Index: src/utils/SkPatchUtils.cpp |
diff --git a/src/utils/SkPatchUtils.cpp b/src/utils/SkPatchUtils.cpp |
index d12019551da52b91c948becb7a939306171aba1d..a0be328f6cbea9bb00fd829906ccfbfc0d3b218a 100644 |
--- a/src/utils/SkPatchUtils.cpp |
+++ b/src/utils/SkPatchUtils.cpp |
@@ -204,11 +204,28 @@ bool SkPatchUtils::getVertexData(SkPatchUtils::VertexData* data, const SkPoint c |
if (lodX < 1 || lodY < 1 || NULL == cubics || NULL == data) { |
return false; |
} |
- |
- // number of indices is limited by size of uint16_t, so we clamp it to avoid overflow |
- data->fVertexCount = SkMin32((lodX + 1) * (lodY + 1), 65536); |
- lodX = SkMin32(lodX, 255); |
- lodY = SkMin32(lodY, 255); |
+ |
+ // check for overflow in multiplication |
+ const int64_t lodX64 = (lodX + 1), |
+ lodY64 = (lodY + 1), |
+ mult64 = lodX64 * lodY64; |
+ if (mult64 > SK_MaxS32) { |
+ return false; |
+ } |
+ data->fVertexCount = SkToS32(mult64); |
+ |
+ // it is recommended to generate draw calls of no more than 65536 indices, so we never generate |
+ // more than 60000 indices. To accomplish that we resize the LOD and vertex count |
+ if (data->fVertexCount > 10000 || lodX > 200 || lodY > 200) { |
+ SkScalar weightX = static_cast<SkScalar>(lodX) / (lodX + lodY); |
+ SkScalar weightY = static_cast<SkScalar>(lodY) / (lodX + lodY); |
+ |
+ // 200 comes from the 100 * 2 which is the max value of vertices because of the limit of |
+ // 60000 indices ( sqrt(60000 / 6) that comes from data->fIndexCount = lodX * lodY * 6) |
+ lodX = static_cast<int>(weightX * 200); |
+ lodY = static_cast<int>(weightY * 200); |
+ data->fVertexCount = (lodX + 1) * (lodY + 1); |
+ } |
data->fIndexCount = lodX * lodY * 6; |
data->fPoints = SkNEW_ARRAY(SkPoint, data->fVertexCount); |