special-case edge-building for polygons (paths with only lines)

makes the dashing bench faster (from 13.4 -> 11.5 ticks)
Review URL: https://codereview.appspot.com/6449080

git-svn-id: http://skia.googlecode.com/svn/trunk@4916 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 17 insertions, 4 deletions

diff --git a/src/core/SkEdgeBuilder.h b/src/core/SkEdgeBuilder.h
index ae21f05b31..714e2b9c86 100644
--- a/src/core/SkEdgeBuilder.h
+++ b/src/core/SkEdgeBuilder.h
@@ -20,19 +20,32 @@ class SkEdgeBuilder {
 public:
     SkEdgeBuilder();
     
+    // returns the number of built edges. The array of those edge pointers
+    // is returned from edgeList().
     int build(const SkPath& path, const SkIRect* clip, int shiftUp);
-
-    SkEdge** edgeList() { return fList.begin(); }
-
+    
+    SkEdge** edgeList() { return fEdgeList; }
+    
 private:
     SkChunkAlloc        fAlloc;
     SkTDArray<SkEdge*>  fList;
-    int                 fShiftUp;
+    
+    /*
+     *  If we're in general mode, we allcoate the pointers in fList, and this
+     *  will point at fList.begin(). If we're in polygon mode, fList will be
+     *  empty, as we will have preallocated room for the pointers in fAlloc's
+     *  block, and fEdgeList will point into that.
+     */
+    SkEdge**            fEdgeList;
 
+    int                 fShiftUp;
+    
     void addLine(const SkPoint pts[]);
     void addQuad(const SkPoint pts[]);
     void addCubic(const SkPoint pts[]);
     void addClipper(SkEdgeClipper*);
+
+    int buildPoly(const SkPath& path, const SkIRect* clip, int shiftUp);
 };
 
 #endif