Implement color filter as GrGLEffect

tests/GpuColorFilterTest.cpp

Index: tests/GpuColorFilterTest.cpp
diff --git a/tests/GpuColorFilterTest.cpp b/tests/GpuColorFilterTest.cpp
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+++ b/tests/GpuColorFilterTest.cpp
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+
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#if SK_SUPPORT_GPU
+
+#include "GrContext.h"
+#include "GrContextFactory.h"
+#include "GrEffect.h"
+#include "SkColorFilter.h"
+#include "Test.h"
+#include "SkGr.h"
+
+namespace {
+
+static GrColor filterColor(const GrColor& color, uint32_t flags)  {
+    uint32_t mask = 0;
+    if (flags & kR_GrColorComponentFlag) {
+        mask = 0xFF << GrColor_SHIFT_R;
+    }
+    if (flags & kG_GrColorComponentFlag) {
+        mask |= 0xFF << GrColor_SHIFT_G;
+    }
+    if (flags & kB_GrColorComponentFlag) {
+        mask |= 0xFF << GrColor_SHIFT_B;
+    }
+    if (flags & kA_GrColorComponentFlag) {
+        mask |= 0xFF << GrColor_SHIFT_A;
+    }
+    return color & mask;
+}
+
+static void test_getConstantColorComponents(skiatest::Reporter* reporter, GrContext* grContext) {
+    struct GetConstantComponentTestCase {
+        // "Shape drawn with"
+        uint32_t inputComponents; // "rgb of", "red of", "alpha of", ...
+        GrColor inputColor;       // "[color]"
+
+        SkColor filterColor;      // "with filter color [color]"
+        SkXfermode::Mode filterMode; // "in mode [mode]"
+
+        // "produces"
+        uint32_t outputComponents; // "rgb of", "red of", "alpha of", ...
+        GrColor outputColor;       // "[color]"
+    };
+
+    // Shorthands.
+    enum {
+        kR = kR_GrColorComponentFlag,
+        kG = kG_GrColorComponentFlag,
+        kB = kB_GrColorComponentFlag,
+        kA = kA_GrColorComponentFlag,
+        kRGB = kRGB_GrColorComponentFlags,
+        kRGBA = kRGBA_GrColorComponentFlags
+    };
+
+    // Note: below, SkColors are non-premultiplied, where as GrColors are premultiplied.
+
+    const SkColor c1 = SkColorSetARGB(200, 200, 200, 200);
+    const SkColor c2 = SkColorSetARGB(60, 60, 60, 60);
+    const GrColor gr_c1 = SkColor2GrColor(c1);
+    const GrColor gr_c2 = SkColor2GrColor(c2);
+
+    const GrColor gr_black = GrColorPackRGBA(0, 0, 0, 0);
+    const GrColor gr_white = GrColorPackRGBA(255, 255, 255, 255);
+    const GrColor gr_whiteTrans = GrColorPackRGBA(128, 128, 128, 128);
+
+    GetConstantComponentTestCase filterTests[] = {
+        // A color filtered with Clear produces black.
+        { kRGBA, gr_white, SK_ColorBLACK, SkXfermode::kClear_Mode, kRGBA, gr_black },
+        { kRGBA, gr_c1,    SK_ColorWHITE, SkXfermode::kClear_Mode, kRGBA, gr_black },
+        { kR,    gr_white, c1,            SkXfermode::kClear_Mode, kRGBA, gr_black },
+
+        // A color filtered with a color in mode Src, produces the filter color.
+        { kRGBA, gr_c2, c1, SkXfermode::kSrc_Mode, kRGBA, gr_c1 },
+        { kA,    gr_c1, c1, SkXfermode::kSrc_Mode, kRGBA, gr_c1 },
+
+        // A color filtered with SrcOver produces a color.
+        { kRGBA, gr_whiteTrans, SkColorSetARGB(128, 200, 200, 200), SkXfermode::kSrcOver_Mode, kRGBA, GrColorPackRGBA(164, 164, 164, 192)},
+        // An unknown color with known alpha filtered with SrcOver produces an unknown color with known alpha.
+        { kA   , gr_whiteTrans, SkColorSetARGB(128, 200, 200, 200), SkXfermode::kSrcOver_Mode, kA   , GrColorPackRGBA(0, 0, 0, 192)},
+        // A color with unknown alpha filtered with SrcOver produces a color with unknown alpha.
+        { kRGB , gr_whiteTrans, SkColorSetARGB(128, 200, 200, 200), SkXfermode::kSrcOver_Mode, kRGB, GrColorPackRGBA(164, 164, 164, 0)},
+
+        // A color filtered with DstOver produces a color.
+        { kRGBA, gr_whiteTrans, SkColorSetARGB(128, 200, 200, 200), SkXfermode::kDstOver_Mode, kRGBA, GrColorPackRGBA(178, 178, 178, 192)},
+        // An unknown color with known alpha filtered with DstOver produces an unknown color with known alpha.
+        { kA   , gr_whiteTrans, SkColorSetARGB(128, 200, 200, 200), SkXfermode::kDstOver_Mode, kA   , GrColorPackRGBA(0, 0, 0, 192)},
+        // A color with unknown alpha filtered with DstOver produces an unknown color.
+        { kRGB , gr_whiteTrans, SkColorSetARGB(128, 200, 200, 200), SkXfermode::kDstOver_Mode, 0    , gr_black},
+
+        // An unknown color with known alpha and red component filtered with Multiply produces an unknown color with known red and alpha.
+        { kR|kA , gr_whiteTrans, SkColorSetARGB(128, 200, 200, 200), SkXfermode::kModulate_Mode, kR|kA, GrColorPackRGBA(50, 0, 0, 64) }
+    };
+
+    for (size_t i = 0; i < SK_ARRAY_COUNT(filterTests); ++i) {
+        const GetConstantComponentTestCase& test = filterTests[i];
+        SkAutoTUnref<SkColorFilter> cf(SkColorFilter::CreateModeFilter(test.filterColor, test.filterMode));
+        SkAutoTUnref<GrEffectRef> grEffect(cf->asNewEffect(grContext));
+        GrColor color = test.inputColor;
+        uint32_t components = test.inputComponents;
+        grEffect->get()->getConstantColorComponents(&color, &components);
+
+        REPORTER_ASSERT(reporter, filterColor(color, components) == test.outputColor);
+        REPORTER_ASSERT(reporter, test.outputComponents == components);
+    }
+}
+
+static void TestGpuColorFilter(skiatest::Reporter* reporter, GrContextFactory* factory) {
+    for (int type = 0; type < GrContextFactory::kLastGLContextType; ++type) {
+        GrContextFactory::GLContextType glType = static_cast<GrContextFactory::GLContextType>(type);
+
+        GrContext* grContext = factory->get(glType);
+        if (NULL == grContext) {
+            continue;
+        }
+
+        test_getConstantColorComponents(reporter, grContext);
+    }
+}
+
+}
+
+#include "TestClassDef.h"
+DEFINE_GPUTESTCLASS("GpuColorFilter", TestGpuColorFilterClass, TestGpuColorFilter)
+
+#endif