C++ GrDrawState::positionAttributeIndex方法代码示例

//.........这里部分代码省略.........

    if (readsDst) {
        GrAssert(NULL != dstCopy);
        desc->fDstRead = GrGLShaderBuilder::KeyForDstRead(dstCopy->texture(), gpu->glCaps());
        GrAssert(0 != desc->fDstRead);
    } else {
        desc->fDstRead = 0;
    }

    desc->fCoverageOutput = kModulate_CoverageOutput;

    // Currently the experimental GS will only work with triangle prims (and it doesn't do anything
    // other than pass through values from the VS to the FS anyway).
#if GR_GL_EXPERIMENTAL_GS
#if 0
    desc->fExperimentalGS = gpu->caps().geometryShaderSupport();
#else
    desc->fExperimentalGS = false;
#endif
#endif

    // We leave this set to kNumStages until we discover that the coverage/color distinction is
    // material to the generated program. We do this to avoid distinct keys that generate equivalent
    // programs.
    desc->fFirstCoverageStage = GrDrawState::kNumStages;
    // This tracks the actual first coverage stage.
    int firstCoverageStage = GrDrawState::kNumStages;
    desc->fDiscardIfZeroCoverage = false; // Enabled below if stenciling and there is coverage.
    bool hasCoverage = false;
    // If we're rendering coverage-as-color then it's as though there are no coverage stages.
    if (!drawState.isCoverageDrawing()) {
        // We can have coverage either through a stage or coverage vertex attributes.
        if (drawState.getFirstCoverageStage() <= lastEnabledStage) {
            firstCoverageStage = drawState.getFirstCoverageStage();
            hasCoverage = true;
        } else {
            hasCoverage = requiresCoverageAttrib;
        }
    }

    if (hasCoverage) {
        // color filter is applied between color/coverage computation
        if (SkXfermode::kDst_Mode != desc->fColorFilterXfermode) {
            desc->fFirstCoverageStage = firstCoverageStage;
        }

        // If we're stenciling then we want to discard samples that have zero coverage
        if (drawState.getStencil().doesWrite()) {
            desc->fDiscardIfZeroCoverage = true;
            desc->fFirstCoverageStage = firstCoverageStage;
        }

        if (gpu->caps()->dualSourceBlendingSupport() &&
            !(blendOpts & (GrDrawState::kEmitCoverage_BlendOptFlag |
                           GrDrawState::kCoverageAsAlpha_BlendOptFlag))) {
            if (kZero_GrBlendCoeff == dstCoeff) {
                // write the coverage value to second color
                desc->fCoverageOutput =  kSecondaryCoverage_CoverageOutput;
                desc->fFirstCoverageStage = firstCoverageStage;
            } else if (kSA_GrBlendCoeff == dstCoeff) {
                // SA dst coeff becomes 1-(1-SA)*coverage when dst is partially covered.
                desc->fCoverageOutput = kSecondaryCoverageISA_CoverageOutput;
                desc->fFirstCoverageStage = firstCoverageStage;
            } else if (kSC_GrBlendCoeff == dstCoeff) {
                // SA dst coeff becomes 1-(1-SA)*coverage when dst is partially covered.
                desc->fCoverageOutput = kSecondaryCoverageISC_CoverageOutput;
                desc->fFirstCoverageStage = firstCoverageStage;
            }
        } else if (readsDst &&
                   kOne_GrBlendCoeff == drawState.getSrcBlendCoeff() &&
                   kZero_GrBlendCoeff == drawState.getDstBlendCoeff()) {
            desc->fCoverageOutput = kCombineWithDst_CoverageOutput;
            desc->fFirstCoverageStage = firstCoverageStage;
        }
    }

    desc->fPositionAttributeIndex = drawState.positionAttributeIndex();
    desc->fLocalCoordAttributeIndex = drawState.localCoordAttributeIndex();

    // For constant color and coverage we need an attribute with an index beyond those already set
    int availableAttributeIndex = drawState.getVertexAttribCount();
    if (requiresColorAttrib) {
        desc->fColorAttributeIndex = drawState.colorVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == desc->fColorInput) {
        GrAssert(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        desc->fColorAttributeIndex = availableAttributeIndex;
        availableAttributeIndex++;
    } else {
        desc->fColorAttributeIndex = -1;
    }

    if (requiresCoverageAttrib) {
        desc->fCoverageAttributeIndex = drawState.coverageVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == desc->fCoverageInput) {
        GrAssert(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        desc->fCoverageAttributeIndex = availableAttributeIndex;
    } else {
        desc->fCoverageAttributeIndex = -1;
    }
}

//.........这里部分代码省略.........
    bool covIsSolidWhite = !requiresCoverageAttrib && 0xffffffff == drawState.getCoverageColor();

    if (skipCoverage) {
        header->fCoverageInput = kTransBlack_ColorInput;
    } else if (covIsSolidWhite || !inputCoverageIsUsed) {
        header->fCoverageInput = kSolidWhite_ColorInput;
    } else if (defaultToUniformInputs && !requiresCoverageAttrib) {
        header->fCoverageInput = kUniform_ColorInput;
    } else {
        header->fCoverageInput = kAttribute_ColorInput;
        header->fHasVertexCode = true;
    }

    if (readsDst) {
        SkASSERT(NULL != dstCopy || gpu->caps()->dstReadInShaderSupport());
        const GrTexture* dstCopyTexture = NULL;
        if (NULL != dstCopy) {
            dstCopyTexture = dstCopy->texture();
        }
        header->fDstReadKey = GrGLShaderBuilder::KeyForDstRead(dstCopyTexture, gpu->glCaps());
        SkASSERT(0 != header->fDstReadKey);
    } else {
        header->fDstReadKey = 0;
    }

    if (readFragPosition) {
        header->fFragPosKey = GrGLShaderBuilder::KeyForFragmentPosition(drawState.getRenderTarget(),
                                                                      gpu->glCaps());
    } else {
        header->fFragPosKey = 0;
    }

    // Record attribute indices
    header->fPositionAttributeIndex = drawState.positionAttributeIndex();
    header->fLocalCoordAttributeIndex = drawState.localCoordAttributeIndex();

    // For constant color and coverage we need an attribute with an index beyond those already set
    int availableAttributeIndex = drawState.getVertexAttribCount();
    if (requiresColorAttrib) {
        header->fColorAttributeIndex = drawState.colorVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == header->fColorInput) {
        SkASSERT(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        header->fColorAttributeIndex = availableAttributeIndex;
        availableAttributeIndex++;
    } else {
        header->fColorAttributeIndex = -1;
    }

    if (requiresCoverageAttrib) {
        header->fCoverageAttributeIndex = drawState.coverageVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == header->fCoverageInput) {
        SkASSERT(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        header->fCoverageAttributeIndex = availableAttributeIndex;
    } else {
        header->fCoverageAttributeIndex = -1;
    }

    // Here we deal with whether/how we handle color and coverage separately.

    // Set this default and then possibly change our mind if there is coverage.
    header->fCoverageOutput = kModulate_CoverageOutput;

    // If we do have coverage determine whether it matters.
    bool separateCoverageFromColor = false;
    if (!drawState.isCoverageDrawing() && !skipCoverage &&
        (drawState.numCoverageStages() > 0 || requiresCoverageAttrib)) {

//.........这里部分代码省略.........

    bool covIsSolidWhite = !requiresCoverageAttrib && 0xffffffff == drawState.getCoverageColor();

    if ((covIsSolidWhite || !inputCoverageIsUsed) && !skipCoverage) {
        header->fCoverageInput = kAllOnes_ColorInput;
    } else if (defaultToUniformInputs && !requiresCoverageAttrib && inputCoverageIsUsed) {
        header->fCoverageInput = kUniform_ColorInput;
    } else {
        header->fCoverageInput = kAttribute_ColorInput;
        header->fRequiresVertexShader = true;
    }

    if (readsDst) {
        SkASSERT(NULL != dstCopy || gpu->caps()->dstReadInShaderSupport());
        const GrTexture* dstCopyTexture = NULL;
        if (NULL != dstCopy) {
            dstCopyTexture = dstCopy->texture();
        }
        header->fDstReadKey = GrGLFragmentShaderBuilder::KeyForDstRead(dstCopyTexture,
                gpu->glCaps());
        SkASSERT(0 != header->fDstReadKey);
    } else {
        header->fDstReadKey = 0;
    }

    if (readFragPosition) {
        header->fFragPosKey = GrGLFragmentShaderBuilder::KeyForFragmentPosition(
                drawState.getRenderTarget(), gpu->glCaps());
    } else {
        header->fFragPosKey = 0;
    }

    // Record attribute indices
    header->fPositionAttributeIndex = drawState.positionAttributeIndex();
    header->fLocalCoordAttributeIndex = drawState.localCoordAttributeIndex();

    // For constant color and coverage we need an attribute with an index beyond those already set
    int availableAttributeIndex = drawState.getVertexAttribCount();
    if (requiresColorAttrib) {
        header->fColorAttributeIndex = drawState.colorVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == header->fColorInput) {
        SkASSERT(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        header->fColorAttributeIndex = availableAttributeIndex;
        availableAttributeIndex++;
    } else {
        header->fColorAttributeIndex = -1;
    }

    if (requiresCoverageAttrib) {
        header->fCoverageAttributeIndex = drawState.coverageVertexAttributeIndex();
    } else if (GrGLProgramDesc::kAttribute_ColorInput == header->fCoverageInput) {
        SkASSERT(availableAttributeIndex < GrDrawState::kMaxVertexAttribCnt);
        header->fCoverageAttributeIndex = availableAttributeIndex;
    } else {
        header->fCoverageAttributeIndex = -1;
    }

    // Here we deal with whether/how we handle color and coverage separately.

    // Set this default and then possibly change our mind if there is coverage.
    header->fCoverageOutput = kModulate_CoverageOutput;

    // If we do have coverage determine whether it matters.
    bool separateCoverageFromColor = drawState.hasGeometryProcessor();
    if (!drawState.isCoverageDrawing() && !skipCoverage &&
        (drawState.numCoverageStages() > 0 ||