Exact Ganesh Gradients for Special Cases

src/effects/gradients/SkGradientShader.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Sk4fLinearGradient.h"
 #include "SkGradientShaderPriv.h"
 #include "SkLinearGradient.h"
@@ skipping 210 matching lines @@
     desc.fPos = fOrigPos;
     desc.fCount = fColorCount;
     desc.fTileMode = fTileMode;
     desc.fGradFlags = fGradFlags;
 
     const SkMatrix& m = this->getLocalMatrix();
     desc.fLocalMatrix = m.isIdentity() ? nullptr : &m;
     desc.flatten(buffer);
 }
 
-SkGradientShaderBase::GpuColorType SkGradientShaderBase::getGpuColorType(SkColor colors[3]) const {
-    if (fColorCount <= 3) {
-        memcpy(colors, fOrigColors, fColorCount * sizeof(SkColor));
+static inline bool close_to_one_half(const SkFixed& val) {

[bsalomon, 2016/08/09 19:46:23]

I think we have something like SkScalarNearlyEqual

+    return SkScalarAbs(SkFixedToScalar(val) - SK_ScalarHalf) < SK_Scalar1 / 1000;
+}
+
+GrGradientEffect::ColorType GrGradientEffect::determineColorTypeAndNumHardStops(
+        const SkGradientShaderBase& shader) {
+#if GR_GL_USE_ACCURATE_HARD_STOP_GRADIENTS
+    if (shader.fOrigPos) {
+        if (4 == shader.fColorCount) {
+            if (SkScalarNearlyEqual(shader.fOrigPos[0], 0.0f) &&
+                SkScalarNearlyEqual(shader.fOrigPos[1], 0.5f) &&
+                SkScalarNearlyEqual(shader.fOrigPos[2], 0.5f) &&
+                SkScalarNearlyEqual(shader.fOrigPos[3], 1.0f)) {
+
+                return kHardStopCentered_ColorType;
+            }
+        } else if (3 == shader.fColorCount) {
+            if (SkScalarNearlyEqual(shader.fOrigPos[0], 0.0f) &&
+                SkScalarNearlyEqual(shader.fOrigPos[1], 0.0f) &&
+                SkScalarNearlyEqual(shader.fOrigPos[2], 1.0f)) {
+
+                return kHardStopLeftEdged_ColorType;
+            } else if (SkScalarNearlyEqual(shader.fOrigPos[0], 0.0f) &&
+                       SkScalarNearlyEqual(shader.fOrigPos[1], 1.0f) &&
+                       SkScalarNearlyEqual(shader.fOrigPos[2], 1.0f)) {
+                
+                return kHardStopRightEdged_ColorType;
+            }
+        }
+    }
+#endif
+
+    if (SkShader::kClamp_TileMode == shader.getTileMode()) {
+        if (2 == shader.fColorCount) {
+            return kTwo_ColorType;
+        } else if (3 == shader.fColorCount &&
+                   close_to_one_half(shader.getRecs()[1].fPos)) {
+            return kThree_ColorType;
+        }
     }
 
-    if (SkShader::kClamp_TileMode == fTileMode) {
-        if (2 == fColorCount) {
-            return kTwo_GpuColorType;
-        } else if (3 == fColorCount &&
-                   (SkScalarAbs(
-                    SkFixedToScalar(fRecs[1].fPos) - SK_ScalarHalf) < SK_Scalar1 / 1000)) {
-            return kThree_GpuColorType;
-        }
-    }
-    return kTexture_GpuColorType;
+    return kTexture_ColorType;
 }
 
 void SkGradientShaderBase::FlipGradientColors(SkColor* colorDst, Rec* recDst,
                                               SkColor* colorSrc, Rec* recSrc,
                                               int count) {
     SkAutoSTArray<8, SkColor> colorsTemp(count);
     for (int i = 0; i < count; ++i) {
         int offset = count - i - 1;
         colorsTemp[i] = colorSrc[offset];
     }
@@ skipping 648 matching lines @@
 
 #include "effects/GrTextureStripAtlas.h"
 #include "GrContext.h"
 #include "GrInvariantOutput.h"
 #include "gl/GrGLContext.h"
 #include "glsl/GrGLSLFragmentShaderBuilder.h"
 #include "glsl/GrGLSLProgramDataManager.h"
 #include "glsl/GrGLSLUniformHandler.h"
 #include "SkGr.h"
 
-GrGradientEffect::GLSLProcessor::GLSLProcessor()
-    : fCachedYCoord(SK_ScalarMax) {
-}
-
 void GrGradientEffect::GLSLProcessor::emitUniforms(GrGLSLUniformHandler* uniformHandler,
                                                    const GrGradientEffect& ge) {
 
-    if (SkGradientShaderBase::kTwo_GpuColorType == ge.getColorType()) { // 2 Color case
-        fColorStartUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
-                                                    kVec4f_GrSLType, kDefault_GrSLPrecision,
-                                                    "GradientStartColor");
-        fColorEndUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
-                                                  kVec4f_GrSLType, kDefault_GrSLPrecision,
-                                                  "GradientEndColor");
+    switch (ge.getColorType()) {
+#if GR_GL_USE_ACCURATE_HARD_STOP_GRADIENTS
+        case GrGradientEffect::kHardStopCentered_ColorType:

[bsalomon, 2016/08/09 19:46:23]

Any reason to now always use a uniform array for colors (expect in the texture
case)? Could have a function that converts the ColorType enum to a color count
and much of the code could be unified.

+        case GrGradientEffect::kHardStopLeftEdged_ColorType:
+        case GrGradientEffect::kHardStopRightEdged_ColorType:
+            fColorsUni = uniformHandler->addUniformArray(kFragment_GrShaderFlag,
+                                                         kVec4f_GrSLType,
+                                                         kDefault_GrSLPrecision,
+                                                         "Colors",
+                                                         kHardStopCentered_ColorType == ge.getColorType() ? 4 : 3);
 
-    } else if (SkGradientShaderBase::kThree_GpuColorType == ge.getColorType()) { // 3 Color Case
-        fColorStartUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
-                                                    kVec4f_GrSLType,  kDefault_GrSLPrecision,
-                                                    "GradientStartColor");
-        fColorMidUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
-                                                  kVec4f_GrSLType, kDefault_GrSLPrecision,
-                                                  "GradientMidColor");
-        fColorEndUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
-                                                  kVec4f_GrSLType, kDefault_GrSLPrecision,
-                                                  "GradientEndColor");
+            break;
+#endif
+        case GrGradientEffect::kTwo_ColorType:
+            fColorStartUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
+                                                        kVec4f_GrSLType,
+                                                        kDefault_GrSLPrecision,
+                                                        "GradientStartColor");
+            fColorEndUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
+                                                      kVec4f_GrSLType,
+                                                      kDefault_GrSLPrecision,
+                                                      "GradientEndColor");
 
-    } else { // if not a fast case
-        fFSYUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
-                                             kFloat_GrSLType, kDefault_GrSLPrecision,
-                                             "GradientYCoordFS");
+            break;
+
+        case GrGradientEffect::kThree_ColorType:
+            fColorStartUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
+                                                        kVec4f_GrSLType,
+                                                        kDefault_GrSLPrecision,
+                                                        "GradientStartColor");
+            fColorMidUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
+                                                      kVec4f_GrSLType,
+                                                      kDefault_GrSLPrecision,
+                                                      "GradientMidColor");
+            fColorEndUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
+                                                      kVec4f_GrSLType,
+                                                      kDefault_GrSLPrecision,
+                                                      "GradientEndColor");
+
+            break;
+
+        case GrGradientEffect::kTexture_ColorType:
+            fFSYUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
+                                                 kFloat_GrSLType, kDefault_GrSLPrecision,
+                                                 "GradientYCoordFS");
+
+            break;
     }
 }
 
-static inline void set_color_uni(const GrGLSLProgramDataManager& pdman,
+static inline void set_after_interp_color_uni(const GrGLSLProgramDataManager& pdman,
                                  const GrGLSLProgramDataManager::UniformHandle uni,
                                  const SkColor* color) {
        pdman.set4f(uni,
                    SkColorGetR(*color) / 255.f,
                    SkColorGetG(*color) / 255.f,
                    SkColorGetB(*color) / 255.f,
                    SkColorGetA(*color) / 255.f);
 }
 
-static inline void set_mul_color_uni(const GrGLSLProgramDataManager& pdman,
-                                     const GrGLSLProgramDataManager::UniformHandle uni,
-                                     const SkColor* color){
+static inline void set_before_interp_color_uni(const GrGLSLProgramDataManager& pdman,
+                                        const GrGLSLProgramDataManager::UniformHandle uni,
+                                        const SkColor* color){
        float a = SkColorGetA(*color) / 255.f;
        float aDiv255 = a / 255.f;
        pdman.set4f(uni,
                    SkColorGetR(*color) * aDiv255,
                    SkColorGetG(*color) * aDiv255,
                    SkColorGetB(*color) * aDiv255,
                    a);
 }
 
+static inline void set_after_interp_color_uni_array(const GrGLSLProgramDataManager& pdman,
+                                       const GrGLSLProgramDataManager::UniformHandle uni,
+                                       const SkTDArray<SkColor>& colors) {
+    int count = colors.count();
+    constexpr int kSmallCount = 10;
+
+    SkAutoSTArray<4*kSmallCount, float> vals(4*count);
+
+    for (int i = 0; i < colors.count(); i++) {
+        // RGBA
+        vals[4*i + 0] = SkColorGetR(colors[i]) / 255.f;
+        vals[4*i + 1] = SkColorGetG(colors[i]) / 255.f;
+        vals[4*i + 2] = SkColorGetB(colors[i]) / 255.f;
+        vals[4*i + 3] = SkColorGetA(colors[i]) / 255.f;
+    }
+
+    pdman.set4fv(uni, colors.count(), vals.get());
+}
+
+static inline void set_before_interp_color_uni_array(const GrGLSLProgramDataManager& pdman,
+                                              const GrGLSLProgramDataManager::UniformHandle uni,
+                                              const SkTDArray<SkColor>& colors) {
+    int count = colors.count();
+    constexpr int kSmallCount = 10;
+
+    SkAutoSTArray<4*kSmallCount, float> vals(4*count);
+
+    for (int i = 0; i < count; i++) {
+        float a = SkColorGetA(colors[i]) / 255.f;
+        float aDiv255 = a / 255.f;
+
+        // RGBA
+        vals[4*i + 0] = SkColorGetR(colors[i]) * aDiv255;
+        vals[4*i + 1] = SkColorGetG(colors[i]) * aDiv255;
+        vals[4*i + 2] = SkColorGetB(colors[i]) * aDiv255;
+        vals[4*i + 3] = a;
+    }
+
+    pdman.set4fv(uni, count, vals.get());
+}
+
 void GrGradientEffect::GLSLProcessor::onSetData(const GrGLSLProgramDataManager& pdman,
                                                 const GrProcessor& processor) {
-
     const GrGradientEffect& e = processor.cast<GrGradientEffect>();
 
+    switch (e.getColorType()) {
+#if GR_GL_USE_ACCURATE_HARD_STOP_GRADIENTS
+        case GrGradientEffect::kHardStopCentered_ColorType:
+        case GrGradientEffect::kHardStopLeftEdged_ColorType:
+        case GrGradientEffect::kHardStopRightEdged_ColorType: {
+            if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
+                set_before_interp_color_uni_array(pdman, fColorsUni, e.fAllColors);
+            } else {
+                set_after_interp_color_uni_array(pdman, fColorsUni, e.fAllColors);
+            }
 
-    if (SkGradientShaderBase::kTwo_GpuColorType == e.getColorType()){
-
-        if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
-            set_mul_color_uni(pdman, fColorStartUni, e.getColors(0));
-            set_mul_color_uni(pdman, fColorEndUni,   e.getColors(1));
-        } else {
-            set_color_uni(pdman, fColorStartUni, e.getColors(0));
-            set_color_uni(pdman, fColorEndUni,   e.getColors(1));
+            break;
+        }
+#endif
+        case GrGradientEffect::kTwo_ColorType: {
+            if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
+                set_before_interp_color_uni(pdman, fColorStartUni, e.getColors(0));
+                set_before_interp_color_uni(pdman, fColorEndUni, e.getColors(1));
+            } else {
+                set_after_interp_color_uni(pdman, fColorStartUni, e.getColors(0));
+                set_after_interp_color_uni(pdman, fColorEndUni, e.getColors(1));
+            }
+            break;
         }
 
-    } else if (SkGradientShaderBase::kThree_GpuColorType == e.getColorType()){
+        case GrGradientEffect::kThree_ColorType: {
+            if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
+                set_before_interp_color_uni(pdman, fColorStartUni, e.getColors(0));
+                set_before_interp_color_uni(pdman, fColorMidUni, e.getColors(1));
+                set_before_interp_color_uni(pdman, fColorEndUni, e.getColors(2));
+            } else {
+                set_after_interp_color_uni(pdman, fColorStartUni, e.getColors(0));
+                set_after_interp_color_uni(pdman, fColorMidUni, e.getColors(1));
+                set_after_interp_color_uni(pdman, fColorEndUni, e.getColors(2));
+            }
+            break;
+        }
 
-        if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
-            set_mul_color_uni(pdman, fColorStartUni, e.getColors(0));
-            set_mul_color_uni(pdman, fColorMidUni,   e.getColors(1));
-            set_mul_color_uni(pdman, fColorEndUni,   e.getColors(2));
-        } else {
-            set_color_uni(pdman, fColorStartUni, e.getColors(0));
-            set_color_uni(pdman, fColorMidUni,   e.getColors(1));
-            set_color_uni(pdman, fColorEndUni,   e.getColors(2));
-        }
-    } else {
-
-        SkScalar yCoord = e.getYCoord();
-        if (yCoord != fCachedYCoord) {
-            pdman.set1f(fFSYUni, yCoord);
-            fCachedYCoord = yCoord;
+        case GrGradientEffect::kTexture_ColorType: {
+            SkScalar yCoord = e.getYCoord();
+            if (yCoord != fCachedYCoord) {
+                pdman.set1f(fFSYUni, yCoord);
+                fCachedYCoord = yCoord;
+            }
+            break;
         }
     }
 }
 
-
 uint32_t GrGradientEffect::GLSLProcessor::GenBaseGradientKey(const GrProcessor& processor) {
     const GrGradientEffect& e = processor.cast<GrGradientEffect>();
 
     uint32_t key = 0;
 
-    if (SkGradientShaderBase::kTwo_GpuColorType == e.getColorType()) {
-        key |= kTwoColorKey;
-    } else if (SkGradientShaderBase::kThree_GpuColorType == e.getColorType()) {
-        key |= kThreeColorKey;
-    }
-
     if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
         key |= kPremulBeforeInterpKey;
     }
 
+    if (GrGradientEffect::kTwo_ColorType == e.getColorType()) {
+        key |= kTwoColorKey;
+    } else if (GrGradientEffect::kThree_ColorType == e.getColorType()) {
+        key |= kThreeColorKey;
+    }
+#if GR_GL_USE_ACCURATE_HARD_STOP_GRADIENTS
+    else if (GrGradientEffect::kHardStopCentered_ColorType == e.getColorType()) {
+        key |= kHardStopCenteredKey;
+    } else if (GrGradientEffect::kHardStopLeftEdged_ColorType == e.getColorType()) {
+        key |= kHardStopZeroZeroOneKey;
+    } else if (GrGradientEffect::kHardStopRightEdged_ColorType == e.getColorType()) {
+        key |= kHardStopZeroOneOneKey;
+    }
+   
+    if (SkShader::TileMode::kClamp_TileMode == e.fTileMode) {
+        key |= kClampTileMode;
+    } else if (SkShader::TileMode::kRepeat_TileMode == e.fTileMode) {
+        key |= kRepeatTileMode;
+    } else {
+        key |= kMirrorTileMode;
+    }
+#endif
+
     return key;
 }
 
 void GrGradientEffect::GLSLProcessor::emitColor(GrGLSLFPFragmentBuilder* fragBuilder,
                                                 GrGLSLUniformHandler* uniformHandler,
                                                 const GrGLSLCaps* glslCaps,
                                                 const GrGradientEffect& ge,
                                                 const char* gradientTValue,
                                                 const char* outputColor,
                                                 const char* inputColor,
                                                 const SamplerHandle* texSamplers) {
-    if (SkGradientShaderBase::kTwo_GpuColorType == ge.getColorType()){
-        fragBuilder->codeAppendf("\tvec4 colorTemp = mix(%s, %s, clamp(%s, 0.0, 1.0));\n",
-                                 uniformHandler->getUniformVariable(fColorStartUni).c_str(),
-                                 uniformHandler->getUniformVariable(fColorEndUni).c_str(),
-                                 gradientTValue);
-        // Note that we could skip this step if both colors are known to be opaque. Two
-        // considerations:
-        // The gradient SkShader reporting opaque is more restrictive than necessary in the two pt
-        // case. Make sure the key reflects this optimization (and note that it can use the same
-        // shader as thekBeforeIterp case). This same optimization applies to the 3 color case
-        // below.
-        if (GrGradientEffect::kAfterInterp_PremulType == ge.getPremulType()) {
-            fragBuilder->codeAppend("\tcolorTemp.rgb *= colorTemp.a;\n");
+    switch (ge.getColorType()) {
+#if GR_GL_USE_ACCURATE_HARD_STOP_GRADIENTS
+        case kHardStopCentered_ColorType: {
+            const char* t      = gradientTValue;
+            const char* colors = uniformHandler->getUniformCStr(fColorsUni);
+
+            fragBuilder->codeAppendf("float clamp_t = clamp(%s, 0.0, 1.0);", t);
+
+            // Account for tile mode
+            if (SkShader::kRepeat_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("clamp_t = fract(%s);", t);
+            } else if (SkShader::kMirror_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("if (%s < 0.0 || %s > 1.0) {", t, t);
+                fragBuilder->codeAppendf("    if (mod(floor(%s), 2.0) == 0.0) {", t);
+                fragBuilder->codeAppendf("        clamp_t = fract(%s);", t);
+                fragBuilder->codeAppendf("    } else {");
+                fragBuilder->codeAppendf("        clamp_t = 1.0 - fract(%s);", t);
+                fragBuilder->codeAppendf("    }");
+                fragBuilder->codeAppendf("}");
+            }
+
+            // Calculate color
+            fragBuilder->codeAppendf("float relative_t = fract(2.0 * clamp_t);");
+            if (SkShader::kClamp_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("relative_t += step(1.0, %s);", t);
+            }
+            fragBuilder->codeAppendf("vec4 colorTemp = mix(%s[0], %s[1], relative_t);", colors, colors);
+            fragBuilder->codeAppendf("if (clamp_t >= 0.5) {");
+            fragBuilder->codeAppendf("    colorTemp = mix(%s[2], %s[3], relative_t);", colors, colors);
+            fragBuilder->codeAppendf("}");
+
+            if (GrGradientEffect::kAfterInterp_PremulType == ge.getPremulType()) {
+                fragBuilder->codeAppend("colorTemp.rgb *= colorTemp.a;");
+            }
+            fragBuilder->codeAppendf("%s = %s;", outputColor, (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
+
+            break;
         }
 
-        fragBuilder->codeAppendf("\t%s = %s;\n", outputColor,
-                                 (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
-    } else if (SkGradientShaderBase::kThree_GpuColorType == ge.getColorType()) {
-        fragBuilder->codeAppendf("\tfloat oneMinus2t = 1.0 - (2.0 * (%s));\n",
-                                 gradientTValue);
-        fragBuilder->codeAppendf("\tvec4 colorTemp = clamp(oneMinus2t, 0.0, 1.0) * %s;\n",
-                                 uniformHandler->getUniformVariable(fColorStartUni).c_str());
-        if (!glslCaps->canUseMinAndAbsTogether()) {
-            // The Tegra3 compiler will sometimes never return if we have
-            // min(abs(oneMinus2t), 1.0), or do the abs first in a separate expression.
-            fragBuilder->codeAppend("\tfloat minAbs = abs(oneMinus2t);\n");
-            fragBuilder->codeAppend("\tminAbs = minAbs > 1.0 ? 1.0 : minAbs;\n");
-            fragBuilder->codeAppendf("\tcolorTemp += (1.0 - minAbs) * %s;\n",
-                                     uniformHandler->getUniformVariable(fColorMidUni).c_str());
-        } else {
-            fragBuilder->codeAppendf("\tcolorTemp += (1.0 - min(abs(oneMinus2t), 1.0)) * %s;\n",
-                                     uniformHandler->getUniformVariable(fColorMidUni).c_str());
-        }
-        fragBuilder->codeAppendf("\tcolorTemp += clamp(-oneMinus2t, 0.0, 1.0) * %s;\n",
-                                 uniformHandler->getUniformVariable(fColorEndUni).c_str());
-        if (GrGradientEffect::kAfterInterp_PremulType == ge.getPremulType()) {
-            fragBuilder->codeAppend("\tcolorTemp.rgb *= colorTemp.a;\n");
+        case kHardStopLeftEdged_ColorType: {
+            const char* t      = gradientTValue;
+            const char* colors = uniformHandler->getUniformCStr(fColorsUni);
+
+            fragBuilder->codeAppendf("float clamp_t = clamp(%s, 0.0, 1.0);", t);
+
+            // Account for tile mode
+            if (SkShader::kRepeat_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("clamp_t = fract(%s);", t);
+            } else if (SkShader::kMirror_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("if (%s < 0.0 || %s > 1.0) {", t, t);
+                fragBuilder->codeAppendf("    if (mod(floor(%s), 2.0) == 0.0) {", t);
+                fragBuilder->codeAppendf("        clamp_t = fract(%s);", t);
+                fragBuilder->codeAppendf("    } else {");
+                fragBuilder->codeAppendf("        clamp_t = 1.0 - fract(%s);", t);
+                fragBuilder->codeAppendf("    }");
+                fragBuilder->codeAppendf("}");
+            }
+
+            fragBuilder->codeAppendf("vec4 colorTemp = mix(%s[1], %s[2], clamp_t);", colors, colors);
+            if (SkShader::kClamp_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("if (%s < 0.0) {", t);
+                fragBuilder->codeAppendf("    colorTemp = %s[0];", colors);
+                fragBuilder->codeAppendf("}");
+            }
+
+            if (GrGradientEffect::kAfterInterp_PremulType == ge.getPremulType()) {
+                fragBuilder->codeAppend("colorTemp.rgb *= colorTemp.a;");
+            }
+            fragBuilder->codeAppendf("%s = %s;", outputColor, (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
+
+            break;
         }
 
-        fragBuilder->codeAppendf("\t%s = %s;\n", outputColor,
-                                 (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
-    } else {
-        fragBuilder->codeAppendf("\tvec2 coord = vec2(%s, %s);\n",
-                                 gradientTValue,
-                                 uniformHandler->getUniformVariable(fFSYUni).c_str());
-        fragBuilder->codeAppendf("\t%s = ", outputColor);
-        fragBuilder->appendTextureLookupAndModulate(inputColor,
-                                                    texSamplers[0],
-                                                    "coord");
-        fragBuilder->codeAppend(";\n");
+        case kHardStopRightEdged_ColorType: {
+            const char* t      = gradientTValue;
+            const char* colors = uniformHandler->getUniformCStr(fColorsUni);
+
+            fragBuilder->codeAppendf("float clamp_t = clamp(%s, 0.0, 1.0);", t);
+
+            // Account for tile mode
+            if (SkShader::kRepeat_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("clamp_t = fract(%s);", t);
+            } else if (SkShader::kMirror_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("if (%s < 0.0 || %s > 1.0) {", t, t);
+                fragBuilder->codeAppendf("    if (mod(floor(%s), 2.0) == 0.0) {", t);
+                fragBuilder->codeAppendf("        clamp_t = fract(%s);", t);
+                fragBuilder->codeAppendf("    } else {");
+                fragBuilder->codeAppendf("        clamp_t = 1.0 - fract(%s);", t);
+                fragBuilder->codeAppendf("    }");
+                fragBuilder->codeAppendf("}");
+            }
+
+            fragBuilder->codeAppendf("vec4 colorTemp = mix(%s[0], %s[1], clamp_t);", colors, colors);
+            if (SkShader::kClamp_TileMode == ge.fTileMode) {
+                fragBuilder->codeAppendf("if (%s > 1.0) {", t);
+                fragBuilder->codeAppendf("    colorTemp = %s[2];", colors);
+                fragBuilder->codeAppendf("}");
+            }
+
+            if (GrGradientEffect::kAfterInterp_PremulType == ge.getPremulType()) {
+                fragBuilder->codeAppend("colorTemp.rgb *= colorTemp.a;");
+            }
+            fragBuilder->codeAppendf("%s = %s;", outputColor, (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
+
+            break;
+        }
+#endif
+
+        case kTwo_ColorType: {
+            const char* t     = gradientTValue;
+            const char* start = uniformHandler->getUniformCStr(fColorStartUni);
+            const char* end   = uniformHandler->getUniformCStr(fColorEndUni);
+
+            fragBuilder->codeAppendf("vec4 colorTemp = mix(%s, %s, clamp(%s, 0.0, 1.0));", start, end, t);
+
+            // We could skip this step if both colors are known to be opaque. Two
+            // considerations:
+            // The gradient SkShader reporting opaque is more restrictive than necessary in the two pt
+            // case. Make sure the key reflects this optimization (and note that it can use the same
+            // shader as thekBeforeIterp case). This same optimization applies to the 3 color case
+            // below.
+            if (GrGradientEffect::kAfterInterp_PremulType == ge.getPremulType()) {
+                fragBuilder->codeAppend("colorTemp.rgb *= colorTemp.a;");
+            }
+
+            fragBuilder->codeAppendf("%s = %s;", outputColor, (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
+
+            break;
+        }
+
+        case kThree_ColorType: {
+            const char* t     = gradientTValue;
+            const char* start = uniformHandler->getUniformCStr(fColorStartUni);
+            const char* mid   = uniformHandler->getUniformCStr(fColorMidUni);
+            const char* end   = uniformHandler->getUniformCStr(fColorEndUni);
+
+            fragBuilder->codeAppendf("float oneMinus2t = 1.0 - (2.0 * %s);", t);
+            fragBuilder->codeAppendf("vec4 colorTemp = clamp(oneMinus2t, 0.0, 1.0) * %s;", start);
+            if (!glslCaps->canUseMinAndAbsTogether()) {
+                // The Tegra3 compiler will sometimes never return if we have
+                // min(abs(oneMinus2t), 1.0), or do the abs first in a separate expression.
+                fragBuilder->codeAppendf("float minAbs = abs(oneMinus2t);");
+                fragBuilder->codeAppendf("minAbs = minAbs > 1.0 ? 1.0 : minAbs;");
+                fragBuilder->codeAppendf("colorTemp += (1.0 - minAbs) * %s;", mid);
+            } else {
+                fragBuilder->codeAppendf("colorTemp += (1.0 - min(abs(oneMinus2t), 1.0)) * %s;", mid);
+            }
+            fragBuilder->codeAppendf("colorTemp += clamp(-oneMinus2t, 0.0, 1.0) * %s;", end);
+
+            if (GrGradientEffect::kAfterInterp_PremulType == ge.getPremulType()) {
+                fragBuilder->codeAppend("colorTemp.rgb *= colorTemp.a;");
+            }
+
+            fragBuilder->codeAppendf("%s = %s;", outputColor, (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
+
+            break;
+        }
+
+        case kTexture_ColorType: {
+            const char* fsyuni = uniformHandler->getUniformCStr(fFSYUni);
+
+            fragBuilder->codeAppendf("vec2 coord = vec2(%s, %s);", gradientTValue, fsyuni);
+            fragBuilder->codeAppendf("%s = ", outputColor);
+            fragBuilder->appendTextureLookupAndModulate(inputColor, texSamplers[0], "coord");
+            fragBuilder->codeAppend(";");
+
+            break;
+        }
     }
 }
 
 /////////////////////////////////////////////////////////////////////
 
 GrGradientEffect::GrGradientEffect(GrContext* ctx,
                                    const SkGradientShaderBase& shader,
                                    const SkMatrix& matrix,
                                    SkShader::TileMode tileMode) {
 
     fIsOpaque = shader.isOpaque();
 
-    fColorType = shader.getGpuColorType(&fColors[0]);
+    fColorType = this->determineColorTypeAndNumHardStops(shader);
 
-    // The two and three color specializations do not currently support tiling.
-    if (SkGradientShaderBase::kTwo_GpuColorType == fColorType ||
-        SkGradientShaderBase::kThree_GpuColorType == fColorType) {
-        fRow = -1;
+    if (kTexture_ColorType != fColorType) {
+        if (shader.fOrigColors) {
+            fAllColors.setReserve(shader.fColorCount);

[bsalomon, 2016/08/09 19:46:23]

Maybe just call this fColors?

+            fAllColors = SkTDArray<SkColor>(shader.fOrigColors, shader.fColorCount);

[bsalomon, 2016/08/09 19:46:23]

Does this do a move?

[fmenozzi, 2016/08/09 20:45:49]

I don't think so; the ctor for SkTDArray that takes an array and a count just
does a memcpy on the underlying data.

[bsalomon, 2016/08/10 13:18:35]

It looks like this will call SkTDArray<T>& operator=(SkTDArray<T>&& src) which
will move the right side into fAllColors by swapping the two arrays. So that is
good. However, that means that the allocation used by setReserved will be freed
when the temporary goes out of scope. So I think this would be more efficient if
the the setReserved calls are removed (save a call to malloc and free).

+        }
 
-        if (SkGradientShader::kInterpolateColorsInPremul_Flag & shader.getGradFlags()) {
+#if GR_GL_USE_ACCURATE_HARD_STOP_GRADIENTS
+        if (shader.fOrigPos) {
+            fPositions.setReserve(shader.fColorCount);
+            fPositions = SkTDArray<SkScalar>(shader.fOrigPos, shader.fColorCount);
+        }
+
+        fTileMode = tileMode;
+#endif
+    }
+
+    switch (fColorType) {
+        // The two and three color specializations do not currently support tiling.
+        case kTwo_ColorType:
+        case kThree_ColorType:
+#if GR_GL_USE_ACCURATE_HARD_STOP_GRADIENTS
+        case kHardStopLeftEdged_ColorType:
+        case kHardStopRightEdged_ColorType:
+        case kHardStopCentered_ColorType:
+#endif
+            fRow = -1;
+
+            if (SkGradientShader::kInterpolateColorsInPremul_Flag & shader.getGradFlags()) {
+                fPremulType = kBeforeInterp_PremulType;
+            } else {
+                fPremulType = kAfterInterp_PremulType;
+            }
+
+            fCoordTransform.reset(kCoordSet, matrix);
+
+            break;
+        case kTexture_ColorType:
+            // doesn't matter how this is set, just be consistent because it is part of the effect key.
             fPremulType = kBeforeInterp_PremulType;
-        } else {
-            fPremulType = kAfterInterp_PremulType;
-        }
-        fCoordTransform.reset(kCoordSet, matrix);
-    } else {
-        // doesn't matter how this is set, just be consistent because it is part of the effect key.
-        fPremulType = kBeforeInterp_PremulType;
-        SkBitmap bitmap;
-        shader.getGradientTableBitmap(&bitmap);
 
-        GrTextureStripAtlas::Desc desc;
-        desc.fWidth  = bitmap.width();
-        desc.fHeight = 32;
-        desc.fRowHeight = bitmap.height();
-        desc.fContext = ctx;
-        desc.fConfig = SkImageInfo2GrPixelConfig(bitmap.info(), *ctx->caps());
-        fAtlas = GrTextureStripAtlas::GetAtlas(desc);
-        SkASSERT(fAtlas);
+            SkBitmap bitmap;
+            shader.getGradientTableBitmap(&bitmap);
 
-        // We always filter the gradient table. Each table is one row of a texture, always y-clamp.
-        GrTextureParams params;
-        params.setFilterMode(GrTextureParams::kBilerp_FilterMode);
-        params.setTileModeX(tileMode);
+            GrTextureStripAtlas::Desc desc;
+            desc.fWidth  = bitmap.width();
+            desc.fHeight = 32;
+            desc.fRowHeight = bitmap.height();
+            desc.fContext = ctx;
+            desc.fConfig = SkImageInfo2GrPixelConfig(bitmap.info(), *ctx->caps());
+            fAtlas = GrTextureStripAtlas::GetAtlas(desc);
+            SkASSERT(fAtlas);
 
-        fRow = fAtlas->lockRow(bitmap);
-        if (-1 != fRow) {
-            fYCoord = fAtlas->getYOffset(fRow) + SK_ScalarHalf * fAtlas->getNormalizedTexelHeight();
-            fCoordTransform.reset(kCoordSet, matrix, fAtlas->getTexture(), params.filterMode());
-            fTextureAccess.reset(fAtlas->getTexture(), params);
-        } else {
-            SkAutoTUnref<GrTexture> texture(
-                GrRefCachedBitmapTexture(ctx, bitmap, params, SkSourceGammaTreatment::kRespect));
-            if (!texture) {
-                return;
+            // We always filter the gradient table. Each table is one row of a texture, always y-clamp.
+            GrTextureParams params;
+            params.setFilterMode(GrTextureParams::kBilerp_FilterMode);
+            params.setTileModeX(tileMode);
+
+            fRow = fAtlas->lockRow(bitmap);
+            if (-1 != fRow) {
+                fYCoord = fAtlas->getYOffset(fRow) + SK_ScalarHalf * fAtlas->getNormalizedTexelHeight();
+                fCoordTransform.reset(kCoordSet, matrix, fAtlas->getTexture(), params.filterMode());
+                fTextureAccess.reset(fAtlas->getTexture(), params);
+            } else {
+                SkAutoTUnref<GrTexture> texture(
+                    GrRefCachedBitmapTexture(ctx, bitmap, params, SkSourceGammaTreatment::kRespect));
+                if (!texture) {
+                    return;
+                }
+                fCoordTransform.reset(kCoordSet, matrix, texture, params.filterMode());
+                fTextureAccess.reset(texture, params);
+                fYCoord = SK_ScalarHalf;
             }
-            fCoordTransform.reset(kCoordSet, matrix, texture, params.filterMode());
-            fTextureAccess.reset(texture, params);
-            fYCoord = SK_ScalarHalf;
-        }
-        this->addTextureAccess(&fTextureAccess);
+
+            this->addTextureAccess(&fTextureAccess);
+
+            break;
     }
+
     this->addCoordTransform(&fCoordTransform);
 }
 
 GrGradientEffect::~GrGradientEffect() {
     if (this->useAtlas()) {
         fAtlas->unlockRow(fRow);
     }
 }
 
 bool GrGradientEffect::onIsEqual(const GrFragmentProcessor& processor) const {
-    const GrGradientEffect& s = processor.cast<GrGradientEffect>();
+    const GrGradientEffect& ge = processor.cast<GrGradientEffect>();
 
-    if (this->fColorType == s.getColorType()){
-
-        if (SkGradientShaderBase::kTwo_GpuColorType == fColorType) {
-            if (this->getPremulType() != s.getPremulType() ||
-                *this->getColors(0) != *s.getColors(0) ||
-                *this->getColors(1) != *s.getColors(1)) {
-                return false;
-            }
-        } else if (SkGradientShaderBase::kThree_GpuColorType == fColorType) {
-            if (this->getPremulType() != s.getPremulType() ||
-                *this->getColors(0) != *s.getColors(0) ||
-                *this->getColors(1) != *s.getColors(1) ||
-                *this->getColors(2) != *s.getColors(2)) {
+    if (this->fColorType == ge.getColorType()) {
+        if (kTexture_ColorType == fColorType) {
+            if (fYCoord != ge.getYCoord()) {
                 return false;
             }
         } else {
-            if (fYCoord != s.getYCoord()) {
+            if (this->getPremulType() != ge.getPremulType() ||
+                this->fAllColors.count() != ge.fAllColors.count()) {
                 return false;
             }
+
+            for (int i = 0; i < this->fAllColors.count(); i++) {
+                if (*this->getColors(i) != *ge.getColors(i)) {
+                    return false;
+                }
+            }
         }
 
-        SkASSERT(this->useAtlas() == s.useAtlas());
+        SkASSERT(this->useAtlas() == ge.useAtlas());
         return true;
     }
 
     return false;
 }
 
 void GrGradientEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
     if (fIsOpaque) {
         inout->mulByUnknownOpaqueFourComponents();
     } else {
@@ skipping 19 matching lines @@
             (*stops)[i] = stop;
             stop = i < outColors - 1 ? stop + random->nextUScalar1() * (1.f - stop) : 1.f;
         }
     }
     *tm = static_cast<SkShader::TileMode>(random->nextULessThan(SkShader::kTileModeCount));
 
     return outColors;
 }
 
 #endif