Fix double blend in GrAAConvexPathRenderer

src/gpu/GrAAConvexPathRenderer.cpp

Index: src/gpu/GrAAConvexPathRenderer.cpp
diff --git a/src/gpu/GrAAConvexPathRenderer.cpp b/src/gpu/GrAAConvexPathRenderer.cpp
index 1813803d8ad7ea41a7556ee1d32b01c366be8f60..690feb7be0ee629cad50676776778a64bfbf7703 100644
--- a/src/gpu/GrAAConvexPathRenderer.cpp
+++ b/src/gpu/GrAAConvexPathRenderer.cpp
@@ -425,20 +425,28 @@ static void create_vertices(const SegmentArray&  segments,
             verts[*v + 3].fD0 = verts[*v + 3].fD1 = -SK_Scalar1;
             verts[*v + 4].fD0 = verts[*v + 4].fD1 = -SK_Scalar1;
 
-            idxs[*i + 0] = *v + 0;
-            idxs[*i + 1] = *v + 2;
-            idxs[*i + 2] = *v + 1;
+            idxs[*i + 0] = *v + 3;
+            idxs[*i + 1] = *v + 1;
+            idxs[*i + 2] = *v + 2;
 
-            idxs[*i + 3] = *v + 3;
-            idxs[*i + 4] = *v + 1;
+            idxs[*i + 3] = *v + 4;
+            idxs[*i + 4] = *v + 3;
             idxs[*i + 5] = *v + 2;
 
-            idxs[*i + 6] = *v + 4;
-            idxs[*i + 7] = *v + 3;
-            idxs[*i + 8] = *v + 2;
+            *i += 6;
+
+            // Draw the interior fan if it exists.
+            // TODO: Detect and combine colinear segments. This will ensure we catch every case
+            // with no interior, and that the resulting shared edge uses the same endpoints.
+            if (count >= 3) {
+                idxs[*i + 0] = *v + 0;
+                idxs[*i + 1] = *v + 2;
+                idxs[*i + 2] = *v + 1;
+
+                *i += 3;
+            }
 
             *v += 5;
-            *i += 9;
         } else {
             SkPoint qpts[] = {sega.endPt(), segb.fPts[0], segb.fPts[1]};
 
@@ -482,12 +490,20 @@ static void create_vertices(const SegmentArray&  segments,
             idxs[*i + 7] = *v + 3;
             idxs[*i + 8] = *v + 4;
 
-            idxs[*i +  9] = *v + 0;
-            idxs[*i + 10] = *v + 2;
-            idxs[*i + 11] = *v + 1;
+            *i += 9;
+
+            // Draw the interior fan if it exists.
+            // TODO: Detect and combine colinear segments. This will ensure we catch every case
+            // with no interior, and that the resulting shared edge uses the same endpoints.
+            if (count >= 3) {

[Chris Dalton, 2015/04/29 16:38:04]

I decided to err on the side of minimal code change, but let me know if you want
me to rearrange things so we only write fanPt to the vertex array when we take
this branch.

+                idxs[*i + 0] = *v + 0;
+                idxs[*i + 1] = *v + 2;
+                idxs[*i + 2] = *v + 1;
+
+                *i += 3;
+            }
 
             *v += 6;
-            *i += 12;
         }
     }
 }