Stop using mix() to implement hard-light in shader.

src/core/SkXfermode.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 "SkXfermode.h"
@@ skipping 1117 matching lines @@
             return drawEffect.castEffect<XferEffect>().mode();
         }
 
         virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE {}
 
     private:
         static void HardLight(GrGLShaderBuilder* builder,
                               const char* final,
                               const char* src,
                               const char* dst) {
-            builder->fsCodeAppendf("\t\t%s.rgb = mix(2.0 * %s.rgb * %s.rgb, ",
-                                   final, src, dst);
-            builder->fsCodeAppendf("%s.aaa * %s.aaa - 2.0 * (%s.aaa - %s.rgb) * (%s.aaa - %s.rgb),",
-                                   src, dst, dst, dst, src, src);
-            builder->fsCodeAppendf("vec3(greaterThan(2.0 * %s.rgb, %s.aaa)));\n",
-                                   src, src);
+            static const char kComponents[] = {'r', 'g', 'b'};
+            for (size_t i = 0; i < SK_ARRAY_COUNT(kComponents); ++i) {
+                char component = kComponents[i];
+                builder->fsCodeAppendf("\t\tif (2.0 * %s.%c <= %s.a) {\n", src, component, src);
+                builder->fsCodeAppendf("\t\t\t%s.%c = 2.0 * %s.%c * %s.%c;\n", final, component, src, component, dst, component);
+                builder->fsCodeAppend("\t\t} else {\n");
+                builder->fsCodeAppendf("\t\t\t%s.%c = %s.a * %s.a - 2.0 * (%s.a - %s.%c) * (%s.a - %s.%c);\n",
+                                       final, component, src, dst, dst, dst, component, src, src, component);
+                builder->fsCodeAppend("\t\t}\n");
+            }
             builder->fsCodeAppendf("\t\t%s.rgb += %s.rgb * (1.0 - %s.a) + %s.rgb * (1.0 - %s.a);\n",
                                    final, src, dst, dst, src);
         }
 
         // Does one component of color-dodge
         static void ColorDodgeComponent(GrGLShaderBuilder* builder,
                                         const char* final,
                                         const char* src,
                                         const char* dst,
                                         const char component) {
@@ skipping 205 matching lines @@
     SkXfermode::Mode fMode;
 
     typedef GrEffect INHERITED;
 };
 
 GR_DEFINE_EFFECT_TEST(XferEffect);
 GrEffectRef* XferEffect::TestCreate(SkMWCRandom* rand,
                                     GrContext*,
                                     const GrDrawTargetCaps&,
                                     GrTexture*[]) {
-    int mode;
-    do {
-        mode = rand->nextRangeU(SkXfermode::kLastCoeffMode + 1, SkXfermode::kLastSeparableMode);
-    } while (mode == SkXfermode::kHardLight_Mode);
+    int mode = rand->nextRangeU(SkXfermode::kLastCoeffMode + 1, SkXfermode::kLastSeparableMode);
 
     static AutoEffectUnref gEffect(SkNEW_ARGS(XferEffect, (static_cast<SkXfermode::Mode>(mode))));
     return CreateEffectRef(gEffect);
 }
 
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////
 
@@ skipping 585 matching lines @@
     return proc16;
 }
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkProcCoeffXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkClearXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSrcXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDstInXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDstOutXfermode)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END