gecko-dev/gfx/layers/opengl/Composer2D.h

63 строки
2.0 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=8 et :
*/
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_layers_Composer2D_h
#define mozilla_layers_Composer2D_h
#include "gfxTypes.h"
#include "nsISupportsImpl.h"
/**
* Many platforms have dedicated hardware for simple composition.
* This hardware is usually faster or more power efficient than the
* GPU. However, in exchange for this better performance, generality
* has to be sacrificed: no 3d transforms, no intermediate surfaces,
* no special shader effects, loss of other goodies depending on the
* platform.
*
* Composer2D is a very simple interface to this class of hardware
* that allows an implementation to "try rendering" with the fast
* path. If the given layer tree requires more generality than the
* hardware provides, the implementation should bail and have the
* layer manager fall back on full GPU composition.
*/
class gfxMatrix;
namespace mozilla {
namespace layers {
class Layer;
class THEBES_API Composer2D {
NS_INLINE_DECL_REFCOUNTING(Composer2D)
public:
virtual ~Composer2D() {}
/**
* Return true if |aRoot| met the implementation's criteria for fast
* composition and the render was successful. Return false to fall
* back on the GPU.
*
* |aWorldTransform| must be applied to |aRoot|'s subtree when
* rendering to the framebuffer. This is a global transform on the
* entire scene, defined in GL space. If the Composer2D
* implementation is unable to honor the transform, it should return
* false.
*
* Currently, when TryRender() returns true, the entire framebuffer
* must have been rendered.
*/
virtual bool TryRender(Layer* aRoot, const gfxMatrix& aWorldTransform) = 0;
};
} // namespace layers
} // namespace mozilla
#endif // mozilla_layers_Composer2D_h