From 6335a729769b06f0d6a1450c7c02e03f95bbb049 Mon Sep 17 00:00:00 2001 From: joshualitt Date: Tue, 1 Sep 2015 06:50:55 -0700 Subject: Move PathRenderers to batches folder BUG=skia: Review URL: https://codereview.chromium.org/1306143005 --- src/gpu/batches/GrTessellatingPathRenderer.cpp | 1660 ++++++++++++++++++++++++ 1 file changed, 1660 insertions(+) create mode 100644 src/gpu/batches/GrTessellatingPathRenderer.cpp (limited to 'src/gpu/batches/GrTessellatingPathRenderer.cpp') diff --git a/src/gpu/batches/GrTessellatingPathRenderer.cpp b/src/gpu/batches/GrTessellatingPathRenderer.cpp new file mode 100644 index 0000000000..bc9a6b5d04 --- /dev/null +++ b/src/gpu/batches/GrTessellatingPathRenderer.cpp @@ -0,0 +1,1660 @@ +/* + * 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 "GrTessellatingPathRenderer.h" + +#include "GrBatchFlushState.h" +#include "GrBatchTest.h" +#include "GrDefaultGeoProcFactory.h" +#include "GrPathUtils.h" +#include "GrVertices.h" +#include "GrResourceCache.h" +#include "GrResourceProvider.h" +#include "SkChunkAlloc.h" +#include "SkGeometry.h" + +#include "batches/GrVertexBatch.h" + +#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 + * 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 +}; + +/***************************************************************************************/ + +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. + +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); + } + } + return d; +} + +struct TessInfo { + SkScalar fTolerance; + int fVertexCount; +}; + +bool cache_match(GrVertexBuffer* vertexBuffer, SkScalar tol, int* vertexCount) { + if (!vertexBuffer) { + return false; + } + const SkData* data = vertexBuffer->getUniqueKey().getCustomData(); + SkASSERT(data); + const TessInfo* info = static_cast(data->data()); + if (info->fTolerance == 0 || info->fTolerance < 3.0f * tol) { + *vertexCount = info->fVertexCount; + return true; + } + return false; +} + +}; + +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 + // simpler algorithms. + return !IsStrokeHairlineOrEquivalent(*args.fStroke, *args.fViewMatrix, nullptr) && + !args.fAntiAlias && !args.fPath->isConvex(); +} + +class TessellatingPathBatch : public GrVertexBatch { +public: + + static GrDrawBatch* Create(const GrColor& color, + const SkPath& path, + const GrStrokeInfo& stroke, + const SkMatrix& viewMatrix, + SkRect clipBounds) { + return new TessellatingPathBatch(color, path, stroke, viewMatrix, clipBounds); + } + + const char* name() const override { return "TessellatingPathBatch"; } + + void getInvariantOutputColor(GrInitInvariantOutput* out) const override { + out->setKnownFourComponents(fColor); + } + + void getInvariantOutputCoverage(GrInitInvariantOutput* out) const override { + out->setUnknownSingleComponent(); + } + +private: + void initBatchTracker(const GrPipelineOptimizations& opt) override { + // Handle any color overrides + if (!opt.readsColor()) { + fColor = GrColor_ILLEGAL; + } + opt.getOverrideColorIfSet(&fColor); + fPipelineInfo = opt; + } + + int tessellate(GrUniqueKey* key, + GrResourceProvider* resourceProvider, + SkAutoTUnref& vertexBuffer, + bool canMapVB) { + SkPath path; + GrStrokeInfo stroke(fStroke); + if (stroke.isDashed()) { + if (!stroke.applyDashToPath(&path, &stroke, fPath)) { + return 0; + } + } else { + path = fPath; + } + if (!stroke.isFillStyle()) { + stroke.setResScale(SkScalarAbs(fViewMatrix.getMaxScale())); + if (!stroke.applyToPath(&path, path)) { + return 0; + } + 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; + 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 vertexCount = 0; + for (Poly* poly = polys; poly; poly = poly->fNext) { + if (apply_fill_type(fillType, poly->fWinding) && poly->fCount >= 3) { + vertexCount += (poly->fCount - 2) * (WIREFRAME ? 6 : 3); + } + } + if (0 == vertexCount) { + return 0; + } + + size_t size = vertexCount * 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[vertexCount]; + } + SkDEBUGCODE(SkPoint* end = ) polys_to_triangles(polys, fillType, verts); + SkASSERT(static_cast(end - verts) == vertexCount); + LOG("vertex count: %d\n", vertexCount); + if (canMapVB) { + vertexBuffer->unmap(); + } else { + vertexBuffer->updateData(verts, vertexCount * sizeof(SkPoint)); + delete[] verts; + } + + + if (!fPath.isVolatile()) { + TessInfo info; + info.fTolerance = isLinear ? 0 : tol; + info.fVertexCount = vertexCount; + SkAutoTUnref data(SkData::NewWithCopy(&info, sizeof(info))); + key->setCustomData(data.get()); + resourceProvider->assignUniqueKeyToResource(*key, vertexBuffer.get()); + SkPathPriv::AddGenIDChangeListener(fPath, new PathInvalidator(*key)); + } + return vertexCount; + } + + void onPrepareDraws(Target* target) override { + // construct a cache key from the path's genID and the view matrix + static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain(); + GrUniqueKey key; + int clipBoundsSize32 = + fPath.isInverseFillType() ? sizeof(fClipBounds) / sizeof(uint32_t) : 0; + int strokeDataSize32 = fStroke.computeUniqueKeyFragmentData32Cnt(); + GrUniqueKey::Builder builder(&key, kDomain, 2 + clipBoundsSize32 + strokeDataSize32); + builder[0] = fPath.getGenerationID(); + builder[1] = fPath.getFillType(); + // For inverse fills, the tessellation is dependent on clip bounds. + if (fPath.isInverseFillType()) { + memcpy(&builder[2], &fClipBounds, sizeof(fClipBounds)); + } + fStroke.asUniqueKeyFragment(&builder[2 + clipBoundsSize32]); + builder.finish(); + GrResourceProvider* rp = target->resourceProvider(); + SkAutoTUnref vertexBuffer(rp->findAndRefTByUniqueKey(key)); + int vertexCount; + SkScalar screenSpaceTol = GrPathUtils::kDefaultTolerance; + SkScalar tol = GrPathUtils::scaleToleranceToSrc( + screenSpaceTol, fViewMatrix, fPath.getBounds()); + if (!cache_match(vertexBuffer.get(), tol, &vertexCount)) { + bool canMapVB = GrCaps::kNone_MapFlags != target->caps().mapBufferFlags(); + vertexCount = tessellate(&key, rp, vertexBuffer, canMapVB); + } + + if (vertexCount == 0) { + return; + } + + SkAutoTUnref gp; + { + using namespace GrDefaultGeoProcFactory; + + Color color(fColor); + LocalCoords localCoords(fPipelineInfo.readsLocalCoords() ? + LocalCoords::kUsePosition_Type : + LocalCoords::kUnused_Type); + Coverage::Type coverageType; + if (fPipelineInfo.readsCoverage()) { + coverageType = Coverage::kSolid_Type; + } else { + coverageType = Coverage::kNone_Type; + } + Coverage coverage(coverageType); + gp.reset(GrDefaultGeoProcFactory::Create(color, coverage, localCoords, + fViewMatrix)); + } + + target->initDraw(gp, this->pipeline()); + SkASSERT(gp->getVertexStride() == sizeof(SkPoint)); + + GrPrimitiveType primitiveType = WIREFRAME ? kLines_GrPrimitiveType + : kTriangles_GrPrimitiveType; + GrVertices vertices; + vertices.init(primitiveType, vertexBuffer.get(), 0, vertexCount); + target->draw(vertices); + } + + bool onCombineIfPossible(GrBatch*, const GrCaps&) override { return false; } + + TessellatingPathBatch(const GrColor& color, + const SkPath& path, + const GrStrokeInfo& stroke, + const SkMatrix& viewMatrix, + const SkRect& clipBounds) + : fColor(color) + , fPath(path) + , fStroke(stroke) + , fViewMatrix(viewMatrix) + , fClipBounds(clipBounds) { + this->initClassID(); + + fBounds = path.getBounds(); + if (!stroke.isFillStyle()) { + SkScalar radius = SkScalarHalf(stroke.getWidth()); + if (stroke.getJoin() == SkPaint::kMiter_Join) { + SkScalar scale = stroke.getMiter(); + if (scale > SK_Scalar1) { + radius = SkScalarMul(radius, scale); + } + } + fBounds.outset(radius, radius); + } + viewMatrix.mapRect(&fBounds); + } + + GrColor fColor; + SkPath fPath; + GrStrokeInfo fStroke; + SkMatrix fViewMatrix; + SkRect fClipBounds; // in source space + GrPipelineOptimizations fPipelineInfo; +}; + +bool GrTessellatingPathRenderer::onDrawPath(const DrawPathArgs& args) { + SkASSERT(!args.fAntiAlias); + const GrRenderTarget* rt = args.fPipelineBuilder->getRenderTarget(); + if (nullptr == rt) { + return false; + } + + SkIRect clipBoundsI; + args.fPipelineBuilder->clip().getConservativeBounds(rt, &clipBoundsI); + SkRect clipBounds = SkRect::Make(clipBoundsI); + SkMatrix vmi; + if (!args.fViewMatrix->invert(&vmi)) { + return false; + } + vmi.mapRect(&clipBounds); + SkAutoTUnref batch(TessellatingPathBatch::Create(args.fColor, *args.fPath, + *args.fStroke, *args.fViewMatrix, + clipBounds)); + args.fTarget->drawBatch(*args.fPipelineBuilder, batch); + + return true; +} + +/////////////////////////////////////////////////////////////////////////////////////////////////// + +#ifdef GR_TEST_UTILS + +DRAW_BATCH_TEST_DEFINE(TesselatingPathBatch) { + GrColor color = GrRandomColor(random); + SkMatrix viewMatrix = GrTest::TestMatrixInvertible(random); + SkPath path = GrTest::TestPath(random); + SkRect clipBounds = GrTest::TestRect(random); + SkMatrix vmi; + bool result = viewMatrix.invert(&vmi); + if (!result) { + SkFAIL("Cannot invert matrix\n"); + } + vmi.mapRect(&clipBounds); + GrStrokeInfo strokeInfo = GrTest::TestStrokeInfo(random); + return TessellatingPathBatch::Create(color, path, strokeInfo, viewMatrix, clipBounds); +} + +#endif -- cgit v1.2.3