Reland "Add some optimizations to PolyUtils"
This is a reland of 8bb0db3d07450880d346d808018708416c928657
Original change's description:
> Add some optimizations to PolyUtils
>
> * Switch inset/offset code to use a linked list rather than an array
> * Use std::set to store active edge list for IsSimplePolygon rather than array
> * Pre-alloc the priority queue for IsSimplePolygon
> * When adding radial curves, expand the array all at once rather than pushing
> one at a time.
>
> Bug: skia:
> Change-Id: I692f8c29c500c41ec1d1be39d924d8a752676bf4
> Reviewed-on: https://skia-review.googlesource.com/140787
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> Commit-Queue: Jim Van Verth <jvanverth@google.com>
Bug: skia:
Change-Id: I3f5d42cfb941deab2b28bed020b37ce199e91d3d
Reviewed-on: https://skia-review.googlesource.com/142200
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
diff --git a/bench/PolyUtilsBench.cpp b/bench/PolyUtilsBench.cpp
index 1b987fa..e03c51c 100644
--- a/bench/PolyUtilsBench.cpp
+++ b/bench/PolyUtilsBench.cpp
@@ -9,12 +9,12 @@
#include "SkPolyUtils.h"
class PolyUtilsBench : public Benchmark {
+public:
// Evaluate SkTriangulateSimplePolygon's performance (via derived classes) on:
// a non-self-intersecting star, a circle of tiny line segments and a self-intersecting star
+ enum class Type { kConvexCheck, kSimpleCheck, kInsetConvex, kOffsetSimple, kTessellateSimple };
- SkString fName;
-public:
- PolyUtilsBench() {}
+ PolyUtilsBench(Type type) : fType(type) {}
virtual void appendName(SkString*) = 0;
virtual void makePoly(SkTDArray<SkPoint>* poly) = 0;
@@ -24,32 +24,84 @@
const char* onGetName() override {
fName = "poly_utils_";
this->appendName(&fName);
+ switch (fType) {
+ case Type::kConvexCheck:
+ fName.append("_c");
+ break;
+ case Type::kSimpleCheck:
+ fName.append("_s");
+ break;
+ case Type::kInsetConvex:
+ fName.append("_i");
+ break;
+ case Type::kOffsetSimple:
+ fName.append("_o");
+ break;
+ case Type::kTessellateSimple:
+ fName.append("_t");
+ break;
+ }
return fName.c_str();
}
void onDraw(int loops, SkCanvas* canvas) override {
SkTDArray<SkPoint> poly;
this->makePoly(&poly);
- SkAutoSTMalloc<64, uint16_t> indexMap(poly.count());
- for (int i = 0; i < poly.count(); ++i) {
- indexMap[i] = i;
- }
- SkTDArray<uint16_t> triangleIndices;
- for (int i = 0; i < loops; i++) {
- if (SkIsSimplePolygon(poly.begin(), poly.count())) {
- SkTriangulateSimplePolygon(poly.begin(), indexMap, poly.count(),
- &triangleIndices);
- }
+ switch (fType) {
+ case Type::kConvexCheck:
+ for (int i = 0; i < loops; i++) {
+ (void)SkIsConvexPolygon(poly.begin(), poly.count());
+ }
+ break;
+ case Type::kSimpleCheck:
+ for (int i = 0; i < loops; i++) {
+ (void)SkIsSimplePolygon(poly.begin(), poly.count());
+ }
+ break;
+ case Type::kInsetConvex:
+ if (SkIsConvexPolygon(poly.begin(), poly.count())) {
+ SkTDArray<SkPoint> result;
+ for (int i = 0; i < loops; i++) {
+ (void)SkInsetConvexPolygon(poly.begin(), poly.count(), 10, &result);
+ (void)SkInsetConvexPolygon(poly.begin(), poly.count(), 40, &result);
+ }
+ }
+ break;
+ case Type::kOffsetSimple:
+ if (SkIsSimplePolygon(poly.begin(), poly.count())) {
+ SkTDArray<SkPoint> result;
+ for (int i = 0; i < loops; i++) {
+ (void)SkOffsetSimplePolygon(poly.begin(), poly.count(), 10, &result);
+ (void)SkOffsetSimplePolygon(poly.begin(), poly.count(), -10, &result);
+ }
+ }
+ break;
+ case Type::kTessellateSimple:
+ if (SkIsSimplePolygon(poly.begin(), poly.count())) {
+ SkAutoSTMalloc<64, uint16_t> indexMap(poly.count());
+ for (int i = 0; i < poly.count(); ++i) {
+ indexMap[i] = i;
+ }
+ SkTDArray<uint16_t> triangleIndices;
+ for (int i = 0; i < loops; i++) {
+ SkTriangulateSimplePolygon(poly.begin(), indexMap, poly.count(),
+ &triangleIndices);
+ }
+ }
+ break;
}
}
private:
+ SkString fName;
+ Type fType;
+
typedef Benchmark INHERITED;
};
class StarPolyUtilsBench : public PolyUtilsBench {
public:
- StarPolyUtilsBench() {}
+ StarPolyUtilsBench(PolyUtilsBench::Type type) : INHERITED(type) {}
void appendName(SkString* name) override {
name->append("star");
@@ -77,7 +129,7 @@
class CirclePolyUtilsBench : public PolyUtilsBench {
public:
- CirclePolyUtilsBench() {}
+ CirclePolyUtilsBench(PolyUtilsBench::Type type) : INHERITED(type) {}
void appendName(SkString* name) override {
name->append("circle");
@@ -101,7 +153,7 @@
class IntersectingPolyUtilsBench : public PolyUtilsBench {
public:
- IntersectingPolyUtilsBench() {}
+ IntersectingPolyUtilsBench(PolyUtilsBench::Type type) : INHERITED(type) {}
void appendName(SkString* name) override {
name->append("intersecting");
@@ -125,6 +177,18 @@
typedef PolyUtilsBench INHERITED;
};
-DEF_BENCH(return new StarPolyUtilsBench();)
-DEF_BENCH(return new CirclePolyUtilsBench();)
-DEF_BENCH(return new IntersectingPolyUtilsBench();)
+DEF_BENCH(return new StarPolyUtilsBench(PolyUtilsBench::Type::kConvexCheck);)
+DEF_BENCH(return new StarPolyUtilsBench(PolyUtilsBench::Type::kSimpleCheck);)
+DEF_BENCH(return new StarPolyUtilsBench(PolyUtilsBench::Type::kInsetConvex);)
+DEF_BENCH(return new StarPolyUtilsBench(PolyUtilsBench::Type::kOffsetSimple);)
+DEF_BENCH(return new StarPolyUtilsBench(PolyUtilsBench::Type::kTessellateSimple);)
+DEF_BENCH(return new CirclePolyUtilsBench(PolyUtilsBench::Type::kConvexCheck);)
+DEF_BENCH(return new CirclePolyUtilsBench(PolyUtilsBench::Type::kSimpleCheck);)
+DEF_BENCH(return new CirclePolyUtilsBench(PolyUtilsBench::Type::kInsetConvex);)
+DEF_BENCH(return new CirclePolyUtilsBench(PolyUtilsBench::Type::kOffsetSimple);)
+DEF_BENCH(return new CirclePolyUtilsBench(PolyUtilsBench::Type::kTessellateSimple);)
+DEF_BENCH(return new IntersectingPolyUtilsBench(PolyUtilsBench::Type::kConvexCheck);)
+DEF_BENCH(return new IntersectingPolyUtilsBench(PolyUtilsBench::Type::kSimpleCheck);)
+DEF_BENCH(return new IntersectingPolyUtilsBench(PolyUtilsBench::Type::kInsetConvex);)
+DEF_BENCH(return new IntersectingPolyUtilsBench(PolyUtilsBench::Type::kOffsetSimple);)
+DEF_BENCH(return new IntersectingPolyUtilsBench(PolyUtilsBench::Type::kTessellateSimple);)
diff --git a/src/core/SkTDPQueue.h b/src/core/SkTDPQueue.h
index 5dca491..6e2a09c 100644
--- a/src/core/SkTDPQueue.h
+++ b/src/core/SkTDPQueue.h
@@ -30,6 +30,7 @@
class SkTDPQueue {
public:
SkTDPQueue() {}
+ SkTDPQueue(int reserve) { fArray.setReserve(reserve); }
SkTDPQueue(SkTDPQueue&&) = default;
SkTDPQueue& operator =(SkTDPQueue&&) = default;
diff --git a/src/utils/SkPolyUtils.cpp b/src/utils/SkPolyUtils.cpp
index b76d270..ed4b71d 100644
--- a/src/utils/SkPolyUtils.cpp
+++ b/src/utils/SkPolyUtils.cpp
@@ -7,6 +7,7 @@
#include "SkPolyUtils.h"
+#include <set>
#include "SkPointPriv.h"
#include "SkTArray.h"
#include "SkTemplates.h"
@@ -298,34 +299,32 @@
return true;
}
-struct EdgeData {
+struct OffsetEdge {
+ OffsetEdge* fPrev;
+ OffsetEdge* fNext;
OffsetSegment fInset;
SkPoint fIntersection;
SkScalar fTValue;
- uint16_t fStart;
uint16_t fEnd;
uint16_t fIndex;
- bool fValid;
- void init() {
+ void init(uint16_t start = 0, uint16_t end = 0) {
fIntersection = fInset.fP0;
fTValue = SK_ScalarMin;
- fStart = 0;
- fEnd = 0;
- fIndex = 0;
- fValid = true;
- }
-
- void init(uint16_t start, uint16_t end) {
- fIntersection = fInset.fP0;
- fTValue = SK_ScalarMin;
- fStart = start;
fEnd = end;
fIndex = start;
- fValid = true;
}
};
+static void remove_node(const OffsetEdge* node, OffsetEdge** head) {
+ // remove from linked list
+ node->fPrev->fNext = node->fNext;
+ node->fNext->fPrev = node->fPrev;
+ if (node == *head) {
+ *head = (node->fNext == node) ? nullptr : node->fNext;
+ }
+}
+
//////////////////////////////////////////////////////////////////////////////////
// The objective here is to inset all of the edges by the given distance, and then
@@ -354,115 +353,117 @@
}
// set up
- SkAutoSTMalloc<64, EdgeData> edgeData(inputPolygonSize);
- for (int i = 0; i < inputPolygonSize; ++i) {
- int j = (i + 1) % inputPolygonSize;
- int k = (i + 2) % inputPolygonSize;
- if (!inputPolygonVerts[i].isFinite()) {
+ SkAutoSTMalloc<64, OffsetEdge> edgeData(inputPolygonSize);
+ int prev = inputPolygonSize - 1;
+ for (int curr = 0; curr < inputPolygonSize; prev = curr, ++curr) {
+ int next = (curr + 1) % inputPolygonSize;
+ if (!inputPolygonVerts[curr].isFinite()) {
return false;
}
// check for convexity just to be sure
- if (compute_side(inputPolygonVerts[i], inputPolygonVerts[j],
- inputPolygonVerts[k])*winding < 0) {
+ if (compute_side(inputPolygonVerts[prev], inputPolygonVerts[curr],
+ inputPolygonVerts[next])*winding < 0) {
return false;
}
- if (!SkOffsetSegment(inputPolygonVerts[i], inputPolygonVerts[j],
- insetDistanceFunc(inputPolygonVerts[i]),
- insetDistanceFunc(inputPolygonVerts[j]),
+ edgeData[curr].fPrev = &edgeData[prev];
+ edgeData[curr].fNext = &edgeData[next];
+ if (!SkOffsetSegment(inputPolygonVerts[curr], inputPolygonVerts[next],
+ insetDistanceFunc(inputPolygonVerts[curr]),
+ insetDistanceFunc(inputPolygonVerts[next]),
winding,
- &edgeData[i].fInset.fP0, &edgeData[i].fInset.fP1)) {
+ &edgeData[curr].fInset.fP0, &edgeData[curr].fInset.fP1)) {
return false;
}
- edgeData[i].init();
+ edgeData[curr].init();
}
- int prevIndex = inputPolygonSize - 1;
- int currIndex = 0;
+ OffsetEdge* head = &edgeData[0];
+ OffsetEdge* currEdge = head;
+ OffsetEdge* prevEdge = currEdge->fPrev;
int insetVertexCount = inputPolygonSize;
int iterations = 0;
- while (prevIndex != currIndex) {
+ while (head && prevEdge != currEdge) {
++iterations;
// we should check each edge against each other edge at most once
if (iterations > inputPolygonSize*inputPolygonSize) {
return false;
}
- if (!edgeData[prevIndex].fValid) {
- prevIndex = (prevIndex + inputPolygonSize - 1) % inputPolygonSize;
- continue;
- }
-
SkScalar s, t;
SkPoint intersection;
- if (compute_intersection(edgeData[prevIndex].fInset, edgeData[currIndex].fInset,
+ if (compute_intersection(prevEdge->fInset, currEdge->fInset,
&intersection, &s, &t)) {
// if new intersection is further back on previous inset from the prior intersection
- if (s < edgeData[prevIndex].fTValue) {
+ if (s < prevEdge->fTValue) {
// no point in considering this one again
- edgeData[prevIndex].fValid = false;
+ remove_node(prevEdge, &head);
--insetVertexCount;
// go back one segment
- prevIndex = (prevIndex + inputPolygonSize - 1) % inputPolygonSize;
+ prevEdge = prevEdge->fPrev;
// we've already considered this intersection, we're done
- } else if (edgeData[currIndex].fTValue > SK_ScalarMin &&
+ } else if (currEdge->fTValue > SK_ScalarMin &&
SkPointPriv::EqualsWithinTolerance(intersection,
- edgeData[currIndex].fIntersection,
+ currEdge->fIntersection,
1.0e-6f)) {
break;
} else {
// add intersection
- edgeData[currIndex].fIntersection = intersection;
- edgeData[currIndex].fTValue = t;
+ currEdge->fIntersection = intersection;
+ currEdge->fTValue = t;
// go to next segment
- prevIndex = currIndex;
- currIndex = (currIndex + 1) % inputPolygonSize;
+ prevEdge = currEdge;
+ currEdge = currEdge->fNext;
}
} else {
// if prev to right side of curr
- int side = winding*compute_side(edgeData[currIndex].fInset.fP0,
- edgeData[currIndex].fInset.fP1,
- edgeData[prevIndex].fInset.fP1);
- if (side < 0 && side == winding*compute_side(edgeData[currIndex].fInset.fP0,
- edgeData[currIndex].fInset.fP1,
- edgeData[prevIndex].fInset.fP0)) {
+ int side = winding*compute_side(currEdge->fInset.fP0,
+ currEdge->fInset.fP1,
+ prevEdge->fInset.fP1);
+ if (side < 0 && side == winding*compute_side(currEdge->fInset.fP0,
+ currEdge->fInset.fP1,
+ prevEdge->fInset.fP0)) {
// no point in considering this one again
- edgeData[prevIndex].fValid = false;
+ remove_node(prevEdge, &head);
--insetVertexCount;
// go back one segment
- prevIndex = (prevIndex + inputPolygonSize - 1) % inputPolygonSize;
+ prevEdge = prevEdge->fPrev;
} else {
// move to next segment
- edgeData[currIndex].fValid = false;
+ remove_node(currEdge, &head);
--insetVertexCount;
- currIndex = (currIndex + 1) % inputPolygonSize;
+ currEdge = currEdge->fNext;
}
}
}
// store all the valid intersections that aren't nearly coincident
// TODO: look at the main algorithm and see if we can detect these better
- static constexpr SkScalar kCleanupTolerance = 0.01f;
-
insetPolygon->reset();
- if (insetVertexCount >= 0) {
- insetPolygon->setReserve(insetVertexCount);
- }
- currIndex = -1;
- for (int i = 0; i < inputPolygonSize; ++i) {
- if (edgeData[i].fValid && (currIndex == -1 ||
- !SkPointPriv::EqualsWithinTolerance(edgeData[i].fIntersection,
- (*insetPolygon)[currIndex],
- kCleanupTolerance))) {
- *insetPolygon->push() = edgeData[i].fIntersection;
- currIndex++;
+ if (head) {
+ static constexpr SkScalar kCleanupTolerance = 0.01f;
+ if (insetVertexCount >= 0) {
+ insetPolygon->setReserve(insetVertexCount);
}
- }
- // make sure the first and last points aren't coincident
- if (currIndex >= 1 &&
- SkPointPriv::EqualsWithinTolerance((*insetPolygon)[0], (*insetPolygon)[currIndex],
- kCleanupTolerance)) {
- insetPolygon->pop();
+ int currIndex = 0;
+ OffsetEdge* currEdge = head;
+ *insetPolygon->push() = currEdge->fIntersection;
+ currEdge = currEdge->fNext;
+ while (currEdge != head) {
+ if (!SkPointPriv::EqualsWithinTolerance(currEdge->fIntersection,
+ (*insetPolygon)[currIndex],
+ kCleanupTolerance)) {
+ *insetPolygon->push() = currEdge->fIntersection;
+ currIndex++;
+ }
+ currEdge = currEdge->fNext;
+ }
+ // make sure the first and last points aren't coincident
+ if (currIndex >= 1 &&
+ SkPointPriv::EqualsWithinTolerance((*insetPolygon)[0], (*insetPolygon)[currIndex],
+ kCleanupTolerance)) {
+ insetPolygon->pop();
+ }
}
return SkIsConvexPolygon(insetPolygon->begin(), insetPolygon->count());
@@ -504,6 +505,7 @@
static bool Left(const Vertex& qv0, const Vertex& qv1) {
return left(qv0.fPosition, qv1.fPosition);
}
+
// packed to fit into 16 bytes (one cache line)
SkPoint fPosition;
uint16_t fIndex; // index in unsorted polygon
@@ -517,30 +519,60 @@
kNextLeft_VertexFlag = 0x2,
};
-struct Edge {
+struct ActiveEdge {
+ ActiveEdge(const SkPoint& p0, const SkPoint& p1, int32_t index0, int32_t index1)
+ : fSegment({p0, p1})
+ , fIndex0(index0)
+ , fIndex1(index1) {}
+
// returns true if "this" is above "that"
- bool above(const Edge& that, SkScalar tolerance = SK_ScalarNearlyZero) {
- SkASSERT(this->fSegment.fP0.fX < that.fSegment.fP0.fX ||
- SkScalarNearlyEqual(this->fSegment.fP0.fX, that.fSegment.fP0.fX, tolerance));
+ bool above(const ActiveEdge& that) const {
+ SkASSERT(this->fSegment.fP0.fX <= that.fSegment.fP0.fX);
+ const SkScalar kTolerance = SK_ScalarNearlyZero * SK_ScalarNearlyZero;
+ SkVector u = this->fSegment.fP1 - this->fSegment.fP0;
// The idea here is that if the vector between the origins of the two segments (dv)
// rotates counterclockwise up to the vector representing the "this" segment (u),
// then we know that "this" is above that. If the result is clockwise we say it's below.
- SkVector dv = that.fSegment.fP0 - this->fSegment.fP0;
- SkVector u = this->fSegment.fP1 - this->fSegment.fP0;
- SkScalar cross = dv.cross(u);
- if (cross > tolerance) {
- return true;
- } else if (cross < -tolerance) {
+ if (this->fIndex0 != that.fIndex0) {
+ SkVector dv = that.fSegment.fP0 - this->fSegment.fP0;
+ SkScalar cross = dv.cross(u);
+ if (cross > kTolerance) {
+ return true;
+ } else if (cross < -kTolerance) {
+ return false;
+ }
+ } else if (this->fIndex1 == that.fIndex1) {
+ // they're the same edge
return false;
}
- // If the result is 0 then either the two origins are equal or the origin of "that"
+ // At this point either the two origins are nearly equal or the origin of "that"
// lies on dv. So then we try the same for the vector from the tail of "this"
// to the head of "that". Again, ccw means "this" is above "that".
- dv = that.fSegment.fP1 - this->fSegment.fP0;
- return (dv.cross(u) > tolerance);
+ SkVector dv = that.fSegment.fP1 - this->fSegment.fP0;
+ SkScalar cross = dv.cross(u);
+ if (cross > kTolerance) {
+ return true;
+ } else if (cross < -kTolerance) {
+ return false;
+ }
+ // If the previous check fails, the two segments are nearly collinear
+ // First check y-coord of first endpoints
+ if (this->fSegment.fP0.fX < that.fSegment.fP0.fX) {
+ return (this->fSegment.fP0.fY >= that.fSegment.fP0.fY);
+ } else if (this->fSegment.fP0.fY > that.fSegment.fP0.fY) {
+ return true;
+ } else if (this->fSegment.fP0.fY < that.fSegment.fP0.fY) {
+ return false;
+ }
+ // The first endpoints are the same, so check the other endpoint
+ if (this->fSegment.fP1.fX < that.fSegment.fP1.fX) {
+ return (this->fSegment.fP1.fY >= that.fSegment.fP1.fY);
+ } else {
+ return (this->fSegment.fP1.fY > that.fSegment.fP1.fY);
+ }
}
- bool intersect(const Edge& that) const {
+ bool intersect(const ActiveEdge& that) const {
SkPoint intersection;
SkScalar s, t;
// check first to see if these edges are neighbors in the polygon
@@ -551,78 +583,69 @@
return compute_intersection(this->fSegment, that.fSegment, &intersection, &s, &t);
}
- bool operator==(const Edge& that) const {
+ bool operator==(const ActiveEdge& that) const {
return (this->fIndex0 == that.fIndex0 && this->fIndex1 == that.fIndex1);
}
- bool operator!=(const Edge& that) const {
+ bool operator!=(const ActiveEdge& that) const {
return !operator==(that);
}
+ bool operator<(const ActiveEdge& that) const {
+ if (this->fSegment.fP0.fX > that.fSegment.fP0.fX) {
+ return !that.above(*this);
+ }
+ return this->above(that);
+ }
+
OffsetSegment fSegment;
int32_t fIndex0; // indices for previous and next vertex
int32_t fIndex1;
};
-class EdgeList {
+class ActiveEdgeList {
public:
- void reserve(int count) { fEdges.reserve(count); }
+ void reserve(int count) { }
- bool insert(const Edge& newEdge) {
- // linear search for now (expected case is very few active edges)
- int insertIndex = 0;
- while (insertIndex < fEdges.count() && fEdges[insertIndex].above(newEdge)) {
- ++insertIndex;
- }
- // if we intersect with the existing edge above or below us
- // then we know this polygon is not simple, so don't insert, just fail
- if (insertIndex > 0 && newEdge.intersect(fEdges[insertIndex - 1])) {
- return false;
- }
- if (insertIndex < fEdges.count() && newEdge.intersect(fEdges[insertIndex])) {
+ bool insert(const SkPoint& p0, const SkPoint& p1, int32_t index0, int32_t index1) {
+ std::pair<Iterator, bool> result = fEdgeTree.emplace(p0, p1, index0, index1);
+ if (!result.second) {
return false;
}
- fEdges.push_back();
- for (int i = fEdges.count() - 1; i > insertIndex; --i) {
- fEdges[i] = fEdges[i - 1];
+ Iterator& curr = result.first;
+ if (curr != fEdgeTree.begin() && curr->intersect(*std::prev(curr))) {
+ return false;
}
- fEdges[insertIndex] = newEdge;
+ Iterator next = std::next(curr);
+ if (next != fEdgeTree.end() && curr->intersect(*next)) {
+ return false;
+ }
return true;
}
- bool remove(const Edge& edge) {
- SkASSERT(fEdges.count() > 0);
-
- // linear search for now (expected case is very few active edges)
- int removeIndex = 0;
- while (removeIndex < fEdges.count() && fEdges[removeIndex] != edge) {
- ++removeIndex;
- }
- // we'd better find it or something is wrong
- SkASSERT(removeIndex < fEdges.count());
-
- // if we intersect with the edge above or below us
- // then we know this polygon is not simple, so don't remove, just fail
- if (removeIndex > 0 && fEdges[removeIndex].intersect(fEdges[removeIndex - 1])) {
+ bool remove(const ActiveEdge& edge) {
+ auto element = fEdgeTree.find(edge);
+ // this better not happen
+ if (element == fEdgeTree.end()) {
return false;
}
- if (removeIndex < fEdges.count() - 1) {
- if (fEdges[removeIndex].intersect(fEdges[removeIndex + 1])) {
- return false;
- }
- // copy over the old entry
- memmove(&fEdges[removeIndex], &fEdges[removeIndex + 1],
- sizeof(Edge)*(fEdges.count() - removeIndex - 1));
+ if (element != fEdgeTree.begin() && element->intersect(*std::prev(element))) {
+ return false;
+ }
+ Iterator next = std::next(element);
+ if (next != fEdgeTree.end() && element->intersect(*next)) {
+ return false;
}
- fEdges.pop_back();
+ fEdgeTree.erase(element);
return true;
}
private:
- SkSTArray<1, Edge> fEdges;
+ std::set<ActiveEdge> fEdgeTree;
+ typedef std::set<ActiveEdge>::iterator Iterator;
};
// Here we implement a sweep line algorithm to determine whether the provided points
@@ -636,10 +659,7 @@
return false;
}
- SkTDPQueue <Vertex, Vertex::Left> vertexQueue;
- EdgeList sweepLine;
-
- sweepLine.reserve(polygonSize);
+ SkTDPQueue <Vertex, Vertex::Left> vertexQueue(polygonSize);
for (int i = 0; i < polygonSize; ++i) {
Vertex newVertex;
if (!polygon[i].isFinite()) {
@@ -661,31 +681,31 @@
// pop each vertex from the queue and generate events depending on
// where it lies relative to its neighboring edges
+ ActiveEdgeList sweepLine;
+ sweepLine.reserve(polygonSize);
while (vertexQueue.count() > 0) {
const Vertex& v = vertexQueue.peek();
// check edge to previous vertex
if (v.fFlags & kPrevLeft_VertexFlag) {
- Edge edge{ { polygon[v.fPrevIndex], v.fPosition }, v.fPrevIndex, v.fIndex };
+ ActiveEdge edge(polygon[v.fPrevIndex], v.fPosition, v.fPrevIndex, v.fIndex);
if (!sweepLine.remove(edge)) {
break;
}
} else {
- Edge edge{ { v.fPosition, polygon[v.fPrevIndex] }, v.fIndex, v.fPrevIndex };
- if (!sweepLine.insert(edge)) {
+ if (!sweepLine.insert(v.fPosition, polygon[v.fPrevIndex], v.fIndex, v.fPrevIndex)) {
break;
}
}
// check edge to next vertex
if (v.fFlags & kNextLeft_VertexFlag) {
- Edge edge{ { polygon[v.fNextIndex], v.fPosition }, v.fNextIndex, v.fIndex };
+ ActiveEdge edge(polygon[v.fNextIndex], v.fPosition, v.fNextIndex, v.fIndex);
if (!sweepLine.remove(edge)) {
break;
}
} else {
- Edge edge{ { v.fPosition, polygon[v.fNextIndex] }, v.fIndex, v.fNextIndex };
- if (!sweepLine.insert(edge)) {
+ if (!sweepLine.insert(v.fPosition, polygon[v.fNextIndex], v.fIndex, v.fNextIndex)) {
break;
}
}
@@ -698,6 +718,15 @@
///////////////////////////////////////////////////////////////////////////////////////////
+// helper function for SkOffsetSimplePolygon
+static void setup_offset_edge(OffsetEdge* currEdge,
+ const SkPoint& endpoint0, const SkPoint& endpoint1,
+ int startIndex, int endIndex) {
+ currEdge->fInset.fP0 = endpoint0;
+ currEdge->fInset.fP1 = endpoint1;
+ currEdge->init(startIndex, endIndex);
+}
+
bool SkOffsetSimplePolygon(const SkPoint* inputPolygonVerts, int inputPolygonSize,
std::function<SkScalar(const SkPoint&)> offsetDistanceFunc,
SkTDArray<SkPoint>* offsetPolygon, SkTDArray<int>* polygonIndices) {
@@ -736,7 +765,7 @@
}
// build initial offset edge list
- SkSTArray<64, EdgeData> edgeData(inputPolygonSize);
+ SkSTArray<64, OffsetEdge> edgeData(inputPolygonSize);
int prevIndex = inputPolygonSize - 1;
int currIndex = 0;
int nextIndex = 1;
@@ -754,126 +783,143 @@
&rotSin, &rotCos, &numSteps)) {
return false;
}
+ auto currEdge = edgeData.push_back_n(SkTMax(numSteps, 1));
for (int i = 0; i < numSteps - 1; ++i) {
SkVector currNormal = SkVector::Make(prevNormal.fX*rotCos - prevNormal.fY*rotSin,
prevNormal.fY*rotCos + prevNormal.fX*rotSin);
- EdgeData& edge = edgeData.push_back();
- edge.fInset.fP0 = inputPolygonVerts[currIndex] + prevNormal;
- edge.fInset.fP1 = inputPolygonVerts[currIndex] + currNormal;
- edge.init(currIndex, currIndex);
+ setup_offset_edge(currEdge,
+ inputPolygonVerts[currIndex] + prevNormal,
+ inputPolygonVerts[currIndex] + currNormal,
+ currIndex, currIndex);
prevNormal = currNormal;
+ ++currEdge;
}
- EdgeData& edge = edgeData.push_back();
- edge.fInset.fP0 = inputPolygonVerts[currIndex] + prevNormal;
- edge.fInset.fP1 = inputPolygonVerts[currIndex] + normal0[currIndex];
- edge.init(currIndex, currIndex);
+ setup_offset_edge(currEdge,
+ inputPolygonVerts[currIndex] + prevNormal,
+ inputPolygonVerts[currIndex] + normal0[currIndex],
+ currIndex, currIndex);
+ ++currEdge;
+
}
// Add the edge
- EdgeData& edge = edgeData.push_back();
- edge.fInset.fP0 = inputPolygonVerts[currIndex] + normal0[currIndex];
- edge.fInset.fP1 = inputPolygonVerts[nextIndex] + normal1[nextIndex];
- edge.init(currIndex, nextIndex);
+ auto edge = edgeData.push_back_n(1);
+ setup_offset_edge(edge,
+ inputPolygonVerts[currIndex] + normal0[currIndex],
+ inputPolygonVerts[nextIndex] + normal1[nextIndex],
+ currIndex, nextIndex);
prevIndex = currIndex;
currIndex++;
nextIndex = (nextIndex + 1) % inputPolygonSize;
}
+ // build linked list
+ // we have to do this as a post-process step because we might have reallocated
+ // the array when adding fans for reflex verts
+ prevIndex = edgeData.count()-1;
+ for (int currIndex = 0; currIndex < edgeData.count(); prevIndex = currIndex, ++currIndex) {
+ int nextIndex = (currIndex + 1) % edgeData.count();
+ edgeData[currIndex].fPrev = &edgeData[prevIndex];
+ edgeData[currIndex].fNext = &edgeData[nextIndex];
+ }
+
+ // now clip edges
int edgeDataSize = edgeData.count();
- prevIndex = edgeDataSize - 1;
- currIndex = 0;
- int insetVertexCount = edgeDataSize;
+ auto head = &edgeData[0];
+ auto currEdge = head;
+ auto prevEdge = currEdge->fPrev;
+ int offsetVertexCount = edgeDataSize;
int iterations = 0;
- while (prevIndex != currIndex) {
+ while (head && prevEdge != currEdge) {
++iterations;
// we should check each edge against each other edge at most once
if (iterations > edgeDataSize*edgeDataSize) {
return false;
}
- if (!edgeData[prevIndex].fValid) {
- prevIndex = (prevIndex + edgeDataSize - 1) % edgeDataSize;
- continue;
- }
- if (!edgeData[currIndex].fValid) {
- currIndex = (currIndex + 1) % edgeDataSize;
- continue;
- }
-
SkScalar s, t;
SkPoint intersection;
- if (compute_intersection(edgeData[prevIndex].fInset, edgeData[currIndex].fInset,
+ if (compute_intersection(prevEdge->fInset, currEdge->fInset,
&intersection, &s, &t)) {
// if new intersection is further back on previous inset from the prior intersection
- if (s < edgeData[prevIndex].fTValue) {
+ if (s < prevEdge->fTValue) {
// no point in considering this one again
- edgeData[prevIndex].fValid = false;
- --insetVertexCount;
+ remove_node(prevEdge, &head);
+ --offsetVertexCount;
// go back one segment
- prevIndex = (prevIndex + edgeDataSize - 1) % edgeDataSize;
+ prevEdge = prevEdge->fPrev;
// we've already considered this intersection, we're done
- } else if (edgeData[currIndex].fTValue > SK_ScalarMin &&
+ } else if (currEdge->fTValue > SK_ScalarMin &&
SkPointPriv::EqualsWithinTolerance(intersection,
- edgeData[currIndex].fIntersection,
+ currEdge->fIntersection,
1.0e-6f)) {
break;
} else {
// add intersection
- edgeData[currIndex].fIntersection = intersection;
- edgeData[currIndex].fTValue = t;
- edgeData[currIndex].fIndex = edgeData[prevIndex].fEnd;
+ currEdge->fIntersection = intersection;
+ currEdge->fTValue = t;
+ currEdge->fIndex = prevEdge->fEnd;
// go to next segment
- prevIndex = currIndex;
- currIndex = (currIndex + 1) % edgeDataSize;
+ prevEdge = currEdge;
+ currEdge = currEdge->fNext;
}
} else {
// If there is no intersection, we want to minimize the distance between
// the point where the segment lines cross and the segments themselves.
- SkScalar prevPrevIndex = (prevIndex + edgeDataSize - 1) % edgeDataSize;
- SkScalar currNextIndex = (currIndex + 1) % edgeDataSize;
- SkScalar dist0 = compute_crossing_distance(edgeData[currIndex].fInset,
- edgeData[prevPrevIndex].fInset);
- SkScalar dist1 = compute_crossing_distance(edgeData[prevIndex].fInset,
- edgeData[currNextIndex].fInset);
+ OffsetEdge* prevPrevEdge = prevEdge->fPrev;
+ OffsetEdge* currNextEdge = currEdge->fNext;
+ SkScalar dist0 = compute_crossing_distance(currEdge->fInset,
+ prevPrevEdge->fInset);
+ SkScalar dist1 = compute_crossing_distance(prevEdge->fInset,
+ currNextEdge->fInset);
if (dist0 < dist1) {
- edgeData[prevIndex].fValid = false;
- prevIndex = prevPrevIndex;
+ remove_node(prevEdge, &head);
+ prevEdge = prevPrevEdge;
} else {
- edgeData[currIndex].fValid = false;
- currIndex = currNextIndex;
+ remove_node(currEdge, &head);
+ currEdge = currNextEdge;
}
- --insetVertexCount;
+ --offsetVertexCount;
}
}
// store all the valid intersections that aren't nearly coincident
// TODO: look at the main algorithm and see if we can detect these better
- static constexpr SkScalar kCleanupTolerance = 0.01f;
-
offsetPolygon->reset();
- offsetPolygon->setReserve(insetVertexCount);
- currIndex = -1;
- for (int i = 0; i < edgeData.count(); ++i) {
- if (edgeData[i].fValid && (currIndex == -1 ||
- !SkPointPriv::EqualsWithinTolerance(edgeData[i].fIntersection,
- (*offsetPolygon)[currIndex],
- kCleanupTolerance))) {
- *offsetPolygon->push() = edgeData[i].fIntersection;
- if (polygonIndices) {
- *polygonIndices->push() = edgeData[i].fIndex;
- }
- currIndex++;
+ if (head) {
+ static constexpr SkScalar kCleanupTolerance = 0.01f;
+ if (offsetVertexCount >= 0) {
+ offsetPolygon->setReserve(offsetVertexCount);
}
- }
- // make sure the first and last points aren't coincident
- if (currIndex >= 1 &&
- SkPointPriv::EqualsWithinTolerance((*offsetPolygon)[0], (*offsetPolygon)[currIndex],
- kCleanupTolerance)) {
- offsetPolygon->pop();
+ int currIndex = 0;
+ OffsetEdge* currEdge = head;
+ *offsetPolygon->push() = currEdge->fIntersection;
if (polygonIndices) {
- polygonIndices->pop();
+ *polygonIndices->push() = currEdge->fIndex;
+ }
+ currEdge = currEdge->fNext;
+ while (currEdge != head) {
+ if (!SkPointPriv::EqualsWithinTolerance(currEdge->fIntersection,
+ (*offsetPolygon)[currIndex],
+ kCleanupTolerance)) {
+ *offsetPolygon->push() = currEdge->fIntersection;
+ if (polygonIndices) {
+ *polygonIndices->push() = currEdge->fIndex;
+ }
+ currIndex++;
+ }
+ currEdge = currEdge->fNext;
+ }
+ // make sure the first and last points aren't coincident
+ if (currIndex >= 1 &&
+ SkPointPriv::EqualsWithinTolerance((*offsetPolygon)[0], (*offsetPolygon)[currIndex],
+ kCleanupTolerance)) {
+ offsetPolygon->pop();
+ if (polygonIndices) {
+ polygonIndices->pop();
+ }
}
}
diff --git a/tests/InsetConvexPolyTest.cpp b/tests/InsetConvexPolyTest.cpp
index facabb7..aaaf591 100644
--- a/tests/InsetConvexPolyTest.cpp
+++ b/tests/InsetConvexPolyTest.cpp
@@ -65,7 +65,7 @@
// past full inset
result = SkInsetConvexPolygon(rrectPoly.begin(), rrectPoly.count(), 75, &insetPoly);
REPORTER_ASSERT(reporter, !result);
- REPORTER_ASSERT(reporter, insetPoly.count() == 0);
+ REPORTER_ASSERT(reporter, insetPoly.count() == 1);
// troublesome case
SkTDArray<SkPoint> clippedRRectPoly;