenderState(adjustedFrontFace == GL_CW ? D3DRS_STENCILZFAIL : D3DRS_CCW_STENCILZFAIL, 
                                   es2dx::ConvertStencilOp(mState.stencilBackPassDepthFail));
            mDevice->SetRenderState(adjustedFrontFace == GL_CW ? D3DRS_STENCILPASS : D3DRS_CCW_STENCILPASS, 
                                   es2dx::ConvertStencilOp(mState.stencilBackPassDepthPass));
        }
        else
        {
            mDevice->SetRenderState(D3DRS_STENCILENABLE, FALSE);
        }

        mStencilStateDirty = false;
        mFrontFaceDirty = false;
    }

    if (mMaskStateDirty)
    {
        int colorMask = es2dx::ConvertColorMask(mState.colorMaskRed, mState.colorMaskGreen, 
                                                mState.colorMaskBlue, mState.colorMaskAlpha);
        if (colorMask == 0 && !zeroColorMaskAllowed)
        {
            // Enable green channel, but set blending so nothing will be drawn.
            mDevice->SetRenderState(D3DRS_COLORWRITEENABLE, D3DCOLORWRITEENABLE_GREEN);
            mDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);

            mDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_ZERO);
            mDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_ONE);
            mDevice->SetRenderState(D3DRS_BLENDOP, D3DBLENDOP_ADD);
        }
        else
        {
            mDevice->SetRenderState(D3DRS_COLORWRITEENABLE, colorMask);
        }
        mDevice->SetRenderState(D3DRS_ZWRITEENABLE, mState.depthMask ? TRUE : FALSE);

        mMaskStateDirty = false;
    }

    if (mPolygonOffsetStateDirty)
    {
        if (mState.polygonOffsetFill)
        {
            gl::Renderbuffer *depthbuffer = framebufferObject->getDepthbuffer();
            if (depthbuffer)
            {
                mDevice->SetRenderState(D3DRS_SLOPESCALEDEPTHBIAS, *((DWORD*)&mState.polygonOffsetFactor));
                float depthBias = ldexp(mState.polygonOffsetUnits, -(int)(depthbuffer->getDepthSize()));
                mDevice->SetRenderState(D3DRS_DEPTHBIAS, *((DWORD*)&depthBias));
            }
        }
        else
        {
            mDevice->SetRenderState(D3DRS_SLOPESCALEDEPTHBIAS, 0);
            mDevice->SetRenderState(D3DRS_DEPTHBIAS, 0);
        }

        mPolygonOffsetStateDirty = false;
    }

    if (mSampleStateDirty)
    {
        if (mState.sampleAlphaToCoverage)
        {
            FIXME("Sample alpha to coverage is unimplemented.");
        }

        mDevice->SetRenderState(D3DRS_MULTISAMPLEANTIALIAS, TRUE);
        if (mState.sampleCoverage)
        {
            unsigned int mask = 0;
            if (mState.sampleCoverageValue != 0)
            {
                float threshold = 0.5f;

                for (int i = 0; i < framebufferObject->getSamples(); ++i)
                {
                    mask <<= 1;

                    if ((i + 1) * mState.sampleCoverageValue >= threshold)
                    {
                        threshold += 1.0f;
                        mask |= 1;
                    }
                }
            }
            
            if (mState.sampleCoverageInvert)
            {
                mask = ~mask;
            }

            mDevice->SetRenderState(D3DRS_MULTISAMPLEMASK, mask);
        }
        else
        {
            mDevice->SetRenderState(D3DRS_MULTISAMPLEMASK, 0xFFFFFFFF);
        }

        mSampleStateDirty = false;
    }

    if (mDitherStateDirty)
    {
        mDevice->SetRenderState(D3DRS_DITHERENABLE, mState.dither ? TRUE : FALSE);

        mDitherStateDirty = false;
    }
}

GLenum Context::applyVertexBuffer(GLint first, GLsizei count, GLsizei instances, GLsizei *repeatDraw)
{
    TranslatedAttribute attributes[MAX_VERTEX_ATTRIBS];

    GLenum err = mVertexDataManager->prepareVertexData(first, count, attributes, instances);
    if (err != GL_NO_ERROR)
    {
        return err;
    }

    return mVertexDeclarationCache.applyDeclaration(mDevice, attributes, getCurrentProgram(), instances, repeatDraw);
}

// Applies the indices and element array bindings to the Direct3D 9 device
GLenum Context::applyIndexBuffer(const GLvoid *indices, GLsizei count, GLenum mode, GLenum type, TranslatedIndexData *indexInfo)
{
    GLenum err = mIndexDataManager->prepareIndexData(type, count, mState.elementArrayBuffer.get(), indices, indexInfo);

    if (err == GL_NO_ERROR)
    {
        if (indexInfo->serial != mAppliedIBSerial)
        {
            mDevice->SetIndices(indexInfo->indexBuffer);
            mAppliedIBSerial = indexInfo->serial;
        }
    }

    return err;
}

// Applies the shaders and shader constants to the Direct3D 9 device
void Context::applyShaders()
{
    Program *programObject = getCurrentProgram();
    if (programObject->getSerial() != mAppliedProgramSerial)
    {
        IDirect3DVertexShader9 *vertexShader = programObject->getVertexShader();
        IDirect3DPixelShader9 *pixelShader = programObject->getPixelShader();

        mDevice->SetPixelShader(pixelShader);
        mDevice->SetVertexShader(vertexShader);
        programObject->dirtyAllUniforms();
        mAppliedProgramSerial = programObject->getSerial();
    }

    programObject->applyUniforms();
}

// Applies the textures and sampler states to the Direct3D 9 device
void Context::applyTextures()
{
    applyTextures(SAMPLER_PIXEL);

    if (mSupportsVertexTexture)
    {
        applyTextures(SAMPLER_VERTEX);
    }
}

// For each Direct3D 9 sampler of either the pixel or vertex stage,
// looks up the corresponding OpenGL texture image unit and texture type,
// and sets the texture and its addressing/filtering state (or NULL when inactive).
void Context::applyTextures(SamplerType type)
{
    Program *programObject = getCurrentProgram();

    int samplerCount = (type == SAMPLER_PIXEL) ? MAX_TEXTURE_IMAGE_UNITS : MAX_VERTEX_TEXTURE_IMAGE_UNITS_VTF;   // Range of Direct3D 9 samplers of given sampler type
    unsigned int *appliedTextureSerial = (type == SAMPLER_PIXEL) ? mAppliedTextureSerialPS : mAppliedTextureSerialVS;
    int d3dSamplerOffset = (type == SAMPLER_PIXEL) ? 0 : D3DVERTEXTEXTURESAMPLER0;
    int samplerRange = programObject->getUsedSamplerRange(type);

    for (int samplerIndex = 0; samplerIndex < samplerRange; samplerIndex++)
    {
        int textureUnit = programObject->getSamplerMapping(type, samplerIndex);   // OpenGL texture image unit index
        int d3dSampler = samplerIndex + d3dSamplerOffset;

        if (textureUnit != -1)
        {
            TextureType textureType = programObject->getSamplerTextureType(type, samplerIndex);

            Texture *texture = getSamplerTexture(textureUnit, textureType);
            unsigned int texSerial = texture->getTextureSerial();

            if (appliedTextureSerial[samplerIndex] != texSerial || texture->hasDirtyParameters() || texture->hasDirtyImages())
            {
                IDirect3DBaseTexture9 *d3dTexture = texture->getTexture();

                if (d3dTexture)
                {
                    if (appliedTextureSerial[samplerIndex] != texSerial || texture->hasDirtyParameters())
                    {
                        GLenum wrapS = texture->getWrapS();
                        GLenum wrapT = texture->getWrapT();
                        GLenum minFilter = texture->getMinFilter();
                        GLenum magFilter = texture->getMagFilter();

                        mDevice->SetSamplerState(d3dSampler, D3DSAMP_ADDRESSU, es2dx::ConvertTextureWrap(wrapS));
                        mDevice->SetSamplerState(d3dSampler, D3DSAMP_ADDRESSV, es2dx::ConvertTextureWrap(wrapT));

                        mDevice->SetSamplerState(d3dSampler, D3DSAMP_MAGFILTER, es2dx::ConvertMagFilter(magFilter));
                        D3DTEXTUREFILTERTYPE d3dMinFilter, d3dMipFilter;
                        es2dx::ConvertMinFilter(minFilter, &d3dMinFilter, &d3dMipFilter);
                        mDevice->SetSamplerState(d3dSampler, D3DSAMP_MINFILTER, d3dMinFilter);
                        mDevice->SetSamplerState(d3dSampler, D3DSAMP_MIPFILTER, d3dMipFilter);
                    }

                    if (appliedTextureSerial[samplerIndex] != texSerial || texture->hasDirtyImages())
                    {
                        mDevice->SetTexture(d3dSampler, d3dTexture);
                    }
                }
                else
                {
                    mDevice->SetTexture(d3dSampler, getIncompleteTexture(textureType)->getTexture());
                }

                appliedTextureSerial[samplerIndex] = texSerial;
                texture->resetDirty();
            }
        }
        else
        {
            if (appliedTextureSerial[samplerIndex] != 0)
            {
                mDevice->SetTexture(d3dSampler, NULL);
                appliedTextureSerial[samplerIndex] = 0;
            }
        }
    }

    for (int samplerIndex = samplerRange; samplerIndex < samplerCount; samplerIndex++)
    {
        if (appliedTextureSerial[samplerIndex] != 0)
        {
            mDevice->SetTexture(samplerIndex + d3dSamplerOffset, NULL);
            appliedTextureSerial[samplerIndex] = 0;
        }
    }
}

void Context::readPixels(GLint x, GLint y, GLsizei width, GLsizei height,
                         GLenum format, GLenum type, GLsizei *bufSize, void* pixels)
{
    Framebuffer *framebuffer = getReadFramebuffer();

    if (framebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE)
    {
        return error(GL_INVALID_FRAMEBUFFER_OPERATION);
    }

    if (getReadFramebufferHandle() != 0 && framebuffer->getSamples() != 0)
    {
        return error(GL_INVALID_OPERATION);
    }

    GLsizei outputPitch = ComputePitch(width, format, type, mState.packAlignment);
    // sized query sanity check
    if (bufSize)
    {
        int requiredSize = outputPitch * height;
        if (requiredSize > *bufSize)
        {
            return error(GL_INVALID_OPERATION);
        }
    }

    IDirect3DSurface9 *renderTarget = framebuffer->getRenderTarget();
    if (!renderTarget)
    {
        return;   // Context must be lost, return silently
    }

    D3DSURFACE_DESC desc;
    renderTarget->GetDesc(&desc);

    if (desc.MultiSampleType != D3DMULTISAMPLE_NONE)
    {
        UNIMPLEMENTED();   // FIXME: Requires resolve using StretchRect into non-multisampled render target
        renderTarget->Release();
        return error(GL_OUT_OF_MEMORY);
    }

    HRESULT result;
    IDirect3DSurface9 *systemSurface = NULL;
    bool directToPixels = getPackReverseRowOrder() && getPackAlignment() <= 4 && mDisplay->isD3d9ExDevice() &&
                          x == 0 && y == 0 && UINT(width) == desc.Width && UINT(height) == desc.Height &&
                          desc.Format == D3DFMT_A8R8G8B8 && format == GL_BGRA_EXT && type == GL_UNSIGNED_BYTE;
    if (directToPixels)
    {
        // Use the pixels ptr as a shared handle to write directly into client's memory
        result = mDevice->CreateOffscreenPlainSurface(desc.Width, desc.Height, desc.Format,
                                                      D3DPOOL_SYSTEMMEM, &systemSurface, &pixels);
        if (FAILED(result))
        {
            // Try again without the shared handle
            directToPixels = false;
        }
    }

    if (!directToPixels)
    {
        result = mDevice->CreateOffscreenPlainSurface(desc.Width, desc.Height, desc.Format,
                                                      D3DPOOL_SYSTEMMEM, &systemSurface, NULL);
        if (FAILED(result))
        {
            ASSERT(result == D3DERR_OUTOFVIDEOMEMORY || result == E_OUTOFMEMORY);
            return error(GL_OUT_OF_MEMORY);
        }
    }

    result = mDevice->GetRenderTargetData(renderTarget, systemSurface);
    renderTarget->Release();
    renderTarget = NULL;

    if (FAILED(result))
    {
        systemSurface->Release();

        // It turns out that D3D will sometimes produce more error
        // codes than those documented.
        if (checkDeviceLost(result))
            return error(GL_OUT_OF_MEMORY);
        else
        {
            UNREACHABLE();
            return;
        }

    }

    if (directToPixels)
    {
        systemSurface->Release();
        return;
    }

    D3DLOCKED_RECT lock;
    RECT rect = transformPixelRect(x, y, width, height, desc.Height);
    rect.left = clamp(rect.left, 0L, static_cast<LONG>(desc.Width));
    rect.top = clamp(rect.top, 0L, static_cast<LONG>(desc.Height));
    rect.right = clamp(rect.right, 0L, static_cast<LONG>(desc.Width));
    rect.bottom = clamp(rect.bottom, 0L, static_cast<LONG>(desc.Height));

    result = systemSurface->LockRect(&lock, &rect, D3DLOCK_READONLY);

    if (FAILED(result))
    {
        UNREACHABLE();
        systemSurface->Release();

        return;   // No sensible error to generate
    }

    unsigned char *dest = (unsigned char*)pixels;
    unsigned short *dest16 = (unsigned short*)pixels;

    unsigned char *source;
    int inputPitch;
    if (getPackReverseRowOrder())
    {
        source = (unsigned char*)lock.pBits;
        inputPitch = lock.Pitch;
    }
    else
    {
        source = ((unsigned char*)lock.pBits) + lock.Pitch * (rect.bottom - rect.top - 1);
        inputPitch = -lock.Pitch;
    }

    for (int j = 0; j < rect.bottom - rect.top; j++)
    {
        if (desc.Format == D3DFMT_A8R8G8B8 &&
            format == GL_BGRA_EXT &&
            type == GL_UNSIGNED_BYTE)
        {
            // Fast path for EXT_read_format_bgra, given
            // an RGBA source buffer.  Note that buffers with no
            // alpha go through the slow path below.
            memcpy(dest + j * outputPitch,
                   source + j * inputPitch,
                   (rect.right - rect.left) * 4);
            continue;
        }

        for (int i = 0; i < rect.right - rect.left; i++)
        {
            float r;
            float g;
            float b;
            float a;

            switch (desc.Format)
            {
              case D3DFMT_R5G6B5:
                {
                    unsigned short rgb = *(unsigned short*)(source + 2 * i + j * inputPitch);

                    a = 1.0f;
                    b = (rgb & 0x001F) * (1.0f / 0x001F);
                    g = (rgb & 0x07E0) * (1.0f / 0x07E0);
                    r = (rgb & 0xF800) * (1.0f / 0xF800);
                }
                break;
              case D3DFMT_A1R5G5B5:
                {
                    unsigned short argb = *(unsigned short*)(source + 2 * i + j * inputPitch);

                    a = (argb & 0x8000) ? 1.0f : 0.0f;
                    b = (argb & 0x001F) * (1.0f / 0x001F);
                    g = (argb & 0x03E0) * (1.0f / 0x03E0);
                    r = (argb & 0x7C00) * (1.0f / 0x7C00);
                }
                break;
              case D3DFMT_A8R8G8B8:
                {
                    unsigned int argb = *(unsigned int*)(source + 4 * i + j * inputPitch);

                    a = (argb & 0xFF000000) * (1.0f / 0xFF000000);
                    b = (argb & 0x000000FF) * (1.0f / 0x000000FF);
                    g = (argb & 0x0000FF00) * (1.0f / 0x0000FF00);
                    r = (argb & 0x00FF0000) * (1.0f / 0x00FF0000);
                }
                break;
              case D3DFMT_X8R8G8B8:
                {
                    unsigned int xrgb = *(unsigned int*)(source + 4 * i + j * inputPitch);

                    a = 1.0f;
                    b = (xrgb & 0x000000FF) * (1.0f / 0x000000FF);
                    g = (xrgb & 0x0000FF00) * (1.0f / 0x0000FF00);
                    r = (xrgb & 0x00FF0000) * (1.0f / 0x00FF0000);
                }
                break;
              case D3DFMT_A2R10G10B10:
                {
                    unsigned int argb = *(unsigned int*)(source + 4 * i + j * inputPitch);

                    a = (argb & 0xC0000000) * (1.0f / 0xC0000000);
                    b = (argb & 0x000003FF) * (1.0f / 0x000003FF);
                    g = (argb & 0x000FFC00) * (1.0f / 0x000FFC00);
                    r = (argb & 0x3FF00000) * (1.0f / 0x3FF00000);
                }
                break;
              case D3DFMT_A32B32G32R32F:
                {
                    // float formats in D3D are stored rgba, rather than the other way round
                    r = *((float*)(source + 16 * i + j * inputPitch) + 0);
                    g = *((float*)(source + 16 * i + j * inputPitch) + 1);
                    b = *((float*)(source + 16 * i + j * inputPitch) + 2);
                    a = *((float*)(source + 16 * i + j * inputPitch) + 3);
                }
                break;
              case D3DFMT_A16B16G16R16F:
                {
                    // float formats in D3D are stored rgba, rather than the other way round
                    float abgr[4];

                    D3DXFloat16To32Array(abgr, (D3DXFLOAT16*)(source + 8 * i + j * inputPitch), 4);

                    a = abgr[3];
                    b = abgr[2];
                    g = abgr[1];
                    r = abgr[0];
                }
                break;
              default:
                UNIMPLEMENTED();   // FIXME
                UNREACHABLE();
                return;
            }

            switch (format)
            {
              case GL_RGBA:
                switch (type)
                {
                  case GL_UNSIGNED_BYTE:
                    dest[4 * i + j * outputPitch + 0] = (unsigned char)(255 * r + 0.5f);
                    dest[4 * i + j * outputPitch + 1] = (unsigned char)(255 * g + 0.5f);
                    dest[4 * i + j * outputPitch + 2] = (unsigned char)(255 * b + 0.5f);
                    dest[4 * i + j * outputPitch + 3] = (unsigned char)(255 * a + 0.5f);
                    break;
                  default: UNREACHABLE();
                }
                break;
              case GL_BGRA_EXT:
                switch (type)
                {
                  case GL_UNSIGNED_BYTE:
                    dest[4 * i + j * outputPitch + 0] = (unsigned char)(255 * b + 0.5f);
                    dest[4 * i + j * outputPitch + 1] = (unsigned char)(255 * g + 0.5f);
                    dest[4 * i + j * outputPitch + 2] = (unsigned char)(255 * r + 0.5f);
                    dest[4 * i + j * outputPitch + 3] = (unsigned char)(255 * a + 0.5f);
                    break;
                  case GL_UNSIGNED_SHORT_4_4_4_4_REV_EXT:
                    // According to the desktop GL spec in the "Transfer of Pixel Rectangles" section
                    // this type is packed as follows:
                    //   15   14   13   12   11   10    9    8    7    6    5    4    3    2    1    0
                    //  --------------------------------------------------------------------------------
                    // |       4th         |        3rd         |        2nd        |   1st component   |
                    //  --------------------------------------------------------------------------------
                    // in the case of BGRA_EXT, B is the first component, G the second, and so forth.
                    dest16[i + j * outputPitch / sizeof(unsigned short)] =
                        ((unsigned short)(15 * a + 0.5f) << 12)|
                        ((unsigned short)(15 * r + 0.5f) << 8) |
                        ((unsigned short)(15 * g + 0.5f) << 4) |
                        ((unsigned short)(15 * b + 0.5f) << 0);
                    break;
                  case GL_UNSIGNED_SHORT_1_5_5_5_REV_EXT:
                    // According to the desktop GL spec in the "Transfer of Pixel Rectangles" section
                    // this type is packed as follows:
                    //   15   14   13   12   11   10    9    8    7    6    5    4    3    2    1    0
                    //  --------------------------------------------------------------------------------
                    // | 4th |          3rd           |           2nd          |      1st component     |
                    //  --------------------------------------------------------------------------------
                    // in the case of BGRA_EXT, B is the first component, G the second, and so forth.
                    dest16[i + j * outputPitch / sizeof(unsigned short)] =
                        ((unsigned short)(     a + 0.5f) << 15) |
                        ((unsigned short)(31 * r + 0.5f) << 10) |
                        ((unsigned short)(31 * g + 0.5f) << 5) |
                        ((unsigned short)(31 * b + 0.5f) << 0);
                    break;
                  default: UNREACHABLE();
                }
                break;
              case GL_RGB:   // IMPLEMENTATION_COLOR_READ_FORMAT
                switch (type)
                {
                  case GL_UNSIGNED_SHORT_5_6_5:   // IMPLEMENTATION_COLOR_READ_TYPE
                    dest16[i + j * outputPitch / sizeof(unsigned short)] = 
                        ((unsigned short)(31 * b + 0.5f) << 0) |
                        ((unsigned short)(63 * g + 0.5f) << 5) |
                        ((unsigned short)(31 * r + 0.5f) << 11);
                    break;
                  default: UNREACHABLE();
                }
                break;
              default: UNREACHABLE();
            }
        }
    }

    systemSurface->UnlockRect();

    systemSurface->Release();
}

void Context::clear(GLbitfield mask)
{
    Framebuffer *framebufferObject = getDrawFramebuffer();

    if (!framebufferObject || framebufferObject->completeness() != GL_FRAMEBUFFER_COMPLETE)
    {
        return error(GL_INVALID_FRAMEBUFFER_OPERATION);
    }

    DWORD flags = 0;

    if (mask & GL_COLOR_BUFFER_BIT)
    {
        mask &= ~GL_COLOR_BUFFER_BIT;

        if (framebufferObject->getColorbufferType() != GL_NONE)
        {
            flags |= D3DCLEAR_TARGET;
        }
    }

    if (mask & GL_DEPTH_BUFFER_BIT)
    {
        mask &= ~GL_DEPTH_BUFFER_BIT;
        if (mState.depthMask && framebufferObject->getDepthbufferType() != GL_NONE)
        {
            flags |= D3DCLEAR_ZBUFFER;
        }
    }

    GLuint stencilUnmasked = 0x0;

    if (mask & GL_STENCIL_BUFFER_BIT)
    {
        mask &= ~GL_STENCIL_BUFFER_BIT;
        if (framebufferObject->getStencilbufferType() != GL_NONE)
        {
            IDirect3DSurface9 *depthStencil = framebufferObject->getStencilbuffer()->getDepthStencil();
            if (!depthStencil)
            {
                ERR("Depth stencil pointer unexpectedly null.");
                return;
            }
            
            D3DSURFACE_DESC desc;
            depthStencil->GetDesc(&desc);

            unsigned int stencilSize = dx2es::GetStencilSize(desc.Format);
            stencilUnmasked = (0x1 << stencilSize) - 1;

            if (stencilUnmasked != 0x0)
            {
                flags |= D3DCLEAR_STENCIL;
            }
        }
    }

    if (mask != 0)
    {
        return error(GL_INVALID_VALUE);
    }

    if (!applyRenderTarget(true))   // Clips the clear to the scissor rectangle but not the viewport
    {
        return;
    }

    D3DCOLOR color = D3DCOLOR_ARGB(unorm<8>(mState.colorClearValue.alpha), 
                                   unorm<8>(mState.colorClearValue.red), 
                                   unorm<8>(mState.colorClearValue.green), 
                                   unorm<8>(mState.colorClearValue.blue));
    float depth = clamp01(mState.depthClearValue);
    int stencil = mState.stencilClearValue & 0x000000FF;

    bool alphaUnmasked = (dx2es::GetAlphaSize(mRenderTargetDesc.Format) == 0) || mState.colorMaskAlpha;

    const bool needMaskedStencilClear = (flags & D3DCLEAR_STENCIL) &&
                                        (mState.stencilWritemask & stencilUnmasked) != stencilUnmasked;
    const bool needMaskedColorClear = (flags & D3DCLEAR_TARGET) &&
                                      !(mState.colorMaskRed && mState.colorMaskGreen &&
                                        mState.colorMaskBlue && alphaUnmasked);

    if (needMaskedColorClear || needMaskedStencilClear)
    {
        // State which is altered in all paths from this point to the clear call is saved.
        // State which is altered in only some paths will be flagged dirty in the case that
        //  that path is taken.
        HRESULT hr;
        if (mMaskedClearSavedState == NULL)
        {
            hr = mDevice->BeginStateBlock();
            ASSERT(SUCCEEDED(hr) || hr == D3DERR_OUTOFVIDEOMEMORY || hr == E_OUTOFMEMORY);

            mDevice->SetRenderState(D3DRS_ZWRITEENABLE, FALSE);
            mDevice->SetRenderState(D3DRS_ZFUNC, D3DCMP_ALWAYS);
            mDevice->SetRenderState(D3DRS_ZENABLE, FALSE);
            mDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
            mDevice->SetRenderState(D3DRS_FILLMODE, D3DFILL_SOLID);
            mDevice->SetRenderState(D3DRS_ALPHATESTENABLE, FALSE);
            mDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
            mDevice->SetRenderState(D3DRS_CLIPPLANEENABLE, 0);
            mDevice->SetRenderState(D3DRS_COLORWRITEENABLE, 0);
            mDevice->SetRenderState(D3DRS_STENCILENABLE, FALSE);
            mDevice->SetPixelShader(NULL);
            mDevice->SetVertexShader(NULL);
            mDevice->SetFVF(D3DFVF_XYZRHW | D3DFVF_DIFFUSE);
            mDevice->SetStreamSource(0, NULL, 0, 0);
            mDevice->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, TRUE);
            mDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_SELECTARG1);
            mDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TFACTOR);
            mDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_SELECTARG1);
            mDevice->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TFACTOR);
            mDevice->SetRenderState(D3DRS_TEXTUREFACTOR, color);
            mDevice->SetRenderState(D3DRS_MULTISAMPLEMASK, 0xFFFFFFFF);
            
            for(int i = 0; i < MAX_VERTEX_ATTRIBS; i++)
            {
                mDevice->SetStreamSourceFreq(i, 1);
            }

            hr = mDevice->EndStateBlock(&mMaskedClearSavedState);
            ASSERT(SUCCEEDED(hr) || hr == D3DERR_OUTOFVIDEOMEMORY || hr == E_OUTOFMEMORY);
        }

        ASSERT(mMaskedClearSavedState != NULL);

        if (mMaskedClearSavedState != NULL)
        {
            hr = mMaskedClearSavedState->Capture();
            ASSERT(SUCCEEDED(hr));
        }

        mDevice->SetRenderState(D3DRS_ZWRITEENABLE, FALSE);
        mDevice->SetRenderState(D3DRS_ZFUNC, D3DCMP_ALWAYS);
        mDevice->SetRenderState(D3DRS_ZENABLE, FALSE);
        mDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
        mDevice->SetRenderState(D3DRS_FILLMODE, D3DFILL_SOLID);
        mDevice->SetRenderState(D3DRS_ALPHATESTENABLE, FALSE);
        mDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
        mDevice->SetRenderState(D3DRS_CLIPPLANEENABLE, 0);

        if (flags & D3DCLEAR_TARGET)
        {
            mDevice->SetRenderState(D3DRS_COLORWRITEENABLE, es2dx::ConvertColorMask(mState.colorMaskRed, mState.colorMaskGreen, mState.colorMaskBlue, mState.colorMaskAlpha));
        }
        else
        {
            mDevice->SetRenderState(D3DRS_COLORWRITEENABLE, 0);
        }

        if (stencilUnmasked != 0x0 && (flags & D3DCLEAR_STENCIL))
        {
            mDevice->SetRenderState(D3DRS_STENCILENABLE, TRUE);
            mDevice->SetRenderState(D3DRS_TWOSIDEDSTENCILMODE, FALSE);
            mDevice->SetRenderState(D3DRS_STENCILFUNC, D3DCMP_ALWAYS);
            mDevice->SetRenderState(D3DRS_STENCILREF, stencil);
            mDevice->SetRenderState(D3DRS_STENCILWRITEMASK, mState.stencilWritemask);
            mDevice->SetRenderState(D3DRS_STENCILFAIL, D3DSTENCILOP_REPLACE);
            mDevice->SetRenderState(D3DRS_STENCILZFAIL, D3DSTENCILOP_REPLACE);
            mDevice->SetRenderState(D3DRS_STENCILPASS, D3DSTENCILOP_REPLACE);
            mStencilStateDirty = true;
        }
        else
        {
            mDevice->SetRenderState(D3DRS_STENCILENABLE, FALSE);
        }

        mDevice->SetPixelShader(NULL);
        mDevice->SetVertexShader(NULL);
        mDevice->SetFVF(D3DFVF_XYZRHW);
        mDevice->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, TRUE);
        mDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_SELECTARG1);
        mDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TFACTOR);
        mDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_SELECTARG1);
        mDevice->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TFACTOR);
        mDevice->SetRenderState(D3DRS_TEXTUREFACTOR, color);
        mDevice->SetRenderState(D3DRS_MULTISAMPLEMASK, 0xFFFFFFFF);

        for(int i = 0; i < MAX_VERTEX_ATTRIBS; i++)
        {
            mDevice->SetStreamSourceFreq(i, 1);
        }

        float quad[4][4];   // A quadrilateral covering the target, aligned to match the edges
        quad[0][0] = -0.5f;
        quad[0][1] = mRenderTargetDesc.Height - 0.5f;
        quad[0][2] = 0.0f;
        quad[0][3] = 1.0f;

        quad[1][0] = mRenderTargetDesc.Width - 0.5f;
        quad[1][1] = mRenderTargetDesc.Height - 0.5f;
        quad[1][2] = 0.0f;
        quad[1][3] = 1.0f;

        quad[2][0] = -0.5f;
        quad[2][1] = -0.5f;
        quad[2][2] = 0.0f;
        quad[2][3] = 1.0f;

        quad[3][0] = mRenderTargetDesc.Width - 0.5f;
        quad[3][1] = -0.5f;
        quad[3][2] = 0.0f;
        quad[3][3] = 1.0f;

        mDisplay->startScene();
        mDevice->DrawPrimitiveUP(D3DPT_TRIANGLESTRIP, 2, quad, sizeof(float[4]));

        if (flags & D3DCLEAR_ZBUFFER)
        {
            mDevice->SetRenderState(D3DRS_ZENABLE, TRUE);
            mDevice->SetRenderState(D3DRS_ZWRITEENABLE, TRUE);
            mDevice->Clear(0, NULL, D3DCLEAR_ZBUFFER, color, depth, stencil);
        }

        if (mMaskedClearSavedState != NULL)
        {
            mMaskedClearSavedState->Apply();
        }
    }
    else if (flags)
    {
        mDevice->Clear(0, NULL, flags, color, depth, stencil);
    }
}

void Context::drawArrays(GLenum mode, GLint first, GLsizei count, GLsizei instances)
{
    if (!mState.currentProgram)
    {
        return error(GL_INVALID_OPERATION);
    }

    D3DPRIMITIVETYPE primitiveType;
    int primitiveCount;

    if(!es2dx::ConvertPrimitiveType(mode, count, &primitiveType, &primitiveCount))
        return error(GL_INVALID_ENUM);

    if (primitiveCount <= 0)
    {
        return;
    }

    if (!applyRenderTarget(false))
    {
        return;
    }

    applyState(mode);

    GLsizei repeatDraw = 1;
    GLenum err = applyVertexBuffer(first, count, instances, &repeatDraw);
    if (err != GL_NO_ERROR)
    {
        return error(err);
    }

    applyShaders();
    applyTextures();

    if (!getCurrentProgram()->validateSamplers(false))
    {
        return error(GL_INVALID_OPERATION);
    }

    if (!cullSkipsDraw(mode))
    {
        mDisplay->startScene();
        
        if (mode == GL_LINE_LOOP)
        {
            drawLineLoop(count, GL_NONE, NULL, 0);
        }
        else if (instances > 0)
        {
            StaticIndexBuffer *countingIB = mIndexDataManager->getCountingIndices(count);
            if (countingIB)
            {
                if (mAppliedIBSerial != countingIB->getSerial())
                {
                    mDevice->SetIndices(countingIB->getBuffer());
                    mAppliedIBSerial = countingIB->getSerial();
                }

                for (int i = 0; i < repeatDraw; i++)
                {
                    mDevice->DrawIndexedPrimitive(primitiveType, 0, 0, count, 0, primitiveCount);
                }
            }
            else
            {
                ERR("Could not create a counting index buffer for glDrawArraysInstanced.");
                return error(GL_OUT_OF_MEMORY);
            }
        }
        else   // Regular case
        {
            mDevice->DrawPrimitive(primitiveType, 0, primitiveCount);
        }
    }
}

void Context::drawElements(GLenum mode, GLsizei count, GLenum type, const GLvoid *indices, GLsizei instances)
{
    if (!mState.currentProgram)
    {
        return error(GL_INVALID_OPERATION);
    }

    if (!indices && !mState.elementArrayBuffer)
    {
        return error(GL_INVALID_OPERATION);
    }

    D3DPRIMITIVETYPE primitiveType;
    int primitiveCount;

    if(!es2dx::ConvertPrimitiveType(mode, count, &primitiveType, &primitiveCount))
        return error(GL_INVALID_ENUM);

    if (primitiveCount <= 0)
    {
        return;
    }

    if (!applyRenderTarget(false))
    {
        return;
    }

    applyState(mode);

    TranslatedIndexData indexInfo;
    GLenum err = applyIndexBuffer(indices, count, mode, type, &indexInfo);
    if (err != GL_NO_ERROR)
    {
        return error(err);
    }

    GLsizei vertexCount = indexInfo.maxIndex - indexInfo.minIndex + 1;
    GLsizei repeatDraw = 1;
    err = applyVertexBuffer(indexInfo.minIndex, vertexCount, instances, &repeatDraw);
    if (err != GL_NO_ERROR)
    {
        return error(err);
    }

    applyShaders();
    applyTextures();

    if (!getCurrentProgram()->validateSamplers(false))
    {
        return error(GL_INVALID_OPERATION);
    }

    if (!cullSkipsDraw(mode))
    {
        mDisplay->startScene();

        if (mode == GL_LINE_LOOP)
        {
            drawLineLoop(count, type, indices, indexInfo.minIndex);   
        }
        else
        {
            for (int i = 0; i < repeatDraw; i++)
            {
                mDevice->DrawIndexedPrimitive(primitiveType, -(INT)indexInfo.minIndex, indexInfo.minIndex, vertexCount, indexInfo.startIndex, primitiveCount);
            }
        }
    }
}

// Implements glFlush when block is false, glFinish when block is true
void Context::sync(bool block)
{
    mDisplay->sync(block);
}

void Context::drawLineLoop(GLsizei count, GLenum type, const GLvoid *indices, int minIndex)
{
    // Get the raw indices for an indexed draw
    if (type != GL_NONE && mState.elementArrayBuffer.get())
    {
        Buffer *indexBuffer = mState.elementArrayBuffer.get();
        intptr_t offset = reinterpret_cast<intptr_t>(indices);
        indices = static_cast<const GLubyte*>(indexBuffer->data()) + offset;
    }

    UINT startIndex = 0;
    bool succeeded = false;

    if (supports32bitIndices())
    {
        const int spaceNeeded = (count + 1) * sizeof(unsigned int);

        if (!mLineLoopIB)
        {
            mLineLoopIB = new StreamingIndexBuffer(mDevice, INITIAL_INDEX_BUFFER_SIZE, D3DFMT_INDEX32);
        }

        if (mLineLoopIB)
        {
            mLineLoopIB->reserveSpace(spaceNeeded, GL_UNSIGNED_INT);

            UINT offset = 0;
            unsigned int *data = static_cast<unsigned int*>(mLineLoopIB->map(spaceNeeded, &offset));
            startIndex = offset / 4;
            
            if (data)
            {
                switch (type)
                {
                  case GL_NONE:   // Non-indexed draw
                    for (int i = 0; i < count; i++)
                    {
                        data[i] = i;
                    }
                    data[count] = 0;
                    break;
                  case GL_UNSIGNED_BYTE:
                    for (int i = 0; i < count; i++)
                    {
                        data[i] = static_cast<const GLubyte*>(indices)[i];
                    }
                    data[count] = static_cast<const GLubyte*>(indices)[0];
                    break;
                  case GL_UNSIGNED_SHORT:
                    for (int i = 0; i < count; i++)
                    {
                        data[i] = static_cast<const GLushort*>(indices)[i];
                    }
                    data[count] = static_cast<const GLushort*>(indices)[0];
                    break;
                  case GL_UNSIGNED_INT:
                    for (int i = 0; i < count; i++)
                    {
                        data[i] = static_cast<const GLuint*>(indices)[i];
                    }
                    data[count] = static_cast<const GLuint*>(indices)[0];
                    break;
                  default: UNREACHABLE();
                }

                mLineLoopIB->unmap();
                succeeded = true;
            }
        }
    }
    else
    {
        const int spaceNeeded = (count + 1) * sizeof(unsigned short);

        if (!mLineLoopIB)
        {
            mLineLoopIB = new StreamingIndexBuffer(mDevice, INITIAL_INDEX_BUFFER_SIZE, D3DFMT_INDEX16);
        }

        if (mLineLoopIB)
        {
            mLineLoopIB->reserveSpace(spaceNeeded, GL_UNSIGNED_SHORT);

            UINT offset = 0;
            unsigned short *data = static_cast<unsigned short*>(mLineLoopIB->map(spaceNeeded, &offset));
            startIndex = offset / 2;
            
            if (data)
            {
                switch (type)
                {
                  case GL_NONE:   // Non-indexed draw
                    for (int i = 0; i < count; i++)
                    {
                        data[i] = i;
                    }
                    data[count] = 0;
                    break;
                  case GL_UNSIGNED_BYTE:
                    for (int i = 0; i < count; i++)
                    {
                        data[i] = static_cast<const GLubyte*>(indices)[i];
                    }
                    data[count] = static_cast<const GLubyte*>(indices)[0];
                    break;
                  case GL_UNSIGNED_SHORT:
                    for (int i = 0; i < count; i++)
                    {
                        data[i] = static_cast<const GLushort*>(indices)[i];
                    }
                    data[count] = static_cast<const GLushort*>(indices)[0];
                    break;
                  case GL_UNSIGNED_INT:
                    for (int i = 0; i < count; i++)
                    {
                        data[i] = static_cast<const GLuint*>(indices)[i];
                    }
                    data[count] = static_cast<const GLuint*>(indices)[0];
                    break;
                  default: UNREACHABLE();
                }

                mLineLoopIB->unmap();
                succeeded = true;
            }
        }
    }
    
    if (succeeded)
    {
        if (mAppliedIBSerial != mLineLoopIB->getSerial())
        {
            mDevice->SetIndices(mLineLoopIB->getBuffer());
            mAppliedIBSerial = mLineLoopIB->getSerial();
        }

        mDevice->DrawIndexedPrimitive(D3DPT_LINESTRIP, -minIndex, minIndex, count, startIndex, count);
    }
    else
    {
        ERR("Could not create a looping index buffer for GL_LINE_LOOP.");
        return error(GL_OUT_OF_MEMORY);
    }
}

void Context::recordInvalidEnum()
{
    mInvalidEnum = true;
}

void Context::recordInvalidValue()
{
    mInvalidValue = true;
}

void Context::recordInvalidOperation()
{
    mInvalidOperation = true;
}

void Context::recordOutOfMemory()
{
    mOutOfMemory = true;
}

void Context::recordInvalidFramebufferOperation()
{
    mInvalidFramebufferOperation = true;
}

// Get one of the recorded errors and clear its flag, if any.
// [OpenGL ES 2.0.24] section 2.5 page 13.
GLenum Context::getError()
{
    if (mInvalidEnum)
    {
        mInvalidEnum = false;

        return GL_INVALID_ENUM;
    }

    if (mInvalidValue)
    {
        mInvalidValue = false;

        return GL_INVALID_VALUE;
    }

    if (mInvalidOperation)
    {
        mInvalidOperation = false;

        return GL_INVALID_OPERATION;
    }

    if (mOutOfMemory)
    {
        mOutOfMemory = false;

        return GL_OUT_OF_MEMORY;
    }

    if (mInvalidFramebufferOperation)
    {
        mInvalidFramebufferOperation = false;

        return GL_INVALID_FRAMEBUFFER_OPERATION;
    }

    return GL_NO_ERROR;
}

GLenum Context::getResetStatus()
{
    if (mResetStatus == GL_NO_ERROR)
    {
        bool lost = mDisplay->testDeviceLost();

        if (lost)
        {
            mDisplay->notifyDeviceLost();   // Sets mResetStatus
        }
    }

    GLenum status = mResetStatus;

    if (mResetStatus != GL_NO_ERROR)
    {
        if (mDisplay->testDeviceResettable())
        {
            mResetStatus = GL_NO_ERROR;
        }
    }
    
    return status;
}

bool Context::isResetNotificationEnabled()
{
    return (mResetStrategy == GL_LOSE_CONTEXT_ON_RESET_EXT);
}

bool Context::supportsShaderModel3() const
{
    return mSupportsShaderModel3;
}

int Context::getMaximumVaryingVectors() const
{
    return mSupportsShaderModel3 ? MAX_VARYING_VECTORS_SM3 : MAX_VARYING_VECTORS_SM2;
}

unsigned int Context::getMaximumVertexTextureImageUnits() const
{
    return mSupportsVertexTexture ? MAX_VERTEX_TEXTURE_IMAGE_UNITS_VTF : 0;
}

unsigned int Context::getMaximumCombinedTextureImageUnits() const
{
    return MAX_TEXTURE_IMAGE_UNITS + getMaximumVertexTextureImageUnits();
}

int Context::getMaximumFragmentUniformVectors() const
{
    return mSupportsShaderModel3 ? MAX_FRAGMENT_UNIFORM_VECTORS_SM3 : MAX_FRAGMENT_UNIFORM_VECTORS_SM2;
}

int Context::getMaxSupportedSamples() const
{
    return mMaxSupportedSamples;
}

int Context::getNearestSupportedSamples(D3DFORMAT format, int requested) const
{
    if (requested == 0)
    {
        return requested;
    }

    std::map<D3DFORMAT, bool *>::const_iterator itr = mMultiSampleSupport.find(format);
    if (itr == mMultiSampleSupport.end())
    {
        return -1;
    }

    for (int i = requested; i <= D3DMULTISAMPLE_16_SAMPLES; ++i)
    {
        if (itr->second[i] && i != D3DMULTISAMPLE_NONMASKABLE)
        {
            return i;
        }
    }

    return -1;
}

bool Context::supportsEventQueries() const
{
    return mSupportsEventQueries;
}

bool Context::supportsOcclusionQueries() const
{
    return mSupportsOcclusionQueries;
}

bool Context::supportsDXT1Textures() const
{
    return mSupportsDXT1Textures;
}

bool Context::supportsDXT3Textures() const
{
    return mSupportsDXT3Textures;
}

bool Context::supportsDXT5Textures() const
{
    return mSupportsDXT5Textures;
}

bool Context::supportsFloat32Textures() const
{
    return mSupportsFloat32Textures;
}

bool Context::supportsFloat32LinearFilter() const
{
    return mSupportsFloat32LinearFilter;
}

bool Context::supportsFloat32RenderableTextures() const
{
    return mSupportsFloat32RenderableTextures;
}

bool Context::supportsFloat16Textures() const
{
    return mSupportsFloat16Textures;
}

bool Context::supportsFloat16LinearFilter() const
{
    return mSupportsFloat16LinearFilter;
}

bool Context::supportsFloat16RenderableTextures() const
{
    return mSupportsFloat16RenderableTextures;
}

int Context::getMaximumRenderbufferDimension() const
{
    return mMaxRenderbufferDimension;
}

int Context::getMaximumTextureDimension() const
{
    return mMaxTextureDimension;
}

int Context::getMaximumCubeTextureDimension() const
{
    return mMaxCubeTextureDimension;
}

int Context::getMaximumTextureLevel() const
{
    return mMaxTextureLevel;
}

bool Context::supportsLuminanceTextures() const
{
    return mSupportsLuminanceTextures;
}

bool Context::supportsLuminanceAlphaTextures() const
{
    return mSupportsLuminanceAlphaTextures;
}

bool Context::supports32bitIndices() const
{
    return mSupports32bitIndices;
}

bool Context::supportsNonPower2Texture() const
{
    return mSupportsNonPower2Texture;
}

bool Context::supportsInstancing() const
{
    return mSupportsInstancing;
}

void Context::detachBuffer(GLuint buffer)
{
    // [OpenGL ES 2.0.24] section 2.9 page 22:
    // If a buffer object is deleted while it is bound, all bindings to that object in the current context
    // (i.e. in the thread that called Delete-Buffers) are reset to zero.

    if (mState.arrayBuffer.id() == buffer)
    {
        mState.arrayBuffer.set(NULL);
    }

    if (mState.elementArrayBuffer.id() == buffer)
    {
        mState.elementArrayBuffer.set(NULL);
    }

    for (int attribute = 0; attribute < MAX_VERTEX_ATTRIBS; attribute++)
    {
        if (mState.vertexAttribute[attribute].mBoundBuffer.id() == buffer)
        {
            mState.vertexAttribute[attribute].mBoundBuffer.set(NULL);
        }
    }
}

void Context::detachTexture(GLuint texture)
{
    // [OpenGL ES 2.0.24] section 3.8 page 84:
    // If a texture object is deleted, it is as if all texture units which are bound to that texture object are
    // rebound to texture object zero

    for (int type = 0; type < TEXTURE_TYPE_COUNT; type++)
    {
        for (int sampler = 0; sampler < MAX_COMBINED_TEXTURE_IMAGE_UNITS_VTF; sampler++)
        {
            if (mState.samplerTexture[type][sampler].id() == texture)
            {
                mState.samplerTexture[type][sampler].set(NULL);
            }
        }
    }

    // [OpenGL ES 2.0.24] section 4.4 page 112:
    // If a texture object is deleted while its image is attached to the currently bound framebuffer, then it is
    // as if FramebufferTexture2D had been called, with a texture of 0, for each attachment point to which this
    // image was attached in the currently bound framebuffer.

    Framebuffer *readFramebuffer = getReadFramebuffer();
    Framebuffer *drawFramebuffer = getDrawFramebuffer();

    if (readFramebuffer)
    {
        readFramebuffer->detachTexture(texture);
    }

    if (drawFramebuffer && drawFramebuffer != readFramebuffer)
    {
        drawFramebuffer->detachTexture(texture);
    }
}

void Context::detachFramebuffer(GLuint framebuffer)
{
    // [OpenGL ES 2.0.24] section 4.4 page 107:
    // If a framebuffer that is currently bound to the target FRAMEBUFFER is deleted, it is as though
    // BindFramebuffer had been executed with the target of FRAMEBUFFER and framebuffer of zero.

    if (mState.readFramebuffer == framebuffer)
    {
        bindReadFramebuffer(0);
    }

    if (mState.drawFramebuffer == framebuffer)
    {
        bindDrawFramebuffer(0);
    }
}

void Context::detachRenderbuffer(GLuint renderbuffer)
{
    // [OpenGL ES 2.0.24] section 4.4 page 109:
    // If a renderbuffer that is currently bound to RENDERBUFFER is deleted, it is as though BindRenderbuffer
    // had been executed with the target RENDERBUFFER and name of zero.

    if (mState.renderbuffer.id() == renderbuffer)
    {
        bindRenderbuffer(0);
    }

    // [OpenGL ES 2.0.24] section 4.4 page 111:
    // If a renderbuffer object is deleted while its image is attached to the currently bound framebuffer,
    // then it is as if FramebufferRenderbuffer had been called, with a renderbuffer of 0, for each attachment
    // point to which this image was attached in the currently bound framebuffer.

    Framebuffer *readFramebuffer = getReadFramebuffer();
    Framebuffer *drawFramebuffer = getDrawFramebuffer();

    if (readFramebuffer)
    {
        readFramebuffer->detachRenderbuffer(renderbuffer);
    }

    if (drawFramebuffer && drawFramebuffer != readFramebuffer)
    {
        drawFramebuffer->detachRenderbuffer(renderbuffer);
    }
}

Texture *Context::getIncompleteTexture(TextureType type)
{
    Texture *t = mIncompleteTextures[type].get();

    if (t == NULL)
    {
        static const GLubyte color[] = { 0, 0, 0, 255 };

        switch (type)
        {
          default:
            UNREACHABLE();
            // default falls through to TEXTURE_2D

          case TEXTURE_2D:
            {
                Texture2D *incomplete2d = new Texture2D(Texture::INCOMPLETE_TEXTURE_ID);
                incomplete2d->setImage(0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, 1, color);
                t = incomplete2d;
            }
            break;

          case TEXTURE_CUBE:
            {
              TextureCubeMap *incompleteCube = new TextureCubeMap(Texture::INCOMPLETE_TEXTURE_ID);

              incompleteCube->setImagePosX(0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, 1, color);
              incompleteCube->setImageNegX(0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, 1, color);
              incompleteCube->setImagePosY(0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, 1, color);
              incompleteCube->setImageNegY(0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, 1, color);
              incompleteCube->setImagePosZ(0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, 1, color);
              incompleteCube->setImageNegZ(0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, 1, color);

              t = incompleteCube;
            }
            break;
        }

        mIncompleteTextures[type].set(t);
    }

    return t;
}

bool Context::cullSkipsDraw(GLenum drawMode)
{
    return mState.cullFace && mState.cullMode == GL_FRONT_AND_BACK && isTriangleMode(drawMode);
}

bool Context::isTriangleMode(GLenum drawMode)
{
    switch (drawMode)
    {
      case GL_TRIANGLES:
      case GL_TRIANGLE_FAN:
      case GL_TRIANGLE_STRIP:
        return true;
      case GL_POINTS:
      case GL_LINES:
      case GL_LINE_LOOP:
      case GL_LINE_STRIP:
        return false;
      default: UNREACHABLE();
    }

    return false;
}

void Context::setVertexAttrib(GLuint index, const GLfloat *values)
{
    ASSERT(index < gl::MAX_VERTEX_ATTRIBS);

    mState.vertexAttribute[index].mCurrentValue[0] = values[0];
    mState.vertexAttribute[index].mCurrentValue[1] = values[1];
    mState.vertexAttribute[index].mCurrentValue[2] = values[2];
    mState.vertexAttribute[index].mCurrentValue[3] = values[3];

    mVertexDataManager->dirtyCurrentValue(index);
}

void Context::setVertexAttribDivisor(GLuint index, GLuint divisor)
{
    ASSERT(index < gl::MAX_VERTEX_ATTRIBS);

    mState.vertexAttribute[index].mDivisor = divisor;
}

// keep list sorted in following order
// OES extensions
// EXT extensions
// Vendor extensions
void Context::initExtensionString()
{
    mExtensionString = "";

    // OES extensions
    if (supports32bitIndices())
    {
        mExtensionString += "GL_OES_element_index_uint ";
    }

    mExtensionString += "GL_OES_packed_depth_stencil ";
    mExtensionString += "GL_OES_rgb8_rgba8 ";
    mExtensionString += "GL_OES_standard_derivatives ";

    if (supportsFloat16Textures())
    {
        mExtensionString += "GL_OES_texture_half_float ";
    }
    if (supportsFloat16LinearFilter())
    {
        mExtensionString += "GL_OES_texture_half_float_linear ";
    }
    if (supportsFloat32Textures())
    {
        mExtensionString += "GL_OES_texture_float ";
    }
    if (supportsFloat32LinearFilter())
    {
        mExtensionString += "GL_OES_texture_float_linear ";
    }

    if (supportsNonPower2Texture())
    {
        mExtensionString += "GL_OES_texture_npot ";
    }

    // Multi-vendor (EXT) extensions
    if (supportsOcclusionQueries())
    {
        mExtensionString += "GL_EXT_occlusion_query_boolean ";
    }

    mExtensionString += "GL_EXT_read_format_bgra ";
    mExtensionString += "GL_EXT_robustness ";

    if (supportsDXT1Textures())
    {
        mExtensionString += "GL_EXT_texture_compression_dxt1 ";
    }

    mExtensionString += "GL_EXT_texture_format_BGRA8888 ";
    mExtensionString += "GL_EXT_texture_storage ";

    // ANGLE-specific extensions
    mExtensionString += "GL_ANGLE_framebuffer_blit ";
    if (getMaxSupportedSamples() != 0)
    {
        mExtensionString += "GL_ANGLE_framebuffer_multisample ";
    }

    if (supportsInstancing())
    {
        mExtensionString += "GL_ANGLE_instanced_arrays ";
    }

    mExtensionString += "GL_ANGLE_pack_reverse_row_order ";

    if (supportsDXT3Textures())
    {
        mExtensionString += "GL_ANGLE_texture_compression_dxt3 ";
    }
    if (supportsDXT5Textures())
    {
        mExtensionString += "GL_ANGLE_texture_compression_dxt5 ";
    }

    mExtensionString += "GL_ANGLE_texture_usage ";
    mExtensionString += "GL_ANGLE_translated_shader_source ";

    // Other vendor-specific extensions
    if (supportsEventQueries())
    {
        mExtensionString += "GL_NV_fence ";
    }

    std::string::size_type end = mExtensionString.find_last_not_of(' ');
    if (end != std::string::npos)
    {
        mExtensionString.resize(end+1);
    }
}

const char *Context::getExtensionString() const
{
    return mExtensionString.c_str();
}

void Context::initRendererString()
{
    D3DADAPTER_IDENTIFIER9 *identifier = mDisplay->getAdapterIdentifier();

    mRendererString = "ANGLE (";
    mRendererString += identifier->Description;
    mRendererString += ")";
}

const char *Context::getRendererString() const
{
    return mRendererString.c_str();
}

void Context::blitFramebuffer(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, 
                              GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1,
                              GLbitfield mask)
{
    Framebuffer *readFramebuffer = getReadFramebuffer();
    Framebuffer *drawFramebuffer = getDrawFramebuffer();

    if (!readFramebuffer || readFramebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE ||
        !drawFramebuffer || drawFramebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE)
    {
        return error(GL_INVALID_FRAMEBUFFER_OPERATION);
    }

    if (drawFramebuffer->getSamples() != 0)
    {
        return error(GL_INVALID_OPERATION);
    }

    int readBufferWidth = readFramebuffer->getColorbuffer()->getWidth();
    int readBufferHeight = readFramebuffer->getColorbuffer()->getHeight();
    int drawBufferWidth = drawFramebuffer->getColorbuffer()->getWidth();
    int drawBufferHeight = drawFramebuffer->getColorbuffer()->getHeight();

    RECT sourceRect;
    RECT destRect;

    if (srcX0 < srcX1)
    {
        sourceRect.left = srcX0;
        sourceRect.right = srcX1;
        destRect.left = dstX0;
        destRect.right = dstX1;
    }
    else
    {
        sourceRect.left = srcX1;
        destRect.left = dstX1;
        sourceRect.right = srcX0;
        destRect.right = dstX0;
    }

    if (srcY0 < srcY1)
    {
        sourceRect.top = readBufferHeight - srcY1;
        destRect.top = drawBufferHeight - dstY1;
        sourceRect.bottom = readBufferHeight - srcY0;
        destRect.bottom = drawBufferHeight - dstY0;
    }
    else
    {
        sourceRect.top = readBufferHeight - srcY0;
        destRect.top = drawBufferHeight - dstY0;
        sourceRect.bottom = readBufferHeight - srcY1;
        destRect.bottom = drawBufferHeight - dstY1;
    }

    RECT sourceScissoredRect = sourceRect;
    RECT destScissoredRect = destRect;

    if (mState.scissorTest)
    {
        // Only write to parts of the destination framebuffer which pass the scissor test
        // Please note: the destRect is now in D3D-style coordinates, so the *top* of the
        // rect will be checked against scissorY, rather than the bottom.
        if (destRect.left < mState.scissorX)
        {
            int xDiff = mState.scissorX - destRect.left;
            destScissoredRect.left = mState.scissorX;
            sourceScissoredRect.left += xDiff;
        }

        if (destRect.right > mState.scissorX + mState.scissorWidth)
        {
            int xDiff = destRect.right - (mState.scissorX + mState.scissorWidth);
            destScissoredRect.right = mState.scissorX + mState.scissorWidth;
            sourceScissoredRect.right -= xDiff;
        }

        if (destRect.top < mState.scissorY)
        {
            int yDiff = mState.scissorY - destRect.top;
            destScissoredRect.top = mState.scissorY;
            sourceScissoredRect.top += yDiff;
        }

        if (destRect.bottom > mState.scissorY + mState.scissorHeight)
        {
            int yDiff = destRect.bottom - (mState.scissorY + mState.scissorHeight);
            destScissoredRect.bottom = mState.scissorY + mState.scissorHeight;
            sourceScissoredRect.bottom -= yDiff;
        }
    }

    bool blitRenderTarget = false;
    bool blitDepthStencil = false;

    RECT sourceTrimmedRect = sourceScissoredRect;
    RECT destTrimmedRect = destScissoredRect;

    // The source & destination rectangles also may need to be trimmed if they fall out of the bounds of 
    // the actual draw and read surfaces.
    if (sourceTrimmedRect.left < 0)
    {
        int xDiff = 0 - sourceTrimmedRect.left;
        sourceTrimmedRect.left = 0;
        destTrimmedRect.left += xDiff;
    }

    if (sourceTrimmedRect.right > readBufferWidth)
    {
        int xDiff = sourceTrimmedRect.right - readBufferWidth;
        sourceTrimmedRect.right = readBufferWidth;
        destTrimmedRect.right -= xDiff;
    }

    if (sourceTrimmedRect.top < 0)
    {
        int yDiff = 0 - sourceTrimmedRect.top;
        sourceTrimmedRect.top = 0;
        destTrimmedRect.top += yDiff;
    }

    if (sourceTrimmedRect.bottom > readBufferHeight)
    {
        int yDiff = sourceTrimmedRect.bottom - readBufferHeight;
        sourceTrimmedRect.bottom = readBufferHeight;
        destTrimmedRect.bottom -= yDiff;
    }

    if (destTrimmedRect.left < 0)
    {
        int xDiff = 0 - destTrimmedRect.left;
        destTrimmedRect.left = 0;
        sourceTrimmedRect.left += xDiff;
    }

    if (destTrimmedRect.right > drawBufferWidth)
    {
        int xDiff = destTrimmedRect.right - drawBufferWidth;
        destTrimmedRect.right = drawBufferWidth;
        sourceTrimmedRect.right -= xDiff;
    }

    if (destTrimmedRect.top < 0)
    {
        int yDiff = 0 - destTrimmedRect.top;
        destTrimmedRect.top = 0;
        sourceTrimmedRect.top += yDiff;
    }

    if (destTrimmedRect.bottom > drawBufferHeight)
    {
        int yDiff = destTrimmedRect.bottom - drawBufferHeight;
        destTrimmedRect.bottom = drawBufferHeight;
        sourceTrimmedRect.bottom -= yDiff;
    }

    bool partialBufferCopy = false;
    if (sourceTrimmedRect.bottom - sourceTrimmedRect.top < readBufferHeight ||
        sourceTrimmedRect.right - sourceTrimmedRect.left < readBufferWidth || 
        destTrimmedRect.bottom - destTrimmedRect.top < drawBufferHeight ||
        destTrimmedRect.right - destTrimmedRect.left < drawBufferWidth ||
        sourceTrimmedRect.top != 0 || destTrimmedRect.top != 0 || sourceTrimmedRect.left != 0 || destTrimmedRect.left != 0)
    {
        partialBufferCopy = true;
    }

    if (mask & GL_COLOR_BUFFER_BIT)
    {
        const bool validReadType = readFramebuffer->getColorbufferType() == GL_TEXTURE_2D ||
            readFramebuffer->getColorbufferType() == GL_RENDERBUFFER;
        const bool validDrawType = drawFramebuffer->getColorbufferType() == GL_TEXTURE_2D ||
            drawFramebuffer->getColorbufferType() == GL_RENDERBUFFER;
        if (!validReadType || !validDrawType ||
            readFramebuffer->getColorbuffer()->getD3DFormat() != drawFramebuffer->getColorbuffer()->getD3DFormat())
        {
            ERR("Color buffer format conversion in BlitFramebufferANGLE not supported by this implementation");
            return error(GL_INVALID_OPERATION);
        }
        
        if (partialBufferCopy && readFramebuffer->getSamples() != 0)
        {
            return error(GL_INVALID_OPERATION);
        }

        blitRenderTarget = true;

    }

    if (mask & (GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT))
    {
        Renderbuffer *readDSBuffer = NULL;
        Renderbuffer *drawDSBuffer = NULL;

        // We support OES_packed_depth_stencil, and do not support a separately attached depth and stencil buffer, so if we have
        // both a depth and stencil buffer, it will be the same buffer.

        if (mask & GL_DEPTH_BUFFER_BIT)
        {
            if (readFramebuffer->getDepthbuffer() && drawFramebuffer->getDepthbuffer())
            {
                if (readFramebuffer->getDepthbufferType() != drawFramebuffer->getDepthbufferType() ||
                    readFramebuffer->getDepthbuffer()->getD3DFormat() != drawFramebuffer->getDepthbuffer()->getD3DFormat())
                {
                    return error(GL_INVALID_OPERATION);
                }

                blitDepthStencil = true;
                readDSBuffer = readFramebuffer->getDepthbuffer();
                drawDSBuffer = drawFramebuffer->getDepthbuffer();
            }
        }

        if (mask & GL_STENCIL_BUFFER_BIT)
        {
            if (readFramebuffer->getStencilbuffer() && drawFramebuffer->getStencilbuffer())
            {
                if (readFramebuffer->getStencilbufferType() != drawFramebuffer->getStencilbufferType() ||
                    readFramebuffer->getStencilbuffer()->getD3DFormat() != drawFramebuffer->getStencilbuffer()->getD3DFormat())
                {
                    return error(GL_INVALID_OPERATION);
                }

                blitDepthStencil = true;
                readDSBuffer = readFramebuffer->getStencilbuffer();
                drawDSBuffer = drawFramebuffer->getStencilbuffer();
            }
        }

        if (partialBufferCopy)
        {
            ERR("Only whole-buffer depth and stencil blits are supported by this implementation.");
            return error(GL_INVALID_OPERATION); // only whole-buffer copies are permitted
        }

        if ((drawDSBuffer && drawDSBuffer->getSamples() != 0) || 
            (readDSBuffer && readDSBuffer->getSamples() != 0))
        {
            return error(GL_INVALID_OPERATION);
        }
    }

    if (blitRenderTarget || blitDepthStencil)
    {
        mDisplay->endScene();

        if (blitRenderTarget)
        {
            IDirect3DSurface9* readRenderTarget = readFramebuffer->getRenderTarget();
            IDirect3DSurface9* drawRenderTarget = drawFramebuffer->getRenderTarget();

            HRESULT result = mDevice->StretchRect(readRenderTarget, &sourceTrimmedRect, 
                                                  drawRenderTarget, &destTrimmedRect, D3DTEXF_NONE);

            readRenderTarget->Release();
            drawRenderTarget->Release();

            if (FAILED(result))
            {
                ERR("BlitFramebufferANGLE failed: StretchRect returned %x.", result);
                return;
            }
        }

        if (blitDepthStencil)
        {
            HRESULT result = mDevice->StretchRect(readFramebuffer->getDepthStencil(), NULL, drawFramebuffer->getDepthStencil(), NULL, D3DTEXF_NONE);

            if (FAILED(result))
            {
                ERR("BlitFramebufferANGLE failed: StretchRect returned %x.", result);
                return;
            }
        }
    }
}

VertexDeclarationCache::VertexDeclarationCache() : mMaxLru(0)
{
    for (int i = 0; i < NUM_VERTEX_DECL_CACHE_ENTRIES; i++)
    {
        mVertexDeclCache[i].vertexDeclaration = NULL;
        mVertexDeclCache[i].lruCount = 0;
    }
}

VertexDeclarationCache::~VertexDeclarationCache()
{
    for (int i = 0; i < NUM_VERTEX_DECL_CACHE_ENTRIES; i++)
    {
        if (mVertexDeclCache[i].vertexDeclaration)
        {
            mVertexDeclCache[i].vertexDeclaration->Release();
        }
    }
}

GLenum VertexDeclarationCache::applyDeclaration(IDirect3DDevice9 *device, TranslatedAttribute attributes[], Program *program, GLsizei instances, GLsizei *repeatDraw)
{
    *repeatDraw = 1;

    int indexedAttribute = MAX_VERTEX_ATTRIBS;
    int instancedAttribute = MAX_VERTEX_ATTRIBS;

    if (instances > 0)
    {
        // Find an indexed attribute to be mapped to D3D stream 0
        for (int i = 0; i < MAX_VERTEX_ATTRIBS; i++)
        {
            if (attributes[i].active)
            {
                if (indexedAttribute == MAX_VERTEX_ATTRIBS)
                {
                    if (attributes[i].divisor == 0)
                    {
                        indexedAttribute = i;
                    }
                }
                else if (instancedAttribute == MAX_VERTEX_ATTRIBS)
                {
                    if (attributes[i].divisor != 0)
                    {
                        instancedAttribute = i;
                    }
                }
                else break;   // Found both an indexed and instanced attribute
            }
        }

        if (indexedAttribute == MAX_VERTEX_ATTRIBS)
        {
            return GL_INVALID_OPERATION;
        }
    }

    D3DVERTEXELEMENT9 elements[MAX_VERTEX_ATTRIBS + 1];
    D3DVERTEXELEMENT9 *element = &elements[0];

    for (int i = 0; i < MAX_VERTEX_ATTRIBS; i++)
    {
        if (attributes[i].active)
        {
            int stream = i;

            if (instances > 0)
            {
                // Due to a bug on ATI cards we can't enable instancing when none of the attributes are instanced.
                if (instancedAttribute == MAX_VERTEX_ATTRIBS)
                {
                    *repeatDraw = instances;
                }
                else
                {
                    if (i == indexedAttribute)
                    {
                        stream = 0;
                    }
                    else if (i == 0)
                    {
                        stream = indexedAttribute;
                    }

                    UINT frequency = 1;
                    
                    if (attributes[i].divisor == 0)
                    {
                        frequency = D3DSTREAMSOURCE_INDEXEDDATA | instances;
                    }
                    else
                    {
                        frequency = D3DSTREAMSOURCE_INSTANCEDATA | attributes[i].divisor;
                    }
                    
                    device->SetStreamSourceFreq(stream, frequency);
                    mInstancingEnabled = true;
                }
            }

            if (mAppliedVBs[stream].serial != attributes[i].serial ||
                mAppliedVBs[stream].stride != attributes[i].stride ||
                mAppliedVBs[stream].offset != attributes[i].offset)
            {
                device->SetStreamSource(stream, attributes[i].vertexBuffer, attributes[i].offset, attributes[i].stride);
                mAppliedVBs[stream].serial = attributes[i].serial;
                mAppliedVBs[stream].stride = attributes[i].stride;
                mAppliedVBs[stream].offset = attributes[i].offset;
            }

            element->Stream = stream;
            element->Offset = 0;
            element->Type = attributes[i].type;
            element->Method = D3DDECLMETHOD_DEFAULT;
            element->Usage = D3DDECLUSAGE_TEXCOORD;
            element->UsageIndex = program->getSemanticIndex(i);
            element++;
        }
    }

    if (instances == 0 || instancedAttribute == MAX_VERTEX_ATTRIBS)
    {
        if (mInstancingEnabled)
        {
            for (int i = 0; i < MAX_VERTEX_ATTRIBS; i++)
            {
                device->SetStreamSourceFreq(i, 1);
            }

            mInstancingEnabled = false;
        }
    }

    static const D3DVERTEXELEMENT9 end = D3DDECL_END();
    *(element++) = end;

    for (int i = 0; i < NUM_VERTEX_DECL_CACHE_ENTRIES; i++)
    {
        VertexDeclCacheEntry *entry = &mVertexDeclCache[i];
        if (memcmp(entry->cachedElements, elements, (element - elements) * sizeof(D3DVERTEXELEMENT9)) == 0 && entry->vertexDeclaration)
        {
            entry->lruCount = ++mMaxLru;
            if(entry->vertexDeclaration != mLastSetVDecl)
            {
                device->SetVertexDeclaration(entry->vertexDeclaration);
                mLastSetVDecl = entry->vertexDeclaration;
            }

            return GL_NO_ERROR;
        }
    }

    VertexDeclCacheEntry *lastCache = mVertexDeclCache;

    for (int i = 0; i < NUM_VERTEX_DECL_CACHE_ENTRIES; i++)
    {
        if (mVertexDeclCache[i].lruCount < lastCache->lruCount)
        {
            lastCache = &mVertexDeclCache[i];
        }
    }

    if (lastCache->vertexDeclaration != NULL)
    {
        lastCache->vertexDeclaration->Release();
        lastCache->vertexDeclaration = NULL;
        // mLastSetVDecl is set to the replacement, so we don't have to worry
        // about it.
    }

    memcpy(lastCache->cachedElements, elements, (element - elements) * sizeof(D3DVERTEXELEMENT9));
    device->CreateVertexDeclaration(elements, &lastCache->vertexDeclaration);
    device->SetVertexDeclaration(lastCache->vertexDeclaration);
    mLastSetVDecl = lastCache->vertexDeclaration;
    lastCache->lruCount = ++mMaxLru;

    return GL_NO_ERROR;
}

void VertexDeclarationCache::markStateDirty()
{
    for (int i = 0; i < MAX_VERTEX_ATTRIBS; i++)
    {
        mAppliedVBs[i].serial = 0;
    }

    mLastSetVDecl = NULL;
    mInstancingEnabled = true;   // Forces it to be disabled when not used
}

}

extern "C"
{
gl::Context *glCreateContext(const egl::Config *config, const gl::Context *shareContext, bool notifyResets, bool robustAccess)
{
    return new gl::Context(config, shareContext, notifyResets, robustAccess);
}

void glDestroyContext(gl::Context *context)
{
    delete context;

    if (context == gl::getContext())
    {
        gl::makeCurrent(NULL, NULL, NULL);
    }
}

void glMakeCurrent(gl::Context *context, egl::Display *display, egl::Surface *surface)
{
    gl::makeCurrent(context, display, surface);
}

gl::Context *glGetCurrentContext()
{
    return gl::getContext();
}
}