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// 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 "base/logging.h"
#include "components/display_compositor/gl_helper_readback_support.h"
#include "gpu/GLES2/gl2extchromium.h"
#include "third_party/skia/include/core/SkImageInfo.h"
namespace display_compositor {
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;
display_compositor::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 display_compositor
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