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      1 /*
      2  * Copyright 2013 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "GrGLProgramDesc.h"
      9 #include "GrBackendEffectFactory.h"
     10 #include "GrDrawEffect.h"
     11 #include "GrEffect.h"
     12 #include "GrGLShaderBuilder.h"
     13 #include "GrGpuGL.h"
     14 
     15 #include "SkChecksum.h"
     16 
     17 namespace {
     18 inline GrGLEffect::EffectKey get_key_and_update_stats(const GrEffectStage& stage,
     19                                                       const GrGLCaps& caps,
     20                                                       bool useExplicitLocalCoords,
     21                                                       bool* setTrueIfReadsDst,
     22                                                       bool* setTrueIfReadsPos,
     23                                                       bool* setTrueIfHasVertexCode) {
     24     const GrEffectRef& effect = *stage.getEffect();
     25     const GrBackendEffectFactory& factory = effect->getFactory();
     26     GrDrawEffect drawEffect(stage, useExplicitLocalCoords);
     27     if (effect->willReadDstColor()) {
     28         *setTrueIfReadsDst = true;
     29     }
     30     if (effect->willReadFragmentPosition()) {
     31         *setTrueIfReadsPos = true;
     32     }
     33     if (effect->hasVertexCode()) {
     34         *setTrueIfHasVertexCode = true;
     35     }
     36     return factory.glEffectKey(drawEffect, caps);
     37 }
     38 }
     39 void GrGLProgramDesc::Build(const GrDrawState& drawState,
     40                             GrGpu::DrawType drawType,
     41                             GrDrawState::BlendOptFlags blendOpts,
     42                             GrBlendCoeff srcCoeff,
     43                             GrBlendCoeff dstCoeff,
     44                             const GrGpuGL* gpu,
     45                             const GrDeviceCoordTexture* dstCopy,
     46                             SkTArray<const GrEffectStage*, true>* colorStages,
     47                             SkTArray<const GrEffectStage*, true>* coverageStages,
     48                             GrGLProgramDesc* desc) {
     49     colorStages->reset();
     50     coverageStages->reset();
     51 
     52     // This should already have been caught
     53     SkASSERT(!(GrDrawState::kSkipDraw_BlendOptFlag & blendOpts));
     54 
     55     bool skipCoverage = SkToBool(blendOpts & GrDrawState::kEmitTransBlack_BlendOptFlag);
     56 
     57     bool skipColor = SkToBool(blendOpts & (GrDrawState::kEmitTransBlack_BlendOptFlag |
     58                                            GrDrawState::kEmitCoverage_BlendOptFlag));
     59     int firstEffectiveColorStage = 0;
     60     bool inputColorIsUsed = true;
     61     if (!skipColor) {
     62         firstEffectiveColorStage = drawState.numColorStages();
     63         while (firstEffectiveColorStage > 0 && inputColorIsUsed) {
     64             --firstEffectiveColorStage;
     65             const GrEffect* effect = drawState.getColorStage(firstEffectiveColorStage).getEffect()->get();
     66             inputColorIsUsed = effect->willUseInputColor();
     67         }
     68     }
     69 
     70     int firstEffectiveCoverageStage = 0;
     71     bool inputCoverageIsUsed = true;
     72     if (!skipCoverage) {
     73         firstEffectiveCoverageStage = drawState.numCoverageStages();
     74         while (firstEffectiveCoverageStage > 0 && inputCoverageIsUsed) {
     75             --firstEffectiveCoverageStage;
     76             const GrEffect* effect = drawState.getCoverageStage(firstEffectiveCoverageStage).getEffect()->get();
     77             inputCoverageIsUsed = effect->willUseInputColor();
     78         }
     79     }
     80 
     81     // The descriptor is used as a cache key. Thus when a field of the
     82     // descriptor will not affect program generation (because of the attribute
     83     // bindings in use or other descriptor field settings) it should be set
     84     // to a canonical value to avoid duplicate programs with different keys.
     85 
     86     bool requiresColorAttrib = !skipColor && drawState.hasColorVertexAttribute();
     87     bool requiresCoverageAttrib = !skipCoverage && drawState.hasCoverageVertexAttribute();
     88     // we only need the local coords if we're actually going to generate effect code
     89     bool requiresLocalCoordAttrib = !(skipCoverage  && skipColor) &&
     90                                     drawState.hasLocalCoordAttribute();
     91 
     92     bool colorIsTransBlack = SkToBool(blendOpts & GrDrawState::kEmitTransBlack_BlendOptFlag);
     93     bool colorIsSolidWhite = (blendOpts & GrDrawState::kEmitCoverage_BlendOptFlag) ||
     94                              (!requiresColorAttrib && 0xffffffff == drawState.getColor()) ||
     95                              (!inputColorIsUsed);
     96 
     97     int numEffects = (skipColor ? 0 : (drawState.numColorStages() - firstEffectiveColorStage)) +
     98                      (skipCoverage ? 0 : (drawState.numCoverageStages() - firstEffectiveCoverageStage));
     99 
    100     size_t newKeyLength = KeyLength(numEffects);
    101     bool allocChanged;
    102     desc->fKey.reset(newKeyLength, SkAutoMalloc::kAlloc_OnShrink, &allocChanged);
    103     if (allocChanged || !desc->fInitialized) {
    104         // make sure any padding in the header is zero if we we haven't used this allocation before.
    105         memset(desc->header(), 0, kHeaderSize);
    106     }
    107     // write the key length
    108     *desc->atOffset<uint32_t, kLengthOffset>() = SkToU32(newKeyLength);
    109 
    110     KeyHeader* header = desc->header();
    111     EffectKey* effectKeys = desc->effectKeys();
    112 
    113     int currEffectKey = 0;
    114     bool readsDst = false;
    115     bool readFragPosition = false;
    116     // We use vertexshader-less shader programs only when drawing paths.
    117     bool hasVertexCode = !(GrGpu::kDrawPath_DrawType == drawType ||
    118                            GrGpu::kDrawPaths_DrawType == drawType);
    119 
    120     if (!skipColor) {
    121         for (int s = firstEffectiveColorStage; s < drawState.numColorStages(); ++s) {
    122             effectKeys[currEffectKey++] =
    123                 get_key_and_update_stats(drawState.getColorStage(s), gpu->glCaps(),
    124                                          requiresLocalCoordAttrib, &readsDst, &readFragPosition,
    125                                          &hasVertexCode);
    126         }
    127     }
    128     if (!skipCoverage) {
    129         for (int s = firstEffectiveCoverageStage; s < drawState.numCoverageStages(); ++s) {
    130             effectKeys[currEffectKey++] =
    131                 get_key_and_update_stats(drawState.getCoverageStage(s), gpu->glCaps(),
    132                                          requiresLocalCoordAttrib, &readsDst, &readFragPosition,
    133                                          &hasVertexCode);
    134         }
    135     }
    136 
    137     header->fHasVertexCode = hasVertexCode || requiresLocalCoordAttrib;
    138     header->fEmitsPointSize = GrGpu::kDrawPoints_DrawType == drawType;
    139 
    140     // Currently the experimental GS will only work with triangle prims (and it doesn't do anything
    141     // other than pass through values from the VS to the FS anyway).
    142 #if GR_GL_EXPERIMENTAL_GS
    143 #if 0
    144     header->fExperimentalGS = gpu->caps().geometryShaderSupport();
    145 #else
    146     header->fExperimentalGS = false;
    147 #endif
    148 #endif
    149     bool defaultToUniformInputs = GR_GL_NO_CONSTANT_ATTRIBUTES || gpu->caps()->pathRenderingSupport();
    150 
    151     if (colorIsTransBlack) {
    152         header->fColorInput = kTransBlack_ColorInput;
    153     } else if (colorIsSolidWhite) {
    154         header->fColorInput = kSolidWhite_ColorInput;
    155     } else if (defaultToUniformInputs && !requiresColorAttrib) {
    156         header->fColorInput = kUniform_ColorInput;
    157     } else {
    158         header->fColorInput = kAttribute_ColorInput;
    159         header->fHasVertexCode = true;
    160     }
    161 
    162     bool covIsSolidWhite = !requiresCoverageAttrib && 0xffffffff == drawState.getCoverageColor();
    163 
    164     if (skipCoverage) {
    165         header->fCoverageInput = kTransBlack_ColorInput;
    166     } else if (covIsSolidWhite || !inputCoverageIsUsed) {
    167         header->fCoverageInput = kSolidWhite_ColorInput;
    168     } else if (defaultToUniformInputs && !requiresCoverageAttrib) {
    169         header->fCoverageInput = kUniform_ColorInput;
    170     } else {
    171         header->fCoverageInput = kAttribute_ColorInput;
    172         header->fHasVertexCode = true;
    173     }
    174 
    175     if (readsDst) {
    176         SkASSERT(NULL != dstCopy || gpu->caps()->dstReadInShaderSupport());
    177         const GrTexture* dstCopyTexture = NULL;
    178         if (NULL != dstCopy) {
    179             dstCopyTexture = dstCopy->texture();
    180         }
    181         header->fDstReadKey = GrGLShaderBuilder::KeyForDstRead(dstCopyTexture, gpu->glCaps());
    182         SkASSERT(0 != header->fDstReadKey);
    183     } else {
    184         header->fDstReadKey = 0;
    185     }
    186 
    187     if (readFragPosition) {
    188         header->fFragPosKey = GrGLShaderBuilder::KeyForFragmentPosition(drawState.getRenderTarget(),
    189                                                                       gpu->glCaps());
    190     } else {
    191         header->fFragPosKey = 0;
    192     }
    193 
    194     // Record attribute indices
    195     header->fPositionAttributeIndex = drawState.positionAttributeIndex();
    196     header->fLocalCoordAttributeIndex = drawState.localCoordAttributeIndex();
    197 
    198     // For constant color and coverage we need an attribute with an index beyond those already set
    199     int availableAttributeIndex = drawState.getVertexAttribCount();
    200     if (requiresColorAttrib) {
    201         header->fColorAttributeIndex = drawState.colorVertexAttributeIndex();
    202     } else if (GrGLProgramDesc::kAttribute_ColorInput == header->fColorInput) {
    203         SkASSERT(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
    204         header->fColorAttributeIndex = availableAttributeIndex;
    205         availableAttributeIndex++;
    206     } else {
    207         header->fColorAttributeIndex = -1;
    208     }
    209 
    210     if (requiresCoverageAttrib) {
    211         header->fCoverageAttributeIndex = drawState.coverageVertexAttributeIndex();
    212     } else if (GrGLProgramDesc::kAttribute_ColorInput == header->fCoverageInput) {
    213         SkASSERT(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
    214         header->fCoverageAttributeIndex = availableAttributeIndex;
    215     } else {
    216         header->fCoverageAttributeIndex = -1;
    217     }
    218 
    219     // Here we deal with whether/how we handle color and coverage separately.
    220 
    221     // Set this default and then possibly change our mind if there is coverage.
    222     header->fCoverageOutput = kModulate_CoverageOutput;
    223 
    224     // If we do have coverage determine whether it matters.
    225     bool separateCoverageFromColor = false;
    226     if (!drawState.isCoverageDrawing() && !skipCoverage &&
    227         (drawState.numCoverageStages() > 0 || requiresCoverageAttrib)) {
    228 
    229         if (gpu->caps()->dualSourceBlendingSupport() &&
    230             !(blendOpts & (GrDrawState::kEmitCoverage_BlendOptFlag |
    231                            GrDrawState::kCoverageAsAlpha_BlendOptFlag))) {
    232             if (kZero_GrBlendCoeff == dstCoeff) {
    233                 // write the coverage value to second color
    234                 header->fCoverageOutput =  kSecondaryCoverage_CoverageOutput;
    235                 separateCoverageFromColor = true;
    236             } else if (kSA_GrBlendCoeff == dstCoeff) {
    237                 // SA dst coeff becomes 1-(1-SA)*coverage when dst is partially covered.
    238                 header->fCoverageOutput = kSecondaryCoverageISA_CoverageOutput;
    239                 separateCoverageFromColor = true;
    240             } else if (kSC_GrBlendCoeff == dstCoeff) {
    241                 // SA dst coeff becomes 1-(1-SA)*coverage when dst is partially covered.
    242                 header->fCoverageOutput = kSecondaryCoverageISC_CoverageOutput;
    243                 separateCoverageFromColor = true;
    244             }
    245         } else if (readsDst &&
    246                    kOne_GrBlendCoeff == srcCoeff &&
    247                    kZero_GrBlendCoeff == dstCoeff) {
    248             header->fCoverageOutput = kCombineWithDst_CoverageOutput;
    249             separateCoverageFromColor = true;
    250         }
    251     }
    252     if (!skipColor) {
    253         for (int s = firstEffectiveColorStage; s < drawState.numColorStages(); ++s) {
    254             colorStages->push_back(&drawState.getColorStage(s));
    255         }
    256     }
    257     if (!skipCoverage) {
    258         SkTArray<const GrEffectStage*, true>* array;
    259         if (separateCoverageFromColor) {
    260             array = coverageStages;
    261         } else {
    262             array = colorStages;
    263         }
    264         for (int s = firstEffectiveCoverageStage; s < drawState.numCoverageStages(); ++s) {
    265             array->push_back(&drawState.getCoverageStage(s));
    266         }
    267     }
    268     header->fColorEffectCnt = colorStages->count();
    269     header->fCoverageEffectCnt = coverageStages->count();
    270 
    271     *desc->checksum() = 0;
    272     *desc->checksum() = SkChecksum::Compute(reinterpret_cast<uint32_t*>(desc->fKey.get()),
    273                                             newKeyLength);
    274     desc->fInitialized = true;
    275 }
    276 
    277 GrGLProgramDesc& GrGLProgramDesc::operator= (const GrGLProgramDesc& other) {
    278     fInitialized = other.fInitialized;
    279     if (fInitialized) {
    280         size_t keyLength = other.keyLength();
    281         fKey.reset(keyLength);
    282         memcpy(fKey.get(), other.fKey.get(), keyLength);
    283     }
    284     return *this;
    285 }
    286