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Correctly triangulate simple polygons.

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This commit is contained in:
GaborFarkas
2016-10-03 23:41:59 +02:00
parent a0089b5126
commit dc27f768d0
1 changed files with 59 additions and 18 deletions
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77
src/ol/render/webgl/imagereplay/index.js
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@@ -1922,21 +1922,18 @@ ol.render.webgl.PolygonReplay.prototype.bridgeHole_ = function(hole, holeMaxX,
ol.render.webgl.PolygonReplay.prototype.triangulate_ = function(list, rtree) {
var ccw = false;
var simple = this.isSimple_(list, rtree);
var pass = 0;
// Start clipping ears
while (list.getLength() > 3) {
if (simple) {
if (!this.clipEars_(list, rtree, simple, ccw)) {
if (!this.classifyPoints_(list, rtree, ccw)) {
// We have the wrongly oriented remains of a self-intersecting polygon.
pass++;
if (pass > 1) {
// Due to the behavior of OL's PIP algorithm, the ear clipping cannot
// introduce touching segments. However, the original data may have some.
if (!this.resolveLocalSelfIntersections_(list, rtree, true)) {
// Something went wrong.
break;
}
ccw = !ccw;
this.classifyPoints_(list, rtree, ccw);
}
}
} else {
@@ -1950,6 +1947,9 @@ ol.render.webgl.PolygonReplay.prototype.triangulate_ = function(list, rtree) {
// We have a really bad polygon, try more time consuming methods.
this.splitPolygon_(list, rtree);
break;
} else {
ccw = !this.isClockwise_(list);
this.classifyPoints_(list, rtree, ccw);
}
}
}
@@ -1993,7 +1993,7 @@ ol.render.webgl.PolygonReplay.prototype.clipEars_ = function(list, rtree, simple
if ((simple || this.getIntersections_({p0: p0, p1: p2}, rtree).length === 0) &&
diagonalIsInside && this.getPointsInTriangle_(p0, p1, p2, rtree, true).length === 0) {
//The diagonal is completely inside the polygon
if (p0.reflex === false || p2.reflex === false ||
if (simple || p0.reflex === false || p2.reflex === false ||
ol.geom.flat.orient.linearRingIsClockwise([s0.p0.x, s0.p0.y, p0.x,
p0.y, p1.x, p1.y, p2.x, p2.y, s3.p1.x, s3.p1.y], 0, 10, 2) === !ccw) {
//The diagonal is persumably valid, we have an ear
@@ -2023,10 +2023,11 @@ ol.render.webgl.PolygonReplay.prototype.clipEars_ = function(list, rtree, simple
* @private
* @param {ol.structs.LinkedList} list Linked list of the polygon.
* @param {ol.structs.RBush} rtree R-Tree of the polygon.
* @param {boolean=} opt_touch Resolve touching segments.
* @return {boolean} There were resolved intersections.
*/
ol.render.webgl.PolygonReplay.prototype.resolveLocalSelfIntersections_ = function(
list, rtree) {
list, rtree, opt_touch) {
var start = list.firstItem();
list.nextItem();
var s0 = start;
@@ -2034,28 +2035,48 @@ ol.render.webgl.PolygonReplay.prototype.resolveLocalSelfIntersections_ = functio
var resolvedIntersections = false;
do {
var intersection = this.calculateIntersection_(s0.p0, s0.p1, s1.p0, s1.p1);
var intersection = this.calculateIntersection_(s0.p0, s0.p1, s1.p0, s1.p1,
opt_touch);
if (intersection) {
var breakCond = false;
var numVertices = this.vertices_.length;
var numIndices = this.indices_.length;
var n = numVertices / 2;
var p = this.createPoint_(intersection[0], intersection[1], n);
var seg = list.prevItem();
list.removeItem();
rtree.remove(seg);
s0.p1 = p;
s1.p0 = p;
rtree.update([Math.min(s0.p0.x, s0.p1.x), Math.min(s0.p0.y, s0.p1.y),
Math.max(s0.p0.x, s0.p1.x), Math.max(s0.p0.y, s0.p1.y)], s0);
rtree.update([Math.min(s1.p0.x, s1.p1.x), Math.min(s1.p0.y, s1.p1.y),
Math.max(s1.p0.x, s1.p1.x), Math.max(s1.p0.y, s1.p1.y)], s1);
breakCond = (seg === start);
var p;
if (opt_touch) {
if (intersection[0] === s0.p0.x && intersection[1] === s0.p0.y) {
list.prevItem();
p = s0.p0;
s1.p0 = p;
rtree.remove(s0);
breakCond = breakCond || (s0 === start);
} else {
p = s1.p1;
s0.p1 = p;
rtree.remove(s1);
breakCond = breakCond || (s1 === start);
}
list.removeItem();
} else {
p = this.createPoint_(intersection[0], intersection[1], n);
s0.p1 = p;
s1.p0 = p;
rtree.update([Math.min(s0.p0.x, s0.p1.x), Math.min(s0.p0.y, s0.p1.y),
Math.max(s0.p0.x, s0.p1.x), Math.max(s0.p0.y, s0.p1.y)], s0);
rtree.update([Math.min(s1.p0.x, s1.p1.x), Math.min(s1.p0.y, s1.p1.y),
Math.max(s1.p0.x, s1.p1.x), Math.max(s1.p0.y, s1.p1.y)], s1);
}
this.indices_[numIndices++] = seg.p0.i;
this.indices_[numIndices++] = seg.p1.i;
this.indices_[numIndices++] = p.i;
resolvedIntersections = true;
if (start === seg) {
if (breakCond) {
break;
}
}
@@ -2086,6 +2107,26 @@ ol.render.webgl.PolygonReplay.prototype.isSimple_ = function(list, rtree) {
};
/**
* @private
* @param {ol.structs.LinkedList} list Linked list of the polygon.
* @return {boolean} Orientation is clockwise.
*/
ol.render.webgl.PolygonReplay.prototype.isClockwise_ = function(list) {
var length = list.getLength() * 2;
var flatCoordinates = new Array(length);
var start = list.firstItem();
var seg = start;
var i = 0;
do {
flatCoordinates[i++] = seg.p0.x;
flatCoordinates[i++] = seg.p0.y;
seg = list.nextItem();
} while (seg !== start);
return ol.geom.flat.orient.linearRingIsClockwise(flatCoordinates, 0, length, 2);
};
/**
* @private
* @param {ol.structs.LinkedList} list Linked list of the polygon.