1/* 2 * Copyright 2015 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8#include "GrTessellator.h" 9 10#include "GrBatchFlushState.h" 11#include "GrBatchTest.h" 12#include "GrDefaultGeoProcFactory.h" 13#include "GrPathUtils.h" 14#include "GrVertices.h" 15#include "GrResourceCache.h" 16#include "GrResourceProvider.h" 17#include "SkGeometry.h" 18#include "SkChunkAlloc.h" 19 20#include "batches/GrVertexBatch.h" 21 22#include <stdio.h> 23 24/* 25 * There are six stages to the algorithm: 26 * 27 * 1) Linearize the path contours into piecewise linear segments (path_to_contours()). 28 * 2) Build a mesh of edges connecting the vertices (build_edges()). 29 * 3) Sort the vertices in Y (and secondarily in X) (merge_sort()). 30 * 4) Simplify the mesh by inserting new vertices at intersecting edges (simplify()). 31 * 5) Tessellate the simplified mesh into monotone polygons (tessellate()). 32 * 6) Triangulate the monotone polygons directly into a vertex buffer (polys_to_triangles()). 33 * 34 * The vertex sorting in step (3) is a merge sort, since it plays well with the linked list 35 * of vertices (and the necessity of inserting new vertices on intersection). 36 * 37 * Stages (4) and (5) use an active edge list, which a list of all edges for which the 38 * sweep line has crossed the top vertex, but not the bottom vertex. It's sorted 39 * left-to-right based on the point where both edges are active (when both top vertices 40 * have been seen, so the "lower" top vertex of the two). If the top vertices are equal 41 * (shared), it's sorted based on the last point where both edges are active, so the 42 * "upper" bottom vertex. 43 * 44 * The most complex step is the simplification (4). It's based on the Bentley-Ottman 45 * line-sweep algorithm, but due to floating point inaccuracy, the intersection points are 46 * not exact and may violate the mesh topology or active edge list ordering. We 47 * accommodate this by adjusting the topology of the mesh and AEL to match the intersection 48 * points. This occurs in three ways: 49 * 50 * A) Intersections may cause a shortened edge to no longer be ordered with respect to its 51 * neighbouring edges at the top or bottom vertex. This is handled by merging the 52 * edges (merge_collinear_edges()). 53 * B) Intersections may cause an edge to violate the left-to-right ordering of the 54 * active edge list. This is handled by splitting the neighbour edge on the 55 * intersected vertex (cleanup_active_edges()). 56 * C) Shortening an edge may cause an active edge to become inactive or an inactive edge 57 * to become active. This is handled by removing or inserting the edge in the active 58 * edge list (fix_active_state()). 59 * 60 * The tessellation steps (5) and (6) are based on "Triangulating Simple Polygons and 61 * Equivalent Problems" (Fournier and Montuno); also a line-sweep algorithm. Note that it 62 * currently uses a linked list for the active edge list, rather than a 2-3 tree as the 63 * paper describes. The 2-3 tree gives O(lg N) lookups, but insertion and removal also 64 * become O(lg N). In all the test cases, it was found that the cost of frequent O(lg N) 65 * insertions and removals was greater than the cost of infrequent O(N) lookups with the 66 * linked list implementation. With the latter, all removals are O(1), and most insertions 67 * are O(1), since we know the adjacent edge in the active edge list based on the topology. 68 * Only type 2 vertices (see paper) require the O(N) lookups, and these are much less 69 * frequent. There may be other data structures worth investigating, however. 70 * 71 * Note that the orientation of the line sweep algorithms is determined by the aspect ratio of the 72 * path bounds. When the path is taller than it is wide, we sort vertices based on increasing Y 73 * coordinate, and secondarily by increasing X coordinate. When the path is wider than it is tall, 74 * we sort by increasing X coordinate, but secondarily by *decreasing* Y coordinate. This is so 75 * that the "left" and "right" orientation in the code remains correct (edges to the left are 76 * increasing in Y; edges to the right are decreasing in Y). That is, the setting rotates 90 77 * degrees counterclockwise, rather that transposing. 78 */ 79 80#define LOGGING_ENABLED 0 81 82#if LOGGING_ENABLED 83#define LOG printf 84#else 85#define LOG(...) 86#endif 87 88#define ALLOC_NEW(Type, args, alloc) new (alloc.allocThrow(sizeof(Type))) Type args 89 90namespace { 91 92struct Vertex; 93struct Edge; 94struct Poly; 95 96template <class T, T* T::*Prev, T* T::*Next> 97void insert(T* t, T* prev, T* next, T** head, T** tail) { 98 t->*Prev = prev; 99 t->*Next = next; 100 if (prev) { 101 prev->*Next = t; 102 } else if (head) { 103 *head = t; 104 } 105 if (next) { 106 next->*Prev = t; 107 } else if (tail) { 108 *tail = t; 109 } 110} 111 112template <class T, T* T::*Prev, T* T::*Next> 113void remove(T* t, T** head, T** tail) { 114 if (t->*Prev) { 115 t->*Prev->*Next = t->*Next; 116 } else if (head) { 117 *head = t->*Next; 118 } 119 if (t->*Next) { 120 t->*Next->*Prev = t->*Prev; 121 } else if (tail) { 122 *tail = t->*Prev; 123 } 124 t->*Prev = t->*Next = nullptr; 125} 126 127/** 128 * Vertices are used in three ways: first, the path contours are converted into a 129 * circularly-linked list of Vertices for each contour. After edge construction, the same Vertices 130 * are re-ordered by the merge sort according to the sweep_lt comparator (usually, increasing 131 * in Y) using the same fPrev/fNext pointers that were used for the contours, to avoid 132 * reallocation. Finally, MonotonePolys are built containing a circularly-linked list of 133 * Vertices. (Currently, those Vertices are newly-allocated for the MonotonePolys, since 134 * an individual Vertex from the path mesh may belong to multiple 135 * MonotonePolys, so the original Vertices cannot be re-used. 136 */ 137 138struct Vertex { 139 Vertex(const SkPoint& point) 140 : fPoint(point), fPrev(nullptr), fNext(nullptr) 141 , fFirstEdgeAbove(nullptr), fLastEdgeAbove(nullptr) 142 , fFirstEdgeBelow(nullptr), fLastEdgeBelow(nullptr) 143 , fProcessed(false) 144#if LOGGING_ENABLED 145 , fID (-1.0f) 146#endif 147 {} 148 SkPoint fPoint; // Vertex position 149 Vertex* fPrev; // Linked list of contours, then Y-sorted vertices. 150 Vertex* fNext; // " 151 Edge* fFirstEdgeAbove; // Linked list of edges above this vertex. 152 Edge* fLastEdgeAbove; // " 153 Edge* fFirstEdgeBelow; // Linked list of edges below this vertex. 154 Edge* fLastEdgeBelow; // " 155 bool fProcessed; // Has this vertex been seen in simplify()? 156#if LOGGING_ENABLED 157 float fID; // Identifier used for logging. 158#endif 159}; 160 161/***************************************************************************************/ 162 163typedef bool (*CompareFunc)(const SkPoint& a, const SkPoint& b); 164 165struct Comparator { 166 CompareFunc sweep_lt; 167 CompareFunc sweep_gt; 168}; 169 170bool sweep_lt_horiz(const SkPoint& a, const SkPoint& b) { 171 return a.fX == b.fX ? a.fY > b.fY : a.fX < b.fX; 172} 173 174bool sweep_lt_vert(const SkPoint& a, const SkPoint& b) { 175 return a.fY == b.fY ? a.fX < b.fX : a.fY < b.fY; 176} 177 178bool sweep_gt_horiz(const SkPoint& a, const SkPoint& b) { 179 return a.fX == b.fX ? a.fY < b.fY : a.fX > b.fX; 180} 181 182bool sweep_gt_vert(const SkPoint& a, const SkPoint& b) { 183 return a.fY == b.fY ? a.fX > b.fX : a.fY > b.fY; 184} 185 186inline SkPoint* emit_vertex(Vertex* v, SkPoint* data) { 187 *data++ = v->fPoint; 188 return data; 189} 190 191SkPoint* emit_triangle(Vertex* v0, Vertex* v1, Vertex* v2, SkPoint* data) { 192#if WIREFRAME 193 data = emit_vertex(v0, data); 194 data = emit_vertex(v1, data); 195 data = emit_vertex(v1, data); 196 data = emit_vertex(v2, data); 197 data = emit_vertex(v2, data); 198 data = emit_vertex(v0, data); 199#else 200 data = emit_vertex(v0, data); 201 data = emit_vertex(v1, data); 202 data = emit_vertex(v2, data); 203#endif 204 return data; 205} 206 207struct EdgeList { 208 EdgeList() : fHead(nullptr), fTail(nullptr) {} 209 Edge* fHead; 210 Edge* fTail; 211}; 212 213/** 214 * An Edge joins a top Vertex to a bottom Vertex. Edge ordering for the list of "edges above" and 215 * "edge below" a vertex as well as for the active edge list is handled by isLeftOf()/isRightOf(). 216 * Note that an Edge will give occasionally dist() != 0 for its own endpoints (because floating 217 * point). For speed, that case is only tested by the callers which require it (e.g., 218 * cleanup_active_edges()). Edges also handle checking for intersection with other edges. 219 * Currently, this converts the edges to the parametric form, in order to avoid doing a division 220 * until an intersection has been confirmed. This is slightly slower in the "found" case, but 221 * a lot faster in the "not found" case. 222 * 223 * The coefficients of the line equation stored in double precision to avoid catastrphic 224 * cancellation in the isLeftOf() and isRightOf() checks. Using doubles ensures that the result is 225 * correct in float, since it's a polynomial of degree 2. The intersect() function, being 226 * degree 5, is still subject to catastrophic cancellation. We deal with that by assuming its 227 * output may be incorrect, and adjusting the mesh topology to match (see comment at the top of 228 * this file). 229 */ 230 231struct Edge { 232 Edge(Vertex* top, Vertex* bottom, int winding) 233 : fWinding(winding) 234 , fTop(top) 235 , fBottom(bottom) 236 , fLeft(nullptr) 237 , fRight(nullptr) 238 , fPrevEdgeAbove(nullptr) 239 , fNextEdgeAbove(nullptr) 240 , fPrevEdgeBelow(nullptr) 241 , fNextEdgeBelow(nullptr) 242 , fLeftPoly(nullptr) 243 , fRightPoly(nullptr) { 244 recompute(); 245 } 246 int fWinding; // 1 == edge goes downward; -1 = edge goes upward. 247 Vertex* fTop; // The top vertex in vertex-sort-order (sweep_lt). 248 Vertex* fBottom; // The bottom vertex in vertex-sort-order. 249 Edge* fLeft; // The linked list of edges in the active edge list. 250 Edge* fRight; // " 251 Edge* fPrevEdgeAbove; // The linked list of edges in the bottom Vertex's "edges above". 252 Edge* fNextEdgeAbove; // " 253 Edge* fPrevEdgeBelow; // The linked list of edges in the top Vertex's "edges below". 254 Edge* fNextEdgeBelow; // " 255 Poly* fLeftPoly; // The Poly to the left of this edge, if any. 256 Poly* fRightPoly; // The Poly to the right of this edge, if any. 257 double fDX; // The line equation for this edge, in implicit form. 258 double fDY; // fDY * x + fDX * y + fC = 0, for point (x, y) on the line. 259 double fC; 260 double dist(const SkPoint& p) const { 261 return fDY * p.fX - fDX * p.fY + fC; 262 } 263 bool isRightOf(Vertex* v) const { 264 return dist(v->fPoint) < 0.0; 265 } 266 bool isLeftOf(Vertex* v) const { 267 return dist(v->fPoint) > 0.0; 268 } 269 void recompute() { 270 fDX = static_cast<double>(fBottom->fPoint.fX) - fTop->fPoint.fX; 271 fDY = static_cast<double>(fBottom->fPoint.fY) - fTop->fPoint.fY; 272 fC = static_cast<double>(fTop->fPoint.fY) * fBottom->fPoint.fX - 273 static_cast<double>(fTop->fPoint.fX) * fBottom->fPoint.fY; 274 } 275 bool intersect(const Edge& other, SkPoint* p) { 276 LOG("intersecting %g -> %g with %g -> %g\n", 277 fTop->fID, fBottom->fID, 278 other.fTop->fID, other.fBottom->fID); 279 if (fTop == other.fTop || fBottom == other.fBottom) { 280 return false; 281 } 282 double denom = fDX * other.fDY - fDY * other.fDX; 283 if (denom == 0.0) { 284 return false; 285 } 286 double dx = static_cast<double>(fTop->fPoint.fX) - other.fTop->fPoint.fX; 287 double dy = static_cast<double>(fTop->fPoint.fY) - other.fTop->fPoint.fY; 288 double sNumer = dy * other.fDX - dx * other.fDY; 289 double tNumer = dy * fDX - dx * fDY; 290 // If (sNumer / denom) or (tNumer / denom) is not in [0..1], exit early. 291 // This saves us doing the divide below unless absolutely necessary. 292 if (denom > 0.0 ? (sNumer < 0.0 || sNumer > denom || tNumer < 0.0 || tNumer > denom) 293 : (sNumer > 0.0 || sNumer < denom || tNumer > 0.0 || tNumer < denom)) { 294 return false; 295 } 296 double s = sNumer / denom; 297 SkASSERT(s >= 0.0 && s <= 1.0); 298 p->fX = SkDoubleToScalar(fTop->fPoint.fX + s * fDX); 299 p->fY = SkDoubleToScalar(fTop->fPoint.fY + s * fDY); 300 return true; 301 } 302 bool isActive(EdgeList* activeEdges) const { 303 return activeEdges && (fLeft || fRight || activeEdges->fHead == this); 304 } 305}; 306 307/***************************************************************************************/ 308 309struct Poly { 310 Poly(int winding) 311 : fWinding(winding) 312 , fHead(nullptr) 313 , fTail(nullptr) 314 , fActive(nullptr) 315 , fNext(nullptr) 316 , fPartner(nullptr) 317 , fCount(0) 318 { 319#if LOGGING_ENABLED 320 static int gID = 0; 321 fID = gID++; 322 LOG("*** created Poly %d\n", fID); 323#endif 324 } 325 typedef enum { kNeither_Side, kLeft_Side, kRight_Side } Side; 326 struct MonotonePoly { 327 MonotonePoly() 328 : fSide(kNeither_Side) 329 , fHead(nullptr) 330 , fTail(nullptr) 331 , fPrev(nullptr) 332 , fNext(nullptr) {} 333 Side fSide; 334 Vertex* fHead; 335 Vertex* fTail; 336 MonotonePoly* fPrev; 337 MonotonePoly* fNext; 338 bool addVertex(Vertex* v, Side side, SkChunkAlloc& alloc) { 339 Vertex* newV = ALLOC_NEW(Vertex, (v->fPoint), alloc); 340 bool done = false; 341 if (fSide == kNeither_Side) { 342 fSide = side; 343 } else { 344 done = side != fSide; 345 } 346 if (fHead == nullptr) { 347 fHead = fTail = newV; 348 } else if (fSide == kRight_Side) { 349 newV->fPrev = fTail; 350 fTail->fNext = newV; 351 fTail = newV; 352 } else { 353 newV->fNext = fHead; 354 fHead->fPrev = newV; 355 fHead = newV; 356 } 357 return done; 358 } 359 360 SkPoint* emit(SkPoint* data) { 361 Vertex* first = fHead; 362 Vertex* v = first->fNext; 363 while (v != fTail) { 364 SkASSERT(v && v->fPrev && v->fNext); 365 Vertex* prev = v->fPrev; 366 Vertex* curr = v; 367 Vertex* next = v->fNext; 368 double ax = static_cast<double>(curr->fPoint.fX) - prev->fPoint.fX; 369 double ay = static_cast<double>(curr->fPoint.fY) - prev->fPoint.fY; 370 double bx = static_cast<double>(next->fPoint.fX) - curr->fPoint.fX; 371 double by = static_cast<double>(next->fPoint.fY) - curr->fPoint.fY; 372 if (ax * by - ay * bx >= 0.0) { 373 data = emit_triangle(prev, curr, next, data); 374 v->fPrev->fNext = v->fNext; 375 v->fNext->fPrev = v->fPrev; 376 if (v->fPrev == first) { 377 v = v->fNext; 378 } else { 379 v = v->fPrev; 380 } 381 } else { 382 v = v->fNext; 383 } 384 } 385 return data; 386 } 387 }; 388 Poly* addVertex(Vertex* v, Side side, SkChunkAlloc& alloc) { 389 LOG("addVertex() to %d at %g (%g, %g), %s side\n", fID, v->fID, v->fPoint.fX, v->fPoint.fY, 390 side == kLeft_Side ? "left" : side == kRight_Side ? "right" : "neither"); 391 Poly* partner = fPartner; 392 Poly* poly = this; 393 if (partner) { 394 fPartner = partner->fPartner = nullptr; 395 } 396 if (!fActive) { 397 fActive = ALLOC_NEW(MonotonePoly, (), alloc); 398 } 399 if (fActive->addVertex(v, side, alloc)) { 400 if (fTail) { 401 fActive->fPrev = fTail; 402 fTail->fNext = fActive; 403 fTail = fActive; 404 } else { 405 fHead = fTail = fActive; 406 } 407 if (partner) { 408 partner->addVertex(v, side, alloc); 409 poly = partner; 410 } else { 411 Vertex* prev = fActive->fSide == Poly::kLeft_Side ? 412 fActive->fHead->fNext : fActive->fTail->fPrev; 413 fActive = ALLOC_NEW(MonotonePoly, , alloc); 414 fActive->addVertex(prev, Poly::kNeither_Side, alloc); 415 fActive->addVertex(v, side, alloc); 416 } 417 } 418 fCount++; 419 return poly; 420 } 421 void end(Vertex* v, SkChunkAlloc& alloc) { 422 LOG("end() %d at %g, %g\n", fID, v->fPoint.fX, v->fPoint.fY); 423 if (fPartner) { 424 fPartner = fPartner->fPartner = nullptr; 425 } 426 addVertex(v, fActive->fSide == kLeft_Side ? kRight_Side : kLeft_Side, alloc); 427 } 428 SkPoint* emit(SkPoint *data) { 429 if (fCount < 3) { 430 return data; 431 } 432 LOG("emit() %d, size %d\n", fID, fCount); 433 for (MonotonePoly* m = fHead; m != nullptr; m = m->fNext) { 434 data = m->emit(data); 435 } 436 return data; 437 } 438 int fWinding; 439 MonotonePoly* fHead; 440 MonotonePoly* fTail; 441 MonotonePoly* fActive; 442 Poly* fNext; 443 Poly* fPartner; 444 int fCount; 445#if LOGGING_ENABLED 446 int fID; 447#endif 448}; 449 450/***************************************************************************************/ 451 452bool coincident(const SkPoint& a, const SkPoint& b) { 453 return a == b; 454} 455 456Poly* new_poly(Poly** head, Vertex* v, int winding, SkChunkAlloc& alloc) { 457 Poly* poly = ALLOC_NEW(Poly, (winding), alloc); 458 poly->addVertex(v, Poly::kNeither_Side, alloc); 459 poly->fNext = *head; 460 *head = poly; 461 return poly; 462} 463 464Vertex* append_point_to_contour(const SkPoint& p, Vertex* prev, Vertex** head, 465 SkChunkAlloc& alloc) { 466 Vertex* v = ALLOC_NEW(Vertex, (p), alloc); 467#if LOGGING_ENABLED 468 static float gID = 0.0f; 469 v->fID = gID++; 470#endif 471 if (prev) { 472 prev->fNext = v; 473 v->fPrev = prev; 474 } else { 475 *head = v; 476 } 477 return v; 478} 479 480Vertex* generate_quadratic_points(const SkPoint& p0, 481 const SkPoint& p1, 482 const SkPoint& p2, 483 SkScalar tolSqd, 484 Vertex* prev, 485 Vertex** head, 486 int pointsLeft, 487 SkChunkAlloc& alloc) { 488 SkScalar d = p1.distanceToLineSegmentBetweenSqd(p0, p2); 489 if (pointsLeft < 2 || d < tolSqd || !SkScalarIsFinite(d)) { 490 return append_point_to_contour(p2, prev, head, alloc); 491 } 492 493 const SkPoint q[] = { 494 { SkScalarAve(p0.fX, p1.fX), SkScalarAve(p0.fY, p1.fY) }, 495 { SkScalarAve(p1.fX, p2.fX), SkScalarAve(p1.fY, p2.fY) }, 496 }; 497 const SkPoint r = { SkScalarAve(q[0].fX, q[1].fX), SkScalarAve(q[0].fY, q[1].fY) }; 498 499 pointsLeft >>= 1; 500 prev = generate_quadratic_points(p0, q[0], r, tolSqd, prev, head, pointsLeft, alloc); 501 prev = generate_quadratic_points(r, q[1], p2, tolSqd, prev, head, pointsLeft, alloc); 502 return prev; 503} 504 505Vertex* generate_cubic_points(const SkPoint& p0, 506 const SkPoint& p1, 507 const SkPoint& p2, 508 const SkPoint& p3, 509 SkScalar tolSqd, 510 Vertex* prev, 511 Vertex** head, 512 int pointsLeft, 513 SkChunkAlloc& alloc) { 514 SkScalar d1 = p1.distanceToLineSegmentBetweenSqd(p0, p3); 515 SkScalar d2 = p2.distanceToLineSegmentBetweenSqd(p0, p3); 516 if (pointsLeft < 2 || (d1 < tolSqd && d2 < tolSqd) || 517 !SkScalarIsFinite(d1) || !SkScalarIsFinite(d2)) { 518 return append_point_to_contour(p3, prev, head, alloc); 519 } 520 const SkPoint q[] = { 521 { SkScalarAve(p0.fX, p1.fX), SkScalarAve(p0.fY, p1.fY) }, 522 { SkScalarAve(p1.fX, p2.fX), SkScalarAve(p1.fY, p2.fY) }, 523 { SkScalarAve(p2.fX, p3.fX), SkScalarAve(p2.fY, p3.fY) } 524 }; 525 const SkPoint r[] = { 526 { SkScalarAve(q[0].fX, q[1].fX), SkScalarAve(q[0].fY, q[1].fY) }, 527 { SkScalarAve(q[1].fX, q[2].fX), SkScalarAve(q[1].fY, q[2].fY) } 528 }; 529 const SkPoint s = { SkScalarAve(r[0].fX, r[1].fX), SkScalarAve(r[0].fY, r[1].fY) }; 530 pointsLeft >>= 1; 531 prev = generate_cubic_points(p0, q[0], r[0], s, tolSqd, prev, head, pointsLeft, alloc); 532 prev = generate_cubic_points(s, r[1], q[2], p3, tolSqd, prev, head, pointsLeft, alloc); 533 return prev; 534} 535 536// Stage 1: convert the input path to a set of linear contours (linked list of Vertices). 537 538void path_to_contours(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, 539 Vertex** contours, SkChunkAlloc& alloc, bool *isLinear) { 540 SkScalar toleranceSqd = tolerance * tolerance; 541 542 SkPoint pts[4]; 543 bool done = false; 544 *isLinear = true; 545 SkPath::Iter iter(path, false); 546 Vertex* prev = nullptr; 547 Vertex* head = nullptr; 548 if (path.isInverseFillType()) { 549 SkPoint quad[4]; 550 clipBounds.toQuad(quad); 551 for (int i = 3; i >= 0; i--) { 552 prev = append_point_to_contour(quad[i], prev, &head, alloc); 553 } 554 head->fPrev = prev; 555 prev->fNext = head; 556 *contours++ = head; 557 head = prev = nullptr; 558 } 559 SkAutoConicToQuads converter; 560 while (!done) { 561 SkPath::Verb verb = iter.next(pts); 562 switch (verb) { 563 case SkPath::kConic_Verb: { 564 SkScalar weight = iter.conicWeight(); 565 const SkPoint* quadPts = converter.computeQuads(pts, weight, toleranceSqd); 566 for (int i = 0; i < converter.countQuads(); ++i) { 567 int pointsLeft = GrPathUtils::quadraticPointCount(quadPts, tolerance); 568 prev = generate_quadratic_points(quadPts[0], quadPts[1], quadPts[2], 569 toleranceSqd, prev, &head, pointsLeft, alloc); 570 quadPts += 2; 571 } 572 *isLinear = false; 573 break; 574 } 575 case SkPath::kMove_Verb: 576 if (head) { 577 head->fPrev = prev; 578 prev->fNext = head; 579 *contours++ = head; 580 } 581 head = prev = nullptr; 582 prev = append_point_to_contour(pts[0], prev, &head, alloc); 583 break; 584 case SkPath::kLine_Verb: { 585 prev = append_point_to_contour(pts[1], prev, &head, alloc); 586 break; 587 } 588 case SkPath::kQuad_Verb: { 589 int pointsLeft = GrPathUtils::quadraticPointCount(pts, tolerance); 590 prev = generate_quadratic_points(pts[0], pts[1], pts[2], toleranceSqd, prev, 591 &head, pointsLeft, alloc); 592 *isLinear = false; 593 break; 594 } 595 case SkPath::kCubic_Verb: { 596 int pointsLeft = GrPathUtils::cubicPointCount(pts, tolerance); 597 prev = generate_cubic_points(pts[0], pts[1], pts[2], pts[3], 598 toleranceSqd, prev, &head, pointsLeft, alloc); 599 *isLinear = false; 600 break; 601 } 602 case SkPath::kClose_Verb: 603 if (head) { 604 head->fPrev = prev; 605 prev->fNext = head; 606 *contours++ = head; 607 } 608 head = prev = nullptr; 609 break; 610 case SkPath::kDone_Verb: 611 if (head) { 612 head->fPrev = prev; 613 prev->fNext = head; 614 *contours++ = head; 615 } 616 done = true; 617 break; 618 } 619 } 620} 621 622inline bool apply_fill_type(SkPath::FillType fillType, int winding) { 623 switch (fillType) { 624 case SkPath::kWinding_FillType: 625 return winding != 0; 626 case SkPath::kEvenOdd_FillType: 627 return (winding & 1) != 0; 628 case SkPath::kInverseWinding_FillType: 629 return winding == 1; 630 case SkPath::kInverseEvenOdd_FillType: 631 return (winding & 1) == 1; 632 default: 633 SkASSERT(false); 634 return false; 635 } 636} 637 638Edge* new_edge(Vertex* prev, Vertex* next, SkChunkAlloc& alloc, Comparator& c) { 639 int winding = c.sweep_lt(prev->fPoint, next->fPoint) ? 1 : -1; 640 Vertex* top = winding < 0 ? next : prev; 641 Vertex* bottom = winding < 0 ? prev : next; 642 return ALLOC_NEW(Edge, (top, bottom, winding), alloc); 643} 644 645void remove_edge(Edge* edge, EdgeList* edges) { 646 LOG("removing edge %g -> %g\n", edge->fTop->fID, edge->fBottom->fID); 647 SkASSERT(edge->isActive(edges)); 648 remove<Edge, &Edge::fLeft, &Edge::fRight>(edge, &edges->fHead, &edges->fTail); 649} 650 651void insert_edge(Edge* edge, Edge* prev, EdgeList* edges) { 652 LOG("inserting edge %g -> %g\n", edge->fTop->fID, edge->fBottom->fID); 653 SkASSERT(!edge->isActive(edges)); 654 Edge* next = prev ? prev->fRight : edges->fHead; 655 insert<Edge, &Edge::fLeft, &Edge::fRight>(edge, prev, next, &edges->fHead, &edges->fTail); 656} 657 658void find_enclosing_edges(Vertex* v, EdgeList* edges, Edge** left, Edge** right) { 659 if (v->fFirstEdgeAbove) { 660 *left = v->fFirstEdgeAbove->fLeft; 661 *right = v->fLastEdgeAbove->fRight; 662 return; 663 } 664 Edge* next = nullptr; 665 Edge* prev; 666 for (prev = edges->fTail; prev != nullptr; prev = prev->fLeft) { 667 if (prev->isLeftOf(v)) { 668 break; 669 } 670 next = prev; 671 } 672 *left = prev; 673 *right = next; 674 return; 675} 676 677void find_enclosing_edges(Edge* edge, EdgeList* edges, Comparator& c, Edge** left, Edge** right) { 678 Edge* prev = nullptr; 679 Edge* next; 680 for (next = edges->fHead; next != nullptr; next = next->fRight) { 681 if ((c.sweep_gt(edge->fTop->fPoint, next->fTop->fPoint) && next->isRightOf(edge->fTop)) || 682 (c.sweep_gt(next->fTop->fPoint, edge->fTop->fPoint) && edge->isLeftOf(next->fTop)) || 683 (c.sweep_lt(edge->fBottom->fPoint, next->fBottom->fPoint) && 684 next->isRightOf(edge->fBottom)) || 685 (c.sweep_lt(next->fBottom->fPoint, edge->fBottom->fPoint) && 686 edge->isLeftOf(next->fBottom))) { 687 break; 688 } 689 prev = next; 690 } 691 *left = prev; 692 *right = next; 693 return; 694} 695 696void fix_active_state(Edge* edge, EdgeList* activeEdges, Comparator& c) { 697 if (edge->isActive(activeEdges)) { 698 if (edge->fBottom->fProcessed || !edge->fTop->fProcessed) { 699 remove_edge(edge, activeEdges); 700 } 701 } else if (edge->fTop->fProcessed && !edge->fBottom->fProcessed) { 702 Edge* left; 703 Edge* right; 704 find_enclosing_edges(edge, activeEdges, c, &left, &right); 705 insert_edge(edge, left, activeEdges); 706 } 707} 708 709void insert_edge_above(Edge* edge, Vertex* v, Comparator& c) { 710 if (edge->fTop->fPoint == edge->fBottom->fPoint || 711 c.sweep_gt(edge->fTop->fPoint, edge->fBottom->fPoint)) { 712 return; 713 } 714 LOG("insert edge (%g -> %g) above vertex %g\n", edge->fTop->fID, edge->fBottom->fID, v->fID); 715 Edge* prev = nullptr; 716 Edge* next; 717 for (next = v->fFirstEdgeAbove; next; next = next->fNextEdgeAbove) { 718 if (next->isRightOf(edge->fTop)) { 719 break; 720 } 721 prev = next; 722 } 723 insert<Edge, &Edge::fPrevEdgeAbove, &Edge::fNextEdgeAbove>( 724 edge, prev, next, &v->fFirstEdgeAbove, &v->fLastEdgeAbove); 725} 726 727void insert_edge_below(Edge* edge, Vertex* v, Comparator& c) { 728 if (edge->fTop->fPoint == edge->fBottom->fPoint || 729 c.sweep_gt(edge->fTop->fPoint, edge->fBottom->fPoint)) { 730 return; 731 } 732 LOG("insert edge (%g -> %g) below vertex %g\n", edge->fTop->fID, edge->fBottom->fID, v->fID); 733 Edge* prev = nullptr; 734 Edge* next; 735 for (next = v->fFirstEdgeBelow; next; next = next->fNextEdgeBelow) { 736 if (next->isRightOf(edge->fBottom)) { 737 break; 738 } 739 prev = next; 740 } 741 insert<Edge, &Edge::fPrevEdgeBelow, &Edge::fNextEdgeBelow>( 742 edge, prev, next, &v->fFirstEdgeBelow, &v->fLastEdgeBelow); 743} 744 745void remove_edge_above(Edge* edge) { 746 LOG("removing edge (%g -> %g) above vertex %g\n", edge->fTop->fID, edge->fBottom->fID, 747 edge->fBottom->fID); 748 remove<Edge, &Edge::fPrevEdgeAbove, &Edge::fNextEdgeAbove>( 749 edge, &edge->fBottom->fFirstEdgeAbove, &edge->fBottom->fLastEdgeAbove); 750} 751 752void remove_edge_below(Edge* edge) { 753 LOG("removing edge (%g -> %g) below vertex %g\n", edge->fTop->fID, edge->fBottom->fID, 754 edge->fTop->fID); 755 remove<Edge, &Edge::fPrevEdgeBelow, &Edge::fNextEdgeBelow>( 756 edge, &edge->fTop->fFirstEdgeBelow, &edge->fTop->fLastEdgeBelow); 757} 758 759void erase_edge_if_zero_winding(Edge* edge, EdgeList* edges) { 760 if (edge->fWinding != 0) { 761 return; 762 } 763 LOG("erasing edge (%g -> %g)\n", edge->fTop->fID, edge->fBottom->fID); 764 remove_edge_above(edge); 765 remove_edge_below(edge); 766 if (edge->isActive(edges)) { 767 remove_edge(edge, edges); 768 } 769} 770 771void merge_collinear_edges(Edge* edge, EdgeList* activeEdges, Comparator& c); 772 773void set_top(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c) { 774 remove_edge_below(edge); 775 edge->fTop = v; 776 edge->recompute(); 777 insert_edge_below(edge, v, c); 778 fix_active_state(edge, activeEdges, c); 779 merge_collinear_edges(edge, activeEdges, c); 780} 781 782void set_bottom(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c) { 783 remove_edge_above(edge); 784 edge->fBottom = v; 785 edge->recompute(); 786 insert_edge_above(edge, v, c); 787 fix_active_state(edge, activeEdges, c); 788 merge_collinear_edges(edge, activeEdges, c); 789} 790 791void merge_edges_above(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c) { 792 if (coincident(edge->fTop->fPoint, other->fTop->fPoint)) { 793 LOG("merging coincident above edges (%g, %g) -> (%g, %g)\n", 794 edge->fTop->fPoint.fX, edge->fTop->fPoint.fY, 795 edge->fBottom->fPoint.fX, edge->fBottom->fPoint.fY); 796 other->fWinding += edge->fWinding; 797 erase_edge_if_zero_winding(other, activeEdges); 798 edge->fWinding = 0; 799 erase_edge_if_zero_winding(edge, activeEdges); 800 } else if (c.sweep_lt(edge->fTop->fPoint, other->fTop->fPoint)) { 801 other->fWinding += edge->fWinding; 802 erase_edge_if_zero_winding(other, activeEdges); 803 set_bottom(edge, other->fTop, activeEdges, c); 804 } else { 805 edge->fWinding += other->fWinding; 806 erase_edge_if_zero_winding(edge, activeEdges); 807 set_bottom(other, edge->fTop, activeEdges, c); 808 } 809} 810 811void merge_edges_below(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c) { 812 if (coincident(edge->fBottom->fPoint, other->fBottom->fPoint)) { 813 LOG("merging coincident below edges (%g, %g) -> (%g, %g)\n", 814 edge->fTop->fPoint.fX, edge->fTop->fPoint.fY, 815 edge->fBottom->fPoint.fX, edge->fBottom->fPoint.fY); 816 other->fWinding += edge->fWinding; 817 erase_edge_if_zero_winding(other, activeEdges); 818 edge->fWinding = 0; 819 erase_edge_if_zero_winding(edge, activeEdges); 820 } else if (c.sweep_lt(edge->fBottom->fPoint, other->fBottom->fPoint)) { 821 edge->fWinding += other->fWinding; 822 erase_edge_if_zero_winding(edge, activeEdges); 823 set_top(other, edge->fBottom, activeEdges, c); 824 } else { 825 other->fWinding += edge->fWinding; 826 erase_edge_if_zero_winding(other, activeEdges); 827 set_top(edge, other->fBottom, activeEdges, c); 828 } 829} 830 831void merge_collinear_edges(Edge* edge, EdgeList* activeEdges, Comparator& c) { 832 if (edge->fPrevEdgeAbove && (edge->fTop == edge->fPrevEdgeAbove->fTop || 833 !edge->fPrevEdgeAbove->isLeftOf(edge->fTop))) { 834 merge_edges_above(edge, edge->fPrevEdgeAbove, activeEdges, c); 835 } else if (edge->fNextEdgeAbove && (edge->fTop == edge->fNextEdgeAbove->fTop || 836 !edge->isLeftOf(edge->fNextEdgeAbove->fTop))) { 837 merge_edges_above(edge, edge->fNextEdgeAbove, activeEdges, c); 838 } 839 if (edge->fPrevEdgeBelow && (edge->fBottom == edge->fPrevEdgeBelow->fBottom || 840 !edge->fPrevEdgeBelow->isLeftOf(edge->fBottom))) { 841 merge_edges_below(edge, edge->fPrevEdgeBelow, activeEdges, c); 842 } else if (edge->fNextEdgeBelow && (edge->fBottom == edge->fNextEdgeBelow->fBottom || 843 !edge->isLeftOf(edge->fNextEdgeBelow->fBottom))) { 844 merge_edges_below(edge, edge->fNextEdgeBelow, activeEdges, c); 845 } 846} 847 848void split_edge(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc); 849 850void cleanup_active_edges(Edge* edge, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc) { 851 Vertex* top = edge->fTop; 852 Vertex* bottom = edge->fBottom; 853 if (edge->fLeft) { 854 Vertex* leftTop = edge->fLeft->fTop; 855 Vertex* leftBottom = edge->fLeft->fBottom; 856 if (c.sweep_gt(top->fPoint, leftTop->fPoint) && !edge->fLeft->isLeftOf(top)) { 857 split_edge(edge->fLeft, edge->fTop, activeEdges, c, alloc); 858 } else if (c.sweep_gt(leftTop->fPoint, top->fPoint) && !edge->isRightOf(leftTop)) { 859 split_edge(edge, leftTop, activeEdges, c, alloc); 860 } else if (c.sweep_lt(bottom->fPoint, leftBottom->fPoint) && 861 !edge->fLeft->isLeftOf(bottom)) { 862 split_edge(edge->fLeft, bottom, activeEdges, c, alloc); 863 } else if (c.sweep_lt(leftBottom->fPoint, bottom->fPoint) && !edge->isRightOf(leftBottom)) { 864 split_edge(edge, leftBottom, activeEdges, c, alloc); 865 } 866 } 867 if (edge->fRight) { 868 Vertex* rightTop = edge->fRight->fTop; 869 Vertex* rightBottom = edge->fRight->fBottom; 870 if (c.sweep_gt(top->fPoint, rightTop->fPoint) && !edge->fRight->isRightOf(top)) { 871 split_edge(edge->fRight, top, activeEdges, c, alloc); 872 } else if (c.sweep_gt(rightTop->fPoint, top->fPoint) && !edge->isLeftOf(rightTop)) { 873 split_edge(edge, rightTop, activeEdges, c, alloc); 874 } else if (c.sweep_lt(bottom->fPoint, rightBottom->fPoint) && 875 !edge->fRight->isRightOf(bottom)) { 876 split_edge(edge->fRight, bottom, activeEdges, c, alloc); 877 } else if (c.sweep_lt(rightBottom->fPoint, bottom->fPoint) && 878 !edge->isLeftOf(rightBottom)) { 879 split_edge(edge, rightBottom, activeEdges, c, alloc); 880 } 881 } 882} 883 884void split_edge(Edge* edge, Vertex* v, EdgeList* activeEdges, Comparator& c, SkChunkAlloc& alloc) { 885 LOG("splitting edge (%g -> %g) at vertex %g (%g, %g)\n", 886 edge->fTop->fID, edge->fBottom->fID, 887 v->fID, v->fPoint.fX, v->fPoint.fY); 888 if (c.sweep_lt(v->fPoint, edge->fTop->fPoint)) { 889 set_top(edge, v, activeEdges, c); 890 } else if (c.sweep_gt(v->fPoint, edge->fBottom->fPoint)) { 891 set_bottom(edge, v, activeEdges, c); 892 } else { 893 Edge* newEdge = ALLOC_NEW(Edge, (v, edge->fBottom, edge->fWinding), alloc); 894 insert_edge_below(newEdge, v, c); 895 insert_edge_above(newEdge, edge->fBottom, c); 896 set_bottom(edge, v, activeEdges, c); 897 cleanup_active_edges(edge, activeEdges, c, alloc); 898 fix_active_state(newEdge, activeEdges, c); 899 merge_collinear_edges(newEdge, activeEdges, c); 900 } 901} 902 903void merge_vertices(Vertex* src, Vertex* dst, Vertex** head, Comparator& c, SkChunkAlloc& alloc) { 904 LOG("found coincident verts at %g, %g; merging %g into %g\n", src->fPoint.fX, src->fPoint.fY, 905 src->fID, dst->fID); 906 for (Edge* edge = src->fFirstEdgeAbove; edge;) { 907 Edge* next = edge->fNextEdgeAbove; 908 set_bottom(edge, dst, nullptr, c); 909 edge = next; 910 } 911 for (Edge* edge = src->fFirstEdgeBelow; edge;) { 912 Edge* next = edge->fNextEdgeBelow; 913 set_top(edge, dst, nullptr, c); 914 edge = next; 915 } 916 remove<Vertex, &Vertex::fPrev, &Vertex::fNext>(src, head, nullptr); 917} 918 919Vertex* check_for_intersection(Edge* edge, Edge* other, EdgeList* activeEdges, Comparator& c, 920 SkChunkAlloc& alloc) { 921 SkPoint p; 922 if (!edge || !other) { 923 return nullptr; 924 } 925 if (edge->intersect(*other, &p)) { 926 Vertex* v; 927 LOG("found intersection, pt is %g, %g\n", p.fX, p.fY); 928 if (p == edge->fTop->fPoint || c.sweep_lt(p, edge->fTop->fPoint)) { 929 split_edge(other, edge->fTop, activeEdges, c, alloc); 930 v = edge->fTop; 931 } else if (p == edge->fBottom->fPoint || c.sweep_gt(p, edge->fBottom->fPoint)) { 932 split_edge(other, edge->fBottom, activeEdges, c, alloc); 933 v = edge->fBottom; 934 } else if (p == other->fTop->fPoint || c.sweep_lt(p, other->fTop->fPoint)) { 935 split_edge(edge, other->fTop, activeEdges, c, alloc); 936 v = other->fTop; 937 } else if (p == other->fBottom->fPoint || c.sweep_gt(p, other->fBottom->fPoint)) { 938 split_edge(edge, other->fBottom, activeEdges, c, alloc); 939 v = other->fBottom; 940 } else { 941 Vertex* nextV = edge->fTop; 942 while (c.sweep_lt(p, nextV->fPoint)) { 943 nextV = nextV->fPrev; 944 } 945 while (c.sweep_lt(nextV->fPoint, p)) { 946 nextV = nextV->fNext; 947 } 948 Vertex* prevV = nextV->fPrev; 949 if (coincident(prevV->fPoint, p)) { 950 v = prevV; 951 } else if (coincident(nextV->fPoint, p)) { 952 v = nextV; 953 } else { 954 v = ALLOC_NEW(Vertex, (p), alloc); 955 LOG("inserting between %g (%g, %g) and %g (%g, %g)\n", 956 prevV->fID, prevV->fPoint.fX, prevV->fPoint.fY, 957 nextV->fID, nextV->fPoint.fX, nextV->fPoint.fY); 958#if LOGGING_ENABLED 959 v->fID = (nextV->fID + prevV->fID) * 0.5f; 960#endif 961 v->fPrev = prevV; 962 v->fNext = nextV; 963 prevV->fNext = v; 964 nextV->fPrev = v; 965 } 966 split_edge(edge, v, activeEdges, c, alloc); 967 split_edge(other, v, activeEdges, c, alloc); 968 } 969 return v; 970 } 971 return nullptr; 972} 973 974void sanitize_contours(Vertex** contours, int contourCnt) { 975 for (int i = 0; i < contourCnt; ++i) { 976 SkASSERT(contours[i]); 977 for (Vertex* v = contours[i];;) { 978 if (coincident(v->fPrev->fPoint, v->fPoint)) { 979 LOG("vertex %g,%g coincident; removing\n", v->fPoint.fX, v->fPoint.fY); 980 if (v->fPrev == v) { 981 contours[i] = nullptr; 982 break; 983 } 984 v->fPrev->fNext = v->fNext; 985 v->fNext->fPrev = v->fPrev; 986 if (contours[i] == v) { 987 contours[i] = v->fNext; 988 } 989 v = v->fPrev; 990 } else { 991 v = v->fNext; 992 if (v == contours[i]) break; 993 } 994 } 995 } 996} 997 998void merge_coincident_vertices(Vertex** vertices, Comparator& c, SkChunkAlloc& alloc) { 999 for (Vertex* v = (*vertices)->fNext; v != nullptr; v = v->fNext) { 1000 if (c.sweep_lt(v->fPoint, v->fPrev->fPoint)) { 1001 v->fPoint = v->fPrev->fPoint; 1002 } 1003 if (coincident(v->fPrev->fPoint, v->fPoint)) { 1004 merge_vertices(v->fPrev, v, vertices, c, alloc); 1005 } 1006 } 1007} 1008 1009// Stage 2: convert the contours to a mesh of edges connecting the vertices. 1010 1011Vertex* build_edges(Vertex** contours, int contourCnt, Comparator& c, SkChunkAlloc& alloc) { 1012 Vertex* vertices = nullptr; 1013 Vertex* prev = nullptr; 1014 for (int i = 0; i < contourCnt; ++i) { 1015 for (Vertex* v = contours[i]; v != nullptr;) { 1016 Vertex* vNext = v->fNext; 1017 Edge* edge = new_edge(v->fPrev, v, alloc, c); 1018 if (edge->fWinding > 0) { 1019 insert_edge_below(edge, v->fPrev, c); 1020 insert_edge_above(edge, v, c); 1021 } else { 1022 insert_edge_below(edge, v, c); 1023 insert_edge_above(edge, v->fPrev, c); 1024 } 1025 merge_collinear_edges(edge, nullptr, c); 1026 if (prev) { 1027 prev->fNext = v; 1028 v->fPrev = prev; 1029 } else { 1030 vertices = v; 1031 } 1032 prev = v; 1033 v = vNext; 1034 if (v == contours[i]) break; 1035 } 1036 } 1037 if (prev) { 1038 prev->fNext = vertices->fPrev = nullptr; 1039 } 1040 return vertices; 1041} 1042 1043// Stage 3: sort the vertices by increasing sweep direction. 1044 1045Vertex* sorted_merge(Vertex* a, Vertex* b, Comparator& c); 1046 1047void front_back_split(Vertex* v, Vertex** pFront, Vertex** pBack) { 1048 Vertex* fast; 1049 Vertex* slow; 1050 if (!v || !v->fNext) { 1051 *pFront = v; 1052 *pBack = nullptr; 1053 } else { 1054 slow = v; 1055 fast = v->fNext; 1056 1057 while (fast != nullptr) { 1058 fast = fast->fNext; 1059 if (fast != nullptr) { 1060 slow = slow->fNext; 1061 fast = fast->fNext; 1062 } 1063 } 1064 1065 *pFront = v; 1066 *pBack = slow->fNext; 1067 slow->fNext->fPrev = nullptr; 1068 slow->fNext = nullptr; 1069 } 1070} 1071 1072void merge_sort(Vertex** head, Comparator& c) { 1073 if (!*head || !(*head)->fNext) { 1074 return; 1075 } 1076 1077 Vertex* a; 1078 Vertex* b; 1079 front_back_split(*head, &a, &b); 1080 1081 merge_sort(&a, c); 1082 merge_sort(&b, c); 1083 1084 *head = sorted_merge(a, b, c); 1085} 1086 1087inline void append_vertex(Vertex* v, Vertex** head, Vertex** tail) { 1088 insert<Vertex, &Vertex::fPrev, &Vertex::fNext>(v, *tail, nullptr, head, tail); 1089} 1090 1091inline void append_vertex_list(Vertex* v, Vertex** head, Vertex** tail) { 1092 insert<Vertex, &Vertex::fPrev, &Vertex::fNext>(v, *tail, v->fNext, head, tail); 1093} 1094 1095Vertex* sorted_merge(Vertex* a, Vertex* b, Comparator& c) { 1096 Vertex* head = nullptr; 1097 Vertex* tail = nullptr; 1098 1099 while (a && b) { 1100 if (c.sweep_lt(a->fPoint, b->fPoint)) { 1101 Vertex* next = a->fNext; 1102 append_vertex(a, &head, &tail); 1103 a = next; 1104 } else { 1105 Vertex* next = b->fNext; 1106 append_vertex(b, &head, &tail); 1107 b = next; 1108 } 1109 } 1110 if (a) { 1111 append_vertex_list(a, &head, &tail); 1112 } 1113 if (b) { 1114 append_vertex_list(b, &head, &tail); 1115 } 1116 return head; 1117} 1118 1119// Stage 4: Simplify the mesh by inserting new vertices at intersecting edges. 1120 1121void simplify(Vertex* vertices, Comparator& c, SkChunkAlloc& alloc) { 1122 LOG("simplifying complex polygons\n"); 1123 EdgeList activeEdges; 1124 for (Vertex* v = vertices; v != nullptr; v = v->fNext) { 1125 if (!v->fFirstEdgeAbove && !v->fFirstEdgeBelow) { 1126 continue; 1127 } 1128#if LOGGING_ENABLED 1129 LOG("\nvertex %g: (%g,%g)\n", v->fID, v->fPoint.fX, v->fPoint.fY); 1130#endif 1131 Edge* leftEnclosingEdge = nullptr; 1132 Edge* rightEnclosingEdge = nullptr; 1133 bool restartChecks; 1134 do { 1135 restartChecks = false; 1136 find_enclosing_edges(v, &activeEdges, &leftEnclosingEdge, &rightEnclosingEdge); 1137 if (v->fFirstEdgeBelow) { 1138 for (Edge* edge = v->fFirstEdgeBelow; edge != nullptr; edge = edge->fNextEdgeBelow) { 1139 if (check_for_intersection(edge, leftEnclosingEdge, &activeEdges, c, alloc)) { 1140 restartChecks = true; 1141 break; 1142 } 1143 if (check_for_intersection(edge, rightEnclosingEdge, &activeEdges, c, alloc)) { 1144 restartChecks = true; 1145 break; 1146 } 1147 } 1148 } else { 1149 if (Vertex* pv = check_for_intersection(leftEnclosingEdge, rightEnclosingEdge, 1150 &activeEdges, c, alloc)) { 1151 if (c.sweep_lt(pv->fPoint, v->fPoint)) { 1152 v = pv; 1153 } 1154 restartChecks = true; 1155 } 1156 1157 } 1158 } while (restartChecks); 1159 for (Edge* e = v->fFirstEdgeAbove; e; e = e->fNextEdgeAbove) { 1160 remove_edge(e, &activeEdges); 1161 } 1162 Edge* leftEdge = leftEnclosingEdge; 1163 for (Edge* e = v->fFirstEdgeBelow; e; e = e->fNextEdgeBelow) { 1164 insert_edge(e, leftEdge, &activeEdges); 1165 leftEdge = e; 1166 } 1167 v->fProcessed = true; 1168 } 1169} 1170 1171// Stage 5: Tessellate the simplified mesh into monotone polygons. 1172 1173Poly* tessellate(Vertex* vertices, SkChunkAlloc& alloc) { 1174 LOG("tessellating simple polygons\n"); 1175 EdgeList activeEdges; 1176 Poly* polys = nullptr; 1177 for (Vertex* v = vertices; v != nullptr; v = v->fNext) { 1178 if (!v->fFirstEdgeAbove && !v->fFirstEdgeBelow) { 1179 continue; 1180 } 1181#if LOGGING_ENABLED 1182 LOG("\nvertex %g: (%g,%g)\n", v->fID, v->fPoint.fX, v->fPoint.fY); 1183#endif 1184 Edge* leftEnclosingEdge = nullptr; 1185 Edge* rightEnclosingEdge = nullptr; 1186 find_enclosing_edges(v, &activeEdges, &leftEnclosingEdge, &rightEnclosingEdge); 1187 Poly* leftPoly = nullptr; 1188 Poly* rightPoly = nullptr; 1189 if (v->fFirstEdgeAbove) { 1190 leftPoly = v->fFirstEdgeAbove->fLeftPoly; 1191 rightPoly = v->fLastEdgeAbove->fRightPoly; 1192 } else { 1193 leftPoly = leftEnclosingEdge ? leftEnclosingEdge->fRightPoly : nullptr; 1194 rightPoly = rightEnclosingEdge ? rightEnclosingEdge->fLeftPoly : nullptr; 1195 } 1196#if LOGGING_ENABLED 1197 LOG("edges above:\n"); 1198 for (Edge* e = v->fFirstEdgeAbove; e; e = e->fNextEdgeAbove) { 1199 LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, 1200 e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); 1201 } 1202 LOG("edges below:\n"); 1203 for (Edge* e = v->fFirstEdgeBelow; e; e = e->fNextEdgeBelow) { 1204 LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, 1205 e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); 1206 } 1207#endif 1208 if (v->fFirstEdgeAbove) { 1209 if (leftPoly) { 1210 leftPoly = leftPoly->addVertex(v, Poly::kRight_Side, alloc); 1211 } 1212 if (rightPoly) { 1213 rightPoly = rightPoly->addVertex(v, Poly::kLeft_Side, alloc); 1214 } 1215 for (Edge* e = v->fFirstEdgeAbove; e != v->fLastEdgeAbove; e = e->fNextEdgeAbove) { 1216 Edge* leftEdge = e; 1217 Edge* rightEdge = e->fNextEdgeAbove; 1218 SkASSERT(rightEdge->isRightOf(leftEdge->fTop)); 1219 remove_edge(leftEdge, &activeEdges); 1220 if (leftEdge->fRightPoly) { 1221 leftEdge->fRightPoly->end(v, alloc); 1222 } 1223 if (rightEdge->fLeftPoly && rightEdge->fLeftPoly != leftEdge->fRightPoly) { 1224 rightEdge->fLeftPoly->end(v, alloc); 1225 } 1226 } 1227 remove_edge(v->fLastEdgeAbove, &activeEdges); 1228 if (!v->fFirstEdgeBelow) { 1229 if (leftPoly && rightPoly && leftPoly != rightPoly) { 1230 SkASSERT(leftPoly->fPartner == nullptr && rightPoly->fPartner == nullptr); 1231 rightPoly->fPartner = leftPoly; 1232 leftPoly->fPartner = rightPoly; 1233 } 1234 } 1235 } 1236 if (v->fFirstEdgeBelow) { 1237 if (!v->fFirstEdgeAbove) { 1238 if (leftPoly && leftPoly == rightPoly) { 1239 // Split the poly. 1240 if (leftPoly->fActive->fSide == Poly::kLeft_Side) { 1241 leftPoly = new_poly(&polys, leftEnclosingEdge->fTop, leftPoly->fWinding, 1242 alloc); 1243 leftPoly->addVertex(v, Poly::kRight_Side, alloc); 1244 rightPoly->addVertex(v, Poly::kLeft_Side, alloc); 1245 leftEnclosingEdge->fRightPoly = leftPoly; 1246 } else { 1247 rightPoly = new_poly(&polys, rightEnclosingEdge->fTop, rightPoly->fWinding, 1248 alloc); 1249 rightPoly->addVertex(v, Poly::kLeft_Side, alloc); 1250 leftPoly->addVertex(v, Poly::kRight_Side, alloc); 1251 rightEnclosingEdge->fLeftPoly = rightPoly; 1252 } 1253 } else { 1254 if (leftPoly) { 1255 leftPoly = leftPoly->addVertex(v, Poly::kRight_Side, alloc); 1256 } 1257 if (rightPoly) { 1258 rightPoly = rightPoly->addVertex(v, Poly::kLeft_Side, alloc); 1259 } 1260 } 1261 } 1262 Edge* leftEdge = v->fFirstEdgeBelow; 1263 leftEdge->fLeftPoly = leftPoly; 1264 insert_edge(leftEdge, leftEnclosingEdge, &activeEdges); 1265 for (Edge* rightEdge = leftEdge->fNextEdgeBelow; rightEdge; 1266 rightEdge = rightEdge->fNextEdgeBelow) { 1267 insert_edge(rightEdge, leftEdge, &activeEdges); 1268 int winding = leftEdge->fLeftPoly ? leftEdge->fLeftPoly->fWinding : 0; 1269 winding += leftEdge->fWinding; 1270 if (winding != 0) { 1271 Poly* poly = new_poly(&polys, v, winding, alloc); 1272 leftEdge->fRightPoly = rightEdge->fLeftPoly = poly; 1273 } 1274 leftEdge = rightEdge; 1275 } 1276 v->fLastEdgeBelow->fRightPoly = rightPoly; 1277 } 1278#if LOGGING_ENABLED 1279 LOG("\nactive edges:\n"); 1280 for (Edge* e = activeEdges.fHead; e != nullptr; e = e->fRight) { 1281 LOG("%g -> %g, lpoly %d, rpoly %d\n", e->fTop->fID, e->fBottom->fID, 1282 e->fLeftPoly ? e->fLeftPoly->fID : -1, e->fRightPoly ? e->fRightPoly->fID : -1); 1283 } 1284#endif 1285 } 1286 return polys; 1287} 1288 1289// This is a driver function which calls stages 2-5 in turn. 1290 1291Poly* contours_to_polys(Vertex** contours, int contourCnt, const SkRect& pathBounds, 1292 SkChunkAlloc& alloc) { 1293 Comparator c; 1294 if (pathBounds.width() > pathBounds.height()) { 1295 c.sweep_lt = sweep_lt_horiz; 1296 c.sweep_gt = sweep_gt_horiz; 1297 } else { 1298 c.sweep_lt = sweep_lt_vert; 1299 c.sweep_gt = sweep_gt_vert; 1300 } 1301#if LOGGING_ENABLED 1302 for (int i = 0; i < contourCnt; ++i) { 1303 Vertex* v = contours[i]; 1304 SkASSERT(v); 1305 LOG("path.moveTo(%20.20g, %20.20g);\n", v->fPoint.fX, v->fPoint.fY); 1306 for (v = v->fNext; v != contours[i]; v = v->fNext) { 1307 LOG("path.lineTo(%20.20g, %20.20g);\n", v->fPoint.fX, v->fPoint.fY); 1308 } 1309 } 1310#endif 1311 sanitize_contours(contours, contourCnt); 1312 Vertex* vertices = build_edges(contours, contourCnt, c, alloc); 1313 if (!vertices) { 1314 return nullptr; 1315 } 1316 1317 // Sort vertices in Y (secondarily in X). 1318 merge_sort(&vertices, c); 1319 merge_coincident_vertices(&vertices, c, alloc); 1320#if LOGGING_ENABLED 1321 for (Vertex* v = vertices; v != nullptr; v = v->fNext) { 1322 static float gID = 0.0f; 1323 v->fID = gID++; 1324 } 1325#endif 1326 simplify(vertices, c, alloc); 1327 return tessellate(vertices, alloc); 1328} 1329 1330Poly* path_to_polys(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, 1331 int contourCnt, SkChunkAlloc& alloc, bool* isLinear) { 1332 SkPath::FillType fillType = path.getFillType(); 1333 if (SkPath::IsInverseFillType(fillType)) { 1334 contourCnt++; 1335 } 1336 SkAutoTDeleteArray<Vertex*> contours(new Vertex* [contourCnt]); 1337 1338 path_to_contours(path, tolerance, clipBounds, contours.get(), alloc, isLinear); 1339 return contours_to_polys(contours.get(), contourCnt, path.getBounds(), alloc); 1340} 1341 1342void get_contour_count_and_size_estimate(const SkPath& path, SkScalar tolerance, int* contourCnt, 1343 int* sizeEstimate) { 1344 int maxPts = GrPathUtils::worstCasePointCount(path, contourCnt, tolerance); 1345 if (maxPts <= 0) { 1346 *contourCnt = 0; 1347 return; 1348 } 1349 if (maxPts > ((int)SK_MaxU16 + 1)) { 1350 SkDebugf("Path not rendered, too many verts (%d)\n", maxPts); 1351 *contourCnt = 0; 1352 return; 1353 } 1354 // For the initial size of the chunk allocator, estimate based on the point count: 1355 // one vertex per point for the initial passes, plus two for the vertices in the 1356 // resulting Polys, since the same point may end up in two Polys. Assume minimal 1357 // connectivity of one Edge per Vertex (will grow for intersections). 1358 *sizeEstimate = maxPts * (3 * sizeof(Vertex) + sizeof(Edge)); 1359} 1360 1361int count_points(Poly* polys, SkPath::FillType fillType) { 1362 int count = 0; 1363 for (Poly* poly = polys; poly; poly = poly->fNext) { 1364 if (apply_fill_type(fillType, poly->fWinding) && poly->fCount >= 3) { 1365 count += (poly->fCount - 2) * (TESSELLATOR_WIREFRAME ? 6 : 3); 1366 } 1367 } 1368 return count; 1369} 1370 1371} // namespace 1372 1373namespace GrTessellator { 1374 1375// Stage 6: Triangulate the monotone polygons into a vertex buffer. 1376 1377int PathToTriangles(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, 1378 GrResourceProvider* resourceProvider, 1379 SkAutoTUnref<GrVertexBuffer>& vertexBuffer, bool canMapVB, bool* isLinear) { 1380 int contourCnt; 1381 int sizeEstimate; 1382 get_contour_count_and_size_estimate(path, tolerance, &contourCnt, &sizeEstimate); 1383 if (contourCnt <= 0) { 1384 *isLinear = true; 1385 return 0; 1386 } 1387 SkChunkAlloc alloc(sizeEstimate); 1388 Poly* polys = path_to_polys(path, tolerance, clipBounds, contourCnt, alloc, isLinear); 1389 SkPath::FillType fillType = path.getFillType(); 1390 int count = count_points(polys, fillType); 1391 if (0 == count) { 1392 return 0; 1393 } 1394 1395 size_t size = count * sizeof(SkPoint); 1396 if (!vertexBuffer.get() || vertexBuffer->gpuMemorySize() < size) { 1397 vertexBuffer.reset(resourceProvider->createVertexBuffer( 1398 size, GrResourceProvider::kStatic_BufferUsage, 0)); 1399 } 1400 if (!vertexBuffer.get()) { 1401 SkDebugf("Could not allocate vertices\n"); 1402 return 0; 1403 } 1404 SkPoint* verts; 1405 if (canMapVB) { 1406 verts = static_cast<SkPoint*>(vertexBuffer->map()); 1407 } else { 1408 verts = new SkPoint[count]; 1409 } 1410 SkPoint* end = verts; 1411 for (Poly* poly = polys; poly; poly = poly->fNext) { 1412 if (apply_fill_type(fillType, poly->fWinding)) { 1413 end = poly->emit(end); 1414 } 1415 } 1416 int actualCount = static_cast<int>(end - verts); 1417 LOG("actual count: %d\n", actualCount); 1418 SkASSERT(actualCount <= count); 1419 if (canMapVB) { 1420 vertexBuffer->unmap(); 1421 } else { 1422 vertexBuffer->updateData(verts, actualCount * sizeof(SkPoint)); 1423 delete[] verts; 1424 } 1425 1426 return actualCount; 1427} 1428 1429int PathToVertices(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds, 1430 GrTessellator::WindingVertex** verts) { 1431 int contourCnt; 1432 int sizeEstimate; 1433 get_contour_count_and_size_estimate(path, tolerance, &contourCnt, &sizeEstimate); 1434 if (contourCnt <= 0) { 1435 return 0; 1436 } 1437 SkChunkAlloc alloc(sizeEstimate); 1438 bool isLinear; 1439 Poly* polys = path_to_polys(path, tolerance, clipBounds, contourCnt, alloc, &isLinear); 1440 SkPath::FillType fillType = path.getFillType(); 1441 int count = count_points(polys, fillType); 1442 if (0 == count) { 1443 *verts = nullptr; 1444 return 0; 1445 } 1446 1447 *verts = new GrTessellator::WindingVertex[count]; 1448 GrTessellator::WindingVertex* vertsEnd = *verts; 1449 SkPoint* points = new SkPoint[count]; 1450 SkPoint* pointsEnd = points; 1451 for (Poly* poly = polys; poly; poly = poly->fNext) { 1452 if (apply_fill_type(fillType, poly->fWinding)) { 1453 SkPoint* start = pointsEnd; 1454 pointsEnd = poly->emit(pointsEnd); 1455 while (start != pointsEnd) { 1456 vertsEnd->fPos = *start; 1457 vertsEnd->fWinding = poly->fWinding; 1458 ++start; 1459 ++vertsEnd; 1460 } 1461 } 1462 } 1463 int actualCount = static_cast<int>(vertsEnd - *verts); 1464 SkASSERT(actualCount <= count); 1465 SkASSERT(pointsEnd - points == actualCount); 1466 delete[] points; 1467 return actualCount; 1468} 1469 1470} // namespace 1471