Added cache to gpu AA clipping

http://codereview.appspot.com/6160046/



git-svn-id: http://skia.googlecode.com/svn/trunk@3828 2bbb7eff-a529-9590-31e7-b0007b416f81

src/gpu/GrClipMaskManager.cpp

@@ -15,7 +15,6 @@
 
 //#define GR_AA_CLIP 1
 
-
 ////////////////////////////////////////////////////////////////////////////////
 void ScissoringSettings::setupScissoring(GrGpu* gpu) {
     if (!fEnableScissoring) {
@@ -366,10 +365,17 @@ bool GrClipMaskManager::createAlphaClipMask(GrGpu* gpu,
     GrRenderTarget* rt = origDrawState->getRenderTarget();
     GrAssert(NULL != rt);
 
+    if (fAACache.canReuse(clipIn, rt->width(), rt->height())) {
+        *result = fAACache.getLastMask();
+        *resultBounds = fAACache.getLastBound();
+        return true;
+    }
+
     GrRect rtRect;
     rtRect.setLTRB(0, 0,
                     GrIntToScalar(rt->width()), GrIntToScalar(rt->height()));
 
+
     // unlike the stencil path the alpha path is not bound to the size of the
     // render target - determine the minimum size required for the mask
     GrRect bounds;
@@ -411,8 +417,9 @@ bool GrClipMaskManager::createAlphaClipMask(GrGpu* gpu,
     GrTexture* accum = gpu->createTexture(desc, NULL, 0);
     GrTexture* temp = gpu->createTexture(desc, NULL, 0);
     if (NULL == accum || NULL == temp) {
-        // TODO: free up accum & temp here!
         fClipMaskInAlpha = false;
+        SkSafeUnref(accum);
+        SkSafeUnref(temp);
         return false;
     }
 
@@ -505,8 +512,11 @@ bool GrClipMaskManager::createAlphaClipMask(GrGpu* gpu,
         }
     }
 
+    fAACache.set(clipIn, rt->width(), rt->height(), accum, bounds);
     *result = accum;
     *resultBounds = bounds;
+    SkSafeUnref(accum);     // fAACache still has a ref to accum
+    SkSafeUnref(temp);
     return true;
 }
 

src/gpu/GrClipMaskManager.h

@@ -11,9 +11,11 @@
 
 #include "GrRect.h"
 #include "SkPath.h"
+#include "GrNoncopyable.h"
+#include "GrClip.h"
+#include "SkRefCnt.h"
 
 class GrGpu;
-class GrClip;
 class GrPathRenderer;
 class GrPathRendererChain;
 class SkPath;
@@ -33,6 +35,57 @@ struct ScissoringSettings {
     void setupScissoring(GrGpu* gpu);
 };
 
+/**
+ * The stencil buffer stores the last clip path - providing a single entry
+ * "cache". This class provides similar functionality for AA clip paths
+ */
+class GrClipMaskCache : public GrNoncopyable {
+public:
+    GrClipMaskCache() 
+    : fLastWidth(-1)
+    , fLastHeight(-1) {
+        fLastBound.MakeEmpty();
+    }
+
+    bool canReuse(const GrClip& clip, int width, int height) {
+        if (fLastWidth >= width &&
+            fLastHeight >= height &&
+            clip == fLastClip) {
+            return true;
+        }
+
+        return false;
+    }
+
+    void set(const GrClip& clip, int width, int height, 
+             GrTexture* mask, const GrRect& bound) {
+
+        fLastWidth = width;
+        fLastHeight = height;
+        fLastClip = clip;
+        SkSafeRef(mask);
+        fLastMask.reset(mask);
+        fLastBound = bound;
+    }
+
+    GrTexture*  getLastMask() {
+        return fLastMask.get();
+    }
+
+    const GrRect& getLastBound() const {
+        return fLastBound;
+    }
+
+protected:
+private:
+    int                     fLastWidth;
+    int                     fLastHeight;
+    GrClip                  fLastClip;
+    SkAutoTUnref<GrTexture> fLastMask;
+    GrRect                  fLastBound;
+
+    typedef GrNoncopyable INHERITED;
+};
 
 /**
  * The clip mask creator handles the generation of the clip mask. If anti 
@@ -42,7 +95,7 @@ struct ScissoringSettings {
  * mask can be represented as a rectangle then scissoring is used. In all
  * cases scissoring is used to bound the range of the clip mask.
  */
-class GrClipMaskManager {
+class GrClipMaskManager : public GrNoncopyable {
 public:
     GrClipMaskManager()
         : fClipMaskInStencil(false)
@@ -67,6 +120,7 @@ protected:
 private:
     bool fClipMaskInStencil;        // is the clip mask in the stencil buffer?
     bool fClipMaskInAlpha;          // is the clip mask in an alpha texture?
+    GrClipMaskCache fAACache;       // cache for the AA path
 
     // must be instantiated after GrGpu object has been given its owning
     // GrContext ptr. (GrGpu is constructed first then handed off to GrContext).
@@ -102,6 +156,7 @@ private:
                                         GrPathFill fill,
                                         bool antiAlias);
 
+    typedef GrNoncopyable INHERITED;
 };
 
 #endif // GrClipMaskManager_DEFINED