Fix 4444 on Vulkan devices who don't support RGBA_4444

tests/PackedConfigsTextureTest.cpp

Index: tests/PackedConfigsTextureTest.cpp
diff --git a/tests/PackedConfigsTextureTest.cpp b/tests/PackedConfigsTextureTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..89ca6acfcc9cdc211358e331254a7c208f84e875
--- /dev/null
+++ b/tests/PackedConfigsTextureTest.cpp
@@ -0,0 +1,144 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * This is a straightforward test of using packed pixel configs (4444, 565).
+ * This test will make sure that these RGBA_4444 and RGB_565 are always supported
+ * as valid texturing configs.
+ */
+
+#include "Test.h"
+
+#if SK_SUPPORT_GPU
+#include "GrContext.h"
+#include "GrTexture.h"
+
+static const int DEV_W = 10, DEV_H = 10;
+static const SkIRect DEV_RECT = SkIRect::MakeWH(DEV_W, DEV_H);
+static const uint8_t TOL = 0x4;
+
+static void check_component(skiatest::Reporter* reporter, uint8_t control, uint8_t test) {
+    uint8_t diff = 0;
+    if (control >= test) {
+        diff = control - test;
+    } else {
+        diff = test - control;
+    }
+    REPORTER_ASSERT(reporter, diff < TOL);
+}
+
+static uint8_t expand_value(uint8_t original, int sigBits) {
+    SkASSERT(sigBits >= 4);
+    uint8_t inSigBitShift = 8 - sigBits;
+    uint8_t duplBitShift = sigBits - inSigBitShift;
+    return (original << inSigBitShift) + (original >> duplBitShift);
+}
+
+static void check_4444(skiatest::Reporter* reporter,
+                       const SkTDArray<uint16_t>& controlData,
+                       const SkTDArray<uint32_t>& readBuffer) {
+    for (int j = 0; j < DEV_H; ++j) {
+        for (int i = 0; i < DEV_W; ++i) {
+            uint16_t control = controlData[i + j * DEV_H];
+            uint32_t test = readBuffer[i + j * DEV_H];
+
+            // Test alpha component
+            uint8_t ctrlComp = expand_value(control & 0xF, 4);
+            uint8_t testComp = GrColorUnpackA(test);
+            check_component(reporter, ctrlComp, testComp);
+
+            // Test blue component
+            ctrlComp = expand_value((control >> 4) & 0xF, 4);
+            testComp = GrColorUnpackB(test);
+            check_component(reporter, ctrlComp, testComp);
+
+            // Test green component
+            ctrlComp = expand_value((control >> 8) & 0xF, 4);
+            testComp = GrColorUnpackG(test);
+            check_component(reporter, ctrlComp, testComp);
+
+            // Test red component
+            ctrlComp = expand_value((control >> 12) & 0xF, 4);
+            testComp = GrColorUnpackR(test);
+            check_component(reporter, ctrlComp, testComp);
+        }
+    }
+}
+
+static void check_565(skiatest::Reporter* reporter,
+                      const SkTDArray<uint16_t>& controlData,
+                      const SkTDArray<GrColor>& readBuffer) {
+    for (int j = 0; j < DEV_H; ++j) {
+        for (int i = 0; i < DEV_W; ++i) {
+            uint16_t control = controlData[i + j * DEV_H];
+            GrColor test = readBuffer[i + j * DEV_H];
+            // Test blue component (5 bit control)
+            uint8_t ctrlComp = expand_value(control & 0x1F, 5);
+            uint8_t testComp = GrColorUnpackB(test);
+            check_component(reporter, ctrlComp, testComp);
+
+            // Test green component (6 bit control)
+            ctrlComp = expand_value((control >> 5) & 0x3F, 6);
+            testComp = GrColorUnpackG(test);
+            check_component(reporter, ctrlComp, testComp);
+
+            // Test red component (5 bit control)
+            ctrlComp = expand_value((control >> 11) & 0x1F, 5);
+            testComp = GrColorUnpackR(test);
+            check_component(reporter, ctrlComp, testComp);
+        }
+    }
+}
+
+template <typename T>
+void runTest(skiatest::Reporter* reporter, GrContext* context,
+             T val1, T val2, int arraySize, GrPixelConfig config) {
+    SkTDArray<T> controlPixelData;
+    // We will read back into an 8888 buffer since 565/4444 read backes aren't supported
+    SkTDArray<GrColor> readBuffer;
+    controlPixelData.setCount(arraySize);
+    readBuffer.setCount(arraySize);
+
+    for (int i = 0; i < arraySize; i += 2) {
+        controlPixelData[i] = val1;
+        controlPixelData[i + 1] = val2;
+    }
+
+    for (int origin = 0; origin < 2; ++origin) {
+        GrSurfaceDesc desc;
+        desc.fFlags = kNone_GrSurfaceFlags;
+        desc.fWidth = DEV_W;
+        desc.fHeight = DEV_H;
+        desc.fConfig = config;
+        desc.fOrigin = 0 == origin ?
+            kTopLeft_GrSurfaceOrigin : kBottomLeft_GrSurfaceOrigin;
+        SkAutoTUnref<GrTexture> fpTexture(context->textureProvider()->createTexture(
+            desc, SkBudgeted::kNo, controlPixelData.begin(), 0));
+        SkASSERT(fpTexture);
+        fpTexture->readPixels(0, 0, DEV_W, DEV_H, kRGBA_8888_GrPixelConfig, readBuffer.begin(), 0);
+        if (kRGBA_4444_GrPixelConfig == config) {
+            check_4444(reporter, controlPixelData, readBuffer);
+        } else {
+            SkASSERT(kRGB_565_GrPixelConfig == config);
+            check_565(reporter, controlPixelData, readBuffer);
+        }
+    }
+}
+
+static const int CONTROL_ARRAY_SIZE = DEV_W * DEV_H;
+
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(RGBA4444TextureTest, reporter, ctxInfo) {
+    runTest<uint16_t>(reporter, ctxInfo.grContext(), 0xFF00, 0xFA62,
+                      CONTROL_ARRAY_SIZE, kRGBA_4444_GrPixelConfig);
+}
+
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(RGB565TextureTest, reporter, ctxInfo) {
+    runTest<uint16_t>(reporter, ctxInfo.grContext(), 0xFF00, 0xFA62,
+                      CONTROL_ARRAY_SIZE, kRGB_565_GrPixelConfig);
+}
+
+#endif