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// 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"
namespace gfx {
class Rect;
class Size;
} // 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(). |texture_unit| selects the texture unit to be used when
// running the shader programs (i.e., specify 0 for GL_TEXTURE0).
// |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, int texture_unit, bool src_texture_needs_y_flip,
CompositingIOSurfaceShaderPrograms* shader_program_cache);
~CompositingIOSurfaceTransformer();
// Resize using bilinear interpolation. Returns false on error. Otherwise,
// the |texture| argument will point to the result and the caller is
// responsible for calling glDeleteTexture(*texture).
//
// 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 allocate three off-screen
// textures, one for each plane, and return them 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.
//
// 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:
// 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 int texture_unit_;
const bool src_texture_needs_y_flip_;
CompositingIOSurfaceShaderPrograms* const shader_program_cache_;
// 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_
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