skia2/include/gpu/GrRenderTarget.h
2013-08-17 00:02:59 +00:00

172 lines
5.6 KiB
C++

/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrRenderTarget_DEFINED
#define GrRenderTarget_DEFINED
#include "GrSurface.h"
#include "SkRect.h"
class GrStencilBuffer;
class GrTexture;
/**
* GrRenderTarget represents a 2D buffer of pixels that can be rendered to.
* A context's render target is set by setRenderTarget(). Render targets are
* created by a createTexture with the kRenderTarget_TextureFlag flag.
* Additionally, GrContext provides methods for creating GrRenderTargets
* that wrap externally created render targets.
*/
class GrRenderTarget : public GrSurface {
public:
SK_DECLARE_INST_COUNT(GrRenderTarget)
// GrResource overrides
virtual size_t sizeInBytes() const SK_OVERRIDE;
// GrSurface overrides
/**
* @return the texture associated with the render target, may be NULL.
*/
virtual GrTexture* asTexture() SK_OVERRIDE { return fTexture; }
virtual const GrTexture* asTexture() const SK_OVERRIDE { return fTexture; }
/**
* @return this render target.
*/
virtual GrRenderTarget* asRenderTarget() SK_OVERRIDE { return this; }
virtual const GrRenderTarget* asRenderTarget() const SK_OVERRIDE {
return this;
}
virtual bool readPixels(int left, int top, int width, int height,
GrPixelConfig config,
void* buffer,
size_t rowBytes = 0,
uint32_t pixelOpsFlags = 0) SK_OVERRIDE;
virtual void writePixels(int left, int top, int width, int height,
GrPixelConfig config,
const void* buffer,
size_t rowBytes = 0,
uint32_t pixelOpsFlags = 0) SK_OVERRIDE;
// GrRenderTarget
/**
* If this RT is multisampled, this is the multisample buffer
* @return the 3D API's handle to this object (e.g. FBO ID in OpenGL)
*/
virtual GrBackendObject getRenderTargetHandle() const = 0;
/**
* If this RT is multisampled, this is the buffer it is resolved to.
* Otherwise, same as getRenderTargetHandle().
* (In GL a separate FBO ID is used for the MSAA and resolved buffers)
* @return the 3D API's handle to this object (e.g. FBO ID in OpenGL)
*/
virtual GrBackendObject getRenderTargetResolvedHandle() const = 0;
/**
* @return true if the surface is multisampled, false otherwise
*/
bool isMultisampled() const { return 0 != fDesc.fSampleCnt; }
/**
* @return the number of samples-per-pixel or zero if non-MSAA.
*/
int numSamples() const { return fDesc.fSampleCnt; }
/**
* Call to indicate the multisample contents were modified such that the
* render target needs to be resolved before it can be used as texture. Gr
* tracks this for its own drawing and thus this only needs to be called
* when the render target has been modified outside of Gr. This has no
* effect on wrapped backend render targets.
*
* @param rect a rect bounding the area needing resolve. NULL indicates
* the whole RT needs resolving.
*/
void flagAsNeedingResolve(const SkIRect* rect = NULL);
/**
* Call to override the region that needs to be resolved.
*/
void overrideResolveRect(const SkIRect rect);
/**
* Call to indicate that GrRenderTarget was externally resolved. This may
* allow Gr to skip a redundant resolve step.
*/
void flagAsResolved() { fResolveRect.setLargestInverted(); }
/**
* @return true if the GrRenderTarget requires MSAA resolving
*/
bool needsResolve() const { return !fResolveRect.isEmpty(); }
/**
* Returns a rect bounding the region needing resolving.
*/
const SkIRect& getResolveRect() const { return fResolveRect; }
/**
* If the render target is multisampled this will perform a multisample
* resolve. Any pending draws to the target are first flushed. This only
* applies to render targets that are associated with GrTextures. After the
* function returns the GrTexture will contain the resolved pixels.
*/
void resolve();
// a MSAA RT may require explicit resolving , it may auto-resolve (e.g. FBO
// 0 in GL), or be unresolvable because the client didn't give us the
// resolve destination.
enum ResolveType {
kCanResolve_ResolveType,
kAutoResolves_ResolveType,
kCantResolve_ResolveType,
};
virtual ResolveType getResolveType() const = 0;
/**
* GrStencilBuffer is not part of the public API.
*/
GrStencilBuffer* getStencilBuffer() const { return fStencilBuffer; }
void setStencilBuffer(GrStencilBuffer* stencilBuffer);
protected:
GrRenderTarget(GrGpu* gpu,
bool isWrapped,
GrTexture* texture,
const GrTextureDesc& desc)
: INHERITED(gpu, isWrapped, desc)
, fStencilBuffer(NULL)
, fTexture(texture) {
fResolveRect.setLargestInverted();
}
// override of GrResource
virtual void onAbandon() SK_OVERRIDE;
virtual void onRelease() SK_OVERRIDE;
private:
friend class GrTexture;
// called by ~GrTexture to remove the non-ref'ed back ptr.
void owningTextureDestroyed() {
SkASSERT(NULL != fTexture);
fTexture = NULL;
}
GrStencilBuffer* fStencilBuffer;
GrTexture* fTexture; // not ref'ed
SkIRect fResolveRect;
typedef GrSurface INHERITED;
};
#endif