GrCaps.h

/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#ifndef GrCaps_DEFINED
#define GrCaps_DEFINED

#include "GrTypes.h"
#include "GrTypesPriv.h"
#include "GrBlend.h"
#include "GrShaderVar.h"
#include "SkRefCnt.h"
#include "SkString.h"

struct GrContextOptions;

class GrShaderCaps : public SkRefCnt {
public:
    struct PrecisionInfo {
        PrecisionInfo() {
            fLogRangeLow = 0;
            fLogRangeHigh = 0;
            fBits = 0;
        }

        bool supported() const { return 0 != fBits; }

        bool operator==(const PrecisionInfo& that) const {
            return fLogRangeLow == that.fLogRangeLow && fLogRangeHigh == that.fLogRangeHigh &&
                   fBits == that.fBits;
        }
        bool operator!=(const PrecisionInfo& that) const { return !(*this == that); }

        int fLogRangeLow;
        int fLogRangeHigh;
        int fBits;
    };

    GrShaderCaps();

    virtual SkString dump() const;

    bool shaderDerivativeSupport() const { return fShaderDerivativeSupport; }
    bool geometryShaderSupport() const { return fGeometryShaderSupport; }
    bool pathRenderingSupport() const { return fPathRenderingSupport; }
    bool dstReadInShaderSupport() const { return fDstReadInShaderSupport; }
    bool dualSourceBlendingSupport() const { return fDualSourceBlendingSupport; }
    bool integerSupport() const { return fIntegerSupport; }
    bool texelBufferSupport() const { return fTexelBufferSupport; }

    const PrecisionInfo& getFloatShaderPrecisionInfo(GrShaderType shaderType,
                                                     GrSLPrecision precision) const {
        return fFloatPrecisions[shaderType][precision];
    };

    bool floatPrecisionVaries() const { return fShaderPrecisionVaries; }

    int pixelLocalStorageSize() const { return fPixelLocalStorageSize; }

    bool plsPathRenderingSupport() const { 
#if GR_ENABLE_PLS_PATH_RENDERING
        return fPLSPathRenderingSupport;
#else
        return false;
#endif
    }

protected:
    void applyOptionsOverrides(const GrContextOptions& options);

    bool fShaderDerivativeSupport : 1;
    bool fGeometryShaderSupport : 1;
    bool fPathRenderingSupport : 1;
    bool fDstReadInShaderSupport : 1;
    bool fDualSourceBlendingSupport : 1;
    bool fIntegerSupport : 1;
    bool fTexelBufferSupport : 1;

    bool fShaderPrecisionVaries;
    PrecisionInfo fFloatPrecisions[kGrShaderTypeCount][kGrSLPrecisionCount];
    int fPixelLocalStorageSize;
    bool fPLSPathRenderingSupport;

private:
    virtual void onApplyOptionsOverrides(const GrContextOptions&) {};
    typedef SkRefCnt INHERITED;
};

class GrCaps : public SkRefCnt {
public:
    GrCaps(const GrContextOptions&);

    virtual SkString dump() const;

    GrShaderCaps* shaderCaps() const { return fShaderCaps; }

    bool npotTextureTileSupport() const { return fNPOTTextureTileSupport; }
    bool mipMapSupport() const { return fMipMapSupport; }

    bool srgbSupport() const { return fSRGBSupport; }
    bool srgbWriteControl() const { return fSRGBWriteControl; }
    bool twoSidedStencilSupport() const { return fTwoSidedStencilSupport; }
    bool stencilWrapOpsSupport() const { return  fStencilWrapOpsSupport; }
    bool discardRenderTargetSupport() const { return fDiscardRenderTargetSupport; }
    bool gpuTracingSupport() const { return fGpuTracingSupport; }
    bool compressedTexSubImageSupport() const { return fCompressedTexSubImageSupport; }
    bool oversizedStencilSupport() const { return fOversizedStencilSupport; }
    bool textureBarrierSupport() const { return fTextureBarrierSupport; }
    bool sampleLocationsSupport() const { return fSampleLocationsSupport; }
    bool multisampleDisableSupport() const { return fMultisampleDisableSupport; }
    bool usesMixedSamples() const { return fUsesMixedSamples; }
    bool preferClientSideDynamicBuffers() const { return fPreferClientSideDynamicBuffers; }

    bool useDrawInsteadOfClear() const { return fUseDrawInsteadOfClear; }
    bool useDrawInsteadOfPartialRenderTargetWrite() const {
        return fUseDrawInsteadOfPartialRenderTargetWrite;
    }

    bool useDrawInsteadOfAllRenderTargetWrites() const {
        return fUseDrawInsteadOfAllRenderTargetWrites;
    }

    bool preferVRAMUseOverFlushes() const { return fPreferVRAMUseOverFlushes; }

    enum class InstancedSupport {
        kNone,
        kBasic,
        kMultisampled,
        kMixedSampled
    };

    InstancedSupport instancedSupport() const { return fInstancedSupport; }

    bool avoidInstancedDrawsToFPTargets() const { return fAvoidInstancedDrawsToFPTargets; }

    enum BlendEquationSupport {
        kBasic_BlendEquationSupport,             //<! Support to select the operator that
                                                 //   combines src and dst terms.
        kAdvanced_BlendEquationSupport,          //<! Additional fixed function support for specific
                                                 //   SVG/PDF blend modes. Requires blend barriers.
        kAdvancedCoherent_BlendEquationSupport,  //<! Advanced blend equation support that does not
                                                 //   require blend barriers, and permits overlap.

        kLast_BlendEquationSupport = kAdvancedCoherent_BlendEquationSupport
    };

    BlendEquationSupport blendEquationSupport() const { return fBlendEquationSupport; }

    bool advancedBlendEquationSupport() const {
        return fBlendEquationSupport >= kAdvanced_BlendEquationSupport;
    }

    bool advancedCoherentBlendEquationSupport() const {
        return kAdvancedCoherent_BlendEquationSupport == fBlendEquationSupport;
    }

    bool canUseAdvancedBlendEquation(GrBlendEquation equation) const {
        SkASSERT(GrBlendEquationIsAdvanced(equation));
        return SkToBool(fAdvBlendEqBlacklist & (1 << equation));
    }

    enum MapFlags {
        kNone_MapFlags   = 0x0,       //<! Cannot map the resource.

        kCanMap_MapFlag  = 0x1,       //<! The resource can be mapped. Must be set for any of
                                      //   the other flags to have meaning.k
        kSubset_MapFlag  = 0x2,       //<! The resource can be partially mapped.
    };

    uint32_t mapBufferFlags() const { return fMapBufferFlags; }

    // Scratch textures not being reused means that those scratch textures
    // that we upload to (i.e., don't have a render target) will not be
    // recycled in the texture cache. This is to prevent ghosting by drivers
    // (in particular for deferred architectures).
    bool reuseScratchTextures() const { return fReuseScratchTextures; }
    bool reuseScratchBuffers() const { return fReuseScratchBuffers; }

    int maxVertexAttributes() const { return fMaxVertexAttributes; }

    int maxRenderTargetSize() const { return fMaxRenderTargetSize; }
    int maxTextureSize() const { return fMaxTextureSize; }
    int maxTileSize() const { SkASSERT(fMaxTileSize <= fMaxTextureSize); return fMaxTileSize; }

    // Will be 0 if MSAA is not supported
    int maxColorSampleCount() const { return fMaxColorSampleCount; }
    // Will be 0 if MSAA is not supported
    int maxStencilSampleCount() const { return fMaxStencilSampleCount; }
    // Will be 0 if raster multisample is not supported. Raster multisample is a special HW mode
    // where the rasterizer runs with more samples than are in the target framebuffer.
    int maxRasterSamples() const { return fMaxRasterSamples; }
    // We require the sample count to be less than maxColorSampleCount and maxStencilSampleCount.
    // If we are using mixed samples, we only care about stencil.
    int maxSampleCount() const {
        if (this->usesMixedSamples()) {
            return this->maxStencilSampleCount();
        } else {
            return SkTMin(this->maxColorSampleCount(), this->maxStencilSampleCount());
        }
    }

    int maxWindowRectangles() const { return fMaxWindowRectangles; }

    virtual bool isConfigTexturable(GrPixelConfig config) const = 0;
    virtual bool isConfigRenderable(GrPixelConfig config, bool withMSAA) const = 0;

    bool suppressPrints() const { return fSuppressPrints; }

    bool immediateFlush() const { return fImmediateFlush; }

    size_t bufferMapThreshold() const {
        SkASSERT(fBufferMapThreshold >= 0);
        return fBufferMapThreshold;
    }

    bool fullClearIsFree() const { return fFullClearIsFree; }

    bool mustClearUploadedBufferData() const { return fMustClearUploadedBufferData; }

    bool sampleShadingSupport() const { return fSampleShadingSupport; }

protected:
    void applyOptionsOverrides(const GrContextOptions& options);

    SkAutoTUnref<GrShaderCaps>    fShaderCaps;

    bool fNPOTTextureTileSupport                     : 1;
    bool fMipMapSupport                              : 1;
    bool fSRGBSupport                                : 1;
    bool fSRGBWriteControl                           : 1;
    bool fTwoSidedStencilSupport                     : 1;
    bool fStencilWrapOpsSupport                      : 1;
    bool fDiscardRenderTargetSupport                 : 1;
    bool fReuseScratchTextures                       : 1;
    bool fReuseScratchBuffers                        : 1;
    bool fGpuTracingSupport                          : 1;
    bool fCompressedTexSubImageSupport               : 1;
    bool fOversizedStencilSupport                    : 1;
    bool fTextureBarrierSupport                      : 1;
    bool fSampleLocationsSupport                     : 1;
    bool fMultisampleDisableSupport                  : 1;
    bool fUsesMixedSamples                           : 1;
    bool fPreferClientSideDynamicBuffers             : 1;
    bool fFullClearIsFree                            : 1;
    bool fMustClearUploadedBufferData                : 1;

    // Driver workaround
    bool fUseDrawInsteadOfClear                      : 1;
    bool fUseDrawInsteadOfPartialRenderTargetWrite   : 1;
    bool fUseDrawInsteadOfAllRenderTargetWrites      : 1;
    bool fAvoidInstancedDrawsToFPTargets             : 1;

    // ANGLE workaround
    bool fPreferVRAMUseOverFlushes                   : 1;

    bool fSampleShadingSupport                       : 1;

    InstancedSupport fInstancedSupport;

    BlendEquationSupport fBlendEquationSupport;
    uint32_t fAdvBlendEqBlacklist;
    GR_STATIC_ASSERT(kLast_GrBlendEquation < 32);

    uint32_t fMapBufferFlags;
    int fBufferMapThreshold;

    int fMaxRenderTargetSize;
    int fMaxVertexAttributes;
    int fMaxTextureSize;
    int fMaxTileSize;
    int fMaxColorSampleCount;
    int fMaxStencilSampleCount;
    int fMaxRasterSamples;
    int fMaxWindowRectangles;

private:
    virtual void onApplyOptionsOverrides(const GrContextOptions&) {};

    bool fSuppressPrints : 1;
    bool fImmediateFlush: 1;

    typedef SkRefCnt INHERITED;
};

#endif