From 8b05cb8a00bdb82e100f1ba74bf4de4a504cceea Mon Sep 17 00:00:00 2001 From: ethannicholas Date: Wed, 6 Jan 2016 11:44:34 -0800 Subject: Broke GrTessellatingPathRenderer's tessellator out into a separate file. GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1557083002 Review URL: https://codereview.chromium.org/1557083002 --- src/gpu/GrTessellator.cpp | 1469 ++++++++++++++++++++++++ src/gpu/GrTessellator.h | 40 + src/gpu/batches/GrTessellatingPathRenderer.cpp | 1422 +---------------------- 3 files changed, 1531 insertions(+), 1400 deletions(-) create mode 100644 src/gpu/GrTessellator.cpp create mode 100644 src/gpu/GrTessellator.h (limited to 'src/gpu') diff --git a/src/gpu/GrTessellator.cpp b/src/gpu/GrTessellator.cpp new file mode 100644 index 0000000000..900a01526b --- /dev/null +++ b/src/gpu/GrTessellator.cpp @@ -0,0 +1,1469 @@ +/* + * Copyright 2015 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#include "GrTessellator.h" + +#include "GrBatchFlushState.h" +#include "GrBatchTest.h" +#include "GrDefaultGeoProcFactory.h" +#include "GrPathUtils.h" +#include "GrVertices.h" +#include "GrResourceCache.h" +#include "GrResourceProvider.h" +#include "SkGeometry.h" +#include "SkChunkAlloc.h" + +#include "batches/GrVertexBatch.h" + +#include + +/* + * There are six stages to the algorithm: + * + * 1) Linearize the path contours into piecewise linear segments (path_to_contours()). + * 2) Build a mesh of edges connecting the vertices (build_edges()). + * 3) Sort the vertices in Y (and secondarily in X) (merge_sort()). + * 4) Simplify the mesh by inserting new vertices at intersecting edges (simplify()). + * 5) Tessellate the simplified mesh into monotone polygons (tessellate()). + * 6) Triangulate the monotone polygons directly into a vertex buffer (polys_to_triangles()). + * + * The vertex sorting in step (3) is a merge sort, since it plays well with the linked list + * of vertices (and the necessity of inserting new vertices on intersection). + * + * Stages (4) and (5) use an active edge list, which a list of all edges for which the + * sweep line has crossed the top vertex, but not the bottom vertex. It's sorted + * left-to-right based on the point where both edges are active (when both top vertices + * have been seen, so the "lower" top vertex of the two). If the top vertices are equal + * (shared), it's sorted based on the last point where both edges are active, so the + * "upper" bottom vertex. + * + * The most complex step is the simplification (4). It's based on the Bentley-Ottman + * line-sweep algorithm, but due to floating point inaccuracy, the intersection points are + * not exact and may violate the mesh topology or active edge list ordering. We + * accommodate this by adjusting the topology of the mesh and AEL to match the intersection + * points. This occurs in three ways: + * + * A) Intersections may cause a shortened edge to no longer be ordered with respect to its + * neighbouring edges at the top or bottom vertex. This is handled by merging the + * edges (merge_collinear_edges()). + * B) Intersections may cause an edge to violate the left-to-right ordering of the + * active edge list. This is handled by splitting the neighbour edge on the + * intersected vertex (cleanup_active_edges()). + * C) Shortening an edge may cause an active edge to become inactive or an inactive edge + * to become active. This is handled by removing or inserting the edge in the active + * edge list (fix_active_state()). + * + * The tessellation steps (5) and (6) are based on "Triangulating Simple Polygons and + * Equivalent Problems" (Fournier and Montuno); also a line-sweep algorithm. Note that it + * currently uses a linked list for the active edge list, rather than a 2-3 tree as the + * paper describes. The 2-3 tree gives O(lg N) lookups, but insertion and removal also + * become O(lg N). In all the test cases, it was found that the cost of frequent O(lg N) + * insertions and removals was greater than the cost of infrequent O(N) lookups with the + * linked list implementation. With the latter, all removals are O(1), and most insertions + * are O(1), since we know the adjacent edge in the active edge list based on the topology. + * Only type 2 vertices (see paper) require the O(N) lookups, and these are much less + * frequent. There may be other data structures worth investigating, however. + * + * Note that the orientation of the line sweep algorithms is determined by the aspect ratio of the + * path bounds. When the path is taller than it is wide, we sort vertices based on increasing Y + * coordinate, and secondarily by increasing X coordinate. When the path is wider than it is tall, + * we sort by increasing X coordinate, but secondarily by *decreasing* Y coordinate. This is so + * that the "left" and "right" orientation in the code remains correct (edges to the left are + * increasing in Y; edges to the right are decreasing in Y). That is, the setting rotates 90 + * degrees counterclockwise, rather that transposing. + */ + +#define LOGGING_ENABLED 0 + +#if LOGGING_ENABLED +#define LOG printf +#else +#define LOG(...) +#endif + +#define ALLOC_NEW(Type, args, alloc) new (alloc.allocThrow(sizeof(Type))) Type args + +namespace { + +struct Vertex; +struct Edge; +struct Poly; + +template +void insert(T* t, T* prev, T* next, T** head, T** tail) { + t->*Prev = prev; + t->*Next = next; + if (prev) { + prev->*Next = t; + } else if (head) { + *head = t; + } + if (next) { + next->*Prev = t; + } else if (tail) { + *tail = t; + } +} + +template +void remove(T* t, T** head, T** tail) { + if (t->*Prev) { + t->*Prev->*Next = t->*Next; + } else if (head) { + *head = t->*Next; + } + if (t->*Next) { + t->*Next->*Prev = t->*Prev; + } else if (tail) { + *tail = t->*Prev; + } + t->*Prev = t->*Next = nullptr; +} + +/** + * Vertices are used in three ways: first, the path contours are converted into a + * circularly-linked list of Vertices for each contour. After edge construction, the same Vertices + * are re-ordered by the merge sort according to the sweep_lt comparator (usually, increasing + * in Y) using the same fPrev/fNext pointers that were used for the contours, to avoid + * reallocation. Finally, MonotonePolys are built containing a circularly-linked list of + * Vertices. (Currently, those Vertices are newly-allocated for the MonotonePolys, since + * an individual Vertex from the path mesh may belong to multiple + * MonotonePolys, so the original Vertices cannot be re-used. + */ + +struct Vertex { + Vertex(const SkPoint& point) + : fPoint(point), fPrev(nullptr), fNext(nullptr) + , fFirstEdgeAbove(nullptr), fLastEdgeAbove(nullptr) + , fFirstEdgeBelow(nullptr), fLastEdgeBelow(nullptr) + , fProcessed(false) +#if LOGGING_ENABLED + , fID (-1.0f) +#endif + {} + SkPoint fPoint; // Vertex position + Vertex* fPrev; // Linked list of contours, then Y-sorted vertices. + Vertex* fNext; // " + Edge* fFirstEdgeAbove; // Linked list of edges above this vertex. + Edge* fLastEdgeAbove; // " + Edge* fFirstEdgeBelow; // Linked list of edges below this vertex. + Edge* fLastEdgeBelow; // " + bool fProcessed; // Has this vertex been seen in simplify()? +#if LOGGING_ENABLED + float fID; // Identifier used for logging. +#endif +}; + +/***************************************************************************************/ + +typedef bool (*CompareFunc)(const SkPoint& a, const SkPoint& b); + +struct Comparator { + CompareFunc sweep_lt; + CompareFunc sweep_gt; +}; + +bool sweep_lt_horiz(const SkPoint& a, const SkPoint& b) { + return a.fX == b.fX ? a.fY > b.fY : a.fX < b.fX; +} + +bool sweep_lt_vert(const SkPoint& a, const SkPoint& b) { + return a.fY == b.fY ? a.fX < b.fX : a.fY < b.fY; +} + +bool sweep_gt_horiz(const SkPoint& a, const SkPoint& b) { + return a.fX == b.fX ? a.fY < b.fY : a.fX > b.fX; +} + +bool sweep_gt_vert(const SkPoint& a, const SkPoint& b) { + return a.fY == b.fY ? a.fX > b.fX : a.fY > b.fY; +} + +inline SkPoint* emit_vertex(Vertex* v, SkPoint* data) { + *data++ = v->fPoint; + return data; +} + +SkPoint* emit_triangle(Vertex* v0, Vertex* v1, Vertex* v2, SkPoint* data) { +#if WIREFRAME + data = emit_vertex(v0, data); + data = emit_vertex(v1, data); + data = emit_vertex(v1, data); + data = emit_vertex(v2, data); + data = emit_vertex(v2, data); + data = emit_vertex(v0, data); +#else + data = emit_vertex(v0, data); + data = emit_vertex(v1, data); + data = emit_vertex(v2, data); +#endif + return data; +} + +struct EdgeList { + EdgeList() : fHead(nullptr), fTail(nullptr) {} + Edge* fHead; + Edge* fTail; +}; + +/** + * An Edge joins a top Vertex to a bottom Vertex. Edge ordering for the list of "edges above" and + * "edge below" a vertex as well as for the active edge list is handled by isLeftOf()/isRightOf(). + * Note that an Edge will give occasionally dist() != 0 for its own endpoints (because floating + * point). For speed, that case is only tested by the callers which require it (e.g., + * cleanup_active_edges()). Edges also handle checking for intersection with other edges. + * Currently, this converts the edges to the parametric form, in order to avoid doing a division + * until an intersection has been confirmed. This is slightly slower in the "found" case, but + * a lot faster in the "not found" case. + * + * The coefficients of the line equation stored in double precision to avoid catastrphic + * cancellation in the isLeftOf() and isRightOf() checks. Using doubles ensures that the result is + * correct in float, since it's a polynomial of degree 2. The intersect() function, being + * degree 5, is still subject to catastrophic cancellation. We deal with that by assuming its + * output may be incorrect, and adjusting the mesh topology to match (see comment at the top of + * this file). + */ + +struct Edge { + Edge(Vertex* top, Vertex* bottom, int winding) + : fWinding(winding) + , fTop(top) + , fBottom(bottom) + , fLeft(nullptr) + , fRight(nullptr) + , fPrevEdgeAbove(nullptr) + , fNextEdgeAbove(nullptr) + , fPrevEdgeBelow(nullptr) + , fNextEdgeBelow(nullptr) + , fLeftPoly(nullptr) + , fRightPoly(nullptr) { + recompute(); + } + int fWinding; // 1 == edge goes downward; -1 = edge goes upward. + Vertex* fTop; // The top vertex in vertex-sort-order (sweep_lt). + Vertex* fBottom; // The bottom vertex in vertex-sort-order. + Edge* fLeft; // The linked list of edges in the active edge list. + Edge* fRight; // " + Edge* fPrevEdgeAbove; // The linked list of edges in the bottom Vertex's "edges above". + Edge* fNextEdgeAbove; // " + Edge* fPrevEdgeBelow; // The linked list of edges in the top Vertex's "edges below". + Edge* fNextEdgeBelow; // " + Poly* fLeftPoly; // The Poly to the left of this edge, if any. + Poly* fRightPoly; // The Poly to the right of this edge, if any. + double fDX; // The line equation for this edge, in implicit form. + double fDY; // fDY * x + fDX * y + fC = 0, for point (x, y) on the line. + double fC; + double dist(const SkPoint& p) const { + return fDY * p.fX - fDX * p.fY + fC; + } + bool isRightOf(Vertex* v) const { + return dist(v->fPoint) < 0.0; + } + bool isLeftOf(Vertex* v) const { + return dist(v->fPoint) > 0.0; + } + void recompute() { + fDX = static_cast(fBottom->fPoint.fX) - fTop->fPoint.fX; + fDY = static_cast(fBottom->fPoint.fY) - fTop->fPoint.fY; + fC = static_cast(fTop->fPoint.fY) * fBottom->fPoint.fX - + static_cast(fTop->fPoint.fX) * fBottom->fPoint.fY; + } + bool intersect(const Edge& other, SkPoint* p) { + LOG("intersecting %g -> %g with %g -> %g\n", + fTop->fID, fBottom->fID, + other.fTop->fID, other.fBottom->fID); + if (fTop == other.fTop || fBottom == other.fBottom) { + return false; + } + double denom = fDX * other.fDY - fDY * other.fDX; + if (denom == 0.0) { + return false; + } + double dx = static_cast(fTop->fPoint.fX) - other.fTop->fPoint.fX; + double dy = static_cast(fTop->fPoint.fY) - other.fTop->fPoint.fY; + double sNumer = dy * other.fDX - dx * other.fDY; + double tNumer = dy * fDX - dx * fDY; + // If (sNumer / denom) or (tNumer / denom) is not in [0..1], exit early. + // This saves us doing the divide below unless absolutely necessary. + if (denom > 0.0 ? (sNumer < 0.0 || sNumer > denom || tNumer < 0.0 || tNumer > denom) + : (sNumer > 0.0 || sNumer < denom || tNumer > 0.0 || tNumer < denom)) { + return false; + } + double s = sNumer / denom; + SkASSERT(s >= 0.0 && s <= 1.0); + p->fX = SkDoubleToScalar(fTop->fPoint.fX + s * fDX); + p->fY = SkDoubleToScalar(fTop->fPoint.fY + s * fDY); + return true; + } + bool isActive(EdgeList* activeEdges) const { + return activeEdges && (fLeft || fRight || activeEdges->fHead == this); + } +}; + +/***************************************************************************************/ + +struct Poly { + Poly(int winding) + : fWinding(winding) + , fHead(nullptr) + , fTail(nullptr) + , fActive(nullptr) + , fNext(nullptr) + , fPartner(nullptr) + , fCount(0) + { +#if LOGGING_ENABLED + static int gID = 0; + fID = gID++; + LOG("*** created Poly %d\n", fID); +#endif + } + typedef enum { kNeither_Side, kLeft_Side, kRight_Side } Side; + struct MonotonePoly { + MonotonePoly() + : fSide(kNeither_Side) + , fHead(nullptr) + , fTail(nullptr) + , fPrev(nullptr) + , fNext(nullptr) {} + Side fSide; + Vertex* fHead; + Vertex* fTail; + MonotonePoly* fPrev; + MonotonePoly* fNext; + bool addVertex(Vertex* v, Side side, SkChunkAlloc& alloc) { + Vertex* newV = ALLOC_NEW(Vertex, (v->fPoint), alloc); + bool done = false; + if (fSide == kNeither_Side) { + fSide = side; + } else { + done = side != fSide; + } + if (fHead == nullptr) { + fHead = fTail = newV; + } else if (fSide == kRight_Side) { + newV->fPrev = fTail; + fTail->fNext = newV; + fTail = newV; + } else { + newV->fNext = fHead; + fHead->fPrev = newV; + fHead = newV; + } + return done; + } + + SkPoint* emit(SkPoint* data) { + Vertex* first = fHead; + Vertex* v = first->fNext; + while (v != fTail) { + SkASSERT(v && v->fPrev && v->fNext); + Vertex* prev = v->fPrev; + Vertex* curr = v; + Vertex* next = v->fNext; + double ax = static_cast(curr->fPoint.fX) - prev->fPoint.fX; + double ay = static_cast(curr->fPoint.fY) - prev->fPoint.fY; + double bx = static_cast(next->fPoint.fX) - curr->fPoint.fX; + double by = static_cast(next->fPoint.fY) - curr->fPoint.fY; + if (ax * by - ay * bx >= 0.0) { + data = emit_triangle(prev, curr, next, data); + v->fPrev->fNext = v->fNext; + v->fNext->fPrev = v->fPrev; + if (v->fPrev == first) { + v = v->fNext; + } else { + v = v->fPrev; + } + } else { + v = v->fNext; + } + } + return data; + } + }; + Poly* addVertex(Vertex* v, Side side, SkChunkAlloc& alloc) { + LOG("addVertex() to %d at %g (%g, %g), %s side\n", fID, v->fID, v->fPoint.fX, v->fPoint.fY, + side == kLeft_Side ? "left" : side == kRight_Side ? "right" : "neither"); + Poly* partner = fPartner; + Poly* poly = this; + if (partner) { + fPartner = partner->fPartner = nullptr; + } + if (!fActive) { + fActive = ALLOC_NEW(MonotonePoly, (), alloc); + } + if (fActive->addVertex(v, side, alloc)) { + if (fTail) { + fActive->fPrev = fTail; + fTail->fNext = fActive; + fTail = fActive; + } else { + fHead = fTail = fActive; + } + if (partner) { + partner->addVertex(v, side, alloc); + poly = partner; + } else { + Vertex* prev = fActive->fSide == Poly::kLeft_Side ? + fActive->fHead->fNext : fActive->fTail->fPrev; + fActive = ALLOC_NEW(MonotonePoly, , alloc); + fActive->addVertex(prev, Poly::kNeither_Side, alloc); + fActive->addVertex(v, side, alloc); + } + } + fCount++; + return poly; + } + void end(Vertex* v, SkChunkAlloc& alloc) { + LOG("end() %d at %g, %g\n", fID, v->fPoint.fX, v->fPoint.fY); + if (fPartner) { + fPartner = fPartner->fPartner = nullptr; + } + addVertex(v, fActive->fSide == kLeft_Side ? kRight_Side : kLeft_Side, alloc); + } + SkPoint* emit(SkPoint *data) { + if (fCount < 3) { + return data; + } + LOG("emit() %d, size %d\n", fID, fCount); + for (MonotonePoly* m = fHead; m != nullptr; m = m->fNext) { + data = m->emit(data); + } + return data; + } + int fWinding; + MonotonePoly* fHead; + MonotonePoly* fTail; + MonotonePoly* fActive; + Poly* fNext; + Poly* fPartner; + int fCount; +#if LOGGING_ENABLED + int fID; +#endif +}; + +/***************************************************************************************/ + +bool coincident(const SkPoint& a, const SkPoint& b) { + return a == b; +} + +Poly* new_poly(Poly** head, Vertex* v, int winding, SkChunkAlloc& alloc) { + Poly* poly = ALLOC_NEW(Poly, (winding), alloc); + poly->addVertex(v, Poly::kNeither_Side, alloc); + poly->fNext = *head; + *head = poly; + return poly; +} + +Vertex* append_point_to_contour(const SkPoint& p, Vertex* prev, Vertex** head, + SkChunkAlloc& alloc) { + Vertex* v = ALLOC_NEW(Vertex, (p), alloc); +#if LOGGING_ENABLED + static float gID = 0.0f; + v->fID = gID++; +#endif + if (prev) { + prev->fNext = v; + v->fPrev = prev; + } else { + *head = v; + } + return v; +} + +Vertex* generate_quadratic_points(const SkPoint& p0, + const SkPoint& p1, + const SkPoint& p2, + SkScalar tolSqd, + Vertex* prev, + Vertex** head, + int pointsLeft, + SkChunkAlloc& alloc) { + SkScalar d = p1.distanceToLineSegmentBetweenSqd(p0, p2); + if (pointsLeft < 2 || d < tolSqd || !SkScalarIsFinite(d)) { + return append_point_to_contour(p2, prev, head, alloc); + } + + const SkPoint q[] = { + { SkScalarAve(p0.fX, p1.fX), SkScalarAve(p0.fY, p1.fY) }, + { SkScalarAve(p1.fX, p2.fX), SkScalarAve(p1.fY, p2.fY) }, + }; + const SkPoint r = { SkScalarAve(q[0].fX, q[1].fX), SkScalarAve(q[0].fY, q[1].fY) }; + + pointsLeft >>= 1; + prev = generate_quadratic_points(p0, q[0], r, tolSqd, prev, head, pointsLeft, alloc); + prev = generate_quadratic_points(r, q[1], p2, tolSqd, prev, head, pointsLeft, alloc); + return prev; +} + +Vertex* generate_cubic_points(const SkPoint& p0, + const SkPoint& p1, + const SkPoint& p2, + const SkPoint& p3, + SkScalar tolSqd, + Vertex* prev, + Vertex** head, + int pointsLeft, + SkChunkAlloc& alloc) { + SkScalar d1 = p1.distanceToLineSegmentBetweenSqd(p0, p3); + SkScalar d2 = p2.distanceToLineSegmentBetweenSqd(p0, p3); + if (pointsLeft < 2 || (d1 < tolSqd && d2 < tolSqd) || + !SkScalarIsFinite(d1) || !SkScalarIsFinite(d2)) { + return append_point_to_contour(p3, prev, head, alloc); + } + const SkPoint q[] = { + { SkScalarAve(p0.fX, p1.fX), SkScalarAve(p0.fY, p1.fY) }, + { SkScalarAve(p1.fX, p2.fX), SkScalarAve(p1.fY, p2.fY) }, + { SkScalarAve(p2.fX, p3.fX), SkScalarAve(p2.fY, p3.fY) } + }; + const SkPoint r[] = { + { SkScalarAve(q[0].fX, q[1].fX), SkScalarAve(q[0].fY, q[1].fY) }, + { SkScalarAve(q[1].fX, q[2].fX), SkScalarAve(q[1].fY, q[2].fY) } + }; + const SkPoint s = { SkScalarAve(r[0].fX, r[1].fX), SkScalarAve(r[0].fY, r[1].fY) }; + pointsLeft >>= 1; + prev = generate_cubic_points(p0, q[0], r[0], s, tolSqd, prev, head, pointsLeft, alloc); + prev = generate_cubic_points(s, r[1], q[2], p3, tolSqd, prev, head, pointsLeft, alloc); + return prev; +} + +// Stage 1: convert the input path to a set of linear contours (linked list of Vertices). + +void path_to_contours(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, + Vertex** contours, SkChunkAlloc& alloc, bool *isLinear) { + SkScalar toleranceSqd = tolerance * tolerance; + + SkPoint pts[4]; + bool done = false; + *isLinear = true; + SkPath::Iter iter(path, false); + Vertex* prev = nullptr; + Vertex* head = nullptr; + if (path.isInverseFillType()) { + SkPoint quad[4]; + clipBounds.toQuad(quad); + for (int i = 3; i >= 0; i--) { + prev = append_point_to_contour(quad[i], prev, &head, alloc); + } + head->fPrev = prev; + prev->fNext = head; + *contours++ = head; + head = prev = nullptr; + } + SkAutoConicToQuads converter; + while (!done) { + SkPath::Verb verb = iter.next(pts); + switch (verb) { + case SkPath::kConic_Verb: { + SkScalar weight = iter.conicWeight(); + const SkPoint* quadPts = converter.computeQuads(pts, weight, toleranceSqd); + for (int i = 0; i < converter.countQuads(); ++i) { + int pointsLeft = GrPathUtils::quadraticPointCount(quadPts, tolerance); + prev = generate_quadratic_points(quadPts[0], quadPts[1], quadPts[2], + toleranceSqd, prev, &head, pointsLeft, alloc); + quadPts += 2; + } + *isLinear = false; + break; + } + case SkPath::kMove_Verb: + if (head) { + head->fPrev = prev; + prev->fNext = head; + *contours++ = head; + } + head = prev = nullptr; + prev = append_point_to_contour(pts[0], prev, &head, alloc); + break; + case SkPath::kLine_Verb: { + prev = append_point_to_contour(pts[1], prev, &head, alloc); + break; + } + case SkPath::kQuad_Verb: { + int pointsLeft = GrPathUtils::quadraticPointCount(pts, tolerance); + prev = generate_quadratic_points(pts[0], pts[1], pts[2], toleranceSqd, prev, + &head, pointsLeft, alloc); + *isLinear = false; + break; + } + case SkPath::kCubic_Verb: { + int pointsLeft = GrPathUtils::cubicPointCount(pts, tolerance); + prev = generate_cubic_points(pts[0], pts[1], pts[2], pts[3], + toleranceSqd, prev, &head, pointsLeft, alloc); + *isLinear = false; + break; + } + case SkPath::kClose_Verb: + if (head) { + head->fPrev = prev; + prev->fNext = head; + *contours++ = head; + } + head = prev = nullptr; + break; + case SkPath::kDone_Verb: + if (head) { + head->fPrev = prev; + prev->fNext = head; + *contours++ = head; + } + done = true; + break; + } + } +} + +inline bool apply_fill_type(SkPath::FillType fillType, int winding) { + switch (fillType) { + case SkPath::kWinding_FillType: + return winding != 0; + case SkPath::kEvenOdd_FillType: + return (winding & 1) != 0; + case SkPath::kInverseWinding_FillType: + return winding == 1; + case SkPath::kInverseEvenOdd_FillType: + return (winding & 1) == 1; + default: + SkASSERT(false); + return false; + } +} + +Edge* new_edge(Vertex* prev, Vertex* next, SkChunkAlloc& alloc, Comparator& c) { + int winding = c.sweep_lt(prev->fPoint, next->fPoint) ? 1 : -1; + Vertex* top = winding < 0 ? next : prev; + Vertex* bottom = winding < 0 ? prev : next; + return ALLOC_NEW(Edge, (top, bottom, winding), alloc); +} + +void remove_edge(Edge* edge, EdgeList* edges) { + LOG("removing edge %g -> %g\n", edge->fTop->fID, edge->fBottom->fID); + SkASSERT(edge->isActive(edges)); + remove(edge, &edges->fHead, &edges->fTail); +} + +void insert_edge(Edge* edge, Edge* prev, EdgeList* edges) { + LOG("inserting edge %g -> %g\n", edge->fTop->fID, edge->fBottom->fID); + SkASSERT(!edge->isActive(edges)); + Edge* next = prev ? prev->fRight : edges->fHead; + insert(edge, prev, next, &edges->fHead, &edges->fTail); +} + +void find_enclosing_edges(Vertex* v, EdgeList* edges, Edge** left, Edge** right) { + if (v->fFirstEdgeAbove) { + *left = v->fFirstEdgeAbove->fLeft; + *right = v->fLastEdgeAbove->fRight; + return; + } + Edge* next = nullptr; + Edge* prev; + for (prev = edges->fTail; prev != nullptr; prev = prev->fLeft) { + if (prev->isLeftOf(v)) { + break; + } + next = prev; + } + *left = prev; + *right = next; + return; +} + +void find_enclosing_edges(Edge* edge, EdgeList* edges, Comparator& c, Edge** left, Edge** right) { + Edge* prev = nullptr; + Edge* next; + for (next = edges->fHead; next != nullptr; next = next->fRight) { + if ((c.sweep_gt(edge->fTop->fPoint, next->fTop->fPoint) && next->isRightOf(edge->fTop)) || + (c.sweep_gt(next->fTop->fPoint, edge->fTop->fPoint) && edge->isLeftOf(next->fTop)) || + (c.sweep_lt(edge->fBottom->fPoint, next->fBottom->fPoint) && + next->isRightOf(edge->fBottom)) || + (c.sweep_lt(next->fBottom->fPoint, edge->fBottom->fPoint) && + edge->isLeftOf(next->fBottom))) { + break; + } + prev = next; + } + *left = prev; + *right = next; + return; +} + +void fix_active_state(Edge* edge, EdgeList* activeEdges, Comparator& c) { + if (edge->isActive(activeEdges)) { + if (edge->fBottom->fProcessed || !edge->fTop->fProcessed) { + remove_edge(edge, activeEdges); + } + } else if (edge->fTop->fProcessed && !edge->fBottom->fProcessed) { + Edge* left; + Edge* right; + find_enclosing_edges(edge, activeEdges, c, &left, &right); + insert_edge(edge, left, activeEdges); + } +} + +void insert_edge_above(Edge* edge, Vertex* v, Comparator& c) { + if (edge->fTop->fPoint == edge->fBottom->fPoint || + c.sweep_gt(edge->fTop->fPoint, edge->fBottom->fPoint)) { + return; + } + LOG("insert edge (%g -> %g) above vertex %g\n", edge->fTop->fID, edge->fBottom->fID, v->fID); + Edge* prev = nullptr; + Edge* next; + for (next = v->fFirstEdgeAbove; next; next = next->fNextEdgeAbove) { + if (next->isRightOf(edge->fTop)) { + break; + } + prev = next; + } + insert( + edge, prev, next, &v->fFirstEdgeAbove, &v->fLastEdgeAbove); +} + +void insert_edge_below(Edge* edge, Vertex* v, Comparator& c) { + if (edge->fTop->fPoint == edge->fBottom->fPoint || + c.sweep_gt(edge->fTop->fPoint, edge->fBottom->fPoint)) { + return; + } + LOG("insert edge (%g -> %g) below vertex %g\n", edge->fTop->fID, edge->fBottom->fID, v->fID); + Edge* prev = nullptr; + Edge* next; + for (next = v->fFirstEdgeBelow; next; next = next->fNextEdgeBelow) { + if (next->isRightOf(edge->fBottom)) { + break; + } + prev = next; + } + insert( + edge, prev, next, &v->fFirstEdgeBelow, &v->fLastEdgeBelow); +} + +void remove_edge_above(Edge* edge) { + LOG("removing edge (%g -> %g) above vertex %g\n", edge->fTop->fID, edge->fBottom->fID, + edge->fBottom->fID); + remove( + edge, &edge->fBottom->fFirstEdgeAbove, &edge->fBottom->fLastEdgeAbove); +} + +void remove_edge_below(Edge* edge) { + LOG("removing edge (%g -> %g) below vertex %g\n", edge->fTop->fID, edge->fBottom->fID, + edge->fTop->fID); + remove( + edge, &edge->fTop->fFirstEdgeBelow, &edge->fTop->fLastEdgeBelow); +} + +void erase_edge_if_zero_winding(Edge* edge, EdgeList* edges) { + if (edge->fWinding != 0) { + return; + } + LOG("erasing edge (%g -> %g)\n", edge->fTop->fID, edge->fBottom->fID); + remove_edge_above(edge); + remove_edge_below(edge); + if (edge->isActive(edges)) { + remove_edge(edge, edges); + } +} + +void merge_collinear_edges(Edge* edge, EdgeList* activeEdges, Comparator& c); + +void set_top(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c) { + remove_edge_below(edge); + edge->fTop = v; + edge->recompute(); + insert_edge_below(edge, v, c); + fix_active_state(edge, activeEdges, c); + merge_collinear_edges(edge, activeEdges, c); +} + +void set_bottom(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c) { + remove_edge_above(edge); + edge->fBottom = v; + edge->recompute(); + insert_edge_above(edge, v, c); + fix_active_state(edge, activeEdges, c); + merge_collinear_edges(edge, activeEdges, c); +} + +void merge_edges_above(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c) { + if (coincident(edge->fTop->fPoint, other->fTop->fPoint)) { + LOG("merging coincident above edges (%g, %g) -> (%g, %g)\n", + edge->fTop->fPoint.fX, edge->fTop->fPoint.fY, + edge->fBottom->fPoint.fX, edge->fBottom->fPoint.fY); + other->fWinding += edge->fWinding; + erase_edge_if_zero_winding(other, activeEdges); + edge->fWinding = 0; + erase_edge_if_zero_winding(edge, activeEdges); + } else if (c.sweep_lt(edge->fTop->fPoint, other->fTop->fPoint)) { + other->fWinding += edge->fWinding; + erase_edge_if_zero_winding(other, activeEdges); + set_bottom(edge, other->fTop, activeEdges, c); + } else { + edge->fWinding += other->fWinding; + erase_edge_if_zero_winding(edge, activeEdges); + set_bottom(other, edge->fTop, activeEdges, c); + } +} + +void merge_edges_below(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c) { + if (coincident(edge->fBottom->fPoint, other->fBottom->fPoint)) { + LOG("merging coincident below edges (%g, %g) -> (%g, %g)\n", + edge->fTop->fPoint.fX, edge->fTop->fPoint.fY, + edge->fBottom->fPoint.fX, edge->fBottom->fPoint.fY); + other->fWinding += edge->fWinding; + erase_edge_if_zero_winding(other, activeEdges); + edge->fWinding = 0; + erase_edge_if_zero_winding(edge, activeEdges); + } else if (c.sweep_lt(edge->fBottom->fPoint, other->fBottom->fPoint)) { + edge->fWinding += other->fWinding; + erase_edge_if_zero_winding(edge, activeEdges); + set_top(other, edge->fBottom, activeEdges, c); + } else { + other->fWinding += edge->fWinding; + erase_edge_if_zero_winding(other, activeEdges); + set_top(edge, other->fBottom, activeEdges, c); + } +} + +void merge_collinear_edges(Edge* edge, EdgeList* activeEdges, Comparator& c) { + if (edge->fPrevEdgeAbove && (edge->fTop == edge->fPrevEdgeAbove->fTop || + !edge->fPrevEdgeAbove->isLeftOf(edge->fTop))) { + merge_edges_above(edge, edge->fPrevEdgeAbove, activeEdges, c); + } else if (edge->fNextEdgeAbove && (edge->fTop == edge->fNextEdgeAbove->fTop || + !edge->isLeftOf(edge->fNextEdgeAbove->fTop))) { + merge_edges_above(edge, edge->fNextEdgeAbove, activeEdges, c); + } + if (edge->fPrevEdgeBelow && (edge->fBottom == edge->fPrevEdgeBelow->fBottom || + !edge->fPrevEdgeBelow->isLeftOf(edge->fBottom))) { + merge_edges_below(edge, edge->fPrevEdgeBelow, activeEdges, c); + } else if (edge->fNextEdgeBelow && (edge->fBottom == edge->fNextEdgeBelow->fBottom || + !edge->isLeftOf(edge->fNextEdgeBelow->fBottom))) { + merge_edges_below(edge, edge->fNextEdgeBelow, activeEdges, c); + } +} + +void split_edge(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc); + +void cleanup_active_edges(Edge* edge, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc) { + Vertex* top = edge->fTop; + Vertex* bottom = edge->fBottom; + if (edge->fLeft) { + Vertex* leftTop = edge->fLeft->fTop; + Vertex* leftBottom = edge->fLeft->fBottom; + if (c.sweep_gt(top->fPoint, leftTop->fPoint) && !edge->fLeft->isLeftOf(top)) { + split_edge(edge->fLeft, edge->fTop, activeEdges, c, alloc); + } else if (c.sweep_gt(leftTop->fPoint, top->fPoint) && !edge->isRightOf(leftTop)) { + split_edge(edge, leftTop, activeEdges, c, alloc); + } else if (c.sweep_lt(bottom->fPoint, leftBottom->fPoint) && + !edge->fLeft->isLeftOf(bottom)) { + split_edge(edge->fLeft, bottom, activeEdges, c, alloc); + } else if (c.sweep_lt(leftBottom->fPoint, bottom->fPoint) && !edge->isRightOf(leftBottom)) { + split_edge(edge, leftBottom, activeEdges, c, alloc); + } + } + if (edge->fRight) { + Vertex* rightTop = edge->fRight->fTop; + Vertex* rightBottom = edge->fRight->fBottom; + if (c.sweep_gt(top->fPoint, rightTop->fPoint) && !edge->fRight->isRightOf(top)) { + split_edge(edge->fRight, top, activeEdges, c, alloc); + } else if (c.sweep_gt(rightTop->fPoint, top->fPoint) && !edge->isLeftOf(rightTop)) { + split_edge(edge, rightTop, activeEdges, c, alloc); + } else if (c.sweep_lt(bottom->fPoint, rightBottom->fPoint) && + !edge->fRight->isRightOf(bottom)) { + split_edge(edge->fRight, bottom, activeEdges, c, alloc); + } else if (c.sweep_lt(rightBottom->fPoint, bottom->fPoint) && + !edge->isLeftOf(rightBottom)) { + split_edge(edge, rightBottom, activeEdges, c, alloc); + } + } +} + +void split_edge(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc) { + LOG("splitting edge (%g -> %g) at vertex %g (%g, %g)\n", + edge->fTop->fID, edge->fBottom->fID, + v->fID, v->fPoint.fX, v->fPoint.fY); + if (c.sweep_lt(v->fPoint, edge->fTop->fPoint)) { + set_top(edge, v, activeEdges, c); + } else if (c.sweep_gt(v->fPoint, edge->fBottom->fPoint)) { + set_bottom(edge, v, activeEdges, c); + } else { + Edge* newEdge = ALLOC_NEW(Edge, (v, edge->fBottom, edge->fWinding), alloc); + insert_edge_below(newEdge, v, c); + insert_edge_above(newEdge, edge->fBottom, c); + set_bottom(edge, v, activeEdges, c); + cleanup_active_edges(edge, activeEdges, c, alloc); + fix_active_state(newEdge, activeEdges, c); + merge_collinear_edges(newEdge, activeEdges, c); + } +} + +void merge_vertices(Vertex* src, Vertex* dst, Vertex** head, Comparator& c, SkChunkAlloc& alloc) { + LOG("found coincident verts at %g, %g; merging %g into %g\n", src->fPoint.fX, src->fPoint.fY, + src->fID, dst->fID); + for (Edge* edge = src->fFirstEdgeAbove; edge;) { + Edge* next = edge->fNextEdgeAbove; + set_bottom(edge, dst, nullptr, c); + edge = next; + } + for (Edge* edge = src->fFirstEdgeBelow; edge;) { + Edge* next = edge->fNextEdgeBelow; + set_top(edge, dst, nullptr, c); + edge = next; + } + remove(src, head, nullptr); +} + +Vertex* check_for_intersection(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c, + SkChunkAlloc& alloc) { + SkPoint p; + if (!edge || !other) { + return nullptr; + } + if (edge->intersect(*other, &p)) { + Vertex* v; + LOG("found intersection, pt is %g, %g\n", p.fX, p.fY); + if (p == edge->fTop->fPoint || c.sweep_lt(p, edge->fTop->fPoint)) { + split_edge(other, edge->fTop, activeEdges, c, alloc); + v = edge->fTop; + } else if (p == edge->fBottom->fPoint || c.sweep_gt(p, edge->fBottom->fPoint)) { + split_edge(other, edge->fBottom, activeEdges, c, alloc); + v = edge->fBottom; + } else if (p == other->fTop->fPoint || c.sweep_lt(p, other->fTop->fPoint)) { + split_edge(edge, other->fTop, activeEdges, c, alloc); + v = other->fTop; + } else if (p == other->fBottom->fPoint || c.sweep_gt(p, other->fBottom->fPoint)) { + split_edge(edge, other->fBottom, activeEdges, c, alloc); + v = other->fBottom; + } else { + Vertex* nextV = edge->fTop; + while (c.sweep_lt(p, nextV->fPoint)) { + nextV = nextV->fPrev; + } + while (c.sweep_lt(nextV->fPoint, p)) { + nextV = nextV->fNext; + } + Vertex* prevV = nextV->fPrev; + if (coincident(prevV->fPoint, p)) { + v = prevV; + } else if (coincident(nextV->fPoint, p)) { + v = nextV; + } else { + v = ALLOC_NEW(Vertex, (p), alloc); + LOG("inserting between %g (%g, %g) and %g (%g, %g)\n", + prevV->fID, prevV->fPoint.fX, prevV->fPoint.fY, + nextV->fID, nextV->fPoint.fX, nextV->fPoint.fY); +#if LOGGING_ENABLED + v->fID = (nextV->fID + prevV->fID) * 0.5f; +#endif + v->fPrev = prevV; + v->fNext = nextV; + prevV->fNext = v; + nextV->fPrev = v; + } + split_edge(edge, v, activeEdges, c, alloc); + split_edge(other, v, activeEdges, c, alloc); + } + return v; + } + return nullptr; +} + +void sanitize_contours(Vertex** contours, int contourCnt) { + for (int i = 0; i < contourCnt; ++i) { + SkASSERT(contours[i]); + for (Vertex* v = contours[i];;) { + if (coincident(v->fPrev->fPoint, v->fPoint)) { + LOG("vertex %g,%g coincident; removing\n", v->fPoint.fX, v->fPoint.fY); + if (v->fPrev == v) { + contours[i] = nullptr; + break; + } + v->fPrev->fNext = v->fNext; + v->fNext->fPrev = v->fPrev; + if (contours[i] == v) { + contours[i] = v->fNext; + } + v = v->fPrev; + } else { + v = v->fNext; + if (v == contours[i]) break; + } + } + } +} + +void merge_coincident_vertices(Vertex** vertices, Comparator& c, SkChunkAlloc& alloc) { + for (Vertex* v = (*vertices)->fNext; v != nullptr; v = v->fNext) { + if (c.sweep_lt(v->fPoint, v->fPrev->fPoint)) { + v->fPoint = v->fPrev->fPoint; + } + if (coincident(v->fPrev->fPoint, v->fPoint)) { + merge_vertices(v->fPrev, v, vertices, c, alloc); + } + } +} + +// Stage 2: convert the contours to a mesh of edges connecting the vertices. + +Vertex* build_edges(Vertex** contours, int contourCnt, Comparator& c, SkChunkAlloc& alloc) { + Vertex* vertices = nullptr; + Vertex* prev = nullptr; + for (int i = 0; i < contourCnt; ++i) { + for (Vertex* v = contours[i]; v != nullptr;) { + Vertex* vNext = v->fNext; + Edge* edge = new_edge(v->fPrev, v, alloc, c); + if (edge->fWinding > 0) { + insert_edge_below(edge, v->fPrev, c); + insert_edge_above(edge, v, c); + } else { + insert_edge_below(edge, v, c); + insert_edge_above(edge, v->fPrev, c); + } + merge_collinear_edges(edge, nullptr, c); + if (prev) { + prev->fNext = v; + v->fPrev = prev; + } else { + vertices = v; + } + prev = v; + v = vNext; + if (v == contours[i]) break; + } + } + if (prev) { + prev->fNext = vertices->fPrev = nullptr; + } + return vertices; +} + +// Stage 3: sort the vertices by increasing sweep direction. + +Vertex* sorted_merge(Vertex* a, Vertex* b, Comparator& c); + +void front_back_split(Vertex* v, Vertex** pFront, Vertex** pBack) { + Vertex* fast; + Vertex* slow; + if (!v || !v->fNext) { + *pFront = v; + *pBack = nullptr; + } else { + slow = v; + fast = v->fNext; + + while (fast != nullptr) { + fast = fast->fNext; + if (fast != nullptr) { + slow = slow->fNext; + fast = fast->fNext; + } + } + + *pFront = v; + *pBack = slow->fNext; + slow->fNext->fPrev = nullptr; + slow->fNext = nullptr; + } +} + +void merge_sort(Vertex** head, Comparator& c) { + if (!*head || !(*head)->fNext) { + return; + } + + Vertex* a; + Vertex* b; + front_back_split(*head, &a, &b); + + merge_sort(&a, c); + merge_sort(&b, c); + + *head = sorted_merge(a, b, c); +} + +inline void append_vertex(Vertex* v, Vertex** head, Vertex** tail) { + insert(v, *tail, nullptr, head, tail); +} + +inline void append_vertex_list(Vertex* v, Vertex** head, Vertex** tail) { + insert(v, *tail, v->fNext, head, tail); +} + +Vertex* sorted_merge(Vertex* a, Vertex* b, Comparator& c) { + Vertex* head = nullptr; + Vertex* tail = nullptr; + + while (a && b) { + if (c.sweep_lt(a->fPoint, b->fPoint)) { + Vertex* next = a->fNext; + append_vertex(a, &head, &tail); + a = next; + } else { + Vertex* next = b->fNext; + append_vertex(b, &head, &tail); + b = next; + } + } + if (a) { + append_vertex_list(a, &head, &tail); + } + if (b) { + append_vertex_list(b, &head, &tail); + } + return head; +} + +// Stage 4: Simplify the mesh by inserting new vertices at intersecting edges. + +void simplify(Vertex* vertices, Comparator& c, SkChunkAlloc& alloc) { + LOG("simplifying complex polygons\n"); + EdgeList activeEdges; + for (Vertex* v = vertices; v != nullptr; v = v->fNext) { + if (!v->fFirstEdgeAbove && !v->fFirstEdgeBelow) { + continue; + } +#if LOGGING_ENABLED + LOG("\nvertex %g: (%g,%g)\n", v->fID, v->fPoint.fX, v->fPoint.fY); +#endif + Edge* leftEnclosingEdge = nullptr; + Edge* rightEnclosingEdge = nullptr; + bool restartChecks; + do { + restartChecks = false; + find_enclosing_edges(v, &activeEdges, &leftEnclosingEdge, &rightEnclosingEdge); + if (v->fFirstEdgeBelow) { + for (Edge* edge = v->fFirstEdgeBelow; edge != nullptr; edge = edge->fNextEdgeBelow) { + if (check_for_intersection(edge, leftEnclosingEdge, &activeEdges, c, alloc)) { + restartChecks = true; + break; + } + if (check_for_intersection(edge, rightEnclosingEdge, &activeEdges, c, alloc)) { + restartChecks = true; + break; + } + } + } else { + if (Vertex* pv = check_for_intersection(leftEnclosingEdge, rightEnclosingEdge, + &activeEdges, c, alloc)) { + if (c.sweep_lt(pv->fPoint, v->fPoint)) { + v = pv; + } + restartChecks = true; + } + + } + } while (restartChecks); + for (Edge* e = v->fFirstEdgeAbove; e; e = e->fNextEdgeAbove) { + remove_edge(e, &activeEdges); + } + Edge* leftEdge = leftEnclosingEdge; + for (Edge* e = v->fFirstEdgeBelow; e; e = e->fNextEdgeBelow) { + insert_edge(e, leftEdge, &activeEdges); + leftEdge = e; + } + v->fProcessed = true; + } +} + +// Stage 5: Tessellate the simplified mesh into monotone polygons. + +Poly* tessellate(Vertex* vertices, SkChunkAlloc& alloc) { + LOG("tessellating simple polygons\n"); + EdgeList activeEdges; + Poly* polys = nullptr; + for (Vertex* v = vertices; v != nullptr; v = v->fNext) { + if (!v->fFirstEdgeAbove && !v->fFirstEdgeBelow) { + continue; + } +#if LOGGING_ENABLED + LOG("\nvertex %g: (%g,%g)\n", v->fID, v->fPoint.fX, v->fPoint.fY); +#endif + Edge* leftEnclosingEdge = nullptr; + Edge* rightEnclosingEdge = nullptr; + find_enclosing_edges(v, &activeEdges, &leftEnclosingEdge, &rightEnclosingEdge); + Poly* leftPoly = nullptr; + Poly* rightPoly = nullptr; + if (v->fFirstEdgeAbove) { + leftPoly = v->fFirstEdgeAbove->fLeftPoly; + rightPoly = v->fLastEdgeAbove->fRightPoly; + } else { + leftPoly = leftEnclosingEdge ? leftEnclosingEdge->fRightPoly : nullptr; + rightPoly = rightEnclosingEdge ? rightEnclosingEdge->fLeftPoly : nullptr; + } +#if LOGGING_ENABLED + LOG("edges above:\n"); + for (Edge* e = v->fFirstEdgeAbove; e; e = e->fNextEdgeAbove) { + LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, + e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); + } + LOG("edges below:\n"); + for (Edge* e = v->fFirstEdgeBelow; e; e = e->fNextEdgeBelow) { + LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, + e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); + } +#endif + if (v->fFirstEdgeAbove) { + if (leftPoly) { + leftPoly = leftPoly->addVertex(v, Poly::kRight_Side, alloc); + } + if (rightPoly) { + rightPoly = rightPoly->addVertex(v, Poly::kLeft_Side, alloc); + } + for (Edge* e = v->fFirstEdgeAbove; e != v->fLastEdgeAbove; e = e->fNextEdgeAbove) { + Edge* leftEdge = e; + Edge* rightEdge = e->fNextEdgeAbove; + SkASSERT(rightEdge->isRightOf(leftEdge->fTop)); + remove_edge(leftEdge, &activeEdges); + if (leftEdge->fRightPoly) { + leftEdge->fRightPoly->end(v, alloc); + } + if (rightEdge->fLeftPoly && rightEdge->fLeftPoly != leftEdge->fRightPoly) { + rightEdge->fLeftPoly->end(v, alloc); + } + } + remove_edge(v->fLastEdgeAbove, &activeEdges); + if (!v->fFirstEdgeBelow) { + if (leftPoly && rightPoly && leftPoly != rightPoly) { + SkASSERT(leftPoly->fPartner == nullptr && rightPoly->fPartner == nullptr); + rightPoly->fPartner = leftPoly; + leftPoly->fPartner = rightPoly; + } + } + } + if (v->fFirstEdgeBelow) { + if (!v->fFirstEdgeAbove) { + if (leftPoly && leftPoly == rightPoly) { + // Split the poly. + if (leftPoly->fActive->fSide == Poly::kLeft_Side) { + leftPoly = new_poly(&polys, leftEnclosingEdge->fTop, leftPoly->fWinding, + alloc); + leftPoly->addVertex(v, Poly::kRight_Side, alloc); + rightPoly->addVertex(v, Poly::kLeft_Side, alloc); + leftEnclosingEdge->fRightPoly = leftPoly; + } else { + rightPoly = new_poly(&polys, rightEnclosingEdge->fTop, rightPoly->fWinding, + alloc); + rightPoly->addVertex(v, Poly::kLeft_Side, alloc); + leftPoly->addVertex(v, Poly::kRight_Side, alloc); + rightEnclosingEdge->fLeftPoly = rightPoly; + } + } else { + if (leftPoly) { + leftPoly = leftPoly->addVertex(v, Poly::kRight_Side, alloc); + } + if (rightPoly) { + rightPoly = rightPoly->addVertex(v, Poly::kLeft_Side, alloc); + } + } + } + Edge* leftEdge = v->fFirstEdgeBelow; + leftEdge->fLeftPoly = leftPoly; + insert_edge(leftEdge, leftEnclosingEdge, &activeEdges); + for (Edge* rightEdge = leftEdge->fNextEdgeBelow; rightEdge; + rightEdge = rightEdge->fNextEdgeBelow) { + insert_edge(rightEdge, leftEdge, &activeEdges); + int winding = leftEdge->fLeftPoly ? leftEdge->fLeftPoly->fWinding : 0; + winding += leftEdge->fWinding; + if (winding != 0) { + Poly* poly = new_poly(&polys, v, winding, alloc); + leftEdge->fRightPoly = rightEdge->fLeftPoly = poly; + } + leftEdge = rightEdge; + } + v->fLastEdgeBelow->fRightPoly = rightPoly; + } +#if LOGGING_ENABLED + LOG("\nactive edges:\n"); + for (Edge* e = activeEdges.fHead; e != nullptr; e = e->fRight) { + LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, + e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); + } +#endif + } + return polys; +} + +// This is a driver function which calls stages 2-5 in turn. + +Poly* contours_to_polys(Vertex** contours, int contourCnt, const SkRect& pathBounds, + SkChunkAlloc& alloc) { + Comparator c; + if (pathBounds.width() > pathBounds.height()) { + c.sweep_lt = sweep_lt_horiz; + c.sweep_gt = sweep_gt_horiz; + } else { + c.sweep_lt = sweep_lt_vert; + c.sweep_gt = sweep_gt_vert; + } +#if LOGGING_ENABLED + for (int i = 0; i < contourCnt; ++i) { + Vertex* v = contours[i]; + SkASSERT(v); + LOG("path.moveTo(%20.20g, %20.20g);\n", v->fPoint.fX, v->fPoint.fY); + for (v = v->fNext; v != contours[i]; v = v->fNext) { + LOG("path.lineTo(%20.20g, %20.20g);\n", v->fPoint.fX, v->fPoint.fY); + } + } +#endif + sanitize_contours(contours, contourCnt); + Vertex* vertices = build_edges(contours, contourCnt, c, alloc); + if (!vertices) { + return nullptr; + } + + // Sort vertices in Y (secondarily in X). + merge_sort(&vertices, c); + merge_coincident_vertices(&vertices, c, alloc); +#if LOGGING_ENABLED + for (Vertex* v = vertices; v != nullptr; v = v->fNext) { + static float gID = 0.0f; + v->fID = gID++; + } +#endif + simplify(vertices, c, alloc); + return tessellate(vertices, alloc); +} + +Poly* path_to_polys(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, + int contourCnt, SkChunkAlloc& alloc, bool* isLinear) { + SkPath::FillType fillType = path.getFillType(); + if (SkPath::IsInverseFillType(fillType)) { + contourCnt++; + } + SkAutoTDeleteArray contours(new Vertex* [contourCnt]); + + path_to_contours(path, tolerance, clipBounds, contours.get(), alloc, isLinear); + return contours_to_polys(contours.get(), contourCnt, path.getBounds(), alloc); +} + +void get_contour_count_and_size_estimate(const SkPath& path, SkScalar tolerance, int* contourCnt, + int* sizeEstimate) { + int maxPts = GrPathUtils::worstCasePointCount(path, contourCnt, tolerance); + if (maxPts <= 0) { + *contourCnt = 0; + return; + } + if (maxPts > ((int)SK_MaxU16 + 1)) { + SkDebugf("Path not rendered, too many verts (%d)\n", maxPts); + *contourCnt = 0; + return; + } + // For the initial size of the chunk allocator, estimate based on the point count: + // one vertex per point for the initial passes, plus two for the vertices in the + // resulting Polys, since the same point may end up in two Polys. Assume minimal + // connectivity of one Edge per Vertex (will grow for intersections). + *sizeEstimate = maxPts * (3 * sizeof(Vertex) + sizeof(Edge)); +} + +int count_points(Poly* polys, SkPath::FillType fillType) { + int count = 0; + for (Poly* poly = polys; poly; poly = poly->fNext) { + if (apply_fill_type(fillType, poly->fWinding) && poly->fCount >= 3) { + count += (poly->fCount - 2) * (TESSELLATOR_WIREFRAME ? 6 : 3); + } + } + return count; +} + +} // namespace + +namespace GrTessellator { + +// Stage 6: Triangulate the monotone polygons into a vertex buffer. + +int PathToTriangles(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, + GrResourceProvider* resourceProvider, + SkAutoTUnref& vertexBuffer, bool canMapVB, bool* isLinear) { + int contourCnt; + int sizeEstimate; + get_contour_count_and_size_estimate(path, tolerance, &contourCnt, &sizeEstimate); + if (contourCnt <= 0) { + return 0; + } + SkChunkAlloc alloc(sizeEstimate); + Poly* polys = path_to_polys(path, tolerance, clipBounds, contourCnt, alloc, isLinear); + SkPath::FillType fillType = path.getFillType(); + int count = count_points(polys, fillType); + if (0 == count) { + return 0; + } + + size_t size = count * sizeof(SkPoint); + if (!vertexBuffer.get() || vertexBuffer->gpuMemorySize() < size) { + vertexBuffer.reset(resourceProvider->createVertexBuffer( + size, GrResourceProvider::kStatic_BufferUsage, 0)); + } + if (!vertexBuffer.get()) { + SkDebugf("Could not allocate vertices\n"); + return 0; + } + SkPoint* verts; + if (canMapVB) { + verts = static_cast(vertexBuffer->map()); + } else { + verts = new SkPoint[count]; + } + SkPoint* end = verts; + for (Poly* poly = polys; poly; poly = poly->fNext) { + if (apply_fill_type(fillType, poly->fWinding)) { + end = poly->emit(end); + } + } + int actualCount = static_cast(end - verts); + LOG("actual count: %d\n", actualCount); + SkASSERT(actualCount <= count); + if (canMapVB) { + vertexBuffer->unmap(); + } else { + vertexBuffer->updateData(verts, actualCount * sizeof(SkPoint)); + delete[] verts; + } + + return actualCount; +} + +int PathToVertices(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, + GrTessellator::WindingVertex** verts) { + int contourCnt; + int sizeEstimate; + get_contour_count_and_size_estimate(path, tolerance, &contourCnt, &sizeEstimate); + if (contourCnt <= 0) { + return 0; + } + SkChunkAlloc alloc(sizeEstimate); + bool isLinear; + Poly* polys = path_to_polys(path, tolerance, clipBounds, contourCnt, alloc, &isLinear); + SkPath::FillType fillType = path.getFillType(); + int count = count_points(polys, fillType); + if (0 == count) { + *verts = nullptr; + return 0; + } + + *verts = new GrTessellator::WindingVertex[count]; + GrTessellator::WindingVertex* vertsEnd = *verts; + SkPoint* points = new SkPoint[count]; + SkPoint* pointsEnd = points; + for (Poly* poly = polys; poly; poly = poly->fNext) { + if (apply_fill_type(fillType, poly->fWinding)) { + SkPoint* start = pointsEnd; + pointsEnd = poly->emit(pointsEnd); + while (start != pointsEnd) { + vertsEnd->fPos = *start; + vertsEnd->fWinding = poly->fWinding; + ++start; + ++vertsEnd; + } + } + } + int actualCount = static_cast(vertsEnd - *verts); + SkASSERT(actualCount <= count); + SkASSERT(pointsEnd - points == actualCount); + delete[] points; + return actualCount; +} + +} // namespace diff --git a/src/gpu/GrTessellator.h b/src/gpu/GrTessellator.h new file mode 100644 index 0000000000..4304920fbc --- /dev/null +++ b/src/gpu/GrTessellator.h @@ -0,0 +1,40 @@ +/* + * Copyright 2015 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#ifndef GrTessellator_DEFINED +#define GrTessellator_DEFINED + +#include "SkPath.h" +#include "GrResourceProvider.h" + +/** + * Provides utility functions for converting paths to a collection of triangles. + */ + +#define TESSELLATOR_WIREFRAME 0 + +namespace GrTessellator { + +struct WindingVertex { + SkPoint fPos; + int fWinding; +}; + +// Triangulates a path to an array of vertices. Each triangle is represented as a set of three +// WindingVertex entries, each of which contains the position and winding count (which is the same +// for all three vertices of a triangle). The 'verts' out parameter is set to point to the resultant +// vertex array. CALLER IS RESPONSIBLE for deleting this buffer to avoid a memory leak! +int PathToVertices(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, + WindingVertex** verts); + +int PathToTriangles(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, + GrResourceProvider* resourceProvider, + SkAutoTUnref& vertexBuffer, bool canMapVB, bool* isLinear); + +} + +#endif diff --git a/src/gpu/batches/GrTessellatingPathRenderer.cpp b/src/gpu/batches/GrTessellatingPathRenderer.cpp index 27e287e9c6..36b6d657cf 100644 --- a/src/gpu/batches/GrTessellatingPathRenderer.cpp +++ b/src/gpu/batches/GrTessellatingPathRenderer.cpp @@ -14,7 +14,7 @@ #include "GrVertices.h" #include "GrResourceCache.h" #include "GrResourceProvider.h" -#include "SkChunkAlloc.h" +#include "GrTessellator.h" #include "SkGeometry.h" #include "batches/GrVertexBatch.h" @@ -22,1322 +22,27 @@ #include /* - * This path renderer tessellates the path into triangles, uploads the triangles to a - * vertex buffer, and renders them with a single draw call. It does not currently do + * This path renderer tessellates the path into triangles using GrTessellator, uploads the triangles + * to a vertex buffer, and renders them with a single draw call. It does not currently do * antialiasing, so it must be used in conjunction with multisampling. - * - * There are six stages to the algorithm: - * - * 1) Linearize the path contours into piecewise linear segments (path_to_contours()). - * 2) Build a mesh of edges connecting the vertices (build_edges()). - * 3) Sort the vertices in Y (and secondarily in X) (merge_sort()). - * 4) Simplify the mesh by inserting new vertices at intersecting edges (simplify()). - * 5) Tessellate the simplified mesh into monotone polygons (tessellate()). - * 6) Triangulate the monotone polygons directly into a vertex buffer (polys_to_triangles()). - * - * The vertex sorting in step (3) is a merge sort, since it plays well with the linked list - * of vertices (and the necessity of inserting new vertices on intersection). - * - * Stages (4) and (5) use an active edge list, which a list of all edges for which the - * sweep line has crossed the top vertex, but not the bottom vertex. It's sorted - * left-to-right based on the point where both edges are active (when both top vertices - * have been seen, so the "lower" top vertex of the two). If the top vertices are equal - * (shared), it's sorted based on the last point where both edges are active, so the - * "upper" bottom vertex. - * - * The most complex step is the simplification (4). It's based on the Bentley-Ottman - * line-sweep algorithm, but due to floating point inaccuracy, the intersection points are - * not exact and may violate the mesh topology or active edge list ordering. We - * accommodate this by adjusting the topology of the mesh and AEL to match the intersection - * points. This occurs in three ways: - * - * A) Intersections may cause a shortened edge to no longer be ordered with respect to its - * neighbouring edges at the top or bottom vertex. This is handled by merging the - * edges (merge_collinear_edges()). - * B) Intersections may cause an edge to violate the left-to-right ordering of the - * active edge list. This is handled by splitting the neighbour edge on the - * intersected vertex (cleanup_active_edges()). - * C) Shortening an edge may cause an active edge to become inactive or an inactive edge - * to become active. This is handled by removing or inserting the edge in the active - * edge list (fix_active_state()). - * - * The tessellation steps (5) and (6) are based on "Triangulating Simple Polygons and - * Equivalent Problems" (Fournier and Montuno); also a line-sweep algorithm. Note that it - * currently uses a linked list for the active edge list, rather than a 2-3 tree as the - * paper describes. The 2-3 tree gives O(lg N) lookups, but insertion and removal also - * become O(lg N). In all the test cases, it was found that the cost of frequent O(lg N) - * insertions and removals was greater than the cost of infrequent O(N) lookups with the - * linked list implementation. With the latter, all removals are O(1), and most insertions - * are O(1), since we know the adjacent edge in the active edge list based on the topology. - * Only type 2 vertices (see paper) require the O(N) lookups, and these are much less - * frequent. There may be other data structures worth investigating, however. - * - * Note that the orientation of the line sweep algorithms is determined by the aspect ratio of the - * path bounds. When the path is taller than it is wide, we sort vertices based on increasing Y - * coordinate, and secondarily by increasing X coordinate. When the path is wider than it is tall, - * we sort by increasing X coordinate, but secondarily by *decreasing* Y coordinate. This is so - * that the "left" and "right" orientation in the code remains correct (edges to the left are - * increasing in Y; edges to the right are decreasing in Y). That is, the setting rotates 90 - * degrees counterclockwise, rather that transposing. */ -#define LOGGING_ENABLED 0 -#define WIREFRAME 0 - -#if LOGGING_ENABLED -#define LOG printf -#else -#define LOG(...) -#endif - -#define ALLOC_NEW(Type, args, alloc) new (alloc.allocThrow(sizeof(Type))) Type args - namespace { -struct Vertex; -struct Edge; -struct Poly; - -template -void insert(T* t, T* prev, T* next, T** head, T** tail) { - t->*Prev = prev; - t->*Next = next; - if (prev) { - prev->*Next = t; - } else if (head) { - *head = t; - } - if (next) { - next->*Prev = t; - } else if (tail) { - *tail = t; - } -} - -template -void remove(T* t, T** head, T** tail) { - if (t->*Prev) { - t->*Prev->*Next = t->*Next; - } else if (head) { - *head = t->*Next; - } - if (t->*Next) { - t->*Next->*Prev = t->*Prev; - } else if (tail) { - *tail = t->*Prev; - } - t->*Prev = t->*Next = nullptr; -} - -/** - * Vertices are used in three ways: first, the path contours are converted into a - * circularly-linked list of Vertices for each contour. After edge construction, the same Vertices - * are re-ordered by the merge sort according to the sweep_lt comparator (usually, increasing - * in Y) using the same fPrev/fNext pointers that were used for the contours, to avoid - * reallocation. Finally, MonotonePolys are built containing a circularly-linked list of - * Vertices. (Currently, those Vertices are newly-allocated for the MonotonePolys, since - * an individual Vertex from the path mesh may belong to multiple - * MonotonePolys, so the original Vertices cannot be re-used. - */ - -struct Vertex { - Vertex(const SkPoint& point) - : fPoint(point), fPrev(nullptr), fNext(nullptr) - , fFirstEdgeAbove(nullptr), fLastEdgeAbove(nullptr) - , fFirstEdgeBelow(nullptr), fLastEdgeBelow(nullptr) - , fProcessed(false) -#if LOGGING_ENABLED - , fID (-1.0f) -#endif - {} - SkPoint fPoint; // Vertex position - Vertex* fPrev; // Linked list of contours, then Y-sorted vertices. - Vertex* fNext; // " - Edge* fFirstEdgeAbove; // Linked list of edges above this vertex. - Edge* fLastEdgeAbove; // " - Edge* fFirstEdgeBelow; // Linked list of edges below this vertex. - Edge* fLastEdgeBelow; // " - bool fProcessed; // Has this vertex been seen in simplify()? -#if LOGGING_ENABLED - float fID; // Identifier used for logging. -#endif -}; - -/***************************************************************************************/ - -typedef bool (*CompareFunc)(const SkPoint& a, const SkPoint& b); - -struct Comparator { - CompareFunc sweep_lt; - CompareFunc sweep_gt; -}; - -bool sweep_lt_horiz(const SkPoint& a, const SkPoint& b) { - return a.fX == b.fX ? a.fY > b.fY : a.fX < b.fX; -} - -bool sweep_lt_vert(const SkPoint& a, const SkPoint& b) { - return a.fY == b.fY ? a.fX < b.fX : a.fY < b.fY; -} - -bool sweep_gt_horiz(const SkPoint& a, const SkPoint& b) { - return a.fX == b.fX ? a.fY < b.fY : a.fX > b.fX; -} - -bool sweep_gt_vert(const SkPoint& a, const SkPoint& b) { - return a.fY == b.fY ? a.fX > b.fX : a.fY > b.fY; -} - -inline SkPoint* emit_vertex(Vertex* v, SkPoint* data) { - *data++ = v->fPoint; - return data; -} - -SkPoint* emit_triangle(Vertex* v0, Vertex* v1, Vertex* v2, SkPoint* data) { -#if WIREFRAME - data = emit_vertex(v0, data); - data = emit_vertex(v1, data); - data = emit_vertex(v1, data); - data = emit_vertex(v2, data); - data = emit_vertex(v2, data); - data = emit_vertex(v0, data); -#else - data = emit_vertex(v0, data); - data = emit_vertex(v1, data); - data = emit_vertex(v2, data); -#endif - return data; -} - -struct EdgeList { - EdgeList() : fHead(nullptr), fTail(nullptr) {} - Edge* fHead; - Edge* fTail; -}; - -/** - * An Edge joins a top Vertex to a bottom Vertex. Edge ordering for the list of "edges above" and - * "edge below" a vertex as well as for the active edge list is handled by isLeftOf()/isRightOf(). - * Note that an Edge will give occasionally dist() != 0 for its own endpoints (because floating - * point). For speed, that case is only tested by the callers which require it (e.g., - * cleanup_active_edges()). Edges also handle checking for intersection with other edges. - * Currently, this converts the edges to the parametric form, in order to avoid doing a division - * until an intersection has been confirmed. This is slightly slower in the "found" case, but - * a lot faster in the "not found" case. - * - * The coefficients of the line equation stored in double precision to avoid catastrphic - * cancellation in the isLeftOf() and isRightOf() checks. Using doubles ensures that the result is - * correct in float, since it's a polynomial of degree 2. The intersect() function, being - * degree 5, is still subject to catastrophic cancellation. We deal with that by assuming its - * output may be incorrect, and adjusting the mesh topology to match (see comment at the top of - * this file). - */ - -struct Edge { - Edge(Vertex* top, Vertex* bottom, int winding) - : fWinding(winding) - , fTop(top) - , fBottom(bottom) - , fLeft(nullptr) - , fRight(nullptr) - , fPrevEdgeAbove(nullptr) - , fNextEdgeAbove(nullptr) - , fPrevEdgeBelow(nullptr) - , fNextEdgeBelow(nullptr) - , fLeftPoly(nullptr) - , fRightPoly(nullptr) { - recompute(); - } - int fWinding; // 1 == edge goes downward; -1 = edge goes upward. - Vertex* fTop; // The top vertex in vertex-sort-order (sweep_lt). - Vertex* fBottom; // The bottom vertex in vertex-sort-order. - Edge* fLeft; // The linked list of edges in the active edge list. - Edge* fRight; // " - Edge* fPrevEdgeAbove; // The linked list of edges in the bottom Vertex's "edges above". - Edge* fNextEdgeAbove; // " - Edge* fPrevEdgeBelow; // The linked list of edges in the top Vertex's "edges below". - Edge* fNextEdgeBelow; // " - Poly* fLeftPoly; // The Poly to the left of this edge, if any. - Poly* fRightPoly; // The Poly to the right of this edge, if any. - double fDX; // The line equation for this edge, in implicit form. - double fDY; // fDY * x + fDX * y + fC = 0, for point (x, y) on the line. - double fC; - double dist(const SkPoint& p) const { - return fDY * p.fX - fDX * p.fY + fC; - } - bool isRightOf(Vertex* v) const { - return dist(v->fPoint) < 0.0; - } - bool isLeftOf(Vertex* v) const { - return dist(v->fPoint) > 0.0; - } - void recompute() { - fDX = static_cast(fBottom->fPoint.fX) - fTop->fPoint.fX; - fDY = static_cast(fBottom->fPoint.fY) - fTop->fPoint.fY; - fC = static_cast(fTop->fPoint.fY) * fBottom->fPoint.fX - - static_cast(fTop->fPoint.fX) * fBottom->fPoint.fY; - } - bool intersect(const Edge& other, SkPoint* p) { - LOG("intersecting %g -> %g with %g -> %g\n", - fTop->fID, fBottom->fID, - other.fTop->fID, other.fBottom->fID); - if (fTop == other.fTop || fBottom == other.fBottom) { - return false; - } - double denom = fDX * other.fDY - fDY * other.fDX; - if (denom == 0.0) { - return false; - } - double dx = static_cast(fTop->fPoint.fX) - other.fTop->fPoint.fX; - double dy = static_cast(fTop->fPoint.fY) - other.fTop->fPoint.fY; - double sNumer = dy * other.fDX - dx * other.fDY; - double tNumer = dy * fDX - dx * fDY; - // If (sNumer / denom) or (tNumer / denom) is not in [0..1], exit early. - // This saves us doing the divide below unless absolutely necessary. - if (denom > 0.0 ? (sNumer < 0.0 || sNumer > denom || tNumer < 0.0 || tNumer > denom) - : (sNumer > 0.0 || sNumer < denom || tNumer > 0.0 || tNumer < denom)) { - return false; - } - double s = sNumer / denom; - SkASSERT(s >= 0.0 && s <= 1.0); - p->fX = SkDoubleToScalar(fTop->fPoint.fX + s * fDX); - p->fY = SkDoubleToScalar(fTop->fPoint.fY + s * fDY); - return true; - } - bool isActive(EdgeList* activeEdges) const { - return activeEdges && (fLeft || fRight || activeEdges->fHead == this); - } -}; - -/***************************************************************************************/ - -struct Poly { - Poly(int winding) - : fWinding(winding) - , fHead(nullptr) - , fTail(nullptr) - , fActive(nullptr) - , fNext(nullptr) - , fPartner(nullptr) - , fCount(0) - { -#if LOGGING_ENABLED - static int gID = 0; - fID = gID++; - LOG("*** created Poly %d\n", fID); -#endif - } - typedef enum { kNeither_Side, kLeft_Side, kRight_Side } Side; - struct MonotonePoly { - MonotonePoly() - : fSide(kNeither_Side) - , fHead(nullptr) - , fTail(nullptr) - , fPrev(nullptr) - , fNext(nullptr) {} - Side fSide; - Vertex* fHead; - Vertex* fTail; - MonotonePoly* fPrev; - MonotonePoly* fNext; - bool addVertex(Vertex* v, Side side, SkChunkAlloc& alloc) { - Vertex* newV = ALLOC_NEW(Vertex, (v->fPoint), alloc); - bool done = false; - if (fSide == kNeither_Side) { - fSide = side; - } else { - done = side != fSide; - } - if (fHead == nullptr) { - fHead = fTail = newV; - } else if (fSide == kRight_Side) { - newV->fPrev = fTail; - fTail->fNext = newV; - fTail = newV; - } else { - newV->fNext = fHead; - fHead->fPrev = newV; - fHead = newV; - } - return done; - } - - SkPoint* emit(SkPoint* data) { - Vertex* first = fHead; - Vertex* v = first->fNext; - while (v != fTail) { - SkASSERT(v && v->fPrev && v->fNext); - Vertex* prev = v->fPrev; - Vertex* curr = v; - Vertex* next = v->fNext; - double ax = static_cast(curr->fPoint.fX) - prev->fPoint.fX; - double ay = static_cast(curr->fPoint.fY) - prev->fPoint.fY; - double bx = static_cast(next->fPoint.fX) - curr->fPoint.fX; - double by = static_cast(next->fPoint.fY) - curr->fPoint.fY; - if (ax * by - ay * bx >= 0.0) { - data = emit_triangle(prev, curr, next, data); - v->fPrev->fNext = v->fNext; - v->fNext->fPrev = v->fPrev; - if (v->fPrev == first) { - v = v->fNext; - } else { - v = v->fPrev; - } - } else { - v = v->fNext; - } - } - return data; - } - }; - Poly* addVertex(Vertex* v, Side side, SkChunkAlloc& alloc) { - LOG("addVertex() to %d at %g (%g, %g), %s side\n", fID, v->fID, v->fPoint.fX, v->fPoint.fY, - side == kLeft_Side ? "left" : side == kRight_Side ? "right" : "neither"); - Poly* partner = fPartner; - Poly* poly = this; - if (partner) { - fPartner = partner->fPartner = nullptr; - } - if (!fActive) { - fActive = ALLOC_NEW(MonotonePoly, (), alloc); - } - if (fActive->addVertex(v, side, alloc)) { - if (fTail) { - fActive->fPrev = fTail; - fTail->fNext = fActive; - fTail = fActive; - } else { - fHead = fTail = fActive; - } - if (partner) { - partner->addVertex(v, side, alloc); - poly = partner; - } else { - Vertex* prev = fActive->fSide == Poly::kLeft_Side ? - fActive->fHead->fNext : fActive->fTail->fPrev; - fActive = ALLOC_NEW(MonotonePoly, , alloc); - fActive->addVertex(prev, Poly::kNeither_Side, alloc); - fActive->addVertex(v, side, alloc); - } - } - fCount++; - return poly; - } - void end(Vertex* v, SkChunkAlloc& alloc) { - LOG("end() %d at %g, %g\n", fID, v->fPoint.fX, v->fPoint.fY); - if (fPartner) { - fPartner = fPartner->fPartner = nullptr; - } - addVertex(v, fActive->fSide == kLeft_Side ? kRight_Side : kLeft_Side, alloc); - } - SkPoint* emit(SkPoint *data) { - if (fCount < 3) { - return data; - } - LOG("emit() %d, size %d\n", fID, fCount); - for (MonotonePoly* m = fHead; m != nullptr; m = m->fNext) { - data = m->emit(data); - } - return data; - } - int fWinding; - MonotonePoly* fHead; - MonotonePoly* fTail; - MonotonePoly* fActive; - Poly* fNext; - Poly* fPartner; - int fCount; -#if LOGGING_ENABLED - int fID; -#endif +struct TessInfo { + SkScalar fTolerance; + int fCount; }; -/***************************************************************************************/ - -bool coincident(const SkPoint& a, const SkPoint& b) { - return a == b; -} - -Poly* new_poly(Poly** head, Vertex* v, int winding, SkChunkAlloc& alloc) { - Poly* poly = ALLOC_NEW(Poly, (winding), alloc); - poly->addVertex(v, Poly::kNeither_Side, alloc); - poly->fNext = *head; - *head = poly; - return poly; -} - -Vertex* append_point_to_contour(const SkPoint& p, Vertex* prev, Vertex** head, - SkChunkAlloc& alloc) { - Vertex* v = ALLOC_NEW(Vertex, (p), alloc); -#if LOGGING_ENABLED - static float gID = 0.0f; - v->fID = gID++; -#endif - if (prev) { - prev->fNext = v; - v->fPrev = prev; - } else { - *head = v; - } - return v; -} - -Vertex* generate_quadratic_points(const SkPoint& p0, - const SkPoint& p1, - const SkPoint& p2, - SkScalar tolSqd, - Vertex* prev, - Vertex** head, - int pointsLeft, - SkChunkAlloc& alloc) { - SkScalar d = p1.distanceToLineSegmentBetweenSqd(p0, p2); - if (pointsLeft < 2 || d < tolSqd || !SkScalarIsFinite(d)) { - return append_point_to_contour(p2, prev, head, alloc); - } - - const SkPoint q[] = { - { SkScalarAve(p0.fX, p1.fX), SkScalarAve(p0.fY, p1.fY) }, - { SkScalarAve(p1.fX, p2.fX), SkScalarAve(p1.fY, p2.fY) }, - }; - const SkPoint r = { SkScalarAve(q[0].fX, q[1].fX), SkScalarAve(q[0].fY, q[1].fY) }; - - pointsLeft >>= 1; - prev = generate_quadratic_points(p0, q[0], r, tolSqd, prev, head, pointsLeft, alloc); - prev = generate_quadratic_points(r, q[1], p2, tolSqd, prev, head, pointsLeft, alloc); - return prev; -} - -Vertex* generate_cubic_points(const SkPoint& p0, - const SkPoint& p1, - const SkPoint& p2, - const SkPoint& p3, - SkScalar tolSqd, - Vertex* prev, - Vertex** head, - int pointsLeft, - SkChunkAlloc& alloc) { - SkScalar d1 = p1.distanceToLineSegmentBetweenSqd(p0, p3); - SkScalar d2 = p2.distanceToLineSegmentBetweenSqd(p0, p3); - if (pointsLeft < 2 || (d1 < tolSqd && d2 < tolSqd) || - !SkScalarIsFinite(d1) || !SkScalarIsFinite(d2)) { - return append_point_to_contour(p3, prev, head, alloc); - } - const SkPoint q[] = { - { SkScalarAve(p0.fX, p1.fX), SkScalarAve(p0.fY, p1.fY) }, - { SkScalarAve(p1.fX, p2.fX), SkScalarAve(p1.fY, p2.fY) }, - { SkScalarAve(p2.fX, p3.fX), SkScalarAve(p2.fY, p3.fY) } - }; - const SkPoint r[] = { - { SkScalarAve(q[0].fX, q[1].fX), SkScalarAve(q[0].fY, q[1].fY) }, - { SkScalarAve(q[1].fX, q[2].fX), SkScalarAve(q[1].fY, q[2].fY) } - }; - const SkPoint s = { SkScalarAve(r[0].fX, r[1].fX), SkScalarAve(r[0].fY, r[1].fY) }; - pointsLeft >>= 1; - prev = generate_cubic_points(p0, q[0], r[0], s, tolSqd, prev, head, pointsLeft, alloc); - prev = generate_cubic_points(s, r[1], q[2], p3, tolSqd, prev, head, pointsLeft, alloc); - return prev; -} - -// Stage 1: convert the input path to a set of linear contours (linked list of Vertices). - -void path_to_contours(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, - Vertex** contours, SkChunkAlloc& alloc, bool *isLinear) { - - SkScalar toleranceSqd = tolerance * tolerance; - - SkPoint pts[4]; - bool done = false; - *isLinear = true; - SkPath::Iter iter(path, false); - Vertex* prev = nullptr; - Vertex* head = nullptr; - if (path.isInverseFillType()) { - SkPoint quad[4]; - clipBounds.toQuad(quad); - for (int i = 3; i >= 0; i--) { - prev = append_point_to_contour(quad[i], prev, &head, alloc); - } - head->fPrev = prev; - prev->fNext = head; - *contours++ = head; - head = prev = nullptr; - } - SkAutoConicToQuads converter; - while (!done) { - SkPath::Verb verb = iter.next(pts); - switch (verb) { - case SkPath::kConic_Verb: { - SkScalar weight = iter.conicWeight(); - const SkPoint* quadPts = converter.computeQuads(pts, weight, toleranceSqd); - for (int i = 0; i < converter.countQuads(); ++i) { - int pointsLeft = GrPathUtils::quadraticPointCount(quadPts, tolerance); - prev = generate_quadratic_points(quadPts[0], quadPts[1], quadPts[2], - toleranceSqd, prev, &head, pointsLeft, alloc); - quadPts += 2; - } - *isLinear = false; - break; - } - case SkPath::kMove_Verb: - if (head) { - head->fPrev = prev; - prev->fNext = head; - *contours++ = head; - } - head = prev = nullptr; - prev = append_point_to_contour(pts[0], prev, &head, alloc); - break; - case SkPath::kLine_Verb: { - prev = append_point_to_contour(pts[1], prev, &head, alloc); - break; - } - case SkPath::kQuad_Verb: { - int pointsLeft = GrPathUtils::quadraticPointCount(pts, tolerance); - prev = generate_quadratic_points(pts[0], pts[1], pts[2], toleranceSqd, prev, - &head, pointsLeft, alloc); - *isLinear = false; - break; - } - case SkPath::kCubic_Verb: { - int pointsLeft = GrPathUtils::cubicPointCount(pts, tolerance); - prev = generate_cubic_points(pts[0], pts[1], pts[2], pts[3], - toleranceSqd, prev, &head, pointsLeft, alloc); - *isLinear = false; - break; - } - case SkPath::kClose_Verb: - if (head) { - head->fPrev = prev; - prev->fNext = head; - *contours++ = head; - } - head = prev = nullptr; - break; - case SkPath::kDone_Verb: - if (head) { - head->fPrev = prev; - prev->fNext = head; - *contours++ = head; - } - done = true; - break; - } - } -} - -inline bool apply_fill_type(SkPath::FillType fillType, int winding) { - switch (fillType) { - case SkPath::kWinding_FillType: - return winding != 0; - case SkPath::kEvenOdd_FillType: - return (winding & 1) != 0; - case SkPath::kInverseWinding_FillType: - return winding == 1; - case SkPath::kInverseEvenOdd_FillType: - return (winding & 1) == 1; - default: - SkASSERT(false); - return false; - } -} - -Edge* new_edge(Vertex* prev, Vertex* next, SkChunkAlloc& alloc, Comparator& c) { - int winding = c.sweep_lt(prev->fPoint, next->fPoint) ? 1 : -1; - Vertex* top = winding < 0 ? next : prev; - Vertex* bottom = winding < 0 ? prev : next; - return ALLOC_NEW(Edge, (top, bottom, winding), alloc); -} - -void remove_edge(Edge* edge, EdgeList* edges) { - LOG("removing edge %g -> %g\n", edge->fTop->fID, edge->fBottom->fID); - SkASSERT(edge->isActive(edges)); - remove(edge, &edges->fHead, &edges->fTail); -} - -void insert_edge(Edge* edge, Edge* prev, EdgeList* edges) { - LOG("inserting edge %g -> %g\n", edge->fTop->fID, edge->fBottom->fID); - SkASSERT(!edge->isActive(edges)); - Edge* next = prev ? prev->fRight : edges->fHead; - insert(edge, prev, next, &edges->fHead, &edges->fTail); -} - -void find_enclosing_edges(Vertex* v, EdgeList* edges, Edge** left, Edge** right) { - if (v->fFirstEdgeAbove) { - *left = v->fFirstEdgeAbove->fLeft; - *right = v->fLastEdgeAbove->fRight; - return; - } - Edge* next = nullptr; - Edge* prev; - for (prev = edges->fTail; prev != nullptr; prev = prev->fLeft) { - if (prev->isLeftOf(v)) { - break; - } - next = prev; - } - *left = prev; - *right = next; - return; -} - -void find_enclosing_edges(Edge* edge, EdgeList* edges, Comparator& c, Edge** left, Edge** right) { - Edge* prev = nullptr; - Edge* next; - for (next = edges->fHead; next != nullptr; next = next->fRight) { - if ((c.sweep_gt(edge->fTop->fPoint, next->fTop->fPoint) && next->isRightOf(edge->fTop)) || - (c.sweep_gt(next->fTop->fPoint, edge->fTop->fPoint) && edge->isLeftOf(next->fTop)) || - (c.sweep_lt(edge->fBottom->fPoint, next->fBottom->fPoint) && - next->isRightOf(edge->fBottom)) || - (c.sweep_lt(next->fBottom->fPoint, edge->fBottom->fPoint) && - edge->isLeftOf(next->fBottom))) { - break; - } - prev = next; - } - *left = prev; - *right = next; - return; -} - -void fix_active_state(Edge* edge, EdgeList* activeEdges, Comparator& c) { - if (edge->isActive(activeEdges)) { - if (edge->fBottom->fProcessed || !edge->fTop->fProcessed) { - remove_edge(edge, activeEdges); - } - } else if (edge->fTop->fProcessed && !edge->fBottom->fProcessed) { - Edge* left; - Edge* right; - find_enclosing_edges(edge, activeEdges, c, &left, &right); - insert_edge(edge, left, activeEdges); - } -} - -void insert_edge_above(Edge* edge, Vertex* v, Comparator& c) { - if (edge->fTop->fPoint == edge->fBottom->fPoint || - c.sweep_gt(edge->fTop->fPoint, edge->fBottom->fPoint)) { - return; - } - LOG("insert edge (%g -> %g) above vertex %g\n", edge->fTop->fID, edge->fBottom->fID, v->fID); - Edge* prev = nullptr; - Edge* next; - for (next = v->fFirstEdgeAbove; next; next = next->fNextEdgeAbove) { - if (next->isRightOf(edge->fTop)) { - break; - } - prev = next; - } - insert( - edge, prev, next, &v->fFirstEdgeAbove, &v->fLastEdgeAbove); -} - -void insert_edge_below(Edge* edge, Vertex* v, Comparator& c) { - if (edge->fTop->fPoint == edge->fBottom->fPoint || - c.sweep_gt(edge->fTop->fPoint, edge->fBottom->fPoint)) { - return; - } - LOG("insert edge (%g -> %g) below vertex %g\n", edge->fTop->fID, edge->fBottom->fID, v->fID); - Edge* prev = nullptr; - Edge* next; - for (next = v->fFirstEdgeBelow; next; next = next->fNextEdgeBelow) { - if (next->isRightOf(edge->fBottom)) { - break; - } - prev = next; - } - insert( - edge, prev, next, &v->fFirstEdgeBelow, &v->fLastEdgeBelow); -} - -void remove_edge_above(Edge* edge) { - LOG("removing edge (%g -> %g) above vertex %g\n", edge->fTop->fID, edge->fBottom->fID, - edge->fBottom->fID); - remove( - edge, &edge->fBottom->fFirstEdgeAbove, &edge->fBottom->fLastEdgeAbove); -} - -void remove_edge_below(Edge* edge) { - LOG("removing edge (%g -> %g) below vertex %g\n", edge->fTop->fID, edge->fBottom->fID, - edge->fTop->fID); - remove( - edge, &edge->fTop->fFirstEdgeBelow, &edge->fTop->fLastEdgeBelow); -} - -void erase_edge_if_zero_winding(Edge* edge, EdgeList* edges) { - if (edge->fWinding != 0) { - return; - } - LOG("erasing edge (%g -> %g)\n", edge->fTop->fID, edge->fBottom->fID); - remove_edge_above(edge); - remove_edge_below(edge); - if (edge->isActive(edges)) { - remove_edge(edge, edges); - } -} - -void merge_collinear_edges(Edge* edge, EdgeList* activeEdges, Comparator& c); - -void set_top(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c) { - remove_edge_below(edge); - edge->fTop = v; - edge->recompute(); - insert_edge_below(edge, v, c); - fix_active_state(edge, activeEdges, c); - merge_collinear_edges(edge, activeEdges, c); -} - -void set_bottom(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c) { - remove_edge_above(edge); - edge->fBottom = v; - edge->recompute(); - insert_edge_above(edge, v, c); - fix_active_state(edge, activeEdges, c); - merge_collinear_edges(edge, activeEdges, c); -} - -void merge_edges_above(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c) { - if (coincident(edge->fTop->fPoint, other->fTop->fPoint)) { - LOG("merging coincident above edges (%g, %g) -> (%g, %g)\n", - edge->fTop->fPoint.fX, edge->fTop->fPoint.fY, - edge->fBottom->fPoint.fX, edge->fBottom->fPoint.fY); - other->fWinding += edge->fWinding; - erase_edge_if_zero_winding(other, activeEdges); - edge->fWinding = 0; - erase_edge_if_zero_winding(edge, activeEdges); - } else if (c.sweep_lt(edge->fTop->fPoint, other->fTop->fPoint)) { - other->fWinding += edge->fWinding; - erase_edge_if_zero_winding(other, activeEdges); - set_bottom(edge, other->fTop, activeEdges, c); - } else { - edge->fWinding += other->fWinding; - erase_edge_if_zero_winding(edge, activeEdges); - set_bottom(other, edge->fTop, activeEdges, c); - } -} - -void merge_edges_below(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c) { - if (coincident(edge->fBottom->fPoint, other->fBottom->fPoint)) { - LOG("merging coincident below edges (%g, %g) -> (%g, %g)\n", - edge->fTop->fPoint.fX, edge->fTop->fPoint.fY, - edge->fBottom->fPoint.fX, edge->fBottom->fPoint.fY); - other->fWinding += edge->fWinding; - erase_edge_if_zero_winding(other, activeEdges); - edge->fWinding = 0; - erase_edge_if_zero_winding(edge, activeEdges); - } else if (c.sweep_lt(edge->fBottom->fPoint, other->fBottom->fPoint)) { - edge->fWinding += other->fWinding; - erase_edge_if_zero_winding(edge, activeEdges); - set_top(other, edge->fBottom, activeEdges, c); - } else { - other->fWinding += edge->fWinding; - erase_edge_if_zero_winding(other, activeEdges); - set_top(edge, other->fBottom, activeEdges, c); - } -} - -void merge_collinear_edges(Edge* edge, EdgeList* activeEdges, Comparator& c) { - if (edge->fPrevEdgeAbove && (edge->fTop == edge->fPrevEdgeAbove->fTop || - !edge->fPrevEdgeAbove->isLeftOf(edge->fTop))) { - merge_edges_above(edge, edge->fPrevEdgeAbove, activeEdges, c); - } else if (edge->fNextEdgeAbove && (edge->fTop == edge->fNextEdgeAbove->fTop || - !edge->isLeftOf(edge->fNextEdgeAbove->fTop))) { - merge_edges_above(edge, edge->fNextEdgeAbove, activeEdges, c); - } - if (edge->fPrevEdgeBelow && (edge->fBottom == edge->fPrevEdgeBelow->fBottom || - !edge->fPrevEdgeBelow->isLeftOf(edge->fBottom))) { - merge_edges_below(edge, edge->fPrevEdgeBelow, activeEdges, c); - } else if (edge->fNextEdgeBelow && (edge->fBottom == edge->fNextEdgeBelow->fBottom || - !edge->isLeftOf(edge->fNextEdgeBelow->fBottom))) { - merge_edges_below(edge, edge->fNextEdgeBelow, activeEdges, c); - } -} - -void split_edge(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc); - -void cleanup_active_edges(Edge* edge, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc) { - Vertex* top = edge->fTop; - Vertex* bottom = edge->fBottom; - if (edge->fLeft) { - Vertex* leftTop = edge->fLeft->fTop; - Vertex* leftBottom = edge->fLeft->fBottom; - if (c.sweep_gt(top->fPoint, leftTop->fPoint) && !edge->fLeft->isLeftOf(top)) { - split_edge(edge->fLeft, edge->fTop, activeEdges, c, alloc); - } else if (c.sweep_gt(leftTop->fPoint, top->fPoint) && !edge->isRightOf(leftTop)) { - split_edge(edge, leftTop, activeEdges, c, alloc); - } else if (c.sweep_lt(bottom->fPoint, leftBottom->fPoint) && - !edge->fLeft->isLeftOf(bottom)) { - split_edge(edge->fLeft, bottom, activeEdges, c, alloc); - } else if (c.sweep_lt(leftBottom->fPoint, bottom->fPoint) && !edge->isRightOf(leftBottom)) { - split_edge(edge, leftBottom, activeEdges, c, alloc); - } - } - if (edge->fRight) { - Vertex* rightTop = edge->fRight->fTop; - Vertex* rightBottom = edge->fRight->fBottom; - if (c.sweep_gt(top->fPoint, rightTop->fPoint) && !edge->fRight->isRightOf(top)) { - split_edge(edge->fRight, top, activeEdges, c, alloc); - } else if (c.sweep_gt(rightTop->fPoint, top->fPoint) && !edge->isLeftOf(rightTop)) { - split_edge(edge, rightTop, activeEdges, c, alloc); - } else if (c.sweep_lt(bottom->fPoint, rightBottom->fPoint) && - !edge->fRight->isRightOf(bottom)) { - split_edge(edge->fRight, bottom, activeEdges, c, alloc); - } else if (c.sweep_lt(rightBottom->fPoint, bottom->fPoint) && - !edge->isLeftOf(rightBottom)) { - split_edge(edge, rightBottom, activeEdges, c, alloc); - } - } -} - -void split_edge(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc) { - LOG("splitting edge (%g -> %g) at vertex %g (%g, %g)\n", - edge->fTop->fID, edge->fBottom->fID, - v->fID, v->fPoint.fX, v->fPoint.fY); - if (c.sweep_lt(v->fPoint, edge->fTop->fPoint)) { - set_top(edge, v, activeEdges, c); - } else if (c.sweep_gt(v->fPoint, edge->fBottom->fPoint)) { - set_bottom(edge, v, activeEdges, c); - } else { - Edge* newEdge = ALLOC_NEW(Edge, (v, edge->fBottom, edge->fWinding), alloc); - insert_edge_below(newEdge, v, c); - insert_edge_above(newEdge, edge->fBottom, c); - set_bottom(edge, v, activeEdges, c); - cleanup_active_edges(edge, activeEdges, c, alloc); - fix_active_state(newEdge, activeEdges, c); - merge_collinear_edges(newEdge, activeEdges, c); - } -} - -void merge_vertices(Vertex* src, Vertex* dst, Vertex** head, Comparator& c, SkChunkAlloc& alloc) { - LOG("found coincident verts at %g, %g; merging %g into %g\n", src->fPoint.fX, src->fPoint.fY, - src->fID, dst->fID); - for (Edge* edge = src->fFirstEdgeAbove; edge;) { - Edge* next = edge->fNextEdgeAbove; - set_bottom(edge, dst, nullptr, c); - edge = next; - } - for (Edge* edge = src->fFirstEdgeBelow; edge;) { - Edge* next = edge->fNextEdgeBelow; - set_top(edge, dst, nullptr, c); - edge = next; - } - remove(src, head, nullptr); -} - -Vertex* check_for_intersection(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c, - SkChunkAlloc& alloc) { - SkPoint p; - if (!edge || !other) { - return nullptr; - } - if (edge->intersect(*other, &p)) { - Vertex* v; - LOG("found intersection, pt is %g, %g\n", p.fX, p.fY); - if (p == edge->fTop->fPoint || c.sweep_lt(p, edge->fTop->fPoint)) { - split_edge(other, edge->fTop, activeEdges, c, alloc); - v = edge->fTop; - } else if (p == edge->fBottom->fPoint || c.sweep_gt(p, edge->fBottom->fPoint)) { - split_edge(other, edge->fBottom, activeEdges, c, alloc); - v = edge->fBottom; - } else if (p == other->fTop->fPoint || c.sweep_lt(p, other->fTop->fPoint)) { - split_edge(edge, other->fTop, activeEdges, c, alloc); - v = other->fTop; - } else if (p == other->fBottom->fPoint || c.sweep_gt(p, other->fBottom->fPoint)) { - split_edge(edge, other->fBottom, activeEdges, c, alloc); - v = other->fBottom; - } else { - Vertex* nextV = edge->fTop; - while (c.sweep_lt(p, nextV->fPoint)) { - nextV = nextV->fPrev; - } - while (c.sweep_lt(nextV->fPoint, p)) { - nextV = nextV->fNext; - } - Vertex* prevV = nextV->fPrev; - if (coincident(prevV->fPoint, p)) { - v = prevV; - } else if (coincident(nextV->fPoint, p)) { - v = nextV; - } else { - v = ALLOC_NEW(Vertex, (p), alloc); - LOG("inserting between %g (%g, %g) and %g (%g, %g)\n", - prevV->fID, prevV->fPoint.fX, prevV->fPoint.fY, - nextV->fID, nextV->fPoint.fX, nextV->fPoint.fY); -#if LOGGING_ENABLED - v->fID = (nextV->fID + prevV->fID) * 0.5f; -#endif - v->fPrev = prevV; - v->fNext = nextV; - prevV->fNext = v; - nextV->fPrev = v; - } - split_edge(edge, v, activeEdges, c, alloc); - split_edge(other, v, activeEdges, c, alloc); - } - return v; - } - return nullptr; -} - -void sanitize_contours(Vertex** contours, int contourCnt) { - for (int i = 0; i < contourCnt; ++i) { - SkASSERT(contours[i]); - for (Vertex* v = contours[i];;) { - if (coincident(v->fPrev->fPoint, v->fPoint)) { - LOG("vertex %g,%g coincident; removing\n", v->fPoint.fX, v->fPoint.fY); - if (v->fPrev == v) { - contours[i] = nullptr; - break; - } - v->fPrev->fNext = v->fNext; - v->fNext->fPrev = v->fPrev; - if (contours[i] == v) { - contours[i] = v->fNext; - } - v = v->fPrev; - } else { - v = v->fNext; - if (v == contours[i]) break; - } - } - } -} - -void merge_coincident_vertices(Vertex** vertices, Comparator& c, SkChunkAlloc& alloc) { - for (Vertex* v = (*vertices)->fNext; v != nullptr; v = v->fNext) { - if (c.sweep_lt(v->fPoint, v->fPrev->fPoint)) { - v->fPoint = v->fPrev->fPoint; - } - if (coincident(v->fPrev->fPoint, v->fPoint)) { - merge_vertices(v->fPrev, v, vertices, c, alloc); - } - } -} - -// Stage 2: convert the contours to a mesh of edges connecting the vertices. - -Vertex* build_edges(Vertex** contours, int contourCnt, Comparator& c, SkChunkAlloc& alloc) { - Vertex* vertices = nullptr; - Vertex* prev = nullptr; - for (int i = 0; i < contourCnt; ++i) { - for (Vertex* v = contours[i]; v != nullptr;) { - Vertex* vNext = v->fNext; - Edge* edge = new_edge(v->fPrev, v, alloc, c); - if (edge->fWinding > 0) { - insert_edge_below(edge, v->fPrev, c); - insert_edge_above(edge, v, c); - } else { - insert_edge_below(edge, v, c); - insert_edge_above(edge, v->fPrev, c); - } - merge_collinear_edges(edge, nullptr, c); - if (prev) { - prev->fNext = v; - v->fPrev = prev; - } else { - vertices = v; - } - prev = v; - v = vNext; - if (v == contours[i]) break; - } - } - if (prev) { - prev->fNext = vertices->fPrev = nullptr; - } - return vertices; -} - -// Stage 3: sort the vertices by increasing sweep direction. - -Vertex* sorted_merge(Vertex* a, Vertex* b, Comparator& c); - -void front_back_split(Vertex* v, Vertex** pFront, Vertex** pBack) { - Vertex* fast; - Vertex* slow; - if (!v || !v->fNext) { - *pFront = v; - *pBack = nullptr; - } else { - slow = v; - fast = v->fNext; - - while (fast != nullptr) { - fast = fast->fNext; - if (fast != nullptr) { - slow = slow->fNext; - fast = fast->fNext; - } - } - - *pFront = v; - *pBack = slow->fNext; - slow->fNext->fPrev = nullptr; - slow->fNext = nullptr; - } -} - -void merge_sort(Vertex** head, Comparator& c) { - if (!*head || !(*head)->fNext) { - return; - } - - Vertex* a; - Vertex* b; - front_back_split(*head, &a, &b); - - merge_sort(&a, c); - merge_sort(&b, c); - - *head = sorted_merge(a, b, c); -} - -inline void append_vertex(Vertex* v, Vertex** head, Vertex** tail) { - insert(v, *tail, nullptr, head, tail); -} - -inline void append_vertex_list(Vertex* v, Vertex** head, Vertex** tail) { - insert(v, *tail, v->fNext, head, tail); -} - -Vertex* sorted_merge(Vertex* a, Vertex* b, Comparator& c) { - Vertex* head = nullptr; - Vertex* tail = nullptr; - - while (a && b) { - if (c.sweep_lt(a->fPoint, b->fPoint)) { - Vertex* next = a->fNext; - append_vertex(a, &head, &tail); - a = next; - } else { - Vertex* next = b->fNext; - append_vertex(b, &head, &tail); - b = next; - } - } - if (a) { - append_vertex_list(a, &head, &tail); - } - if (b) { - append_vertex_list(b, &head, &tail); - } - return head; -} - -// Stage 4: Simplify the mesh by inserting new vertices at intersecting edges. - -void simplify(Vertex* vertices, Comparator& c, SkChunkAlloc& alloc) { - LOG("simplifying complex polygons\n"); - EdgeList activeEdges; - for (Vertex* v = vertices; v != nullptr; v = v->fNext) { - if (!v->fFirstEdgeAbove && !v->fFirstEdgeBelow) { - continue; - } -#if LOGGING_ENABLED - LOG("\nvertex %g: (%g,%g)\n", v->fID, v->fPoint.fX, v->fPoint.fY); -#endif - Edge* leftEnclosingEdge = nullptr; - Edge* rightEnclosingEdge = nullptr; - bool restartChecks; - do { - restartChecks = false; - find_enclosing_edges(v, &activeEdges, &leftEnclosingEdge, &rightEnclosingEdge); - if (v->fFirstEdgeBelow) { - for (Edge* edge = v->fFirstEdgeBelow; edge != nullptr; edge = edge->fNextEdgeBelow) { - if (check_for_intersection(edge, leftEnclosingEdge, &activeEdges, c, alloc)) { - restartChecks = true; - break; - } - if (check_for_intersection(edge, rightEnclosingEdge, &activeEdges, c, alloc)) { - restartChecks = true; - break; - } - } - } else { - if (Vertex* pv = check_for_intersection(leftEnclosingEdge, rightEnclosingEdge, - &activeEdges, c, alloc)) { - if (c.sweep_lt(pv->fPoint, v->fPoint)) { - v = pv; - } - restartChecks = true; - } - - } - } while (restartChecks); - for (Edge* e = v->fFirstEdgeAbove; e; e = e->fNextEdgeAbove) { - remove_edge(e, &activeEdges); - } - Edge* leftEdge = leftEnclosingEdge; - for (Edge* e = v->fFirstEdgeBelow; e; e = e->fNextEdgeBelow) { - insert_edge(e, leftEdge, &activeEdges); - leftEdge = e; - } - v->fProcessed = true; - } -} - -// Stage 5: Tessellate the simplified mesh into monotone polygons. - -Poly* tessellate(Vertex* vertices, SkChunkAlloc& alloc) { - LOG("tessellating simple polygons\n"); - EdgeList activeEdges; - Poly* polys = nullptr; - for (Vertex* v = vertices; v != nullptr; v = v->fNext) { - if (!v->fFirstEdgeAbove && !v->fFirstEdgeBelow) { - continue; - } -#if LOGGING_ENABLED - LOG("\nvertex %g: (%g,%g)\n", v->fID, v->fPoint.fX, v->fPoint.fY); -#endif - Edge* leftEnclosingEdge = nullptr; - Edge* rightEnclosingEdge = nullptr; - find_enclosing_edges(v, &activeEdges, &leftEnclosingEdge, &rightEnclosingEdge); - Poly* leftPoly = nullptr; - Poly* rightPoly = nullptr; - if (v->fFirstEdgeAbove) { - leftPoly = v->fFirstEdgeAbove->fLeftPoly; - rightPoly = v->fLastEdgeAbove->fRightPoly; - } else { - leftPoly = leftEnclosingEdge ? leftEnclosingEdge->fRightPoly : nullptr; - rightPoly = rightEnclosingEdge ? rightEnclosingEdge->fLeftPoly : nullptr; - } -#if LOGGING_ENABLED - LOG("edges above:\n"); - for (Edge* e = v->fFirstEdgeAbove; e; e = e->fNextEdgeAbove) { - LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, - e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); - } - LOG("edges below:\n"); - for (Edge* e = v->fFirstEdgeBelow; e; e = e->fNextEdgeBelow) { - LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, - e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); - } -#endif - if (v->fFirstEdgeAbove) { - if (leftPoly) { - leftPoly = leftPoly->addVertex(v, Poly::kRight_Side, alloc); - } - if (rightPoly) { - rightPoly = rightPoly->addVertex(v, Poly::kLeft_Side, alloc); - } - for (Edge* e = v->fFirstEdgeAbove; e != v->fLastEdgeAbove; e = e->fNextEdgeAbove) { - Edge* leftEdge = e; - Edge* rightEdge = e->fNextEdgeAbove; - SkASSERT(rightEdge->isRightOf(leftEdge->fTop)); - remove_edge(leftEdge, &activeEdges); - if (leftEdge->fRightPoly) { - leftEdge->fRightPoly->end(v, alloc); - } - if (rightEdge->fLeftPoly && rightEdge->fLeftPoly != leftEdge->fRightPoly) { - rightEdge->fLeftPoly->end(v, alloc); - } - } - remove_edge(v->fLastEdgeAbove, &activeEdges); - if (!v->fFirstEdgeBelow) { - if (leftPoly && rightPoly && leftPoly != rightPoly) { - SkASSERT(leftPoly->fPartner == nullptr && rightPoly->fPartner == nullptr); - rightPoly->fPartner = leftPoly; - leftPoly->fPartner = rightPoly; - } - } - } - if (v->fFirstEdgeBelow) { - if (!v->fFirstEdgeAbove) { - if (leftPoly && leftPoly == rightPoly) { - // Split the poly. - if (leftPoly->fActive->fSide == Poly::kLeft_Side) { - leftPoly = new_poly(&polys, leftEnclosingEdge->fTop, leftPoly->fWinding, - alloc); - leftPoly->addVertex(v, Poly::kRight_Side, alloc); - rightPoly->addVertex(v, Poly::kLeft_Side, alloc); - leftEnclosingEdge->fRightPoly = leftPoly; - } else { - rightPoly = new_poly(&polys, rightEnclosingEdge->fTop, rightPoly->fWinding, - alloc); - rightPoly->addVertex(v, Poly::kLeft_Side, alloc); - leftPoly->addVertex(v, Poly::kRight_Side, alloc); - rightEnclosingEdge->fLeftPoly = rightPoly; - } - } else { - if (leftPoly) { - leftPoly = leftPoly->addVertex(v, Poly::kRight_Side, alloc); - } - if (rightPoly) { - rightPoly = rightPoly->addVertex(v, Poly::kLeft_Side, alloc); - } - } - } - Edge* leftEdge = v->fFirstEdgeBelow; - leftEdge->fLeftPoly = leftPoly; - insert_edge(leftEdge, leftEnclosingEdge, &activeEdges); - for (Edge* rightEdge = leftEdge->fNextEdgeBelow; rightEdge; - rightEdge = rightEdge->fNextEdgeBelow) { - insert_edge(rightEdge, leftEdge, &activeEdges); - int winding = leftEdge->fLeftPoly ? leftEdge->fLeftPoly->fWinding : 0; - winding += leftEdge->fWinding; - if (winding != 0) { - Poly* poly = new_poly(&polys, v, winding, alloc); - leftEdge->fRightPoly = rightEdge->fLeftPoly = poly; - } - leftEdge = rightEdge; - } - v->fLastEdgeBelow->fRightPoly = rightPoly; - } -#if LOGGING_ENABLED - LOG("\nactive edges:\n"); - for (Edge* e = activeEdges.fHead; e != nullptr; e = e->fRight) { - LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, - e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); - } -#endif - } - return polys; -} - -// This is a driver function which calls stages 2-5 in turn. - -Poly* contours_to_polys(Vertex** contours, int contourCnt, Comparator& c, SkChunkAlloc& alloc) { -#if LOGGING_ENABLED - for (int i = 0; i < contourCnt; ++i) { - Vertex* v = contours[i]; - SkASSERT(v); - LOG("path.moveTo(%20.20g, %20.20g);\n", v->fPoint.fX, v->fPoint.fY); - for (v = v->fNext; v != contours[i]; v = v->fNext) { - LOG("path.lineTo(%20.20g, %20.20g);\n", v->fPoint.fX, v->fPoint.fY); - } - } -#endif - sanitize_contours(contours, contourCnt); - Vertex* vertices = build_edges(contours, contourCnt, c, alloc); - if (!vertices) { - return nullptr; - } - - // Sort vertices in Y (secondarily in X). - merge_sort(&vertices, c); - merge_coincident_vertices(&vertices, c, alloc); -#if LOGGING_ENABLED - for (Vertex* v = vertices; v != nullptr; v = v->fNext) { - static float gID = 0.0f; - v->fID = gID++; - } -#endif - simplify(vertices, c, alloc); - return tessellate(vertices, alloc); -} - -// Stage 6: Triangulate the monotone polygons into a vertex buffer. +// When the SkPathRef genID changes, invalidate a corresponding GrResource described by key. +class PathInvalidator : public SkPathRef::GenIDChangeListener { +public: + explicit PathInvalidator(const GrUniqueKey& key) : fMsg(key) {} +private: + GrUniqueKeyInvalidatedMessage fMsg; -SkPoint* polys_to_triangles(Poly* polys, SkPath::FillType fillType, SkPoint* data) { - SkPoint* d = data; - for (Poly* poly = polys; poly; poly = poly->fNext) { - if (apply_fill_type(fillType, poly->fWinding)) { - d = poly->emit(d); - } + void onChange() override { + SkMessageBus::Post(fMsg); } - return d; -} - -struct TessInfo { - SkScalar fTolerance; - int fCount; }; bool cache_match(GrVertexBuffer* vertexBuffer, SkScalar tol, int* actualCount) { @@ -1354,27 +59,11 @@ bool cache_match(GrVertexBuffer* vertexBuffer, SkScalar tol, int* actualCount) { return false; } -}; +} // namespace GrTessellatingPathRenderer::GrTessellatingPathRenderer() { } -namespace { - -// When the SkPathRef genID changes, invalidate a corresponding GrResource described by key. -class PathInvalidator : public SkPathRef::GenIDChangeListener { -public: - explicit PathInvalidator(const GrUniqueKey& key) : fMsg(key) {} -private: - GrUniqueKeyInvalidatedMessage fMsg; - - void onChange() override { - SkMessageBus::Post(fMsg); - } -}; - -} // namespace - bool GrTessellatingPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const { // This path renderer can draw all fill styles, all stroke styles except hairlines, but does // not do antialiasing. It can do convex and concave paths, but we'll leave the convex ones to @@ -1435,90 +124,23 @@ private: } stroke.setFillStyle(); } - SkRect pathBounds = path.getBounds(); - Comparator c; - if (pathBounds.width() > pathBounds.height()) { - c.sweep_lt = sweep_lt_horiz; - c.sweep_gt = sweep_gt_horiz; - } else { - c.sweep_lt = sweep_lt_vert; - c.sweep_gt = sweep_gt_vert; - } SkScalar screenSpaceTol = GrPathUtils::kDefaultTolerance; + SkRect pathBounds = path.getBounds(); SkScalar tol = GrPathUtils::scaleToleranceToSrc(screenSpaceTol, fViewMatrix, pathBounds); - int contourCnt; - int maxPts = GrPathUtils::worstCasePointCount(path, &contourCnt, tol); - if (maxPts <= 0) { - return 0; - } - if (maxPts > ((int)SK_MaxU16 + 1)) { - SkDebugf("Path not rendered, too many verts (%d)\n", maxPts); - return 0; - } - SkPath::FillType fillType = path.getFillType(); - if (SkPath::IsInverseFillType(fillType)) { - contourCnt++; - } - LOG("got %d pts, %d contours\n", maxPts, contourCnt); - SkAutoTDeleteArray contours(new Vertex* [contourCnt]); - - // For the initial size of the chunk allocator, estimate based on the point count: - // one vertex per point for the initial passes, plus two for the vertices in the - // resulting Polys, since the same point may end up in two Polys. Assume minimal - // connectivity of one Edge per Vertex (will grow for intersections). - SkChunkAlloc alloc(maxPts * (3 * sizeof(Vertex) + sizeof(Edge))); bool isLinear; - path_to_contours(path, tol, fClipBounds, contours.get(), alloc, &isLinear); - Poly* polys; - polys = contours_to_polys(contours.get(), contourCnt, c, alloc); - int count = 0; - for (Poly* poly = polys; poly; poly = poly->fNext) { - if (apply_fill_type(fillType, poly->fWinding) && poly->fCount >= 3) { - count += (poly->fCount - 2) * (WIREFRAME ? 6 : 3); - } - } - if (0 == count) { - return 0; - } - - size_t size = count * sizeof(SkPoint); - if (!vertexBuffer.get() || vertexBuffer->gpuMemorySize() < size) { - vertexBuffer.reset(resourceProvider->createVertexBuffer( - size, GrResourceProvider::kStatic_BufferUsage, 0)); - } - if (!vertexBuffer.get()) { - SkDebugf("Could not allocate vertices\n"); - return 0; - } - SkPoint* verts; - if (canMapVB) { - verts = static_cast(vertexBuffer->map()); - } else { - verts = new SkPoint[count]; - } - SkPoint* end = polys_to_triangles(polys, fillType, verts); - int actualCount = static_cast(end - verts); - LOG("actual count: %d\n", actualCount); - SkASSERT(actualCount <= count); - if (canMapVB) { - vertexBuffer->unmap(); - } else { - vertexBuffer->updateData(verts, actualCount * sizeof(SkPoint)); - delete[] verts; - } - - + int count = GrTessellator::PathToTriangles(path, tol, fClipBounds, resourceProvider, + vertexBuffer, canMapVB, &isLinear); if (!fPath.isVolatile()) { TessInfo info; info.fTolerance = isLinear ? 0 : tol; - info.fCount = actualCount; + info.fCount = count; SkAutoTUnref data(SkData::NewWithCopy(&info, sizeof(info))); key->setCustomData(data.get()); resourceProvider->assignUniqueKeyToResource(*key, vertexBuffer.get()); SkPathPriv::AddGenIDChangeListener(fPath, new PathInvalidator(*key)); } - return actualCount; + return count; } void onPrepareDraws(Target* target) const override { @@ -1574,8 +196,8 @@ private: target->initDraw(gp, this->pipeline()); SkASSERT(gp->getVertexStride() == sizeof(SkPoint)); - GrPrimitiveType primitiveType = WIREFRAME ? kLines_GrPrimitiveType - : kTriangles_GrPrimitiveType; + GrPrimitiveType primitiveType = TESSELLATOR_WIREFRAME ? kLines_GrPrimitiveType + : kTriangles_GrPrimitiveType; GrVertices vertices; vertices.init(primitiveType, vertexBuffer.get(), 0, actualCount); target->draw(vertices); -- cgit v1.2.3