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cocos_lib/cocos/editor-support/spine/Triangulator.cpp

289 lines
11 KiB

/******************************************************************************
* Spine Runtimes License Agreement
* Last updated January 1, 2020. Replaces all prior versions.
*
* Copyright (c) 2013-2020, Esoteric Software LLC
*
* Integration of the Spine Runtimes into software or otherwise creating
* derivative works of the Spine Runtimes is permitted under the terms and
* conditions of Section 2 of the Spine Editor License Agreement:
* http://esotericsoftware.com/spine-editor-license
*
* Otherwise, it is permitted to integrate the Spine Runtimes into software
* or otherwise create derivative works of the Spine Runtimes (collectively,
* "Products"), provided that each user of the Products must obtain their own
* Spine Editor license and redistribution of the Products in any form must
* include this license and copyright notice.
*
* THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL ESOTERIC SOFTWARE LLC BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
* BUSINESS INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*****************************************************************************/
#ifdef SPINE_UE4
#include "SpinePluginPrivatePCH.h"
#endif
#include <spine/Triangulator.h>
#include <spine/MathUtil.h>
using namespace spine;
Triangulator::~Triangulator() {
ContainerUtil::cleanUpVectorOfPointers(_convexPolygons);
ContainerUtil::cleanUpVectorOfPointers(_convexPolygonsIndices);
}
Vector<int> &Triangulator::triangulate(Vector<float> &vertices) {
size_t vertexCount = vertices.size() >> 1;
Vector<int> &indices = _indices;
indices.clear();
indices.ensureCapacity(vertexCount);
indices.setSize(vertexCount, 0);
for (size_t i = 0; i < vertexCount; ++i) {
indices[i] = i;
}
Vector<bool> &isConcaveArray = _isConcaveArray;
isConcaveArray.ensureCapacity(vertexCount);
isConcaveArray.setSize(vertexCount, 0);
for (size_t i = 0, n = vertexCount; i < n; ++i) {
isConcaveArray[i] = isConcave(i, vertexCount, vertices, indices);
}
Vector<int> &triangles = _triangles;
triangles.clear();
triangles.ensureCapacity(MathUtil::max((int)0, (int)vertexCount - 2) << 2);
while (vertexCount > 3) {
// Find ear tip.
size_t previous = vertexCount - 1, i = 0, next = 1;
// outer:
while (true) {
if (!isConcaveArray[i]) {
int p1 = indices[previous] << 1, p2 = indices[i] << 1, p3 = indices[next] << 1;
float p1x = vertices[p1], p1y = vertices[p1 + 1];
float p2x = vertices[p2], p2y = vertices[p2 + 1];
float p3x = vertices[p3], p3y = vertices[p3 + 1];
for (size_t ii = (next + 1) % vertexCount; ii != previous; ii = (ii + 1) % vertexCount) {
if (!isConcaveArray[ii]) continue;
int v = indices[ii] << 1;
float &vx = vertices[v], vy = vertices[v + 1];
if (positiveArea(p3x, p3y, p1x, p1y, vx, vy)) {
if (positiveArea(p1x, p1y, p2x, p2y, vx, vy)) {
if (positiveArea(p2x, p2y, p3x, p3y, vx, vy)) {
goto break_outer; // break outer;
}
}
}
}
break;
}
break_outer:
if (next == 0) {
do {
if (!isConcaveArray[i]) break;
i--;
} while (i > 0);
break;
}
previous = i;
i = next;
next = (next + 1) % vertexCount;
}
// Cut ear tip.
triangles.add(indices[(vertexCount + i - 1) % vertexCount]);
triangles.add(indices[i]);
triangles.add(indices[(i + 1) % vertexCount]);
indices.removeAt(i);
isConcaveArray.removeAt(i);
vertexCount--;
int previousIndex = (vertexCount + i - 1) % vertexCount;
int nextIndex = i == vertexCount ? 0 : i;
isConcaveArray[previousIndex] = isConcave(previousIndex, vertexCount, vertices, indices);
isConcaveArray[nextIndex] = isConcave(nextIndex, vertexCount, vertices, indices);
}
if (vertexCount == 3) {
triangles.add(indices[2]);
triangles.add(indices[0]);
triangles.add(indices[1]);
}
return triangles;
}
Vector<Vector<float> *> &Triangulator::decompose(Vector<float> &vertices, Vector<int> &triangles) {
Vector<Vector<float> *> &convexPolygons = _convexPolygons;
for (size_t i = 0, n = convexPolygons.size(); i < n; ++i)
_polygonPool.free(convexPolygons[i]);
convexPolygons.clear();
Vector<Vector<int> *> &convexPolygonsIndices = _convexPolygonsIndices;
for (size_t i = 0, n = convexPolygonsIndices.size(); i < n; ++i)
_polygonIndicesPool.free(convexPolygonsIndices[i]);
convexPolygonsIndices.clear();
Vector<int> *polygonIndices = _polygonIndicesPool.obtain();
polygonIndices->clear();
Vector<float> *polygon = _polygonPool.obtain();
polygon->clear();
// Merge subsequent triangles if they form a triangle fan.
int fanBaseIndex = -1, lastwinding = 0;
for (size_t i = 0, n = triangles.size(); i < n; i += 3) {
int t1 = triangles[i] << 1, t2 = triangles[i + 1] << 1, t3 = triangles[i + 2] << 1;
float x1 = vertices[t1], y1 = vertices[t1 + 1];
float x2 = vertices[t2], y2 = vertices[t2 + 1];
float x3 = vertices[t3], y3 = vertices[t3 + 1];
// If the base of the last triangle is the same as this triangle, check if they form a convex polygon (triangle fan).
bool merged = false;
if (fanBaseIndex == t1) {
size_t o = polygon->size() - 4;
Vector<float> &p = *polygon;
int winding1 = winding(p[o], p[o + 1], p[o + 2], p[o + 3], x3, y3);
int winding2 = winding(x3, y3, p[0], p[1], p[2], p[3]);
if (winding1 == lastwinding && winding2 == lastwinding) {
polygon->add(x3);
polygon->add(y3);
polygonIndices->add(t3);
merged = true;
}
}
// Otherwise make this triangle the new base.
if (!merged) {
if (polygon->size() > 0) {
convexPolygons.add(polygon);
convexPolygonsIndices.add(polygonIndices);
} else {
_polygonPool.free(polygon);
_polygonIndicesPool.free(polygonIndices);
}
polygon = _polygonPool.obtain();
polygon->clear();
polygon->add(x1);
polygon->add(y1);
polygon->add(x2);
polygon->add(y2);
polygon->add(x3);
polygon->add(y3);
polygonIndices = _polygonIndicesPool.obtain();
polygonIndices->clear();
polygonIndices->add(t1);
polygonIndices->add(t2);
polygonIndices->add(t3);
lastwinding = winding(x1, y1, x2, y2, x3, y3);
fanBaseIndex = t1;
}
}
if (polygon->size() > 0) {
convexPolygons.add(polygon);
convexPolygonsIndices.add(polygonIndices);
}
// Go through the list of polygons and try to merge the remaining triangles with the found triangle fans.
for (size_t i = 0, n = convexPolygons.size(); i < n; ++i) {
polygonIndices = convexPolygonsIndices[i];
if (polygonIndices->size() == 0) continue;
int firstIndex = (*polygonIndices)[0];
int lastIndex = (*polygonIndices)[polygonIndices->size() - 1];
polygon = convexPolygons[i];
size_t o = polygon->size() - 4;
Vector<float> &p = *polygon;
float prevPrevX = p[o], prevPrevY = p[o + 1];
float prevX = p[o + 2], prevY = p[o + 3];
float firstX = p[0], firstY = p[1];
float secondX = p[2], secondY = p[3];
int winding0 = winding(prevPrevX, prevPrevY, prevX, prevY, firstX, firstY);
for (size_t ii = 0; ii < n; ++ii) {
if (ii == i) continue;
Vector<int> *otherIndicesP = convexPolygonsIndices[ii];
Vector<int> &otherIndices = *otherIndicesP;
if (otherIndices.size() != 3) continue;
int otherFirstIndex = otherIndices[0];
int otherSecondIndex = otherIndices[1];
int otherLastIndex = otherIndices[2];
Vector<float> *otherPolyP = convexPolygons[ii];
Vector<float> &otherPoly = *otherPolyP;
float x3 = otherPoly[otherPoly.size() - 2], y3 = otherPoly[otherPoly.size() - 1];
if (otherFirstIndex != firstIndex || otherSecondIndex != lastIndex) continue;
int winding1 = winding(prevPrevX, prevPrevY, prevX, prevY, x3, y3);
int winding2 = winding(x3, y3, firstX, firstY, secondX, secondY);
if (winding1 == winding0 && winding2 == winding0) {
otherPoly.clear();
otherIndices.clear();
polygon->add(x3);
polygon->add(y3);
polygonIndices->add(otherLastIndex);
prevPrevX = prevX;
prevPrevY = prevY;
prevX = x3;
prevY = y3;
ii = 0;
}
}
}
// Remove empty polygons that resulted from the merge step above.
for (int i = (int)convexPolygons.size() - 1; i >= 0; --i) {
polygon = convexPolygons[i];
if (polygon->size() == 0) {
convexPolygons.removeAt(i);
_polygonPool.free(polygon);
polygonIndices = convexPolygonsIndices[i];
convexPolygonsIndices.removeAt(i);
_polygonIndicesPool.free(polygonIndices);
}
}
return convexPolygons;
}
bool Triangulator::isConcave(int index, int vertexCount, Vector<float> &vertices, Vector<int> &indices) {
int previous = indices[(vertexCount + index - 1) % vertexCount] << 1;
int current = indices[index] << 1;
int next = indices[(index + 1) % vertexCount] << 1;
return !positiveArea(vertices[previous], vertices[previous + 1],
vertices[current], vertices[current + 1],
vertices[next], vertices[next + 1]);
}
bool Triangulator::positiveArea(float p1x, float p1y, float p2x, float p2y, float p3x, float p3y) {
return p1x * (p3y - p2y) + p2x * (p1y - p3y) + p3x * (p2y - p1y) >= 0;
}
int Triangulator::winding(float p1x, float p1y, float p2x, float p2y, float p3x, float p3y) {
float px = p2x - p1x, py = p2y - p1y;
return p3x * py - p3y * px + px * p1y - p1x * py >= 0 ? 1 : -1;
}