Add RGB565 Texture readback support in gl_helper

content/common/gpu/client/gl_helper_unittest.cc

Index: content/common/gpu/client/gl_helper_unittest.cc
diff --git a/content/common/gpu/client/gl_helper_unittest.cc b/content/common/gpu/client/gl_helper_unittest.cc
index 974031f7b6732be0d457f74f5b4ca35516a79002..bfd538f9faca005cca461e88c1a9a235e12de04c 100644
--- a/content/common/gpu/client/gl_helper_unittest.cc
+++ b/content/common/gpu/client/gl_helper_unittest.cc
@@ -662,7 +662,8 @@ class GLHelperTest : public testing::Test {
     helper_->ReadbackTextureSync(
         dst_texture,
         gfx::Rect(0, 0, scaled_xsize, scaled_ysize),
-        static_cast<unsigned char*>(output_pixels.getPixels()));
+        static_cast<unsigned char*>(output_pixels.getPixels()),
+        SkBitmap::kARGB_8888_Config);
     if (flip) {
       // Flip the pixels back.
       FlipSKBitmap(&output_pixels);
@@ -841,6 +842,127 @@ class GLHelperTest : public testing::Test {
     }
   }
 
+  bool ColorComponentsClose(SkColor component1,
+                            SkColor component2,
+                            SkBitmap::Config config) {
+    int c1 = static_cast<int>(component1);
+    int c2 = static_cast<int>(component2);
+    bool result = false;
+    switch (config) {
+      case SkBitmap::kARGB_8888_Config:
+        result = (std::abs(c1 - c2) == 0);
+        break;
+      case SkBitmap::kRGB_565_Config:
+        result = (std::abs(c1 - c2) <= 7);
+        break;
+      default:
+        break;
+    }
+    return result;
+  }
+
+  bool ColorsClose(SkColor color1, SkColor color2, SkBitmap::Config config) {
+    bool red = ColorComponentsClose(SkColorGetR(color1),
+                                    SkColorGetR(color2), config);
+    bool green = ColorComponentsClose(SkColorGetG(color1),
+                                        SkColorGetG(color2), config);
+    bool blue = ColorComponentsClose(SkColorGetB(color1),
+                                     SkColorGetB(color2), config);
+    bool alpha = ColorComponentsClose(SkColorGetA(color1),
+                                      SkColorGetA(color2), config);
+    if (config == SkBitmap::kRGB_565_Config) {
+      return red && blue && green;
+    }
+    return red && blue && green && alpha;
+  }
+
+  bool IsEqual(const SkBitmap& bmp1, const SkBitmap& bmp2) {
+    if (bmp1.isNull() && bmp2.isNull())
+      return true;
+    if (bmp1.width() != bmp2.width() ||
+        bmp1.height() != bmp2.height()) {
+        LOG(ERROR) << "Bitmap geometry check failure";
+        return false;
+    }
+    if (bmp1.getConfig() != bmp2.getConfig())
+      return false;
+
+    SkAutoLockPixels lock1(bmp1);
+    SkAutoLockPixels lock2(bmp2);
+    if (!bmp1.getPixels() || !bmp2.getPixels()) {
+      LOG(ERROR) << "Empty Bitmap!";
+      return false;
+    }
+    for (int y = 0; y < bmp1.height(); ++y) {
+      for (int x = 0; x < bmp1.width(); ++x) {
+        if (!ColorsClose(bmp1.getColor(x,y),
+                         bmp2.getColor(x,y),
+                         bmp1.getConfig())) {
+          LOG(ERROR) << "Bitmap color comparision failure";
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+
+  // Test basic format readback.
+  bool TestTextureFormatReadback(const gfx::Size& src_size,
+                         SkBitmap::Config bitmap_config) {
+    DCHECK((bitmap_config == SkBitmap::kRGB_565_Config) ||
+           (bitmap_config == SkBitmap::kARGB_8888_Config));
+    bool rgb565_format = (bitmap_config == SkBitmap::kRGB_565_Config);
+    if (rgb565_format && !helper_->CanUseRgb565Readback()) {
+      LOG(ERROR) << "RGB565 Format Not supported on this platform";
+      return false;
+    }
+    WebGLId src_texture = context_->createTexture();
+    SkBitmap input_pixels;
+    input_pixels.setConfig(bitmap_config, src_size.width(),
+                           src_size.height());
+    input_pixels.allocPixels();
+    SkAutoLockPixels lock1(input_pixels);
+    // Erase the input bitmap with red color.
+    input_pixels.eraseColor(SK_ColorRED);
+    context_->bindTexture(GL_TEXTURE_2D, src_texture);
+    GLenum format = (bitmap_config == SkBitmap::kRGB_565_Config) ?
+                    GL_RGB : GL_RGBA;
+    GLenum type = (bitmap_config == SkBitmap::kRGB_565_Config) ?
+                  GL_UNSIGNED_SHORT_5_6_5 : GL_UNSIGNED_BYTE;
+    context_->texImage2D(GL_TEXTURE_2D,
+                         0,
+                         format,
+                         src_size.width(),
+                         src_size.height(),
+                         0,
+                         format,
+                         type,
+                         input_pixels.getPixels());
+    SkBitmap output_pixels;
+    output_pixels.setConfig(bitmap_config, src_size.width(),
+                           src_size.height());
+    output_pixels.allocPixels();
+    SkAutoLockPixels lock2(output_pixels);
+    // Initialize the output bitmap with Green color.
+    // When the readback is over output bitmap should have the red color.
+    output_pixels.eraseColor(SK_ColorGREEN);
+    uint8* pixels = static_cast<uint8*>(output_pixels.getPixels());
+    helper_->ReadbackTextureSync(src_texture,
+                                 gfx::Rect(src_size),
+                                 pixels,
+                                 bitmap_config);
+    bool result = IsEqual(input_pixels, output_pixels);
+    if (!result) {
+      LOG(ERROR) << "Bitmap comparision failure";
+      return false;
+    }
+    context_->deleteTexture(src_texture);
+    if (HasFailure()) {
+      return false;
+    }
+    return true;
+  }
+
   // YUV readback test. Create a test pattern, convert to YUV
   // with reference implementation and compare to what gl_helper
   // returns.
@@ -1216,6 +1338,20 @@ class GLHelperTest : public testing::Test {
   std::deque<GLHelperScaling::ScaleOp> x_ops_, y_ops_;
 };
 
+TEST_F(GLHelperTest, RGBAReadBackTest) {
+  const int kTestSize = 64;
+  bool result = TestTextureFormatReadback(gfx::Size(kTestSize,kTestSize),
+                                          SkBitmap::kARGB_8888_Config);
+  EXPECT_EQ(result, true);
+}
+
+TEST_F(GLHelperTest, RGB565ReadBackTest) {
+  const int kTestSize = 64;
+  bool result = TestTextureFormatReadback(gfx::Size(kTestSize,kTestSize),
+                                          SkBitmap::kRGB_565_Config);
+  EXPECT_EQ(result, true);
+}
+
 TEST_F(GLHelperTest, YUVReadbackOptTest) {
   // This test uses the cb_command tracing events to detect how many
   // scaling passes are actually performed by the YUV readback pipeline.