src/gpu/GrContext.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrContext.h"

#include "GrAARectRenderer.h"
#include "GrAtlasTextContext.h"
#include "GrBatch.h"
#include "GrBatchFontCache.h"
#include "GrBatchTarget.h"
#include "GrBatchTest.h"
#include "GrCaps.h"
#include "GrContextOptions.h"
#include "GrDefaultGeoProcFactory.h"
#include "GrDrawContext.h"
#include "GrGpuResource.h"
#include "GrGpuResourcePriv.h"
#include "GrGpu.h"
#include "GrImmediateDrawTarget.h"
#include "GrIndexBuffer.h"
#include "GrInOrderDrawBuffer.h"
#include "GrLayerCache.h"
#include "GrOvalRenderer.h"
#include "GrPathRenderer.h"
#include "GrPathUtils.h"
#include "GrRenderTargetPriv.h"
#include "GrResourceCache.h"
#include "GrResourceProvider.h"
#include "GrSoftwarePathRenderer.h"
#include "GrStencilAndCoverTextContext.h"
#include "GrStrokeInfo.h"
#include "GrSurfacePriv.h"
#include "GrTextBlobCache.h"
#include "GrTexturePriv.h"
#include "GrTraceMarker.h"
#include "GrTracing.h"
#include "GrVertices.h"
#include "SkDashPathPriv.h"
#include "SkConfig8888.h"
#include "SkGr.h"
#include "SkRRect.h"
#include "SkStrokeRec.h"
#include "SkTLazy.h"
#include "SkTLS.h"
#include "SkTraceEvent.h"

#include "effects/GrConfigConversionEffect.h"
#include "effects/GrDashingEffect.h"
#include "effects/GrSingleTextureEffect.h"

#define ASSERT_OWNED_RESOURCE(R) SkASSERT(!(R) || (R)->getContext() == this)
#define RETURN_IF_ABANDONED if (fDrawingMgr.abandoned()) { return; }
#define RETURN_FALSE_IF_ABANDONED if (fDrawingMgr.abandoned()) { return false; }
#define RETURN_NULL_IF_ABANDONED if (fDrawingMgr.abandoned()) { return NULL; }


////////////////////////////////////////////////////////////////////////////////

void GrContext::DrawingMgr::init(GrContext* context) {
#ifdef IMMEDIATE_MODE
    fDrawTarget = SkNEW_ARGS(GrImmediateDrawTarget, (context));
#else
    fDrawTarget = SkNEW_ARGS(GrInOrderDrawBuffer, (context));
#endif    

    fDrawContext = SkNEW_ARGS(GrDrawContext, (context, fDrawTarget));
}

GrContext::DrawingMgr::~DrawingMgr() {
    SkSafeUnref(fDrawTarget);
    SkSafeUnref(fDrawContext);
}

void GrContext::DrawingMgr::abandon() {
    SkSafeSetNull(fDrawTarget);
    fDrawContext->fDrawTarget.reset(NULL);
    SkSafeSetNull(fDrawContext);
}

void GrContext::DrawingMgr::purgeResources() {
    if (fDrawTarget) {
        fDrawTarget->purgeResources();
    }
}

void GrContext::DrawingMgr::reset() {
    if (fDrawTarget) {
        fDrawTarget->reset();
    }
}

void GrContext::DrawingMgr::flush() {
    if (fDrawTarget) {
        fDrawTarget->flush();
    }
}

GrDrawContext* GrContext::DrawingMgr::drawContext() { 
    if (this->abandoned()) {
        return NULL;
    }
    return fDrawContext; 
}

////////////////////////////////////////////////////////////////////////////////


GrContext* GrContext::Create(GrBackend backend, GrBackendContext backendContext) {
    GrContextOptions defaultOptions;
    return Create(backend, backendContext, defaultOptions);
}

GrContext* GrContext::Create(GrBackend backend, GrBackendContext backendContext,
                             const GrContextOptions& options) {
    GrContext* context = SkNEW(GrContext);

    if (context->init(backend, backendContext, options)) {
        return context;
    } else {
        context->unref();
        return NULL;
    }
}

static int32_t gNextID = 1;
static int32_t next_id() {
    int32_t id;
    do {
        id = sk_atomic_inc(&gNextID);
    } while (id == SK_InvalidGenID);
    return id;
}

GrContext::GrContext() : fUniqueID(next_id()) {
    fGpu = NULL;
    fResourceCache = NULL;
    fResourceProvider = NULL;
    fPathRendererChain = NULL;
    fSoftwarePathRenderer = NULL;
    fBatchFontCache = NULL;
    fFlushToReduceCacheSize = false;
    fMaxTextureSizeOverride = 1 << 20;
}

bool GrContext::init(GrBackend backend, GrBackendContext backendContext,
                     const GrContextOptions& options) {
    SkASSERT(!fGpu);

    fGpu = GrGpu::Create(backend, backendContext, options, this);
    if (!fGpu) {
        return false;
    }
    this->initCommon();
    return true;
}

void GrContext::initCommon() {
    fResourceCache = SkNEW(GrResourceCache);
    fResourceCache->setOverBudgetCallback(OverBudgetCB, this);
    fResourceProvider = SkNEW_ARGS(GrResourceProvider, (fGpu, fResourceCache));

    fLayerCache.reset(SkNEW_ARGS(GrLayerCache, (this)));

    fDidTestPMConversions = false;

    fDrawingMgr.init(this);

    // GrBatchFontCache will eventually replace GrFontCache
    fBatchFontCache = SkNEW_ARGS(GrBatchFontCache, (this));

    fTextBlobCache.reset(SkNEW_ARGS(GrTextBlobCache, (TextBlobCacheOverBudgetCB, this)));
}

GrContext::~GrContext() {
    if (!fGpu) {
        return;
    }

    this->flush();

    for (int i = 0; i < fCleanUpData.count(); ++i) {
        (*fCleanUpData[i].fFunc)(this, fCleanUpData[i].fInfo);
    }

    SkDELETE(fResourceProvider);
    SkDELETE(fResourceCache);
    SkDELETE(fBatchFontCache);

    fGpu->unref();
    SkSafeUnref(fPathRendererChain);
    SkSafeUnref(fSoftwarePathRenderer);
}

void GrContext::abandonContext() {
    fResourceProvider->abandon();
    // abandon first to so destructors
    // don't try to free the resources in the API.
    fResourceCache->abandonAll();

    fGpu->contextAbandoned();

    // a path renderer may be holding onto resources that
    // are now unusable
    SkSafeSetNull(fPathRendererChain);
    SkSafeSetNull(fSoftwarePathRenderer);

    fDrawingMgr.abandon();

    fBatchFontCache->freeAll();
    fLayerCache->freeAll();
    fTextBlobCache->freeAll();
}

void GrContext::resetContext(uint32_t state) {
    fGpu->markContextDirty(state);
}

void GrContext::freeGpuResources() {
    this->flush();

    fDrawingMgr.purgeResources();

    fBatchFontCache->freeAll();
    fLayerCache->freeAll();
    // a path renderer may be holding onto resources
    SkSafeSetNull(fPathRendererChain);
    SkSafeSetNull(fSoftwarePathRenderer);

    fResourceCache->purgeAllUnlocked();
}

void GrContext::getResourceCacheUsage(int* resourceCount, size_t* resourceBytes) const {
    if (resourceCount) {
        *resourceCount = fResourceCache->getBudgetedResourceCount();
    }
    if (resourceBytes) {
        *resourceBytes = fResourceCache->getBudgetedResourceBytes();
    }
}

GrTextContext* GrContext::createTextContext(GrRenderTarget* renderTarget,
                                            SkGpuDevice* gpuDevice,
                                            const SkDeviceProperties&
                                            leakyProperties,
                                            bool enableDistanceFieldFonts) {
    if (fGpu->caps()->shaderCaps()->pathRenderingSupport() && renderTarget->isMultisampled()) {
        GrStencilAttachment* sb = renderTarget->renderTargetPriv().attachStencilAttachment();
        if (sb) {
            return GrStencilAndCoverTextContext::Create(this, gpuDevice, leakyProperties);
        }
    } 

    return GrAtlasTextContext::Create(this, gpuDevice, leakyProperties, enableDistanceFieldFonts);
}

////////////////////////////////////////////////////////////////////////////////

bool GrContext::shaderDerivativeSupport() const {
    return fGpu->caps()->shaderCaps()->shaderDerivativeSupport();
}

bool GrContext::isConfigTexturable(GrPixelConfig config) const {
    return fGpu->caps()->isConfigTexturable(config);
}

bool GrContext::npotTextureTileSupport() const {
    return fGpu->caps()->npotTextureTileSupport();
}

void GrContext::OverBudgetCB(void* data) {
    SkASSERT(data);

    GrContext* context = reinterpret_cast<GrContext*>(data);

    // Flush the InOrderDrawBuffer to possibly free up some textures
    context->fFlushToReduceCacheSize = true;
}

void GrContext::TextBlobCacheOverBudgetCB(void* data) {
    SkASSERT(data);

    // Unlike the GrResourceCache, TextBlobs are drawn at the SkGpuDevice level, therefore they
    // cannot use fFlushTorReduceCacheSize because it uses AutoCheckFlush.  The solution is to move
    // drawText calls to below the GrContext level, but this is not trivial because they call
    // drawPath on SkGpuDevice
    GrContext* context = reinterpret_cast<GrContext*>(data);
    context->flush();
}

int GrContext::getMaxTextureSize() const {
    return SkTMin(fGpu->caps()->maxTextureSize(), fMaxTextureSizeOverride);
}

int GrContext::getMaxRenderTargetSize() const {
    return fGpu->caps()->maxRenderTargetSize();
}

int GrContext::getMaxSampleCount() const {
    return fGpu->caps()->maxSampleCount();
}

////////////////////////////////////////////////////////////////////////////////

void GrContext::flush(int flagsBitfield) {
    RETURN_IF_ABANDONED

    if (kDiscard_FlushBit & flagsBitfield) {
        fDrawingMgr.reset();
    } else {
        fDrawingMgr.flush();
    }
    fResourceCache->notifyFlushOccurred();
    fFlushToReduceCacheSize = false;
}

bool sw_convert_to_premul(GrPixelConfig srcConfig, int width, int height, size_t inRowBytes,
                          const void* inPixels, size_t outRowBytes, void* outPixels) {
    SkSrcPixelInfo srcPI;
    if (!GrPixelConfig2ColorAndProfileType(srcConfig, &srcPI.fColorType, NULL)) {
        return false;
    }
    srcPI.fAlphaType = kUnpremul_SkAlphaType;
    srcPI.fPixels = inPixels;
    srcPI.fRowBytes = inRowBytes;

    SkDstPixelInfo dstPI;
    dstPI.fColorType = srcPI.fColorType;
    dstPI.fAlphaType = kPremul_SkAlphaType;
    dstPI.fPixels = outPixels;
    dstPI.fRowBytes = outRowBytes;

    return srcPI.convertPixelsTo(&dstPI, width, height);
}

bool GrContext::writeSurfacePixels(GrSurface* surface,
                                   int left, int top, int width, int height,
                                   GrPixelConfig srcConfig, const void* buffer, size_t rowBytes,
                                   uint32_t pixelOpsFlags) {
    RETURN_FALSE_IF_ABANDONED
    {
        GrTexture* texture = NULL;
        if (!(kUnpremul_PixelOpsFlag & pixelOpsFlags) && (texture = surface->asTexture()) &&
            fGpu->canWriteTexturePixels(texture, srcConfig)) {

            if (!(kDontFlush_PixelOpsFlag & pixelOpsFlags) &&
                surface->surfacePriv().hasPendingIO()) {
                this->flush();
            }
            return fGpu->writeTexturePixels(texture, left, top, width, height,
                                            srcConfig, buffer, rowBytes);
            // Don't need to check kFlushWrites_PixelOp here, we just did a direct write so the
            // upload is already flushed.
        }
    }

    // If we didn't do a direct texture write then we upload the pixels to a texture and draw.
    GrRenderTarget* renderTarget = surface->asRenderTarget();
    if (!renderTarget) {
        return false;
    }

    // We ignore the preferred config unless it is a R/B swap of the src config. In that case
    // we will upload the original src data to a scratch texture but we will spoof it as the swapped
    // config. This scratch will then have R and B swapped. We correct for this by swapping again
    // when drawing the scratch to the dst using a conversion effect.
    bool swapRAndB = false;
    GrPixelConfig writeConfig = srcConfig;
    if (GrPixelConfigSwapRAndB(srcConfig) ==
        fGpu->preferredWritePixelsConfig(srcConfig, renderTarget->config())) {
        writeConfig = GrPixelConfigSwapRAndB(srcConfig);
        swapRAndB = true;
    }

    GrSurfaceDesc desc;
    desc.fWidth = width;
    desc.fHeight = height;
    desc.fConfig = writeConfig;
    SkAutoTUnref<GrTexture> texture(this->textureProvider()->refScratchTexture(desc,
        GrTextureProvider::kApprox_ScratchTexMatch));
    if (!texture) {
        return false;
    }

    SkAutoTUnref<const GrFragmentProcessor> fp;
    SkMatrix textureMatrix;
    textureMatrix.setIDiv(texture->width(), texture->height());

    // allocate a tmp buffer and sw convert the pixels to premul
    SkAutoSTMalloc<128 * 128, uint32_t> tmpPixels(0);

    if (kUnpremul_PixelOpsFlag & pixelOpsFlags) {
        if (!GrPixelConfigIs8888(srcConfig)) {
            return false;
        }
        fp.reset(this->createUPMToPMEffect(texture, swapRAndB, textureMatrix));
        // handle the unpremul step on the CPU if we couldn't create an effect to do it.
        if (!fp) {
            size_t tmpRowBytes = 4 * width;
            tmpPixels.reset(width * height);
            if (!sw_convert_to_premul(srcConfig, width, height, rowBytes, buffer, tmpRowBytes,
                                      tmpPixels.get())) {
                return false;
            }
            rowBytes = tmpRowBytes;
            buffer = tmpPixels.get();
        }
    }
    if (!fp) {
        fp.reset(GrConfigConversionEffect::Create(texture,
                                                  swapRAndB,
                                                  GrConfigConversionEffect::kNone_PMConversion,
                                                  textureMatrix));
    }

    // Even if the client told us not to flush, we still flush here. The client may have known that
    // writes to the original surface caused no data hazards, but they can't know that the scratch
    // we just got is safe.
    if (texture->surfacePriv().hasPendingIO()) {
        this->flush();
    }
    if (!fGpu->writeTexturePixels(texture, 0, 0, width, height,
                                  writeConfig, buffer, rowBytes)) {
        return false;
    }

    SkMatrix matrix;
    matrix.setTranslate(SkIntToScalar(left), SkIntToScalar(top));

    GrDrawContext* drawContext = this->drawContext();
    if (!drawContext) {
        return false;
    }

    GrPaint paint;
    paint.addColorProcessor(fp);

    SkRect rect = SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height));

    drawContext->drawRect(renderTarget, GrClip::WideOpen(), paint, matrix, rect, NULL);

    if (kFlushWrites_PixelOp & pixelOpsFlags) {
        this->flushSurfaceWrites(surface);
    }

    return true;
}

// toggles between RGBA and BGRA
static SkColorType toggle_colortype32(SkColorType ct) {
    if (kRGBA_8888_SkColorType == ct) {
        return kBGRA_8888_SkColorType;
    } else {
        SkASSERT(kBGRA_8888_SkColorType == ct);
        return kRGBA_8888_SkColorType;
    }
}

bool GrContext::readRenderTargetPixels(GrRenderTarget* target,
                                       int left, int top, int width, int height,
                                       GrPixelConfig dstConfig, void* buffer, size_t rowBytes,
                                       uint32_t flags) {
    RETURN_FALSE_IF_ABANDONED
    ASSERT_OWNED_RESOURCE(target);
    SkASSERT(target);

    if (!(kDontFlush_PixelOpsFlag & flags) && target->surfacePriv().hasPendingWrite()) {
        this->flush();
    }

    // Determine which conversions have to be applied: flipY, swapRAnd, and/or unpremul.

    // If fGpu->readPixels would incur a y-flip cost then we will read the pixels upside down. We'll
    // either do the flipY by drawing into a scratch with a matrix or on the cpu after the read.
    bool flipY = fGpu->readPixelsWillPayForYFlip(target, left, top,
                                                 width, height, dstConfig,
                                                 rowBytes);
    // We ignore the preferred config if it is different than our config unless it is an R/B swap.
    // In that case we'll perform an R and B swap while drawing to a scratch texture of the swapped
    // config. Then we will call readPixels on the scratch with the swapped config. The swaps during
    // the draw cancels out the fact that we call readPixels with a config that is R/B swapped from
    // dstConfig.
    GrPixelConfig readConfig = dstConfig;
    bool swapRAndB = false;
    if (GrPixelConfigSwapRAndB(dstConfig) ==
        fGpu->preferredReadPixelsConfig(dstConfig, target->config())) {
        readConfig = GrPixelConfigSwapRAndB(readConfig);
        swapRAndB = true;
    }

    bool unpremul = SkToBool(kUnpremul_PixelOpsFlag & flags);

    if (unpremul && !GrPixelConfigIs8888(dstConfig)) {
        // The unpremul flag is only allowed for these two configs.
        return false;
    }

    SkAutoTUnref<GrTexture> tempTexture;

    // If the src is a texture and we would have to do conversions after read pixels, we instead
    // do the conversions by drawing the src to a scratch texture. If we handle any of the
    // conversions in the draw we set the corresponding bool to false so that we don't reapply it
    // on the read back pixels.
    GrTexture* src = target->asTexture();
    if (src && (swapRAndB || unpremul || flipY)) {
        // Make the scratch a render so we can read its pixels.
        GrSurfaceDesc desc;
        desc.fFlags = kRenderTarget_GrSurfaceFlag;
        desc.fWidth = width;
        desc.fHeight = height;
        desc.fConfig = readConfig;
        desc.fOrigin = kTopLeft_GrSurfaceOrigin;

        // When a full read back is faster than a partial we could always make the scratch exactly
        // match the passed rect. However, if we see many different size rectangles we will trash
        // our texture cache and pay the cost of creating and destroying many textures. So, we only
        // request an exact match when the caller is reading an entire RT.
        GrTextureProvider::ScratchTexMatch match = GrTextureProvider::kApprox_ScratchTexMatch;
        if (0 == left &&
            0 == top &&
            target->width() == width &&
            target->height() == height &&
            fGpu->fullReadPixelsIsFasterThanPartial()) {
            match = GrTextureProvider::kExact_ScratchTexMatch;
        }
        tempTexture.reset(this->textureProvider()->refScratchTexture(desc, match));
        if (tempTexture) {
            // compute a matrix to perform the draw
            SkMatrix textureMatrix;
            textureMatrix.setTranslate(SK_Scalar1 *left, SK_Scalar1 *top);
            textureMatrix.postIDiv(src->width(), src->height());

            SkAutoTUnref<const GrFragmentProcessor> fp;
            if (unpremul) {
                fp.reset(this->createPMToUPMEffect(src, swapRAndB, textureMatrix));
                if (fp) {
                    unpremul = false; // we no longer need to do this on CPU after the read back.
                }
            }
            // If we failed to create a PM->UPM effect and have no other conversions to perform then
            // there is no longer any point to using the scratch.
            if (fp || flipY || swapRAndB) {
                if (!fp) {
                    fp.reset(GrConfigConversionEffect::Create(
                            src, swapRAndB, GrConfigConversionEffect::kNone_PMConversion,
                            textureMatrix));
                }
                swapRAndB = false; // we will handle the swap in the draw.

                // We protect the existing geometry here since it may not be
                // clear to the caller that a draw operation (i.e., drawSimpleRect)
                // can be invoked in this method
                {
                    GrDrawContext* drawContext = this->drawContext();
                    if (!drawContext) {
                        return false;
                    }

                    GrPaint paint;
                    paint.addColorProcessor(fp);

                    SkRect rect = SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height));

                    drawContext->drawRect(tempTexture->asRenderTarget(), GrClip::WideOpen(), paint,
                                          SkMatrix::I(), rect, NULL);                    

                    // we want to read back from the scratch's origin
                    left = 0;
                    top = 0;
                    target = tempTexture->asRenderTarget();
                }
                this->flushSurfaceWrites(target);
            }
        }
    }

    if (!fGpu->readPixels(target,
                          left, top, width, height,
                          readConfig, buffer, rowBytes)) {
        return false;
    }
    // Perform any conversions we weren't able to perform using a scratch texture.
    if (unpremul || swapRAndB) {
        SkDstPixelInfo dstPI;
        if (!GrPixelConfig2ColorAndProfileType(dstConfig, &dstPI.fColorType, NULL)) {
            return false;
        }
        dstPI.fAlphaType = kUnpremul_SkAlphaType;
        dstPI.fPixels = buffer;
        dstPI.fRowBytes = rowBytes;

        SkSrcPixelInfo srcPI;
        srcPI.fColorType = swapRAndB ? toggle_colortype32(dstPI.fColorType) : dstPI.fColorType;
        srcPI.fAlphaType = kPremul_SkAlphaType;
        srcPI.fPixels = buffer;
        srcPI.fRowBytes = rowBytes;

        return srcPI.convertPixelsTo(&dstPI, width, height);
    }
    return true;
}

void GrContext::prepareSurfaceForExternalRead(GrSurface* surface) {
    RETURN_IF_ABANDONED
    SkASSERT(surface);
    ASSERT_OWNED_RESOURCE(surface);
    if (surface->surfacePriv().hasPendingIO()) {
        this->flush();
    }
    GrRenderTarget* rt = surface->asRenderTarget();
    if (fGpu && rt) {
        fGpu->resolveRenderTarget(rt);
    }
}

void GrContext::copySurface(GrSurface* dst, GrSurface* src, const SkIRect& srcRect,
                            const SkIPoint& dstPoint, uint32_t pixelOpsFlags) {
    RETURN_IF_ABANDONED
    if (!src || !dst) {
        return;
    }
    ASSERT_OWNED_RESOURCE(src);
    ASSERT_OWNED_RESOURCE(dst);

    // Since we're going to the draw target and not GPU, no need to check kNoFlush
    // here.
    if (!dst->asRenderTarget()) {
        return;
    }

    GrDrawContext* drawContext = this->drawContext();
    if (!drawContext) {
        return;
    }

    drawContext->copySurface(dst->asRenderTarget(), src, srcRect, dstPoint);

    if (kFlushWrites_PixelOp & pixelOpsFlags) {
        this->flush();
    }
}

void GrContext::flushSurfaceWrites(GrSurface* surface) {
    RETURN_IF_ABANDONED
    if (surface->surfacePriv().hasPendingWrite()) {
        this->flush();
    }
}

/*
 * This method finds a path renderer that can draw the specified path on
 * the provided target.
 * Due to its expense, the software path renderer has split out so it can
 * can be individually allowed/disallowed via the "allowSW" boolean.
 */
GrPathRenderer* GrContext::getPathRenderer(const GrDrawTarget* target,
                                           const GrPipelineBuilder* pipelineBuilder,
                                           const SkMatrix& viewMatrix,
                                           const SkPath& path,
                                           const GrStrokeInfo& stroke,
                                           bool allowSW,
                                           GrPathRendererChain::DrawType drawType,
                                           GrPathRendererChain::StencilSupport* stencilSupport) {

    if (!fPathRendererChain) {
        fPathRendererChain = SkNEW_ARGS(GrPathRendererChain, (this));
    }

    GrPathRenderer* pr = fPathRendererChain->getPathRenderer(target,
                                                             pipelineBuilder,
                                                             viewMatrix,
                                                             path,
                                                             stroke,
                                                             drawType,
                                                             stencilSupport);

    if (!pr && allowSW) {
        if (!fSoftwarePathRenderer) {
            fSoftwarePathRenderer = SkNEW_ARGS(GrSoftwarePathRenderer, (this));
        }
        pr = fSoftwarePathRenderer;
    }

    return pr;
}

////////////////////////////////////////////////////////////////////////////////
bool GrContext::isConfigRenderable(GrPixelConfig config, bool withMSAA) const {
    return fGpu->caps()->isConfigRenderable(config, withMSAA);
}

int GrContext::getRecommendedSampleCount(GrPixelConfig config,
                                         SkScalar dpi) const {
    if (!this->isConfigRenderable(config, true)) {
        return 0;
    }
    int chosenSampleCount = 0;
    if (fGpu->caps()->shaderCaps()->pathRenderingSupport()) {
        if (dpi >= 250.0f) {
            chosenSampleCount = 4;
        } else {
            chosenSampleCount = 16;
        }
    }
    return chosenSampleCount <= fGpu->caps()->maxSampleCount() ?
        chosenSampleCount : 0;
}

namespace {
void test_pm_conversions(GrContext* ctx, int* pmToUPMValue, int* upmToPMValue) {
    GrConfigConversionEffect::PMConversion pmToUPM;
    GrConfigConversionEffect::PMConversion upmToPM;
    GrConfigConversionEffect::TestForPreservingPMConversions(ctx, &pmToUPM, &upmToPM);
    *pmToUPMValue = pmToUPM;
    *upmToPMValue = upmToPM;
}
}

const GrFragmentProcessor* GrContext::createPMToUPMEffect(GrTexture* texture,
                                                          bool swapRAndB,
                                                          const SkMatrix& matrix) {
    if (!fDidTestPMConversions) {
        test_pm_conversions(this, &fPMToUPMConversion, &fUPMToPMConversion);
        fDidTestPMConversions = true;
    }
    GrConfigConversionEffect::PMConversion pmToUPM =
        static_cast<GrConfigConversionEffect::PMConversion>(fPMToUPMConversion);
    if (GrConfigConversionEffect::kNone_PMConversion != pmToUPM) {
        return GrConfigConversionEffect::Create(texture, swapRAndB, pmToUPM, matrix);
    } else {
        return NULL;
    }
}

const GrFragmentProcessor* GrContext::createUPMToPMEffect(GrTexture* texture,
                                                          bool swapRAndB,
                                                          const SkMatrix& matrix) {
    if (!fDidTestPMConversions) {
        test_pm_conversions(this, &fPMToUPMConversion, &fUPMToPMConversion);
        fDidTestPMConversions = true;
    }
    GrConfigConversionEffect::PMConversion upmToPM =
        static_cast<GrConfigConversionEffect::PMConversion>(fUPMToPMConversion);
    if (GrConfigConversionEffect::kNone_PMConversion != upmToPM) {
        return GrConfigConversionEffect::Create(texture, swapRAndB, upmToPM, matrix);
    } else {
        return NULL;
    }
}

//////////////////////////////////////////////////////////////////////////////

void GrContext::getResourceCacheLimits(int* maxTextures, size_t* maxTextureBytes) const {
    if (maxTextures) {
        *maxTextures = fResourceCache->getMaxResourceCount();
    }
    if (maxTextureBytes) {
        *maxTextureBytes = fResourceCache->getMaxResourceBytes();
    }
}

void GrContext::setResourceCacheLimits(int maxTextures, size_t maxTextureBytes) {
    fResourceCache->setLimits(maxTextures, maxTextureBytes);
}

//////////////////////////////////////////////////////////////////////////////

void GrContext::addGpuTraceMarker(const GrGpuTraceMarker* marker) {
    fGpu->addGpuTraceMarker(marker);
}

void GrContext::removeGpuTraceMarker(const GrGpuTraceMarker* marker) {
    fGpu->removeGpuTraceMarker(marker);
}