Implement color filter as GrGLEffect

src/gpu/gl/GrGLProgram.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 "GrGLProgram.h"
 
 #include "GrAllocator.h"
@@ skipping 97 matching lines @@
         case GrGLProgramDesc::kCombineWithDst_CoverageOutput:
             // We should only have set this if the blend was specified as (1, 0)
             SkASSERT(kOne_GrBlendCoeff == *srcCoeff && kZero_GrBlendCoeff == *dstCoeff);
             break;
         default:
             GrCrash("Unexpected coverage output");
             break;
     }
 }
 
-namespace {
-// given two blend coefficients determine whether the src
-// and/or dst computation can be omitted.
-inline void need_blend_inputs(SkXfermode::Coeff srcCoeff,
-                              SkXfermode::Coeff dstCoeff,
-                              bool* needSrcValue,
-                              bool* needDstValue) {
-    if (SkXfermode::kZero_Coeff == srcCoeff) {
-        switch (dstCoeff) {
-            // these all read the src
-            case SkXfermode::kSC_Coeff:
-            case SkXfermode::kISC_Coeff:
-            case SkXfermode::kSA_Coeff:
-            case SkXfermode::kISA_Coeff:
-                *needSrcValue = true;
-                break;
-            default:
-                *needSrcValue = false;
-                break;
-        }
-    } else {
-        *needSrcValue = true;
-    }
-    if (SkXfermode::kZero_Coeff == dstCoeff) {
-        switch (srcCoeff) {
-            // these all read the dst
-            case SkXfermode::kDC_Coeff:
-            case SkXfermode::kIDC_Coeff:
-            case SkXfermode::kDA_Coeff:
-            case SkXfermode::kIDA_Coeff:
-                *needDstValue = true;
-                break;
-            default:
-                *needDstValue = false;
-                break;
-        }
-    } else {
-        *needDstValue = true;
-    }
-}
-
-/**
- * Create a blend_coeff * value string to be used in shader code. Sets empty
- * string if result is trivially zero.
- */
-inline void blend_term_string(SkString* str, SkXfermode::Coeff coeff,
-                       const char* src, const char* dst,
-                       const char* value) {
-    switch (coeff) {
-    case SkXfermode::kZero_Coeff:    /** 0 */
-        *str = "";
-        break;
-    case SkXfermode::kOne_Coeff:     /** 1 */
-        *str = value;
-        break;
-    case SkXfermode::kSC_Coeff:
-        str->printf("(%s * %s)", src, value);
-        break;
-    case SkXfermode::kISC_Coeff:
-        str->printf("((%s - %s) * %s)", GrGLSLExpr<4>::onesStr(), src, value);
-        break;
-    case SkXfermode::kDC_Coeff:
-        str->printf("(%s * %s)", dst, value);
-        break;
-    case SkXfermode::kIDC_Coeff:
-        str->printf("((%s - %s) * %s)", GrGLSLExpr<4>::onesStr(), dst, value);
-        break;
-    case SkXfermode::kSA_Coeff:      /** src alpha */
-        str->printf("(%s.a * %s)", src, value);
-        break;
-    case SkXfermode::kISA_Coeff:     /** inverse src alpha (i.e. 1 - sa) */
-        str->printf("((1.0 - %s.a) * %s)", src, value);
-        break;
-    case SkXfermode::kDA_Coeff:      /** dst alpha */
-        str->printf("(%s.a * %s)", dst, value);
-        break;
-    case SkXfermode::kIDA_Coeff:     /** inverse dst alpha (i.e. 1 - da) */
-        str->printf("((1.0 - %s.a) * %s)", dst, value);
-        break;
-    default:
-        GrCrash("Unexpected xfer coeff.");
-        break;
-    }
-}
-/**
- * Adds a line to the fragment shader code which modifies the color by
- * the specified color filter.
- */
-void add_color_filter(GrGLShaderBuilder* builder,
-                      const char * outputVar,
-                      SkXfermode::Coeff uniformCoeff,
-                      SkXfermode::Coeff colorCoeff,
-                      const char* filterColor,
-                      const char* inColor) {
-    SkString colorStr, constStr;
-    blend_term_string(&colorStr, colorCoeff, filterColor, inColor, inColor);
-    blend_term_string(&constStr, uniformCoeff, filterColor, inColor, filterColor);
-    SkASSERT(!(colorStr.isEmpty() && constStr.isEmpty()));
-
-    GrGLSLExpr<4> result;
-    if (colorStr.isEmpty()) {
-        result = constStr;
-    } else if (constStr.isEmpty()) {
-        result = colorStr;
-    } else {
-        result = GrGLSLAddf<4,4>(colorStr, constStr);
-    }
-
-    builder->fsCodeAppendf("\t%s = %s;\n", outputVar, result.c_str());
-}
-}
-
 GrGLSLExpr<4> GrGLProgram::genInputColor(GrGLShaderBuilder* builder) {
     switch (fDesc.getHeader().fColorInput) {
         case GrGLProgramDesc::kAttribute_ColorInput: {
             GrGLShaderBuilder::VertexBuilder* vertexBuilder = builder->getVertexBuilder();
             SkASSERT(NULL != vertexBuilder);
             vertexBuilder->addAttribute(kVec4f_GrSLType, COL_ATTR_NAME);
             const char *vsName, *fsName;
             vertexBuilder->addVarying(kVec4f_GrSLType, "Color", &vsName, &fsName);
             vertexBuilder->vsCodeAppendf("\t%s = " COL_ATTR_NAME ";\n", vsName);
             return fsName;
@@ skipping 175 matching lines @@
     return true;
 }
 
 bool GrGLProgram::genProgram(const GrEffectStage* colorStages[],
                              const GrEffectStage* coverageStages[]) {
     SkASSERT(0 == fProgramID);
 
     const GrGLProgramDesc::KeyHeader& header = fDesc.getHeader();
     bool hasExplicitLocalCoords = -1 != header.fLocalCoordAttributeIndex;
 
-    // Get the coeffs for the Mode-based color filter, determine if color is needed.
-    SkXfermode::Coeff colorCoeff;
-    SkXfermode::Coeff filterColorCoeff;
-    SkAssertResult(
-        SkXfermode::ModeAsCoeff(static_cast<SkXfermode::Mode>(header.fColorFilterXfermode),
-                                &filterColorCoeff,
-                                &colorCoeff));
-    bool needColor, needFilterColor;
-    need_blend_inputs(filterColorCoeff, colorCoeff, &needFilterColor, &needColor);
-
     // Create the GL effects.
     bool hasVertexShaderEffects = false;
-
-    SkTArray<GrDrawEffect> colorDrawEffects(needColor ? fDesc.numColorEffects() : 0);
-    if (needColor) {
+    bool willUseInputColor = false;
+    SkTArray<GrDrawEffect> colorDrawEffects(fDesc.numColorEffects());
+    if (fDesc.numColorEffects() > 0) {
         this->buildGLEffects(&GrGLProgram::fColorEffects, colorStages, fDesc.numColorEffects(),
-                             hasExplicitLocalCoords, &colorDrawEffects, &hasVertexShaderEffects);
+                             hasExplicitLocalCoords, &colorDrawEffects, &hasVertexShaderEffects, &willUseInputColor);
     }
 
     SkTArray<GrDrawEffect> coverageDrawEffects(fDesc.numCoverageEffects());
     this->buildGLEffects(&GrGLProgram::fCoverageEffects, coverageStages, fDesc.numCoverageEffects(),
-                         hasExplicitLocalCoords, &coverageDrawEffects, &hasVertexShaderEffects);
+                         hasExplicitLocalCoords, &coverageDrawEffects, &hasVertexShaderEffects, &willUseInputColor);
 
     GrGLShaderBuilder builder(fGpu->ctxInfo(), fUniformManager, fDesc, hasVertexShaderEffects);
 
     if (GrGLShaderBuilder::VertexBuilder* vertexBuilder = builder.getVertexBuilder()) {
         const char* viewMName;
         fUniformHandles.fViewMatrixUni = builder.addUniform(GrGLShaderBuilder::kVertex_Visibility,
                                                             kMat33f_GrSLType, "ViewM", &viewMName);
 
         vertexBuilder->vsCodeAppendf("\tvec3 pos3 = %s * vec3(%s, 1);\n"
                                      "\tgl_Position = vec4(pos3.xy, 0, pos3.z);\n",
@@ skipping 15 matching lines @@
 
     GrGLShaderVar colorOutput;
     bool isColorDeclared = GrGLSLSetupFSColorOuput(fGpu->glslGeneration(),
                                                    declared_color_output_name(),
                                                    &colorOutput);
     if (isColorDeclared) {
         builder.fsOutputAppend(colorOutput);
     }
 
     // incoming color to current stage being processed.
-    GrGLSLExpr<4> inColor = this->genInputColor(&builder);
+    GrGLSLExpr<4> inColor;
+    if (willUseInputColor || (0 == fDesc.numColorEffects() && 0 == fDesc.numCoverageEffects())) {
+        inColor = this->genInputColor(&builder);
+    } else {
+        inColor = GrGLSLExpr<4>::Ones();
+    }
 
     // used in order for builder to return the per-stage uniform handles.
     typedef SkTArray<GrGLUniformManager::UniformHandle, true>* UniHandleArrayPtr;
     int maxColorOrCovEffectCnt = GrMax(fDesc.numColorEffects(), fDesc.numCoverageEffects());
     SkAutoTArray<UniHandleArrayPtr> effectUniformArrays(maxColorOrCovEffectCnt);
     SkAutoTArray<GrGLEffect*> glEffects(maxColorOrCovEffectCnt);
 
-    if (needColor) {
+    if (fDesc.numColorEffects()) {
         for (int e = 0; e < fDesc.numColorEffects(); ++e) {
             glEffects[e] = fColorEffects[e].fGLEffect;
             effectUniformArrays[e] = &fColorEffects[e].fSamplerUnis;
         }
 
         builder.emitEffects(glEffects.get(),
                             colorDrawEffects.begin(),
                             fDesc.effectKeys(),
                             fDesc.numColorEffects(),
                             &inColor,
                             effectUniformArrays.get());
     }
 
-    // Insert the color filter. This will soon be replaced by a color effect.
-    if (SkXfermode::kDst_Mode != header.fColorFilterXfermode) {
-        const char* colorFilterColorUniName = NULL;
-        fUniformHandles.fColorFilterUni = builder.addUniform(GrGLShaderBuilder::kFragment_Visibility,
-                                                             kVec4f_GrSLType, "FilterColor",
-                                                             &colorFilterColorUniName);
-
-        builder.fsCodeAppend("\tvec4 filteredColor;\n");
-
-        add_color_filter(&builder, "filteredColor", filterColorCoeff,
-                         colorCoeff, colorFilterColorUniName, inColor.c_str());
-        inColor = "filteredColor";
-    }
-
     ///////////////////////////////////////////////////////////////////////////
     // compute the partial coverage
     GrGLSLExpr<4> inCoverage = this->genInputCoverage(&builder);
 
     for (int e = 0; e < fDesc.numCoverageEffects(); ++e) {
         glEffects[e] = fCoverageEffects[e].fGLEffect;
         effectUniformArrays[e] = &fCoverageEffects[e].fSamplerUnis;
     }
 
     builder.emitEffects(glEffects.get(),
                         coverageDrawEffects.begin(),
                         fDesc.getEffectKeys() + fDesc.numColorEffects(),
                         fDesc.numCoverageEffects(),
                         &inCoverage,
                         effectUniformArrays.get());
 
+    if (!inColor.isValid()) {

[bsalomon, 2013/09/27 13:59:39]

What's this about?

+
+    }
+
     // discard if coverage is zero
     if (header.fDiscardIfZeroCoverage && !inCoverage.isOnes()) {
         if (inCoverage.isZeros()) {
             // This is unfortunate.
             builder.fsCodeAppend("\tdiscard;\n");
         } else {
             builder.fsCodeAppendf("\tif (all(lessThanEqual(%s, vec4(0.0)))) {\n\t\tdiscard;\n\t}\n",
                                   inCoverage.c_str());
         }
     }
@@ skipping 70 matching lines @@
     this->initSamplerUniforms();
 
     return true;
 }
 
 void GrGLProgram::buildGLEffects(SkTArray<EffectAndSamplers> GrGLProgram::* effectSet,
                                  const GrEffectStage* stages[],
                                  int count,
                                  bool hasExplicitLocalCoords,
                                  SkTArray<GrDrawEffect>* drawEffects,
-                                 bool* hasVertexShaderEffects) {
+                                 bool* hasVertexShaderEffects,
+                                 bool* willUseInputColor) {
     for (int e = 0; e < count; ++e) {
         SkASSERT(NULL != stages[e] && NULL != stages[e]->getEffect());
 
         const GrEffectStage& stage = *stages[e];
         SkNEW_APPEND_TO_TARRAY(drawEffects, GrDrawEffect, (stage, hasExplicitLocalCoords));
 
         const GrDrawEffect& drawEffect = (*drawEffects)[e];
         GrGLEffect* effect = (this->*effectSet)[e].fGLEffect =
             (*stage.getEffect())->getFactory().createGLInstance(drawEffect);
 
         if (!*hasVertexShaderEffects && effect->requiresVertexShader(drawEffect)) {
             *hasVertexShaderEffects = true;
         }
     }
+
+    if (count > 0 && (*stages[0]->getEffect())->getWillUseInputColor()) {
+        *willUseInputColor = true;
+    }
 }
 
 bool GrGLProgram::bindOutputsAttribsAndLinkProgram(const GrGLShaderBuilder& builder,
                                                    bool bindColorOut,
                                                    bool bindDualSrcOut) {
     GL_CALL_RET(fProgramID, CreateProgram());
     if (!fProgramID) {
         return false;
     }
 
@@ skipping 135 matching lines @@
         coverage = drawState.getCoverage();
     } else {
         color = drawState.getColor();
         coverage = drawState.getCoverage();
     }
 
     this->setColor(drawState, color, sharedState);
     this->setCoverage(drawState, coverage, sharedState);
     this->setMatrixAndRenderTargetHeight(drawState);
 
-    // Setup the SkXfermode::Mode-based colorfilter uniform if necessary
-    if (fUniformHandles.fColorFilterUni.isValid() &&
-        fColorFilterColor != drawState.getColorFilterColor()) {
-        GrGLfloat c[4];
-        GrColorToRGBAFloat(drawState.getColorFilterColor(), c);
-        fUniformManager.set4fv(fUniformHandles.fColorFilterUni, 0, 1, c);
-        fColorFilterColor = drawState.getColorFilterColor();
-    }
-
     if (NULL != dstCopy) {
         if (fUniformHandles.fDstCopyTopLeftUni.isValid()) {
             fUniformManager.set2f(fUniformHandles.fDstCopyTopLeftUni,
                                   static_cast<GrGLfloat>(dstCopy->offset().fX),
                                   static_cast<GrGLfloat>(dstCopy->offset().fY));
             fUniformManager.set2f(fUniformHandles.fDstCopyScaleUni,
                                   1.f / dstCopy->texture()->width(),
                                   1.f / dstCopy->texture()->height());
             GrGLTexture* texture = static_cast<GrGLTexture*>(dstCopy->texture());
             static GrTextureParams kParams; // the default is clamp, nearest filtering.
             fGpu->bindTexture(fDstCopyTexUnit, kParams, texture);
         } else {
             SkASSERT(!fUniformHandles.fDstCopyScaleUni.isValid());
             SkASSERT(!fUniformHandles.fDstCopySamplerUni.isValid());
         }
     } else {
         SkASSERT(!fUniformHandles.fDstCopyTopLeftUni.isValid());
         SkASSERT(!fUniformHandles.fDstCopyScaleUni.isValid());
         SkASSERT(!fUniformHandles.fDstCopySamplerUni.isValid());
     }
 
     for (int e = 0; e < fColorEffects.count(); ++e) {
-        // We may have omitted the GrGLEffect because of the color filter logic in genProgram.
-        // This can be removed when the color filter is an effect.
-        if (NULL != fColorEffects[e].fGLEffect) {
-            this->setEffectData(*colorStages[e], fColorEffects[e]);
-        }
+        SkASSERT(NULL != fColorEffects[e].fGLEffect);
+        this->setEffectData(*colorStages[e], fColorEffects[e]);
     }
 
     for (int e = 0; e < fCoverageEffects.count(); ++e) {
-        if (NULL != fCoverageEffects[e].fGLEffect) {
-            this->setEffectData(*coverageStages[e], fCoverageEffects[e]);
-        }
+        SkASSERT(NULL != fCoverageEffects[e].fGLEffect);
+        this->setEffectData(*coverageStages[e], fCoverageEffects[e]);
     }
 }
 
 void GrGLProgram::setColor(const GrDrawState& drawState,
                            GrColor color,
                            SharedGLState* sharedState) {
     const GrGLProgramDesc::KeyHeader& header = fDesc.getHeader();
     if (!drawState.hasColorVertexAttribute()) {
         switch (header.fColorInput) {
             case GrGLProgramDesc::kAttribute_ColorInput:
                 SkASSERT(-1 != header.fColorAttributeIndex);
                 if (sharedState->fConstAttribColor != color ||
                     sharedState->fConstAttribColorIndex != header.fColorAttributeIndex) {
                     // OpenGL ES only supports the float varieties of glVertexAttrib
                     GrGLfloat c[4];
                     GrColorToRGBAFloat(color, c);
                     GL_CALL(VertexAttrib4fv(header.fColorAttributeIndex, c));
                     sharedState->fConstAttribColor = color;
                     sharedState->fConstAttribColorIndex = header.fColorAttributeIndex;
                 }
                 break;
             case GrGLProgramDesc::kUniform_ColorInput:
-                if (fColor != color) {
+                if (fColor != color && fUniformHandles.fColorUni.isValid()) {
                     // OpenGL ES doesn't support unsigned byte varieties of glUniform
                     GrGLfloat c[4];
                     GrColorToRGBAFloat(color, c);
                     fUniformManager.set4fv(fUniformHandles.fColorUni, 0, 1, c);
                     fColor = color;
                 }
                 sharedState->fConstAttribColorIndex = -1;
                 break;
             case GrGLProgramDesc::kSolidWhite_ColorInput:
             case GrGLProgramDesc::kTransBlack_ColorInput:
@@ skipping 63 matching lines @@
 
         fMatrixState.fViewMatrix = drawState.getViewMatrix();
         fMatrixState.fRenderTargetSize = size;
         fMatrixState.fRenderTargetOrigin = rt->origin();
 
         GrGLfloat viewMatrix[3 * 3];
         fMatrixState.getGLMatrix<3>(viewMatrix);
         fUniformManager.setMatrix3f(fUniformHandles.fViewMatrixUni, viewMatrix);
     }
 }