1 /* 2 * Copyright 2011 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef GrRenderTarget_DEFINED 9 #define GrRenderTarget_DEFINED 10 11 #include "GrSurface.h" 12 #include "SkRect.h" 13 14 class GrStencilBuffer; 15 class GrTexture; 16 17 /** 18 * GrRenderTarget represents a 2D buffer of pixels that can be rendered to. 19 * A context's render target is set by setRenderTarget(). Render targets are 20 * created by a createTexture with the kRenderTarget_TextureFlag flag. 21 * Additionally, GrContext provides methods for creating GrRenderTargets 22 * that wrap externally created render targets. 23 */ 24 class GrRenderTarget : public GrSurface { 25 public: 26 SK_DECLARE_INST_COUNT(GrRenderTarget) 27 28 // GrResource overrides 29 virtual size_t sizeInBytes() const SK_OVERRIDE; 30 31 // GrSurface overrides 32 /** 33 * @return the texture associated with the render target, may be NULL. 34 */ asTexture()35 virtual GrTexture* asTexture() SK_OVERRIDE { return fTexture; } asTexture()36 virtual const GrTexture* asTexture() const SK_OVERRIDE { return fTexture; } 37 38 /** 39 * @return this render target. 40 */ asRenderTarget()41 virtual GrRenderTarget* asRenderTarget() SK_OVERRIDE { return this; } asRenderTarget()42 virtual const GrRenderTarget* asRenderTarget() const SK_OVERRIDE { 43 return this; 44 } 45 46 virtual bool readPixels(int left, int top, int width, int height, 47 GrPixelConfig config, 48 void* buffer, 49 size_t rowBytes = 0, 50 uint32_t pixelOpsFlags = 0) SK_OVERRIDE; 51 52 virtual void writePixels(int left, int top, int width, int height, 53 GrPixelConfig config, 54 const void* buffer, 55 size_t rowBytes = 0, 56 uint32_t pixelOpsFlags = 0) SK_OVERRIDE; 57 58 // GrRenderTarget 59 /** 60 * If this RT is multisampled, this is the multisample buffer 61 * @return the 3D API's handle to this object (e.g. FBO ID in OpenGL) 62 */ 63 virtual GrBackendObject getRenderTargetHandle() const = 0; 64 65 /** 66 * If this RT is multisampled, this is the buffer it is resolved to. 67 * Otherwise, same as getRenderTargetHandle(). 68 * (In GL a separate FBO ID is used for the MSAA and resolved buffers) 69 * @return the 3D API's handle to this object (e.g. FBO ID in OpenGL) 70 */ 71 virtual GrBackendObject getRenderTargetResolvedHandle() const = 0; 72 73 /** 74 * @return true if the surface is multisampled, false otherwise 75 */ isMultisampled()76 bool isMultisampled() const { return 0 != fDesc.fSampleCnt; } 77 78 /** 79 * @return the number of samples-per-pixel or zero if non-MSAA. 80 */ numSamples()81 int numSamples() const { return fDesc.fSampleCnt; } 82 83 /** 84 * Call to indicate the multisample contents were modified such that the 85 * render target needs to be resolved before it can be used as texture. Gr 86 * tracks this for its own drawing and thus this only needs to be called 87 * when the render target has been modified outside of Gr. This has no 88 * effect on wrapped backend render targets. 89 * 90 * @param rect a rect bounding the area needing resolve. NULL indicates 91 * the whole RT needs resolving. 92 */ 93 void flagAsNeedingResolve(const SkIRect* rect = NULL); 94 95 /** 96 * Call to override the region that needs to be resolved. 97 */ 98 void overrideResolveRect(const SkIRect rect); 99 100 /** 101 * Call to indicate that GrRenderTarget was externally resolved. This may 102 * allow Gr to skip a redundant resolve step. 103 */ flagAsResolved()104 void flagAsResolved() { fResolveRect.setLargestInverted(); } 105 106 /** 107 * @return true if the GrRenderTarget requires MSAA resolving 108 */ needsResolve()109 bool needsResolve() const { return !fResolveRect.isEmpty(); } 110 111 /** 112 * Returns a rect bounding the region needing resolving. 113 */ getResolveRect()114 const SkIRect& getResolveRect() const { return fResolveRect; } 115 116 /** 117 * If the render target is multisampled this will perform a multisample 118 * resolve. Any pending draws to the target are first flushed. This only 119 * applies to render targets that are associated with GrTextures. After the 120 * function returns the GrTexture will contain the resolved pixels. 121 */ 122 void resolve(); 123 124 // a MSAA RT may require explicit resolving , it may auto-resolve (e.g. FBO 125 // 0 in GL), or be unresolvable because the client didn't give us the 126 // resolve destination. 127 enum ResolveType { 128 kCanResolve_ResolveType, 129 kAutoResolves_ResolveType, 130 kCantResolve_ResolveType, 131 }; 132 virtual ResolveType getResolveType() const = 0; 133 134 /** 135 * GrStencilBuffer is not part of the public API. 136 */ getStencilBuffer()137 GrStencilBuffer* getStencilBuffer() const { return fStencilBuffer; } 138 void setStencilBuffer(GrStencilBuffer* stencilBuffer); 139 140 protected: GrRenderTarget(GrGpu * gpu,bool isWrapped,GrTexture * texture,const GrTextureDesc & desc)141 GrRenderTarget(GrGpu* gpu, 142 bool isWrapped, 143 GrTexture* texture, 144 const GrTextureDesc& desc) 145 : INHERITED(gpu, isWrapped, desc) 146 , fStencilBuffer(NULL) 147 , fTexture(texture) { 148 fResolveRect.setLargestInverted(); 149 } 150 151 // override of GrResource 152 virtual void onAbandon() SK_OVERRIDE; 153 virtual void onRelease() SK_OVERRIDE; 154 155 private: 156 friend class GrTexture; 157 // called by ~GrTexture to remove the non-ref'ed back ptr. owningTextureDestroyed()158 void owningTextureDestroyed() { 159 SkASSERT(NULL != fTexture); 160 fTexture = NULL; 161 } 162 163 GrStencilBuffer* fStencilBuffer; 164 GrTexture* fTexture; // not ref'ed 165 166 SkIRect fResolveRect; 167 168 typedef GrSurface INHERITED; 169 }; 170 171 #endif 172