Revert of Introduce components/display_compositor

content/browser/compositor/gl_helper_readback_support.cc

Index: content/browser/compositor/gl_helper_readback_support.cc
diff --git a/content/browser/compositor/gl_helper_readback_support.cc b/content/browser/compositor/gl_helper_readback_support.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c389eda6ba543bf7882d76a8ef626e58b81e95c8
--- /dev/null
+++ b/content/browser/compositor/gl_helper_readback_support.cc
@@ -0,0 +1,172 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/compositor/gl_helper_readback_support.h"
+#include "base/logging.h"
+#include "gpu/GLES2/gl2extchromium.h"
+#include "third_party/skia/include/core/SkImageInfo.h"
+
+namespace content {
+
+GLHelperReadbackSupport::GLHelperReadbackSupport(gpu::gles2::GLES2Interface* gl)
+    : gl_(gl) {
+  InitializeReadbackSupport();
+}
+
+GLHelperReadbackSupport::~GLHelperReadbackSupport() {}
+
+void GLHelperReadbackSupport::InitializeReadbackSupport() {
+  // We are concerned about 16, 32-bit formats only.  The below are the most
+  // used 16, 32-bit formats.  In future if any new format support is needed
+  // that should be added here.  Initialize the array with
+  // GLHelperReadbackSupport::NOT_SUPPORTED as we dont know the supported
+  // formats yet.
+  for (int i = 0; i <= kLastEnum_SkColorType; ++i) {
+    format_support_table_[i] = GLHelperReadbackSupport::NOT_SUPPORTED;
+  }
+  // TODO(sikugu): kAlpha_8_SkColorType support check is failing on mesa.
+  // See crbug.com/415667.
+  CheckForReadbackSupport(kRGB_565_SkColorType);
+  CheckForReadbackSupport(kARGB_4444_SkColorType);
+  CheckForReadbackSupport(kRGBA_8888_SkColorType);
+  CheckForReadbackSupport(kBGRA_8888_SkColorType);
+  // Further any formats, support should be checked here.
+}
+
+void GLHelperReadbackSupport::CheckForReadbackSupport(
+    SkColorType texture_format) {
+  bool supports_format = false;
+  switch (texture_format) {
+    case kRGB_565_SkColorType:
+      supports_format = SupportsFormat(GL_RGB, GL_UNSIGNED_SHORT_5_6_5);
+      break;
+    case kRGBA_8888_SkColorType:
+      // This is the baseline, assume always true.
+      supports_format = true;
+      break;
+    case kBGRA_8888_SkColorType:
+      supports_format = SupportsFormat(GL_BGRA_EXT, GL_UNSIGNED_BYTE);
+      break;
+    case kARGB_4444_SkColorType:
+      supports_format = false;
+      break;
+    default:
+      NOTREACHED();
+      supports_format = false;
+      break;
+  }
+  DCHECK((int)texture_format <= (int)kLastEnum_SkColorType);
+  format_support_table_[texture_format] =
+      supports_format ? GLHelperReadbackSupport::SUPPORTED
+                      : GLHelperReadbackSupport::NOT_SUPPORTED;
+}
+
+void GLHelperReadbackSupport::GetAdditionalFormat(GLenum format,
+                                                  GLenum type,
+                                                  GLenum* format_out,
+                                                  GLenum* type_out) {
+  for (unsigned int i = 0; i < format_cache_.size(); i++) {
+    if (format_cache_[i].format == format && format_cache_[i].type == type) {
+      *format_out = format_cache_[i].read_format;
+      *type_out = format_cache_[i].read_type;
+      return;
+    }
+  }
+
+  const int kTestSize = 64;
+  content::ScopedTexture dst_texture(gl_);
+  ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, dst_texture);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  gl_->TexImage2D(GL_TEXTURE_2D, 0, format, kTestSize, kTestSize, 0, format,
+                  type, NULL);
+  ScopedFramebuffer dst_framebuffer(gl_);
+  ScopedFramebufferBinder<GL_FRAMEBUFFER> framebuffer_binder(gl_,
+                                                             dst_framebuffer);
+  gl_->FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                            dst_texture, 0);
+  GLint format_tmp = 0, type_tmp = 0;
+  gl_->GetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT, &format_tmp);
+  gl_->GetIntegerv(GL_IMPLEMENTATION_COLOR_READ_TYPE, &type_tmp);
+  *format_out = format_tmp;
+  *type_out = type_tmp;
+
+  struct FormatCacheEntry entry = {format, type, *format_out, *type_out};
+  format_cache_.push_back(entry);
+}
+
+bool GLHelperReadbackSupport::SupportsFormat(GLenum format, GLenum type) {
+  // GLES2.0 Specification says this pairing is always supported
+  // with additional format from GL_IMPLEMENTATION_COLOR_READ_FORMAT/TYPE
+  if (format == GL_RGBA && type == GL_UNSIGNED_BYTE)
+    return true;
+
+  bool supports_format = false;
+  GLenum ext_format = 0, ext_type = 0;
+  GetAdditionalFormat(format, type, &ext_format, &ext_type);
+  if ((ext_format == format) && (ext_type == type)) {
+    supports_format = true;
+  }
+  return supports_format;
+}
+
+GLHelperReadbackSupport::FormatSupport
+GLHelperReadbackSupport::GetReadbackConfig(SkColorType color_type,
+                                           bool can_swizzle,
+                                           GLenum* format,
+                                           GLenum* type,
+                                           size_t* bytes_per_pixel) {
+  DCHECK(format && type && bytes_per_pixel);
+  *bytes_per_pixel = 4;
+  *type = GL_UNSIGNED_BYTE;
+  GLenum new_format = 0, new_type = 0;
+  switch (color_type) {
+    case kRGB_565_SkColorType:
+      if (format_support_table_[color_type] ==
+          GLHelperReadbackSupport::SUPPORTED) {
+        *format = GL_RGB;
+        *type = GL_UNSIGNED_SHORT_5_6_5;
+        *bytes_per_pixel = 2;
+        return GLHelperReadbackSupport::SUPPORTED;
+      }
+      break;
+    case kRGBA_8888_SkColorType:
+      *format = GL_RGBA;
+      if (can_swizzle) {
+        // If GL_BGRA_EXT is advertised as the readback format through
+        // GL_IMPLEMENTATION_COLOR_READ_FORMAT then assume it is preferred by
+        // the implementation for performance.
+        GetAdditionalFormat(*format, *type, &new_format, &new_type);
+
+        if (new_format == GL_BGRA_EXT && new_type == GL_UNSIGNED_BYTE) {
+          *format = GL_BGRA_EXT;
+          return GLHelperReadbackSupport::SWIZZLE;
+        }
+      }
+      return GLHelperReadbackSupport::SUPPORTED;
+    case kBGRA_8888_SkColorType:
+      *format = GL_BGRA_EXT;
+      if (format_support_table_[color_type] ==
+          GLHelperReadbackSupport::SUPPORTED)
+        return GLHelperReadbackSupport::SUPPORTED;
+
+      if (can_swizzle) {
+        *format = GL_RGBA;
+        return GLHelperReadbackSupport::SWIZZLE;
+      }
+
+      break;
+    case kARGB_4444_SkColorType:
+      return GLHelperReadbackSupport::NOT_SUPPORTED;
+    default:
+      NOTREACHED();
+      break;
+  }
+
+  return GLHelperReadbackSupport::NOT_SUPPORTED;
+}
+
+}  // namespace content