spine-runtimes/spine-ts/core/src/Triangulator.ts

270 lines
9.9 KiB
TypeScript

/******************************************************************************
* Spine Runtimes Software License v2.5
*
* Copyright (c) 2013-2016, Esoteric Software
* All rights reserved.
*
* You are granted a perpetual, non-exclusive, non-sublicensable, and
* non-transferable license to use, install, execute, and perform the Spine
* Runtimes software and derivative works solely for personal or internal
* use. Without the written permission of Esoteric Software (see Section 2 of
* the Spine Software License Agreement), you may not (a) modify, translate,
* adapt, or develop new applications using the Spine Runtimes or otherwise
* create derivative works or improvements of the Spine Runtimes or (b) remove,
* delete, alter, or obscure any trademarks or any copyright, trademark, patent,
* or other intellectual property or proprietary rights notices on or in the
* Software, including any copy thereof. Redistributions in binary or source
* form must include this license and terms.
*
* THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "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 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 THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*****************************************************************************/
module spine {
export class Triangulator {
private convexPolygons = new Array<Array<number>>();
private convexPolygonsIndices = new Array<Array<number>>();
private indicesArray = new Array<number>();
private isConcaveArray = new Array<boolean>();
private triangles = new Array<number>();
private polygonPool = new Pool<Array<number>>(() => {
return new Array<number>();
});
private polygonIndicesPool = new Pool<Array<number>>(() => {
return new Array<number>();
});
public triangulate (verticesArray: ArrayLike<number>): Array<number> {
let vertices = verticesArray;
let vertexCount = verticesArray.length >> 1;
let indices = this.indicesArray;
indices.length = 0;
for (let i = 0; i < vertexCount; i++)
indices[i] = i;
let isConcave = this.isConcaveArray;
isConcave.length = 0;
for (let i = 0, n = vertexCount; i < n; ++i)
isConcave[i] = Triangulator.isConcave(i, vertexCount, vertices, indices);
let triangles = this.triangles;
triangles.length = 0;
while (vertexCount > 3) {
// Find ear tip.
let previous = vertexCount - 1, i = 0, next = 1;
while (true) {
outer:
if (!isConcave[i]) {
let p1 = indices[previous] << 1, p2 = indices[i] << 1, p3 = indices[next] << 1;
let p1x = vertices[p1], p1y = vertices[p1 + 1];
let p2x = vertices[p2], p2y = vertices[p2 + 1];
let p3x = vertices[p3], p3y = vertices[p3 + 1];
for (let ii = (next + 1) % vertexCount; ii != previous; ii = (ii + 1) % vertexCount) {
if (!isConcave[ii]) continue;
let v = indices[ii] << 1;
let vx = vertices[v], vy = vertices[v + 1];
if (Triangulator.positiveArea(p3x, p3y, p1x, p1y, vx, vy)) {
if (Triangulator.positiveArea(p1x, p1y, p2x, p2y, vx, vy)) {
if (Triangulator.positiveArea(p2x, p2y, p3x, p3y, vx, vy)) break outer;
}
}
}
break;
}
if (next == 0) {
do {
if (!isConcave[i]) break;
i--;
} while (i > 0);
break;
}
previous = i;
i = next;
next = (next + 1) % vertexCount;
}
// Cut ear tip.
triangles.push(indices[(vertexCount + i - 1) % vertexCount]);
triangles.push(indices[i]);
triangles.push(indices[(i + 1) % vertexCount]);
indices.splice(i, 1);
isConcave.splice(i, 1);
vertexCount--;
let previousIndex = (vertexCount + i - 1) % vertexCount;
let nextIndex = i == vertexCount ? 0 : i;
isConcave[previousIndex] = Triangulator.isConcave(previousIndex, vertexCount, vertices, indices);
isConcave[nextIndex] = Triangulator.isConcave(nextIndex, vertexCount, vertices, indices);
}
if (vertexCount == 3) {
triangles.push(indices[2]);
triangles.push(indices[0]);
triangles.push(indices[1]);
}
return triangles;
}
decompose (verticesArray: Array<number>, triangles: Array<number>) : Array<Array<number>> {
let vertices = verticesArray;
let convexPolygons = this.convexPolygons;
this.polygonPool.freeAll(convexPolygons);
convexPolygons.length = 0;
let convexPolygonsIndices = this.convexPolygonsIndices;
this.polygonIndicesPool.freeAll(convexPolygonsIndices);
convexPolygonsIndices.length = 0;
let polygonIndices = this.polygonIndicesPool.obtain();
polygonIndices.length = 0;
let polygon = this.polygonPool.obtain();
polygon.length = 0;
// Merge subsequent triangles if they form a triangle fan.
let fanBaseIndex = -1, lastWinding = 0;
for (let i = 0, n = triangles.length; i < n; i += 3) {
let t1 = triangles[i] << 1, t2 = triangles[i + 1] << 1, t3 = triangles[i + 2] << 1;
let x1 = vertices[t1], y1 = vertices[t1 + 1];
let x2 = vertices[t2], y2 = vertices[t2 + 1];
let 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).
let merged = false;
if (fanBaseIndex == t1) {
let o = polygon.length - 4;
let winding1 = Triangulator.winding(polygon[o], polygon[o + 1], polygon[o + 2], polygon[o + 3], x3, y3);
let winding2 = Triangulator.winding(x3, y3, polygon[0], polygon[1], polygon[2], polygon[3]);
if (winding1 == lastWinding && winding2 == lastWinding) {
polygon.push(x3);
polygon.push(y3);
polygonIndices.push(t3);
merged = true;
}
}
// Otherwise make this triangle the new base.
if (!merged) {
if (polygon.length > 0) {
convexPolygons.push(polygon);
convexPolygonsIndices.push(polygonIndices);
} else {
this.polygonPool.free(polygon)
this.polygonIndicesPool.free(polygonIndices);
}
polygon = this.polygonPool.obtain();
polygon.length = 0;
polygon.push(x1);
polygon.push(y1);
polygon.push(x2);
polygon.push(y2);
polygon.push(x3);
polygon.push(y3);
polygonIndices = this.polygonIndicesPool.obtain();
polygonIndices.length = 0;
polygonIndices.push(t1);
polygonIndices.push(t2);
polygonIndices.push(t3);
lastWinding = Triangulator.winding(x1, y1, x2, y2, x3, y3);
fanBaseIndex = t1;
}
}
if (polygon.length > 0) {
convexPolygons.push(polygon);
convexPolygonsIndices.push(polygonIndices);
}
// Go through the list of polygons and try to merge the remaining triangles with the found triangle fans.
for (let i = 0, n = convexPolygons.length; i < n; i++) {
polygonIndices = convexPolygonsIndices[i];
if (polygonIndices.length == 0) continue;
let firstIndex = polygonIndices[0];
let lastIndex = polygonIndices[polygonIndices.length - 1];
polygon = convexPolygons[i];
let o = polygon.length - 4;
let prevPrevX = polygon[o], prevPrevY = polygon[o + 1];
let prevX = polygon[o + 2], prevY = polygon[o + 3];
let firstX = polygon[0], firstY = polygon[1];
let secondX = polygon[2], secondY = polygon[3];
let winding = Triangulator.winding(prevPrevX, prevPrevY, prevX, prevY, firstX, firstY);
for (let ii = 0; ii < n; ii++) {
if (ii == i) continue;
let otherIndices = convexPolygonsIndices[ii];
if (otherIndices.length != 3) continue;
let otherFirstIndex = otherIndices[0];
let otherSecondIndex = otherIndices[1];
let otherLastIndex = otherIndices[2];
let otherPoly = convexPolygons[ii];
let x3 = otherPoly[otherPoly.length - 2], y3 = otherPoly[otherPoly.length - 1];
if (otherFirstIndex != firstIndex || otherSecondIndex != lastIndex) continue;
let winding1 = Triangulator.winding(prevPrevX, prevPrevY, prevX, prevY, x3, y3);
let winding2 = Triangulator.winding(x3, y3, firstX, firstY, secondX, secondY);
if (winding1 == winding && winding2 == winding) {
otherPoly.length = 0;
otherIndices.length = 0;
polygon.push(x3);
polygon.push(y3);
polygonIndices.push(otherLastIndex);
prevPrevX = prevX;
prevPrevY = prevY;
prevX = x3;
prevY = y3;
ii = 0;
}
}
}
// Remove empty polygons that resulted from the merge step above.
for (let i = convexPolygons.length - 1; i >= 0; i--) {
polygon = convexPolygons[i];
if (polygon.length == 0) {
convexPolygons.splice(i, 1);
this.polygonPool.free(polygon);
polygonIndices = convexPolygonsIndices[i]
convexPolygonsIndices.splice(i, 1)
this.polygonIndicesPool.free(polygonIndices);
}
}
return convexPolygons;
}
private static isConcave (index: number, vertexCount: number, vertices: ArrayLike<number>, indices: ArrayLike<number>): boolean {
let previous = indices[(vertexCount + index - 1) % vertexCount] << 1;
let current = indices[index] << 1;
let next = indices[(index + 1) % vertexCount] << 1;
return !this.positiveArea(vertices[previous], vertices[previous + 1], vertices[current], vertices[current + 1], vertices[next],
vertices[next + 1]);
}
private static positiveArea (p1x: number, p1y: number, p2x: number, p2y: number, p3x: number, p3y: number): boolean {
return p1x * (p3y - p2y) + p2x * (p1y - p3y) + p3x * (p2y - p1y) >= 0;
}
private static winding (p1x: number, p1y: number, p2x: number, p2y: number, p3x: number, p3y: number): number {
let px = p2x - p1x, py = p2y - p1y;
return p3x * py - p3y * px + px * p1y - p1x * py >= 0 ? 1 : -1;
}
}
}