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);
}
static void bloat_quad(const SkPoint qpts[3], const SkMatrix* toDevice,
const SkMatrix* toSrc, BezierVertex verts[kQuadNumVertices]) {
SkASSERT(!toDevice == !toSrc);
// original quad is specified by tri a,b,c
SkPoint a = qpts[0];
SkPoint b = qpts[1];
SkPoint c = qpts[2];
if (toDevice) {
toDevice->mapPoints(&a, 1);
toDevice->mapPoints(&b, 1);
toDevice->mapPoints(&c, 1);
}
// make a new poly where we replace a and c by a 1-pixel wide edges orthog
// to edges ab and bc:
//
// before | after
// | b0
// b |
// |
// | a0 c0
// a c | a1 c1
//
// edges a0->b0 and b0->c0 are parallel to original edges a->b and b->c,
// respectively.
BezierVertex& a0 = verts[0];
BezierVertex& a1 = verts[1];
BezierVertex& b0 = verts[2];
BezierVertex& c0 = verts[3];
BezierVertex& c1 = verts[4];
SkVector ab = b;
ab -= a;
SkVector ac = c;
ac -= a;
SkVector cb = b;
cb -= c;
// We should have already handled degenerates
SkASSERT(ab.length() > 0 && cb.length() > 0);
ab.normalize();
SkVector abN;
abN.setOrthog(ab, SkVector::kLeft_Side);
if (abN.dot(ac) > 0) {
abN.negate();
}
cb.normalize();
SkVector cbN;
cbN.setOrthog(cb, SkVector::kLeft_Side);
if (cbN.dot(ac) < 0) {
cbN.negate();
}
a0.fPos = a;
a0.fPos += abN;
a1.fPos = a;
a1.fPos -= abN;
c0.fPos = c;
c0.fPos += cbN;
c1.fPos = c;
c1.fPos -= cbN;
intersect_lines(a0.fPos, abN, c0.fPos, cbN, &b0.fPos);
if (toSrc) {
toSrc->mapPointsWithStride(&verts[0].fPos, sizeof(BezierVertex), kQuadNumVertices);
}
}
void SkPathStroker::cubic_to(const SkPoint pts[4],
const SkVector& normalAB, const SkVector& unitNormalAB,
SkVector* normalCD, SkVector* unitNormalCD,
int subDivide) {
SkVector ab = pts[1] - pts[0];
SkVector cd = pts[3] - pts[2];
SkVector normalBC, unitNormalBC;
bool degenerateAB = degenerate_vector(ab);
bool degenerateCD = degenerate_vector(cd);
if (degenerateAB && degenerateCD) {
DRAW_LINE:
this->line_to(pts[3], normalAB);
*normalCD = normalAB;
*unitNormalCD = unitNormalAB;
return;
}
if (degenerateAB) {
ab = pts[2] - pts[0];
degenerateAB = degenerate_vector(ab);
}
if (degenerateCD) {
cd = pts[3] - pts[1];
degenerateCD = degenerate_vector(cd);
}
if (degenerateAB || degenerateCD) {
goto DRAW_LINE;
}
SkAssertResult(set_normal_unitnormal(cd, fRadius, normalCD, unitNormalCD));
bool degenerateBC = !set_normal_unitnormal(pts[1], pts[2], fRadius,
&normalBC, &unitNormalBC);
if (degenerateBC || normals_too_curvy(unitNormalAB, unitNormalBC) ||
normals_too_curvy(unitNormalBC, *unitNormalCD)) {
// subdivide if we can
if (--subDivide < 0) {
goto DRAW_LINE;
}
SkPoint tmp[7];
SkVector norm, unit, dummy, unitDummy;
SkChopCubicAtHalf(pts, tmp);
this->cubic_to(&tmp[0], normalAB, unitNormalAB, &norm, &unit,
subDivide);
// we use dummys since we already have a valid (and more accurate)
// normals for CD
this->cubic_to(&tmp[3], norm, unit, &dummy, &unitDummy, subDivide);
} else {
SkVector normalB, normalC;
// need normals to inset/outset the off-curve pts B and C
if (0) { // this is normal to the line between our adjacent pts
normalB = pts[2] - pts[0];
normalB.rotateCCW();
SkAssertResult(normalB.setLength(fRadius));
normalC = pts[3] - pts[1];
normalC.rotateCCW();
SkAssertResult(normalC.setLength(fRadius));
} else { // miter-join
SkVector unitBC = pts[2] - pts[1];
unitBC.normalize();
unitBC.rotateCCW();
normalB = unitNormalAB + unitBC;
normalC = *unitNormalCD + unitBC;
SkScalar dot = SkPoint::DotProduct(unitNormalAB, unitBC);
SkAssertResult(normalB.setLength(SkScalarDiv(fRadius,
SkScalarSqrt((SK_Scalar1 + dot)/2))));
dot = SkPoint::DotProduct(*unitNormalCD, unitBC);
SkAssertResult(normalC.setLength(SkScalarDiv(fRadius,
SkScalarSqrt((SK_Scalar1 + dot)/2))));
}
fOuter.cubicTo( pts[1].fX + normalB.fX, pts[1].fY + normalB.fY,
pts[2].fX + normalC.fX, pts[2].fY + normalC.fY,
pts[3].fX + normalCD->fX, pts[3].fY + normalCD->fY);
fInner.cubicTo( pts[1].fX - normalB.fX, pts[1].fY - normalB.fY,
pts[2].fX - normalC.fX, pts[2].fY - normalC.fY,
pts[3].fX - normalCD->fX, pts[3].fY - normalCD->fY);
}
}
static void create_vertices(const SegmentArray& segments,
const SkPoint& fanPt,
DrawArray* draws,
QuadVertex* verts,
uint16_t* idxs) {
Draw* draw = &draws->push_back();
// alias just to make vert/index assignments easier to read.
int* v = &draw->fVertexCnt;
int* i = &draw->fIndexCnt;
int count = segments.count();
for (int a = 0; a < count; ++a) {
const Segment& sega = segments[a];
int b = (a + 1) % count;
const Segment& segb = segments[b];
// Check whether adding the verts for this segment to the current draw would cause index
// values to overflow.
int vCount = 4;
if (Segment::kLine == segb.fType) {
vCount += 5;
} else {
vCount += 6;
}
if (draw->fVertexCnt + vCount > (1 << 16)) {
verts += *v;
idxs += *i;
draw = &draws->push_back();
v = &draw->fVertexCnt;
i = &draw->fIndexCnt;
}
// FIXME: These tris are inset in the 1 unit arc around the corner
verts[*v + 0].fPos = sega.endPt();
verts[*v + 1].fPos = verts[*v + 0].fPos + sega.endNorm();
verts[*v + 2].fPos = verts[*v + 0].fPos + segb.fMid;
verts[*v + 3].fPos = verts[*v + 0].fPos + segb.fNorms[0];
verts[*v + 0].fUV.set(0,0);
verts[*v + 1].fUV.set(0,-SK_Scalar1);
verts[*v + 2].fUV.set(0,-SK_Scalar1);
verts[*v + 3].fUV.set(0,-SK_Scalar1);
verts[*v + 0].fD0 = verts[*v + 0].fD1 = -SK_Scalar1;
verts[*v + 1].fD0 = verts[*v + 1].fD1 = -SK_Scalar1;
verts[*v + 2].fD0 = verts[*v + 2].fD1 = -SK_Scalar1;
verts[*v + 3].fD0 = verts[*v + 3].fD1 = -SK_Scalar1;
idxs[*i + 0] = *v + 0;
idxs[*i + 1] = *v + 2;
idxs[*i + 2] = *v + 1;
idxs[*i + 3] = *v + 0;
idxs[*i + 4] = *v + 3;
idxs[*i + 5] = *v + 2;
*v += 4;
*i += 6;
if (Segment::kLine == segb.fType) {
verts[*v + 0].fPos = fanPt;
verts[*v + 1].fPos = sega.endPt();
verts[*v + 2].fPos = segb.fPts[0];
verts[*v + 3].fPos = verts[*v + 1].fPos + segb.fNorms[0];
verts[*v + 4].fPos = verts[*v + 2].fPos + segb.fNorms[0];
// we draw the line edge as a degenerate quad (u is 0, v is the
// signed distance to the edge)
SkScalar dist = fanPt.distanceToLineBetween(verts[*v + 1].fPos,
verts[*v + 2].fPos);
verts[*v + 0].fUV.set(0, dist);
verts[*v + 1].fUV.set(0, 0);
verts[*v + 2].fUV.set(0, 0);
verts[*v + 3].fUV.set(0, -SK_Scalar1);
verts[*v + 4].fUV.set(0, -SK_Scalar1);
verts[*v + 0].fD0 = verts[*v + 0].fD1 = -SK_Scalar1;
verts[*v + 1].fD0 = verts[*v + 1].fD1 = -SK_Scalar1;
verts[*v + 2].fD0 = verts[*v + 2].fD1 = -SK_Scalar1;
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 + 3] = *v + 3;
idxs[*i + 4] = *v + 1;
idxs[*i + 5] = *v + 2;
idxs[*i + 6] = *v + 4;
idxs[*i + 7] = *v + 3;
idxs[*i + 8] = *v + 2;
*v += 5;
*i += 9;
} else {
SkPoint qpts[] = {sega.endPt(), segb.fPts[0], segb.fPts[1]};
SkVector midVec = segb.fNorms[0] + segb.fNorms[1];
midVec.normalize();
verts[*v + 0].fPos = fanPt;
verts[*v + 1].fPos = qpts[0];
verts[*v + 2].fPos = qpts[2];
verts[*v + 3].fPos = qpts[0] + segb.fNorms[0];
verts[*v + 4].fPos = qpts[2] + segb.fNorms[1];
verts[*v + 5].fPos = qpts[1] + midVec;
SkScalar c = segb.fNorms[0].dot(qpts[0]);
verts[*v + 0].fD0 = -segb.fNorms[0].dot(fanPt) + c;
verts[*v + 1].fD0 = 0.f;
verts[*v + 2].fD0 = -segb.fNorms[0].dot(qpts[2]) + c;
verts[*v + 3].fD0 = -SK_ScalarMax/100;
verts[*v + 4].fD0 = -SK_ScalarMax/100;
verts[*v + 5].fD0 = -SK_ScalarMax/100;
c = segb.fNorms[1].dot(qpts[2]);
verts[*v + 0].fD1 = -segb.fNorms[1].dot(fanPt) + c;
verts[*v + 1].fD1 = -segb.fNorms[1].dot(qpts[0]) + c;
verts[*v + 2].fD1 = 0.f;
verts[*v + 3].fD1 = -SK_ScalarMax/100;
verts[*v + 4].fD1 = -SK_ScalarMax/100;
verts[*v + 5].fD1 = -SK_ScalarMax/100;
GrPathUtils::QuadUVMatrix toUV(qpts);
toUV.apply<6, sizeof(QuadVertex), sizeof(SkPoint)>(verts + *v);
idxs[*i + 0] = *v + 3;
idxs[*i + 1] = *v + 1;
idxs[*i + 2] = *v + 2;
idxs[*i + 3] = *v + 4;
idxs[*i + 4] = *v + 3;
idxs[*i + 5] = *v + 2;
idxs[*i + 6] = *v + 5;
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;
*v += 6;
*i += 12;
}
}
}
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);
}
