GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType type, const SkPath& path,
const SkVector* offset) {
if (kHairlineAA_GrProcessorEdgeType == type) {
return NULL;
}
if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
!path.isConvex()) {
return NULL;
}
if (path.countPoints() > kMaxEdges) {
return NULL;
}
SkPoint pts[kMaxEdges];
SkScalar edges[3 * kMaxEdges];
SkPath::Direction dir;
SkAssertResult(path.cheapComputeDirection(&dir));
SkVector t;
if (NULL == offset) {
t.set(0, 0);
} else {
t = *offset;
}
int count = path.getPoints(pts, kMaxEdges);
int n = 0;
for (int lastPt = count - 1, i = 0; i < count; lastPt = i++) {
if (pts[lastPt] != pts[i]) {
SkVector v = pts[i] - pts[lastPt];
v.normalize();
if (SkPath::kCCW_Direction == dir) {
edges[3 * n] = v.fY;
edges[3 * n + 1] = -v.fX;
} else {
edges[3 * n] = -v.fY;
edges[3 * n + 1] = v.fX;
}
SkPoint p = pts[i] + t;
edges[3 * n + 2] = -(edges[3 * n] * p.fX + edges[3 * n + 1] * p.fY);
++n;
}
}
if (path.isInverseFillType()) {
type = GrInvertProcessorEdgeType(type);
}
return Create(type, n, edges);
}
GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType type, const SkPath& path,
const SkVector* offset) {
if (kHairlineAA_GrProcessorEdgeType == type) {
return nullptr;
}
if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
!path.isConvex()) {
return nullptr;
}
SkPathPriv::FirstDirection dir;
// The only way this should fail is if the clip is effectively a infinitely thin line. In that
// case nothing is inside the clip. It'd be nice to detect this at a higher level and either
// skip the draw or omit the clip element.
if (!SkPathPriv::CheapComputeFirstDirection(path, &dir)) {
if (GrProcessorEdgeTypeIsInverseFill(type)) {
return GrConstColorProcessor::Create(0xFFFFFFFF,
GrConstColorProcessor::kModulateRGBA_InputMode);
}
return GrConstColorProcessor::Create(0, GrConstColorProcessor::kIgnore_InputMode);
}
SkVector t;
if (nullptr == offset) {
t.set(0, 0);
} else {
t = *offset;
}
SkScalar edges[3 * kMaxEdges];
SkPoint pts[4];
SkPath::Verb verb;
SkPath::Iter iter(path, true);
// SkPath considers itself convex so long as there is a convex contour within it,
// regardless of any degenerate contours such as a string of moveTos before it.
// Iterate here to consume any degenerate contours and only process the points
// on the actual convex contour.
int n = 0;
while ((verb = iter.next(pts, true, true)) != SkPath::kDone_Verb) {
switch (verb) {
case SkPath::kMove_Verb:
SkASSERT(n == 0);
case SkPath::kClose_Verb:
break;
case SkPath::kLine_Verb: {
if (n >= kMaxEdges) {
return nullptr;
}
SkVector v = pts[1] - pts[0];
v.normalize();
if (SkPathPriv::kCCW_FirstDirection == dir) {
edges[3 * n] = v.fY;
edges[3 * n + 1] = -v.fX;
} else {
edges[3 * n] = -v.fY;
edges[3 * n + 1] = v.fX;
}
SkPoint p = pts[1] + t;
edges[3 * n + 2] = -(edges[3 * n] * p.fX + edges[3 * n + 1] * p.fY);
++n;
break;
}
default:
return nullptr;
}
}
if (path.isInverseFillType()) {
type = GrInvertProcessorEdgeType(type);
}
return Create(type, n, edges);
}
