// Copyright (c) 2013 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.
#ifndef CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_TRANSFORMER_MAC_H_
#define CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_TRANSFORMER_MAC_H_
#include <OpenGL/gl.h>
#include "base/basictypes.h"
#include "content/browser/renderer_host/compositing_iosurface_shader_programs_mac.h"
#include "ui/gfx/size.h"
namespace gfx {
class Rect;
} // namespace gfx
namespace content {
// Provides useful image filtering operations that are implemented efficiently
// using OpenGL shader programs.
//
// Note: All methods assume to be called within an active OpenGL context.
class CompositingIOSurfaceTransformer {
public:
// Construct a transformer that always uses the given parameters for texture
// bindings. |texture_target| is one of the valid enums to use with
// glBindTexture().
// |src_texture_needs_y_flip| is true when the |src_texture| argument to any
// of the methods below uses upside-down Y coordinates.
// |shader_program_cache| is not owned by this instance.
CompositingIOSurfaceTransformer(
GLenum texture_target, bool src_texture_needs_y_flip,
CompositingIOSurfaceShaderPrograms* shader_program_cache);
~CompositingIOSurfaceTransformer();
// Delete any references to currently-cached OpenGL objects. This must be
// called within the OpenGL context just before destruction.
void ReleaseCachedGLObjects();
// Resize using bilinear interpolation. Returns false on error. Otherwise,
// the |texture| argument will point to the result. Ownership of the returned
// |texture| remains with CompositingIOSurfaceTransformer (i.e., the caller
// must not delete this texture). The |texture| remains valid until the next
// call to ResizeBilinear() or ReleaseCachedGLObjects().
//
// If the src and dst sizes are identical, this becomes a simple copy into a
// new texture.
//
// Note: This implementation is faulty in that minifications by more than 2X
// will undergo aliasing.
bool ResizeBilinear(GLuint src_texture, const gfx::Rect& src_subrect,
const gfx::Size& dst_size, GLuint* texture);
// Color format conversion from RGB to planar YV12 (also known as YUV420).
//
// YV12 is effectively a twelve bit per pixel format consisting of a full-
// size y (luminance) plane and half-width, half-height u and v (blue and
// red chrominance) planes. This method will return three off-screen
// textures, one for each plane, via the output arguments |texture_y|,
// |texture_u|, and |texture_v|. While the textures are in GL_RGBA format,
// they should be interpreted as the appropriate single-byte, planar format
// after reading the pixel data. The output arguments |packed_y_size| and
// |packed_uv_size| follow from these special semantics: They represent the
// size of their corresponding texture, if it was to be treated like RGBA
// pixel data. That means their widths are in terms of "quads," where one
// quad contains 4 Y (or U or V) pixels.
//
// Ownership of the returned textures remains with
// CompositingIOSurfaceTransformer (i.e., the caller must not delete the
// textures). The textures remain valid until the next call to
// TransformRGBToYV12() or ReleaseCachedGLObjects().
//
// If |src_subrect|'s size does not match |dst_size|, the source will be
// bilinearly interpolated during conversion.
//
// Returns true if successful, and the caller is responsible for deleting the
// output textures.
bool TransformRGBToYV12(
GLuint src_texture, const gfx::Rect& src_subrect,
const gfx::Size& dst_size,
GLuint* texture_y, GLuint* texture_u, GLuint* texture_v,
gfx::Size* packed_y_size, gfx::Size* packed_uv_size);
private:
enum CachedTexture {
RGBA_OUTPUT = 0,
Y_PLANE_OUTPUT,
UUVV_INTERMEDIATE,
U_PLANE_OUTPUT,
V_PLANE_OUTPUT,
NUM_CACHED_TEXTURES
};
// If necessary, generate the texture and/or resize it to the given |size|.
void PrepareTexture(CachedTexture which, const gfx::Size& size);
// If necessary, generate a framebuffer object to be used as an intermediate
// destination for drawing.
void PrepareFramebuffer();
// Target to bind all input and output textures to (which defines the type of
// textures being created and read). Generally, this is
// GL_TEXTURE_RECTANGLE_ARB.
const GLenum texture_target_;
const bool src_texture_needs_y_flip_;
CompositingIOSurfaceShaderPrograms* const shader_program_cache_;
// Cached OpenGL objects.
GLuint textures_[NUM_CACHED_TEXTURES];
gfx::Size texture_sizes_[NUM_CACHED_TEXTURES];
GLuint frame_buffer_;
// Auto-detected and set once in the constructor.
bool system_supports_multiple_draw_buffers_;
DISALLOW_COPY_AND_ASSIGN(CompositingIOSurfaceTransformer);
};
} // namespace content
#endif // CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_TRANSFORMER_MAC_H_