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      1 
      2 /*
      3  * Copyright 2011 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #ifndef GrStencilBuffer_DEFINED
     11 #define GrStencilBuffer_DEFINED
     12 
     13 #include "GrClipData.h"
     14 #include "GrResource.h"
     15 
     16 class GrRenderTarget;
     17 class GrResourceEntry;
     18 class GrResourceKey;
     19 
     20 class GrStencilBuffer : public GrResource {
     21 public:
     22     SK_DECLARE_INST_COUNT(GrStencilBuffer);
     23 
     24     virtual ~GrStencilBuffer() {
     25         // TODO: allow SB to be purged and detach itself from rts
     26     }
     27 
     28     int width() const { return fWidth; }
     29     int height() const { return fHeight; }
     30     int bits() const { return fBits; }
     31     int numSamples() const { return fSampleCnt; }
     32 
     33     // called to note the last clip drawn to this buffer.
     34     void setLastClip(int32_t clipStackGenID,
     35                      const SkIRect& clipSpaceRect,
     36                      const SkIPoint clipSpaceToStencilOffset) {
     37         fLastClipStackGenID = clipStackGenID;
     38         fLastClipStackRect = clipSpaceRect;
     39         fLastClipSpaceOffset = clipSpaceToStencilOffset;
     40     }
     41 
     42     // called to determine if we have to render the clip into SB.
     43     bool mustRenderClip(int32_t clipStackGenID,
     44                         const SkIRect& clipSpaceRect,
     45                         const SkIPoint clipSpaceToStencilOffset) const {
     46         return fLastClipStackGenID != clipStackGenID ||
     47                fLastClipSpaceOffset != clipSpaceToStencilOffset ||
     48                !fLastClipStackRect.contains(clipSpaceRect);
     49     }
     50 
     51     // Places the sb in the cache. The cache takes a ref of the stencil buffer.
     52     void transferToCache();
     53 
     54     static GrResourceKey ComputeKey(int width, int height, int sampleCnt);
     55 
     56 protected:
     57     GrStencilBuffer(GrGpu* gpu, bool isWrapped, int width, int height, int bits, int sampleCnt)
     58         : GrResource(gpu, isWrapped)
     59         , fWidth(width)
     60         , fHeight(height)
     61         , fBits(bits)
     62         , fSampleCnt(sampleCnt)
     63         , fLastClipStackGenID(SkClipStack::kInvalidGenID) {
     64         fLastClipStackRect.setEmpty();
     65     }
     66 
     67 private:
     68 
     69     int fWidth;
     70     int fHeight;
     71     int fBits;
     72     int fSampleCnt;
     73 
     74     int32_t     fLastClipStackGenID;
     75     SkIRect     fLastClipStackRect;
     76     SkIPoint    fLastClipSpaceOffset;
     77 
     78     typedef GrResource INHERITED;
     79 };
     80 
     81 #endif
     82