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