src/tests/gl_tests/MipmapTest.cpp

//
// Copyright 2015 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.
//

#include "test_utils/ANGLETest.h"

using namespace angle;

class MipmapTest : public ANGLETest
{
  protected:
    MipmapTest()
    {
        setWindowWidth(128);
        setWindowHeight(128);
        setConfigRedBits(8);
        setConfigGreenBits(8);
        setConfigBlueBits(8);
        setConfigAlphaBits(8);
    }

    virtual void SetUp()
    {
        ANGLETest::SetUp();

        // Vertex Shader source
        const std::string vs = SHADER_SOURCE
        (
            attribute vec4 aPosition;
            attribute vec2 aTexCoord;
            varying vec2 vTexCoord;

            void main()
            {
                gl_Position = aPosition;
                vTexCoord = aTexCoord;
            }
        );

        // Fragment Shader source
        const std::string fs = SHADER_SOURCE
        (
            precision mediump float;

            uniform sampler2D uTexture;
            varying vec2 vTexCoord;

            void main()
            {
                gl_FragColor = texture2D(uTexture, vTexCoord);
            }
        );

        m2DProgram = CompileProgram(vs, fs);
        if (m2DProgram == 0)
        {
            FAIL() << "shader compilation failed.";
        }

        // A simple vertex shader for the texture cube
        const std::string cubeVS = SHADER_SOURCE
        (
            attribute vec4 aPosition;
            varying vec4 vPosition;
            void main()
            {
                gl_Position = aPosition;
                vPosition = aPosition;
            }
        );

        // A very simple fragment shader to sample from the negative-Y face of a texture cube.
        const std::string cubeFS = SHADER_SOURCE
        (
            precision mediump float;
            uniform samplerCube uTexture;
            varying vec4 vPosition;

            void main()
            {
                gl_FragColor = textureCube(uTexture, vec3(vPosition.x, -1, vPosition.y));
            }
        );

        mCubeProgram = CompileProgram(cubeVS, cubeFS);
        if (mCubeProgram == 0)
        {
            FAIL() << "shader compilation failed.";
        }

        m2DTextureUniformPosition = glGetUniformLocation(m2DProgram, "uTexture");
        m2DPositionAttributePosition = glGetAttribLocation(m2DProgram, "aPosition");
        m2DTexCoordAttributePosition = glGetAttribLocation(m2DProgram, "aTexCoord");

        mCubeTextureUniformPosition = glGetUniformLocation(mCubeProgram, "uTexture");
        mCubePositionAttributePosition = glGetAttribLocation(mCubeProgram, "aPosition");

        mLevelZeroBlueInitData = createRGBInitData(getWindowWidth(), getWindowHeight(), 0, 0, 255); // Blue
        mLevelZeroWhiteInitData = createRGBInitData(getWindowWidth(), getWindowHeight(), 255, 255, 255); // White
        mLevelOneInitData = createRGBInitData((getWindowWidth() / 2), (getWindowHeight() / 2), 0, 255, 0);   // Green
        mLevelTwoInitData = createRGBInitData((getWindowWidth() / 4), (getWindowHeight() / 4), 255, 0, 0);   // Red

        glGenFramebuffers(1, &mOffscreenFramebuffer);
        glGenTextures(1, &mOffscreenTexture2D);

        // Initialize the texture2D to be empty, and don't use mips.
        glBindTexture(GL_TEXTURE_2D, mOffscreenTexture2D);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

        // Bind the texture2D to the offscreen framebuffer's color buffer.
        glBindFramebuffer(GL_FRAMEBUFFER, mOffscreenFramebuffer);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mOffscreenTexture2D, 0);
        ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));

        // Create a non-mipped texture cube. Set the negative-Y face to be blue.
        glGenTextures(1, &mOffscreenTextureCube);
        glBindTexture(GL_TEXTURE_CUBE_MAP, mOffscreenTextureCube);
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
        glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Y, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
        glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, mLevelZeroBlueInitData);
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
        glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);

        // Complete the texture cube without mipmaps to start with.
        glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

        ASSERT_GL_NO_ERROR();
    }

    virtual void TearDown()
    {
        glDeleteProgram(m2DProgram);
        glDeleteProgram(mCubeProgram);
        glDeleteFramebuffers(1, &mOffscreenFramebuffer);
        glDeleteTextures(1, &mOffscreenTexture2D);
        glDeleteTextures(1, &mOffscreenTextureCube);

        SafeDeleteArray(mLevelZeroBlueInitData);
        SafeDeleteArray(mLevelZeroWhiteInitData);
        SafeDeleteArray(mLevelOneInitData);
        SafeDeleteArray(mLevelTwoInitData);

        ANGLETest::TearDown();
    }

    GLubyte *createRGBInitData(GLint width, GLint height, GLint r, GLint g, GLint b)
    {
        GLubyte *data = new GLubyte[3 * width * height];

        for (int i = 0; i < width * height; i+=1)
        {
            data[3 * i + 0] = static_cast<GLubyte>(r);
            data[3 * i + 1] = static_cast<GLubyte>(g);
            data[3 * i + 2] = static_cast<GLubyte>(b);
        }

        return data;
    }

    void ClearAndDrawTexturedQuad(GLuint texture, GLsizei viewportWidth, GLsizei viewportHeight)
    {
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        glClear(GL_COLOR_BUFFER_BIT);

        glViewport(0, 0, viewportWidth, viewportHeight);

        ASSERT_GL_NO_ERROR();

        GLfloat vertexLocations[] =
        {
            -1.0f,  1.0f, 0.0f,
            -1.0f, -1.0f, 0.0f,
             1.0f,  1.0f, 0.0f,
             1.0f, -1.0f, 0.0f,
        };

        GLfloat vertexTexCoords[] =
        {
            0.0f, 1.0f,
            0.0f, 0.0f,
            1.0f, 1.0f,
            1.0f, 0.0f,
        };

        glUseProgram(m2DProgram);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture);
        glUniform1i(m2DTextureUniformPosition, 0);

        glVertexAttribPointer(m2DPositionAttributePosition, 3, GL_FLOAT, GL_FALSE, 0, vertexLocations);
        glEnableVertexAttribArray(m2DPositionAttributePosition);

        glVertexAttribPointer(m2DTexCoordAttributePosition, 2, GL_FLOAT, GL_FALSE, 0, vertexTexCoords);
        glEnableVertexAttribArray(m2DTexCoordAttributePosition);

        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    }

    GLuint m2DProgram;
    GLuint mCubeProgram;
    GLuint mOffscreenFramebuffer;
    GLuint mOffscreenTexture2D;
    GLuint mOffscreenTextureCube;

    GLint m2DTextureUniformPosition;
    GLint m2DPositionAttributePosition;
    GLint m2DTexCoordAttributePosition;

    GLint mCubeTextureUniformPosition;
    GLint mCubePositionAttributePosition;

    GLubyte* mLevelZeroBlueInitData;
    GLubyte* mLevelZeroWhiteInitData;
    GLubyte* mLevelOneInitData;
    GLubyte* mLevelTwoInitData;
};

class MipmapTestES3 : public ANGLETest
{
  protected:
    MipmapTestES3()
    {
        setWindowWidth(128);
        setWindowHeight(128);
        setConfigRedBits(8);
        setConfigGreenBits(8);
        setConfigBlueBits(8);
        setConfigAlphaBits(8);
    }

    virtual void SetUp()
    {
        ANGLETest::SetUp();

        glGenTextures(1, &mTextureArray);
        EXPECT_GL_NO_ERROR();

        ASSERT_GL_NO_ERROR();

        // Don't put "#version ..." on its own line. See [cpp]p1:
        // "If there are sequences of preprocessing tokens within the list of arguments that
        //  would otherwise act as preprocessing directives, the behavior is undefined"
        const std::string vertexShaderSource = SHADER_SOURCE
        (   #version 300 es\n
            precision highp float;
            in vec4 position;
            out vec2 texcoord;

            uniform vec2 textureScale;

            void main()
            {
                gl_Position = vec4(position.xy * textureScale, 0.0, 1.0);
                texcoord = (position.xy * 0.5) + 0.5;
            }
        );

        const std::string fragmentShaderSourceArray = SHADER_SOURCE
        (   #version 300 es\n
            precision highp float;
            uniform highp sampler2DArray tex;
            uniform int slice;
            in vec2 texcoord;
            out vec4 out_FragColor;

            void main()
            {
                out_FragColor = texture(tex, vec3(texcoord, float(slice)));
            }
        );

        mArrayProgram = CompileProgram(vertexShaderSource, fragmentShaderSourceArray);
        if (mArrayProgram == 0)
        {
            FAIL() << "shader compilation failed.";
        }

        mTextureArrayUniformLocation = glGetUniformLocation(mArrayProgram, "tex");
        ASSERT_NE(-1, mTextureArrayUniformLocation);

        mTextureArrayScaleUniformLocation = glGetUniformLocation(mArrayProgram, "textureScale");
        ASSERT_NE(-1, mTextureArrayScaleUniformLocation);

        mTextureArraySliceUniformLocation = glGetUniformLocation(mArrayProgram, "slice");
        ASSERT_NE(-1, mTextureArraySliceUniformLocation);

        glUseProgram(mArrayProgram);
        glUniform2f(mTextureArrayScaleUniformLocation, 1.0f, 1.0f);
        glUseProgram(0);
        ASSERT_GL_NO_ERROR();

        glGenTextures(1, &mTexture3D);

        ASSERT_GL_NO_ERROR();

        const std::string fragmentShaderSource3D = SHADER_SOURCE
        (   #version 300 es\n
            precision highp float;
            uniform highp sampler3D tex;
            uniform float slice;
            uniform float lod;
            in vec2 texcoord;
            out vec4 out_FragColor;

            void main()
            {
                out_FragColor = textureLod(tex, vec3(texcoord, slice), lod);
            }
        );

        m3DProgram = CompileProgram(vertexShaderSource, fragmentShaderSource3D);
        if (m3DProgram == 0)
        {
            FAIL() << "shader compilation failed.";
        }

        mTexture3DUniformLocation = glGetUniformLocation(m3DProgram, "tex");
        ASSERT_NE(-1, mTexture3DUniformLocation);

        mTexture3DScaleUniformLocation = glGetUniformLocation(m3DProgram, "textureScale");
        ASSERT_NE(-1, mTexture3DScaleUniformLocation);

        mTexture3DSliceUniformLocation = glGetUniformLocation(m3DProgram, "slice");
        ASSERT_NE(-1, mTexture3DSliceUniformLocation);

        mTexture3DLODUniformLocation = glGetUniformLocation(m3DProgram, "lod");
        ASSERT_NE(-1, mTexture3DLODUniformLocation);

        glUseProgram(m3DProgram);
        glUniform2f(mTexture3DScaleUniformLocation, 1.0f, 1.0f);
        glUniform1f(mTexture3DLODUniformLocation, 0);
        glUseProgram(0);
        ASSERT_GL_NO_ERROR();
    }

    virtual void TearDown()
    {
        glDeleteTextures(1, &mTextureArray);
        glDeleteProgram(mArrayProgram);

        glDeleteTextures(1, &mTexture3D);
        glDeleteProgram(m3DProgram);

        ANGLETest::TearDown();
    }

    GLuint mTextureArray;
    GLuint mTexture3D;

    GLuint mArrayProgram;
    GLint mTextureArrayUniformLocation;
    GLint mTextureArrayScaleUniformLocation;
    GLint mTextureArraySliceUniformLocation;

    GLuint m3DProgram;
    GLint mTexture3DUniformLocation;
    GLint mTexture3DScaleUniformLocation;
    GLint mTexture3DSliceUniformLocation;
    GLint mTexture3DLODUniformLocation;
};

// This test uses init data for the first three levels of the texture. It passes the level 0 data in, then renders, then level 1, then renders, etc.
// This ensures that renderers using the zero LOD workaround (e.g. D3D11 FL9_3) correctly pass init data to the mipmapped texture,
// even if the the zero-LOD texture is currently in use.
TEST_P(MipmapTest, DISABLED_ThreeLevelsInitData)
{
    // Pass in level zero init data.
    glBindTexture(GL_TEXTURE_2D, mOffscreenTexture2D);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, mLevelZeroBlueInitData);
    ASSERT_GL_NO_ERROR();

    // Disable mips.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

    // Draw a full-sized quad, and check it's blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Draw a half-sized quad, and check it's blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 0, 255, 255);

    // Draw a quarter-sized quad, and check it's blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 0, 255, 255);

    // Complete the texture by initializing the remaining levels.
    int n = 1;
    while (getWindowWidth() / (1U << n) >= 1)
    {
        glTexImage2D(GL_TEXTURE_2D, n, GL_RGB, getWindowWidth() / (1U << n), getWindowWidth() / (1U << n), 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
        ASSERT_GL_NO_ERROR();
        n+=1;
    }

    // Pass in level one init data.
    glTexImage2D(GL_TEXTURE_2D, 1, GL_RGB, getWindowWidth() / 2, getWindowHeight() / 2, 0, GL_RGB, GL_UNSIGNED_BYTE, mLevelOneInitData);
    ASSERT_GL_NO_ERROR();

    // Draw a full-sized quad, and check it's blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Draw a half-sized quad, and check it's blue. We've not enabled mipmaps yet, so our init data for level one shouldn't be used.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 0, 255, 255);

    // Enable mipmaps.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);

    // Draw a half-sized quad, and check it's green.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 255, 0, 255);

    // Draw a quarter-sized quad, and check it's black, since we've not passed any init data for level two.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 0, 0, 255);

    // Pass in level two init data.
    glTexImage2D(GL_TEXTURE_2D, 2, GL_RGB, getWindowWidth() / 4, getWindowHeight() / 4, 0, GL_RGB, GL_UNSIGNED_BYTE, mLevelTwoInitData);
    ASSERT_GL_NO_ERROR();

    // Draw a full-sized quad, and check it's blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Draw a half-sized quad, and check it's green.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 255, 0, 255);

    // Draw a quarter-sized quad, and check it's red.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 255, 0, 0, 255);

    // Now disable mipmaps again, and render multiple sized quads. They should all be blue, since level 0 is blue.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 0, 255, 255);
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 0, 255, 255);

    // Now reset level 0 to white, keeping mipmaps disabled. Then, render various sized quads. They should be white.
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, mLevelZeroWhiteInitData);
    ASSERT_GL_NO_ERROR();

    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 255, 255, 255, 255);
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 255, 255, 255, 255);
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 255, 255, 255, 255);

    // Then enable mipmaps again. The quads should be white, green, red respectively.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);

    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 255, 255, 255, 255);
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 255, 0, 255);
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 255, 0, 0, 255);
}

// This test generates (and uses) mipmaps on a texture using init data. D3D11 will use a non-renderable TextureStorage for this.
// The test then disables mips, renders to level zero of the texture, and reenables mips before using the texture again.
// To do this, D3D11 has to convert the TextureStorage into a renderable one.
// This test ensures that the conversion works correctly.
// In particular, on D3D11 Feature Level 9_3 it ensures that both the zero LOD workaround texture AND the 'normal' texture are copied during conversion.
TEST_P(MipmapTest, GenerateMipmapFromInitDataThenRender)
{
    // Pass in initial data so the texture is blue.
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, mLevelZeroBlueInitData);

    // Then generate the mips.
    glGenerateMipmap(GL_TEXTURE_2D);
    ASSERT_GL_NO_ERROR();

    // Enable mipmaps.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);

    // Now draw the texture to various different sized areas.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Use mip level 1
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 0, 255, 255);

    // Use mip level 2
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 0, 255, 255);

    ASSERT_GL_NO_ERROR();

    // Disable mips. Render a quad using the texture and ensure it's blue.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Clear level 0 of the texture.
    glBindFramebuffer(GL_FRAMEBUFFER, mOffscreenFramebuffer);
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Reenable mips, and try rendering different-sized quads.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);

    // Level 0 is now red, so this should render red.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 255, 0, 0, 255);

    // Use mip level 1, blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 0, 255, 255);

    // Use mip level 2, blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 0, 255, 255);
}

// This test ensures that mips are correctly generated from a rendered image.
// In particular, on D3D11 Feature Level 9_3, the clear call will be performed on the zero-level texture, rather than the mipped one.
// The test ensures that the zero-level texture is correctly copied into the mipped texture before the mipmaps are generated.
TEST_P(MipmapTest, GenerateMipmapFromRenderedImage)
{
    // Bind the offscreen framebuffer/texture.
    glBindFramebuffer(GL_FRAMEBUFFER, mOffscreenFramebuffer);

    // Clear the texture to blue.
    glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Then generate the mips
    glGenerateMipmap(GL_TEXTURE_2D);
    ASSERT_GL_NO_ERROR();

    // Enable mips.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);

    // Now draw the texture to various different sized areas.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Use mip level 1
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 2, getWindowHeight() / 2);
    EXPECT_PIXEL_EQ(getWindowWidth() / 4, getWindowHeight() / 4, 0, 0, 255, 255);

    // Use mip level 2
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 0, 255, 255);
}

// Test to ensure that rendering to a mipmapped texture works, regardless of whether mipmaps are enabled or not.
// TODO: This test hits a texture rebind bug in the D3D11 renderer. Fix this.
TEST_P(MipmapTest, RenderOntoLevelZeroAfterGenerateMipmap)
{
    // TODO(geofflang): Figure out why this is broken on AMD OpenGL
    if ((isAMD() || isIntel()) && getPlatformRenderer() == EGL_PLATFORM_ANGLE_TYPE_OPENGL_ANGLE)
    {
        std::cout << "Test skipped on Intel/AMD OpenGL." << std::endl;
        return;
    }

    // Bind the offscreen texture/framebuffer.
    glBindFramebuffer(GL_FRAMEBUFFER, mOffscreenFramebuffer);

    // Clear the texture to blue.
    glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // From now on, default clear color is black.
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

    // Now, draw the texture to a quad that's the same size as the texture. This draws to the default framebuffer.
    // The quad should be blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Now go back to the texture, and generate mips on it.
    glGenerateMipmap(GL_TEXTURE_2D);
    ASSERT_GL_NO_ERROR();

    // Now try rendering the textured quad again. Note: we've not told GL to use the generated mips.
    // The quad should be blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Now tell GL to use the generated mips.
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
    EXPECT_GL_NO_ERROR();

    // Now render the textured quad again. It should be still be blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 0, 255, 255);

    // Now render the textured quad to an area smaller than the texture (i.e. to force minification). This should be blue.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 0, 255, 255);

    // Now clear the texture to green. This just clears the top level. The lower mips should remain blue.
    glBindFramebuffer(GL_FRAMEBUFFER, mOffscreenFramebuffer);
    glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // From now on, default clear color is black.
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

    // Render a textured quad equal in size to the texture. This should be green, since we just cleared level 0.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 255, 0, 255);

    // Render a small textured quad. This forces minification, so should render blue (the color of levels 1+).
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 0, 255, 255);

    // Disable mipmaps again
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    ASSERT_GL_NO_ERROR();

    // Render a textured quad equal in size to the texture. This should be green, the color of level 0 in the texture.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth(), getWindowHeight());
    EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 0, 255, 0, 255);

    // Render a small textured quad. This would force minification if mips were enabled, but they're not. Therefore, this should be green.
    ClearAndDrawTexturedQuad(mOffscreenTexture2D, getWindowWidth() / 4, getWindowHeight() / 4);
    EXPECT_PIXEL_EQ(getWindowWidth() / 8, getWindowHeight() / 8, 0, 255, 0, 255);
}

// This test ensures that the level-zero workaround for TextureCubes (on D3D11 Feature Level 9_3)
// works as expected. It tests enabling/disabling mipmaps, generating mipmaps, and rendering to level zero.
TEST_P(MipmapTest, TextureCubeGeneralLevelZero)
{
    GLfloat vertexLocations[] =
    {
        -1.0f, 1.0f, 0.0f,
        -1.0f, -1.0f, 0.0f,
        1.0f, 1.0f, 0.0f,
        1.0f, -1.0f, 0.0f,
    };

    // Set up the viewport, program, attributes, sampler and texture for the cube
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glViewport(0, 0, getWindowWidth(), getWindowHeight());
    glUseProgram(mCubeProgram);
    glVertexAttribPointer(mCubePositionAttributePosition, 3, GL_FLOAT, GL_FALSE, 0, vertexLocations);
    glEnableVertexAttribArray(mCubePositionAttributePosition);
    glUniform1i(mCubeTextureUniformPosition, 0);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_CUBE_MAP, mOffscreenTextureCube);

    // Draw. Since the negative-Y face's is blue, this should be blue.
    glClear(GL_COLOR_BUFFER_BIT);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    EXPECT_PIXEL_EQ(0, 0, 0, 0, 255, 255);

    // Generate mipmaps, and render. This should be blue.
    glClear(GL_COLOR_BUFFER_BIT);
    glGenerateMipmap(GL_TEXTURE_CUBE_MAP);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    EXPECT_PIXEL_EQ(0, 0, 0, 0, 255, 255);

    // Draw using a smaller viewport (to force a lower LOD of the texture). This should still be blue.
    glClear(GL_COLOR_BUFFER_BIT);
    glViewport(0, 0, getWindowWidth() / 4, getWindowHeight() / 4);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    EXPECT_PIXEL_EQ(0, 0, 0, 0, 255, 255);

    // Now clear the negative-Y face of the cube to red.
    glBindFramebuffer(GL_FRAMEBUFFER, mOffscreenFramebuffer);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, mOffscreenTextureCube, 0);
    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Switch back to the default framebuffer
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glBindTexture(GL_TEXTURE_CUBE_MAP, mOffscreenTextureCube);

    // Draw using a full-size viewport. This should be red.
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    glViewport(0, 0, getWindowWidth(), getWindowHeight());
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    EXPECT_PIXEL_EQ(0, 0, 255, 0, 0, 255);

    // Draw using a quarter-size viewport, to force a lower LOD. This should be *BLUE*, since we only cleared level zero
    // of the negative-Y face to red, and left its mipmaps blue.
    glClear(GL_COLOR_BUFFER_BIT);
    glViewport(0, 0, getWindowWidth() / 4, getWindowHeight() / 4);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    EXPECT_PIXEL_EQ(0, 0, 0, 0, 255, 255);

    // Disable mipmaps again, and draw a to a quarter-size viewport.
    // Since this should use level zero of the texture, this should be *RED*.
    glClear(GL_COLOR_BUFFER_BIT);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glViewport(0, 0, getWindowWidth() / 4, getWindowHeight() / 4);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}

// This test ensures that rendering to level-zero of a TextureCube works as expected.
TEST_P(MipmapTest, TextureCubeRenderToLevelZero)
{
    GLfloat vertexLocations[] =
    {
        -1.0f,  1.0f, 0.0f,
        -1.0f, -1.0f, 0.0f,
         1.0f,  1.0f, 0.0f,
         1.0f, -1.0f, 0.0f,
    };

    // Set up the viewport, program, attributes, sampler and texture for the cube
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glViewport(0, 0, getWindowWidth(), getWindowHeight());
    glUseProgram(mCubeProgram);
    glVertexAttribPointer(mCubePositionAttributePosition, 3, GL_FLOAT, GL_FALSE, 0, vertexLocations);
    glEnableVertexAttribArray(mCubePositionAttributePosition);
    glUniform1i(mCubeTextureUniformPosition, 0);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_CUBE_MAP, mOffscreenTextureCube);

    // Draw. Since the negative-Y face's is blue, this should be blue.
    glClear(GL_COLOR_BUFFER_BIT);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    EXPECT_PIXEL_EQ(0, 0, 0, 0, 255, 255);

    // Now clear the negative-Y face of the cube to red.
    glBindFramebuffer(GL_FRAMEBUFFER, mOffscreenFramebuffer);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, mOffscreenTextureCube, 0);
    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Switch back to the default framebuffer
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glBindTexture(GL_TEXTURE_CUBE_MAP, mOffscreenTextureCube);

    // Draw using a full-size viewport. This should be red.
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    glViewport(0, 0, getWindowWidth(), getWindowHeight());
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    EXPECT_PIXEL_EQ(0, 0, 255, 0, 0, 255);

    // Draw a to a quarter-size viewport. This should also be red.
    glClear(GL_COLOR_BUFFER_BIT);
    glViewport(0, 0, getWindowWidth() / 4, getWindowHeight() / 4);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    EXPECT_PIXEL_EQ(0, 0, 255, 0, 0, 255);
}

// Creates a mipmapped 2D array texture with three layers, and calls ANGLE's GenerateMipmap.
// Then tests if the mipmaps are rendered correctly for all three layers.
TEST_P(MipmapTestES3, MipmapsForTextureArray)
{
    int px = getWindowWidth() / 2;
    int py = getWindowHeight() / 2;

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D_ARRAY, mTextureArray);

    glTexStorage3D(GL_TEXTURE_2D_ARRAY, 5, GL_RGBA8, 16, 16, 3);

    // Fill the first layer with red
    std::vector<GLubyte> pixels(4 * 16 * 16);
    for (size_t pixelId = 0; pixelId < 16 * 16; ++pixelId)
    {
        pixels[pixelId * 4 + 0] = 255;
        pixels[pixelId * 4 + 1] = 0;
        pixels[pixelId * 4 + 2] = 0;
        pixels[pixelId * 4 + 3] = 255;
    }

    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, 16, 16, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());

    // Fill the second layer with green
    for (size_t pixelId = 0; pixelId < 16 * 16; ++pixelId)
    {
        pixels[pixelId * 4 + 0] = 0;
        pixels[pixelId * 4 + 1] = 255;
        pixels[pixelId * 4 + 2] = 0;
        pixels[pixelId * 4 + 3] = 255;
    }

    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 1, 16, 16, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());

    // Fill the third layer with blue
    for (size_t pixelId = 0; pixelId < 16 * 16; ++pixelId)
    {
        pixels[pixelId * 4 + 0] = 0;
        pixels[pixelId * 4 + 1] = 0;
        pixels[pixelId * 4 + 2] = 255;
        pixels[pixelId * 4 + 3] = 255;
    }

    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 2, 16, 16, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());

    glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
    glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    EXPECT_GL_NO_ERROR();

    glGenerateMipmap(GL_TEXTURE_2D_ARRAY);

    EXPECT_GL_NO_ERROR();

    glUseProgram(mArrayProgram);
    glUniform1i(mTextureArrayUniformLocation, 0);

    EXPECT_GL_NO_ERROR();

    // Draw the first slice
    glUseProgram(mArrayProgram);
    glUniform1i(mTextureArraySliceUniformLocation, 0);
    drawQuad(mArrayProgram, "position", 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_EQ(px, py, 255, 0, 0, 255);

    // Draw the second slice
    glUseProgram(mArrayProgram);
    glUniform1i(mTextureArraySliceUniformLocation, 1);
    drawQuad(mArrayProgram, "position", 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_EQ(px, py, 0, 255, 0, 255);

    // Draw the third slice
    glUseProgram(mArrayProgram);
    glUniform1i(mTextureArraySliceUniformLocation, 2);
    drawQuad(mArrayProgram, "position", 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_EQ(px, py, 0, 0, 255, 255);
}

// Creates a mipmapped 3D texture with two layers, and calls ANGLE's GenerateMipmap.
// Then tests if the mipmaps are rendered correctly for all two layers.
TEST_P(MipmapTestES3, MipmapsForTexture3D)
{
    int px = getWindowWidth() / 2;
    int py = getWindowHeight() / 2;

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_3D, mTexture3D);

    glTexStorage3D(GL_TEXTURE_3D, 5, GL_RGBA8, 16, 16, 2);

    // Fill the first layer with red
    std::vector<GLubyte> pixels(4 * 16 * 16);
    for (size_t pixelId = 0; pixelId < 16 * 16; ++pixelId)
    {
        pixels[pixelId * 4 + 0] = 255;
        pixels[pixelId * 4 + 1] = 0;
        pixels[pixelId * 4 + 2] = 0;
        pixels[pixelId * 4 + 3] = 255;
    }

    glTexSubImage3D(GL_TEXTURE_3D, 0, 0, 0, 0, 16, 16, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());

    // Fill the second layer with green
    for (size_t pixelId = 0; pixelId < 16 * 16; ++pixelId)
    {
        pixels[pixelId * 4 + 0] = 0;
        pixels[pixelId * 4 + 1] = 255;
        pixels[pixelId * 4 + 2] = 0;
        pixels[pixelId * 4 + 3] = 255;
    }

    glTexSubImage3D(GL_TEXTURE_3D, 0, 0, 0, 1, 16, 16, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());

    glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_NEAREST);
    glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    EXPECT_GL_NO_ERROR();

    glGenerateMipmap(GL_TEXTURE_3D);

    EXPECT_GL_NO_ERROR();

    glUseProgram(m3DProgram);
    glUniform1i(mTexture3DUniformLocation, 0);

    EXPECT_GL_NO_ERROR();

    // Mipmap level 0
    // Draw the first slice
    glUseProgram(m3DProgram);
    glUniform1f(mTexture3DLODUniformLocation, 0.);
    glUniform1f(mTexture3DSliceUniformLocation, 0.25f);
    drawQuad(m3DProgram, "position", 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_EQ(px, py, 255, 0, 0, 255);

    // Draw the second slice
    glUseProgram(m3DProgram);
    glUniform1f(mTexture3DSliceUniformLocation, 0.75f);
    drawQuad(m3DProgram, "position", 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_EQ(px, py, 0, 255, 0, 255);

    // Mipmap level 1
    // The second mipmap should only have one slice.

    glUseProgram(m3DProgram);
    glUniform1f(mTexture3DLODUniformLocation, 1.);
    drawQuad(m3DProgram, "position", 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_NEAR(px, py, 127, 127, 0, 255, 1.0);

    glUseProgram(m3DProgram);
    glUniform1f(mTexture3DSliceUniformLocation, 0.75f);
    drawQuad(m3DProgram, "position", 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_NEAR(px, py, 127, 127, 0, 255, 1.0);
}

// Use this to select which configurations (e.g. which renderer, which GLES major version) these tests should be run against.
// Note: we run these tests against 9_3 on WARP due to hardware driver issues on Win7
ANGLE_INSTANTIATE_TEST(MipmapTest,
                       ES2_D3D9(),
                       ES2_D3D11(EGL_EXPERIMENTAL_PRESENT_PATH_COPY_ANGLE),
                       ES2_D3D11(EGL_EXPERIMENTAL_PRESENT_PATH_FAST_ANGLE),
                       ES2_D3D11_FL9_3_WARP(),
                       ES2_OPENGL(),
                       ES3_OPENGL(),
                       ES2_OPENGLES(),
                       ES3_OPENGLES());
ANGLE_INSTANTIATE_TEST(MipmapTestES3, ES3_D3D11(), ES3_OPENGL(), ES3_OPENGLES());