Rewrite SkVertices specified with triangle fans as indexed triangles
Change-Id: Ifaacc426bc657b324f6a885a8ef70b347b048226
Reviewed-on: https://skia-review.googlesource.com/124349
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Chris Dalton <csmartdalton@google.com>
diff --git a/src/core/SkVertices.cpp b/src/core/SkVertices.cpp
index 900247d..c945fc0 100644
--- a/src/core/SkVertices.cpp
+++ b/src/core/SkVertices.cpp
@@ -23,13 +23,37 @@
}
struct SkVertices::Sizes {
- Sizes(int vertexCount, int indexCount, bool hasTexs, bool hasColors) {
+ Sizes(SkVertices::VertexMode mode, int vertexCount, int indexCount, bool hasTexs,
+ bool hasColors) {
SkSafeMath safe;
fVSize = safe.mul(vertexCount, sizeof(SkPoint));
fTSize = hasTexs ? safe.mul(vertexCount, sizeof(SkPoint)) : 0;
fCSize = hasColors ? safe.mul(vertexCount, sizeof(SkColor)) : 0;
+
+ fBuilderTriFanISize = 0;
fISize = safe.mul(indexCount, sizeof(uint16_t));
+ if (kTriangleFan_VertexMode == mode) {
+ int numFanTris = 0;
+ if (indexCount) {
+ fBuilderTriFanISize = fISize;
+ numFanTris = indexCount - 2;
+ } else {
+ numFanTris = vertexCount - 2;
+ // By forcing this to become indexed we are adding a constraint to the maximum
+ // number of vertices.
+ if (3 * numFanTris > (SK_MaxU16 + 1)) {
+ sk_bzero(this, sizeof(*this));
+ return;
+ }
+ }
+ if (numFanTris <= 0) {
+ sk_bzero(this, sizeof(*this));
+ return;
+ }
+ fISize = safe.mul(numFanTris, 3 * sizeof(uint16_t));
+ }
+
fTotal = safe.add(sizeof(SkVertices),
safe.add(fVSize,
safe.add(fTSize,
@@ -51,6 +75,10 @@
size_t fTSize;
size_t fCSize;
size_t fISize;
+
+ // For indexed tri-fans this is the number of amount of space fo indices needed in the builder
+ // before conversion to indexed triangles (or zero if not indexed or not a triangle fan).
+ size_t fBuilderTriFanISize;
};
SkVertices::Builder::Builder(VertexMode mode, int vertexCount, int indexCount,
@@ -58,7 +86,7 @@
bool hasTexs = SkToBool(builderFlags & SkVertices::kHasTexCoords_BuilderFlag);
bool hasColors = SkToBool(builderFlags & SkVertices::kHasColors_BuilderFlag);
this->init(mode, vertexCount, indexCount,
- SkVertices::Sizes(vertexCount, indexCount, hasTexs, hasColors));
+ SkVertices::Sizes(mode, vertexCount, indexCount, hasTexs, hasColors));
}
SkVertices::Builder::Builder(VertexMode mode, int vertexCount, int indexCount,
@@ -73,6 +101,10 @@
}
void* storage = ::operator new (sizes.fTotal);
+ if (sizes.fBuilderTriFanISize) {
+ fIntermediateFanIndices.reset(new uint8_t[sizes.fBuilderTriFanISize]);
+ }
+
fVertices.reset(new (storage) SkVertices);
// need to point past the object to store the arrays
@@ -91,6 +123,27 @@
sk_sp<SkVertices> SkVertices::Builder::detach() {
if (fVertices) {
fVertices->fBounds.set(fVertices->fPositions, fVertices->fVertexCnt);
+ if (fVertices->fMode == kTriangleFan_VertexMode) {
+ if (fIntermediateFanIndices.get()) {
+ SkASSERT(fVertices->fIndexCnt);
+ auto tempIndices = this->indices();
+ for (int t = 0; t < fVertices->fIndexCnt - 2; ++t) {
+ fVertices->fIndices[3 * t + 0] = tempIndices[0];
+ fVertices->fIndices[3 * t + 1] = tempIndices[t + 1];
+ fVertices->fIndices[3 * t + 2] = tempIndices[t + 2];
+ }
+ fVertices->fIndexCnt = 3 * (fVertices->fIndexCnt - 2);
+ } else {
+ SkASSERT(!fVertices->fIndexCnt);
+ for (int t = 0; t < fVertices->fVertexCnt - 2; ++t) {
+ fVertices->fIndices[3 * t + 0] = 0;
+ fVertices->fIndices[3 * t + 1] = SkToU16(t + 1);
+ fVertices->fIndices[3 * t + 2] = SkToU16(t + 2);
+ }
+ fVertices->fIndexCnt = 3 * (fVertices->fVertexCnt - 2);
+ }
+ fVertices->fMode = kTriangles_VertexMode;
+ }
fVertices->fUniqueID = next_id();
return std::move(fVertices); // this will null fVertices after the return
}
@@ -118,7 +171,13 @@
}
uint16_t* SkVertices::Builder::indices() {
- return fVertices ? const_cast<uint16_t*>(fVertices->indices()) : nullptr;
+ if (!fVertices) {
+ return nullptr;
+ }
+ if (fIntermediateFanIndices) {
+ return reinterpret_cast<uint16_t*>(fIntermediateFanIndices.get());
+ }
+ return const_cast<uint16_t*>(fVertices->indices());
}
///////////////////////////////////////////////////////////////////////////////////////////////////
@@ -127,7 +186,7 @@
const SkPoint pos[], const SkPoint texs[],
const SkColor colors[], int indexCount,
const uint16_t indices[]) {
- Sizes sizes(vertexCount, indexCount, texs != nullptr, colors != nullptr);
+ Sizes sizes(mode, vertexCount, indexCount, texs != nullptr, colors != nullptr);
if (!sizes.isValid()) {
return nullptr;
}
@@ -138,13 +197,14 @@
sk_careful_memcpy(builder.positions(), pos, sizes.fVSize);
sk_careful_memcpy(builder.texCoords(), texs, sizes.fTSize);
sk_careful_memcpy(builder.colors(), colors, sizes.fCSize);
- sk_careful_memcpy(builder.indices(), indices, sizes.fISize);
+ size_t isize = (mode == kTriangleFan_VertexMode) ? sizes.fBuilderTriFanISize : sizes.fISize;
+ sk_careful_memcpy(builder.indices(), indices, isize);
return builder.detach();
}
size_t SkVertices::approximateSize() const {
- Sizes sizes(fVertexCnt, fIndexCnt, this->hasTexCoords(), this->hasColors());
+ Sizes sizes(fMode, fVertexCnt, fIndexCnt, this->hasTexCoords(), this->hasColors());
SkASSERT(sizes.isValid());
return sizeof(SkVertices) + sizes.fArrays;
}
@@ -170,8 +230,9 @@
packed |= kHasColors_Mask;
}
- Sizes sizes(fVertexCnt, fIndexCnt, this->hasTexCoords(), this->hasColors());
+ Sizes sizes(fMode, fVertexCnt, fIndexCnt, this->hasTexCoords(), this->hasColors());
SkASSERT(sizes.isValid());
+ SkASSERT(!sizes.fBuilderTriFanISize);
// need to force alignment to 4 for SkWriter32 -- will pad w/ 0s as needed
const size_t size = SkAlign4(kHeaderSize + sizes.fArrays);
@@ -208,7 +269,7 @@
}
const bool hasTexs = SkToBool(packed & kHasTexs_Mask);
const bool hasColors = SkToBool(packed & kHasColors_Mask);
- Sizes sizes(vertexCount, indexCount, hasTexs, hasColors);
+ Sizes sizes(mode, vertexCount, indexCount, hasTexs, hasColors);
if (!sizes.isValid()) {
return nullptr;
}
@@ -222,7 +283,8 @@
reader.read(builder.positions(), sizes.fVSize);
reader.read(builder.texCoords(), sizes.fTSize);
reader.read(builder.colors(), sizes.fCSize);
- reader.read(builder.indices(), sizes.fISize);
+ size_t isize = (mode == kTriangleFan_VertexMode) ? sizes.fBuilderTriFanISize : sizes.fISize;
+ reader.read(builder.indices(), isize);
if (indexCount > 0) {
// validate that the indicies are in range
SkASSERT(indexCount == builder.indexCount());