/
PolygonPipeline.js
926 lines (806 loc) · 35.9 KB
/
PolygonPipeline.js
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/*global define*/
define([
'./DeveloperError',
'./Math',
'./Cartesian2',
'./Cartesian3',
'./Ellipsoid',
'./EllipsoidTangentPlane',
'./defaultValue',
'./pointInsideTriangle2D',
'./ComponentDatatype',
'./PrimitiveType',
'./Queue',
'./WindingOrder'
], function(
DeveloperError,
CesiumMath,
Cartesian2,
Cartesian3,
Ellipsoid,
EllipsoidTangentPlane,
defaultValue,
pointInsideTriangle2D,
ComponentDatatype,
PrimitiveType,
Queue,
WindingOrder) {
"use strict";
function DoublyLinkedList() {
this.head = undefined;
this.tail = undefined;
this.length = 0;
}
DoublyLinkedList.prototype.add = function(item) {
if (typeof item !== 'undefined') {
var node = {
item : item,
previous : this.tail,
next : undefined
};
if (typeof this.tail !== 'undefined') {
this.tail.next = node;
this.tail = node;
} else {
// Insert into empty list.
this.head = node;
this.tail = node;
}
++this.length;
}
};
DoublyLinkedList.prototype.remove = function(item) {
if (typeof item !== 'undefined') {
if (typeof item.previous !== 'undefined' && typeof item.next !== 'undefined') {
item.previous.next = item.next;
item.next.previous = item.previous;
} else if (typeof item.previous !== 'undefined') {
// Remove last node.
item.previous.next = undefined;
this.tail = item.previous;
} else if (typeof item.next !== 'undefined') {
// Remove first node.
item.next.previous = undefined;
this.head = item.next;
} else {
// Remove last node in linked list.
this.head = undefined;
this.tail = undefined;
}
--this.length;
}
};
function isTipConvex(p0, p1, p2) {
var u = p1.subtract(p0);
var v = p2.subtract(p1);
// Use the sign of the z component of the cross product
return ((u.x * v.y) - (u.y * v.x)) >= 0.0;
}
/**
* Returns the index of the vertex with the maximum X value.
*
* @param {Array} positions An array of the Cartesian points defining the polygon's vertices.
* @returns {Number} The index of the positions with the maximum X value.
*
* @private
*/
function getRightmostPositionIndex(positions) {
var maximumX = positions[0].x;
var rightmostPositionIndex = 0;
for ( var i = 0; i < positions.length; i++) {
if (positions[i].x > maximumX) {
maximumX = positions[i].x;
rightmostPositionIndex = i;
}
}
return rightmostPositionIndex;
}
/**
* Returns the index of the ring that contains the rightmost vertex.
*
* @param {Array} rings An array of arrays of Cartesians. Each array contains the vertices defining a polygon.
* @returns {Number} The index of the ring containing the rightmost vertex.
*
* @private
*/
function getRightmostRingIndex(rings) {
var rightmostX = rings[0][0].x;
var rightmostRingIndex = 0;
for ( var ring = 0; ring < rings.length; ring++) {
var maximumX = rings[ring][getRightmostPositionIndex(rings[ring])].x;
if (maximumX > rightmostX) {
rightmostX = maximumX;
rightmostRingIndex = ring;
}
}
return rightmostRingIndex;
}
/**
* Returns a list containing the reflex vertices for a given polygon.
*
* @param {Array} polygon An array of Cartesian elements defining the polygon.
* @returns {Array}
*
* @private
*/
function getReflexVertices(polygon) {
var reflexVertices = [];
for ( var i = 0; i < polygon.length; i++) {
var p0 = polygon[((i - 1) + polygon.length) % polygon.length];
var p1 = polygon[i];
var p2 = polygon[(i + 1) % polygon.length];
if (!isTipConvex(p0, p1, p2)) {
reflexVertices.push(p1);
}
}
return reflexVertices;
}
/**
* Returns true if the given point is contained in the list of positions.
*
* @param {Array} positions A list of Cartesian elements defining a polygon.
* @param {Cartesian} point The point to check.
* @returns {Boolean} <code>true></code> if <code>point</code> is found in <code>polygon</code>, <code>false</code> otherwise.
*
* @private
*/
function isVertex(positions, point) {
for ( var i = 0; i < positions.length; i++) {
if (point.equals(positions[i])) {
return true;
}
}
return false;
}
/**
* Given a point inside a polygon, find the nearest point directly to the right that lies on one of the polygon's edges.
*
* @param {Cartesian} point A point inside the polygon defined by <code>ring</code>.
* @param {Array} ring A list of Cartesian points defining a polygon.
* @param {Array} [edgeIndices] An array containing the indices two endpoints of the edge containing the intersection.
*
* @returns {Cartesian} The intersection point.
* @private
*/
function intersectPointWithRing(point, ring, edgeIndices) {
edgeIndices = defaultValue(edgeIndices, []);
var minDistance = Number.MAX_VALUE;
var rightmostVertexIndex = getRightmostPositionIndex(ring);
var intersection = new Cartesian3(ring[rightmostVertexIndex].x, point.y, 0.0);
edgeIndices.push(rightmostVertexIndex);
edgeIndices.push((rightmostVertexIndex + 1) % ring.length);
var boundaryMinX = ring[0].x;
var boundaryMaxX = boundaryMinX;
for ( var i = 1; i < ring.length; ++i) {
if (ring[i].x < boundaryMinX) {
boundaryMinX = ring[i].x;
} else if (ring[i].x > boundaryMaxX) {
boundaryMaxX = ring[i].x;
}
}
boundaryMaxX += (boundaryMaxX - boundaryMinX);
var point2 = new Cartesian3(boundaryMaxX, point.y, 0.0);
// Find the nearest intersection.
for (i = 0; i < ring.length; i++) {
var v1 = ring[i];
var v2 = ring[(i + 1) % ring.length];
if (((v1.x >= point.x) || (v2.x >= point.x)) && (((v1.y >= point.y) && (v2.y <= point.y)) || ((v1.y <= point.y) && (v2.y >= point.y)))) {
var temp = ((v2.y - v1.y) * (point2.x - point.x)) - ((v2.x - v1.x) * (point2.y - point.y));
if (temp !== 0.0) {
temp = 1.0 / temp;
var ua = (((v2.x - v1.x) * (point.y - v1.y)) - ((v2.y - v1.y) * (point.x - v1.x))) * temp;
var ub = (((point2.x - point.x) * (point.y - v1.y)) - ((point2.y - point.y) * (point.x - v1.x))) * temp;
if ((ua >= 0.0) && (ua <= 1.0) && (ub >= 0.0) && (ub <= 1.0)) {
var tempIntersection = new Cartesian2(point.x + ua * (point2.x - point.x), point.y + ua * (point2.y - point.y));
var dist = tempIntersection.subtract(point);
temp = dist.magnitudeSquared();
if (temp < minDistance) {
intersection = tempIntersection;
minDistance = temp;
edgeIndices[0] = i;
edgeIndices[1] = (i + 1) % ring.length;
}
}
}
}
}
return intersection;
}
/**
* Given an outer ring and multiple inner rings, determine the point on the outer ring that is visible
* to the rightmost vertex of the rightmost inner ring.
*
* @param {Array} outerRing An array of Cartesian points defining the outer boundary of the polygon.
* @param {Array} innerRings An array of arrays of Cartesian points, where each array represents a hole in the polygon.
* @returns {Number} The index of the vertex in <code>outerRing</code> that is mutually visible to the rightmost vertex in <code>inenrRing</code>.
*
* @private
*/
function getMutuallyVisibleVertexIndex(outerRing, innerRings) {
var innerRingIndex = getRightmostRingIndex(innerRings);
var innerRing = innerRings[innerRingIndex];
var innerRingVertexIndex = getRightmostPositionIndex(innerRing);
var innerRingVertex = innerRing[innerRingVertexIndex];
var edgeIndices = [];
var intersection = intersectPointWithRing(innerRingVertex, outerRing, edgeIndices);
var visibleVertex;
if (isVertex(outerRing, intersection)) {
visibleVertex = intersection;
} else {
// Set P to be the edge endpoint closest to the inner ring vertex
var d1 = (outerRing[edgeIndices[0]].subtract(innerRingVertex)).magnitudeSquared();
var d2 = (outerRing[edgeIndices[1]].subtract(innerRingVertex)).magnitudeSquared();
var p = (d1 < d2) ? outerRing[edgeIndices[0]] : outerRing[edgeIndices[1]];
var reflexVertices = getReflexVertices(outerRing);
var reflexIndex = reflexVertices.indexOf(p);
if (reflexIndex !== -1) {
reflexVertices.splice(reflexIndex, 1); // Do not include p if it happens to be reflex.
}
var pointsInside = [];
for ( var i = 0; i < reflexVertices.length; i++) {
var vertex = reflexVertices[i];
if (pointInsideTriangle2D(vertex, innerRingVertex, intersection, p)) {
pointsInside.push(vertex);
}
}
// If all reflexive vertices are outside the triangle formed by points
// innerRingVertex, intersection and P, then P is the visible vertex.
// Otherwise, return the reflex vertex that minimizes the angle between <1,0> and <k, reflex>.
var minAngle = Number.MAX_VALUE;
if (pointsInside.length > 0) {
var v1 = new Cartesian2(1.0, 0.0, 0.0);
for (i = 0; i < pointsInside.length; i++) {
var v2 = pointsInside[i].subtract(innerRingVertex);
var denominator = v1.magnitude() * v2.magnitude();
if (denominator !== 0) {
var angle = Math.abs(Math.acos(v1.dot(v2) / denominator));
if (angle < minAngle) {
minAngle = angle;
p = pointsInside[i];
}
}
}
}
visibleVertex = p;
}
return outerRing.indexOf(visibleVertex);
}
/**
* Given a polygon defined by an outer ring with one or more inner rings (holes), return a single list of points representing
* a polygon with the rightmost hole added to it. The added hole is removed from <code>innerRings</code>.
*
* @param {Array} outerRing An array of Cartesian points defining the outer boundary of the polygon.
* @param {Array} innerRings An array of arrays of Cartesian points, where each array represents a hole in the polygon.
*
* @return A single list of Cartesian points defining the polygon, including the eliminated inner ring.
*
* @private
*/
function eliminateHole(outerRing, innerRings, ellipsoid) {
// Check that the holes are defined in the winding order opposite that of the outer ring.
var windingOrder = PolygonPipeline.computeWindingOrder2D(outerRing);
for ( var i = 0; i < innerRings.length; i++) {
var ring = innerRings[i];
// Ensure each hole's first and last points are the same.
if (!(ring[0]).equals(ring[ring.length - 1])) {
ring.push(ring[0]);
}
var innerWindingOrder = PolygonPipeline.computeWindingOrder2D(ring);
if (innerWindingOrder === windingOrder) {
ring.reverse();
}
}
// Project points onto a tangent plane to find the mutually visible vertex.
var tangentPlane = EllipsoidTangentPlane.fromPoints(outerRing, ellipsoid);
var tangentOuterRing = tangentPlane.projectPointsOntoPlane(outerRing);
var tangentInnerRings = [];
for (i = 0; i < innerRings.length; i++) {
tangentInnerRings.push(tangentPlane.projectPointsOntoPlane(innerRings[i]));
}
var visibleVertexIndex = getMutuallyVisibleVertexIndex(tangentOuterRing, tangentInnerRings);
var innerRingIndex = getRightmostRingIndex(tangentInnerRings);
var innerRingVertexIndex = getRightmostPositionIndex(tangentInnerRings[innerRingIndex]);
var innerRing = innerRings[innerRingIndex];
var newPolygonVertices = [];
for (i = 0; i < outerRing.length; i++) {
newPolygonVertices.push(outerRing[i]);
}
var j;
var holeVerticesToAdd = [];
// If the rightmost inner vertex is not the starting and ending point of the ring,
// then some other point is duplicated in the inner ring and should be skipped once.
if (innerRingVertexIndex !== 0) {
for (j = 0; j <= innerRing.length; j++) {
var index = (j + innerRingVertexIndex) % innerRing.length;
if (index !== 0) {
holeVerticesToAdd.push(innerRing[index]);
}
}
} else {
for (j = 0; j < innerRing.length; j++) {
holeVerticesToAdd.push(innerRing[(j + innerRingVertexIndex) % innerRing.length]);
}
}
var lastVisibleVertexIndex = newPolygonVertices.lastIndexOf(outerRing[visibleVertexIndex]);
holeVerticesToAdd.push(outerRing[lastVisibleVertexIndex]);
var front = newPolygonVertices.slice(0, lastVisibleVertexIndex + 1);
var back = newPolygonVertices.slice(lastVisibleVertexIndex + 1);
newPolygonVertices = front.concat(holeVerticesToAdd, back);
innerRings.splice(innerRingIndex, 1);
return newPolygonVertices;
}
var c3 = new Cartesian3();
function getXZIntersectionOffsetPoints(p, p1, u1, v1) {
p.add(p1.subtract(p, c3).multiplyByScalar(p.y/(p.y-p1.y), c3), u1);
Cartesian3.clone(u1, v1);
offsetPointFromXZPlane(u1, true);
offsetPointFromXZPlane(v1, false);
}
function offsetPointFromXZPlane(p, isBehind) {
if (Math.abs(p.y) < CesiumMath.EPSILON11){
if (isBehind) {
p.y = -CesiumMath.EPSILON11;
} else {
p.y = CesiumMath.EPSILON11;
}
}
}
var scaleToGeodeticHeightN = new Cartesian3();
var scaleToGeodeticHeightP = new Cartesian3();
/**
* DOC_TBA
*
* @exports PolygonPipeline
*/
var PolygonPipeline = {
/**
* DOC_TBA
*
* Cleans up a simple polygon by removing duplicate adjacent positions and making
* the first position not equal the last position.
*
* @exception {DeveloperError} positions is required.
* @exception {DeveloperError} At least three positions are required.
*/
cleanUp : function(positions) {
if (typeof positions === 'undefined') {
throw new DeveloperError('positions is required.');
}
var length = positions.length;
if (length < 3) {
throw new DeveloperError('At least three positions are required.');
}
var cleanedPositions = [];
for ( var i0 = length - 1, i1 = 0; i1 < length; i0 = i1++) {
var v0 = positions[i0];
var v1 = positions[i1];
if (!v0.equals(v1)) {
cleanedPositions.push(v1); // Shallow copy!
}
}
return cleanedPositions;
},
/**
* DOC_TBA
*
* @exception {DeveloperError} positions is required.
* @exception {DeveloperError} At least three positions are required.
*/
computeArea2D : function(positions) {
if (typeof positions === 'undefined') {
throw new DeveloperError('positions is required.');
}
var length = positions.length;
if (length < 3) {
throw new DeveloperError('At least three positions are required.');
}
var area = 0.0;
for ( var i0 = length - 1, i1 = 0; i1 < length; i0 = i1++) {
var v0 = positions[i0];
var v1 = positions[i1];
area += (v0.x * v1.y) - (v1.x * v0.y);
}
return area * 0.5;
},
/**
* DOC_TBA
*
* @return {WindingOrder} DOC_TBA
*
* @exception {DeveloperError} positions is required.
* @exception {DeveloperError} At least three positions are required.
*/
computeWindingOrder2D : function(positions) {
var area = PolygonPipeline.computeArea2D(positions);
return (area >= 0.0) ? WindingOrder.COUNTER_CLOCKWISE : WindingOrder.CLOCKWISE;
},
/**
* DOC_TBA
*
* @exception {DeveloperError} positions is required.
* @exception {DeveloperError} At least three positions are required.
*/
earClip2D : function(positions) {
// PERFORMANCE_IDEA: This is slow at n^3. Make it faster with:
// * http://www.geometrictools.com/Documentation/TriangulationByEarClipping.pdf
// * http://cgm.cs.mcgill.ca/~godfried/publications/triangulation.held.ps.gz
// * http://blogs.agi.com/insight3d/index.php/2008/03/20/triangulation-rhymes-with-strangulation/
if (typeof positions === 'undefined') {
throw new DeveloperError('positions is required.');
}
var length = positions.length;
if (length < 3) {
throw new DeveloperError('At least three positions are required.');
}
var remainingPositions = new DoublyLinkedList();
for ( var i = 0; i < length; ++i) {
remainingPositions.add({
position : positions[i],
index : i
});
}
var indices = [];
var previousNode = remainingPositions.head;
var node = previousNode.next;
var nextNode = node.next;
var bailCount = length * length;
while (remainingPositions.length > 3) {
var p0 = previousNode.item.position;
var p1 = node.item.position;
var p2 = nextNode.item.position;
if (isTipConvex(p0, p1, p2)) {
var isEar = true;
for ( var n = (nextNode.next ? nextNode.next : remainingPositions.head); n !== previousNode; n = (n.next ? n.next : remainingPositions.head)) {
if (pointInsideTriangle2D(n.item.position, p0, p1, p2)) {
isEar = false;
break;
}
}
if (isEar) {
indices.push(previousNode.item.index);
indices.push(node.item.index);
indices.push(nextNode.item.index);
remainingPositions.remove(node);
node = nextNode;
nextNode = nextNode.next ? nextNode.next : remainingPositions.head;
continue;
}
}
previousNode = previousNode.next ? previousNode.next : remainingPositions.head;
node = node.next ? node.next : remainingPositions.head;
nextNode = nextNode.next ? nextNode.next : remainingPositions.head;
if (--bailCount === 0) {
break;
}
}
var n0 = remainingPositions.head;
var n1 = n0.next;
var n2 = n1.next;
indices.push(n0.item.index);
indices.push(n1.item.index);
indices.push(n2.item.index);
return indices;
},
/**
* Subdivides a {@link Polygon} such that no triangles cross the ±180 degree meridian of an ellipsoid.
* @memberof PolygonPipeline
*
* @param {Array} positions The Cartesian positions of triangles that make up a polygon.
* @param {Array} indices The indices of positions in the positions array that make up triangles
*
* @returns {Object} The full set of indices, including those for positions added for newly created triangles
*
* @exception {DeveloperError} positions and indices are required
* @exception {DeveloperError} At least three indices are required.
* @exception {DeveloperError} The number of indices must be divisable by three.
*
* @see Polygon
*
* @example
* var positions = [new Cartesian3(-1, -1, 0), new Cartesian3(-1, 1, 2), new Cartesian3(-1, 2, 2)];
* var indices = [0, 1, 2];
* indices = PolygonPipeline.wrapLongitude(positions, indices);
*/
wrapLongitude : function(positions, indices) {
if ((typeof positions === 'undefined') ||
(typeof indices === 'undefined')) {
throw new DeveloperError('positions and indices are required.');
}
if (indices.length < 3) {
throw new DeveloperError('At least three indices are required.');
}
if (indices.length % 3 !== 0) {
throw new DeveloperError('The number of indices must be divisable by three.');
}
var newIndices = [];
var len = indices.length;
for (var i = 0; i < len; i += 3) {
var i0 = indices[i];
var i1 = indices[i + 1];
var i2 = indices[i + 2];
var p0 = positions[i0];
var p1 = positions[i1];
var p2 = positions[i2];
// In WGS84 coordinates, for a triangle approximately on the
// ellipsoid to cross the IDL, first it needs to be on the
// negative side of the plane x = 0.
if ((p0.x < 0.0) && (p1.x < 0.0) && (p2.x < 0.0)) {
var p0Behind = p0.y < 0.0;
var p1Behind = p1.y < 0.0;
var p2Behind = p2.y < 0.0;
offsetPointFromXZPlane(p0, p0Behind);
offsetPointFromXZPlane(p1, p1Behind);
offsetPointFromXZPlane(p2, p2Behind);
var numBehind = 0;
numBehind += p0Behind ? 1 : 0;
numBehind += p1Behind ? 1 : 0;
numBehind += p2Behind ? 1 : 0;
var u1, u2, v1, v2;
if (numBehind === 1 || numBehind === 2) {
u1 = new Cartesian3();
u2 = new Cartesian3();
v1 = new Cartesian3();
v2 = new Cartesian3();
}
var iu1 = positions.length;
if (numBehind === 1) {
if (p0Behind) {
getXZIntersectionOffsetPoints(p0, p1, u1, v1);
getXZIntersectionOffsetPoints(p0, p2, u2, v2);
positions.push(u1, u2, v1, v2);
newIndices.push(i0, iu1, iu1+1, i1, i2, iu1+3, i1, iu1+3, iu1+2);
} else if (p1Behind) {
getXZIntersectionOffsetPoints(p1, p0, u1, v1);
getXZIntersectionOffsetPoints(p1, p2, u2, v2);
positions.push(u1, u2, v1, v2);
newIndices.push(i1, iu1, iu1+1, i2, i0, iu1+3, i2, iu1+3, iu1+2);
} else if (p2Behind) {
getXZIntersectionOffsetPoints(p2, p0, u1, v1);
getXZIntersectionOffsetPoints(p2, p1, u2, v2);
positions.push(u1, u2, v1, v2);
newIndices.push(i2, iu1, iu1+1, i0, i1, iu1+3, i0, iu1+3, iu1+2);
}
} else if (numBehind === 2) {
if (!p0Behind) {
getXZIntersectionOffsetPoints(p0, p1, u1, v1);
getXZIntersectionOffsetPoints(p0, p2, u2, v2);
positions.push(u1, u2, v1, v2);
newIndices.push(i1, i2, iu1+1, i1, iu1+1, iu1, i0, iu1+2, iu1+3);
} else if (!p1Behind) {
getXZIntersectionOffsetPoints(p1, p2, u1, v1);
getXZIntersectionOffsetPoints(p1, p0, u2, v2);
positions.push(u1, u2, v1, v2);
newIndices.push(i2, i0, iu1+1, i2, iu1+1, iu1, i1, iu1+2, iu1+3);
} else if (!p2Behind) {
getXZIntersectionOffsetPoints(p2, p0, u1, v1);
getXZIntersectionOffsetPoints(p2, p1, u2, v2);
positions.push(u1, u2, v1, v2);
newIndices.push(i0, i1, iu1+1, i0, iu1+1, iu1, i2, iu1+2, iu1+3);
}
} else {
newIndices.push(i0, i1, i2);
}
} else {
newIndices.push(i0, i1, i2);
}
}
return newIndices;
},
/**
* DOC_TBA
*
* @param {DOC_TBA} positions DOC_TBA
* @param {DOC_TBA} indices DOC_TBA
* @param {Number} [granularity] DOC_TBA
*
* @exception {DeveloperError} positions is required.
* @exception {DeveloperError} indices is required.
* @exception {DeveloperError} At least three indices are required.
* @exception {DeveloperError} The number of indices must be divisable by three.
* @exception {DeveloperError} Granularity must be greater than zero.
*/
computeSubdivision : function(positions, indices, granularity) {
if (typeof positions === 'undefined') {
throw new DeveloperError('positions is required.');
}
if (typeof indices === 'undefined') {
throw new DeveloperError('indices is required.');
}
if (indices.length < 3) {
throw new DeveloperError('At least three indices are required.');
}
if (indices.length % 3 !== 0) {
throw new DeveloperError('The number of indices must be divisable by three.');
}
granularity = defaultValue(granularity, CesiumMath.toRadians(1.0));
if (granularity <= 0.0) {
throw new DeveloperError('granularity must be greater than zero.');
}
// Use a queue for triangles that need (or might need) to be subdivided.
var triangles = new Queue();
var indicesLength = indices.length;
for ( var j = 0; j < indicesLength; j += 3) {
triangles.enqueue({
i0 : indices[j],
i1 : indices[j + 1],
i2 : indices[j + 2]
});
}
// New positions due to edge splits are appended to the positions list.
var subdividedPositions = positions.slice(0); // shadow copy!
var subdividedIndices = [];
// Used to make sure shared edges are not split more than once.
var edges = {};
var i;
while (triangles.length > 0) {
var triangle = triangles.dequeue();
var v0 = subdividedPositions[triangle.i0];
var v1 = subdividedPositions[triangle.i1];
var v2 = subdividedPositions[triangle.i2];
var g0 = v0.angleBetween(v1);
var g1 = v1.angleBetween(v2);
var g2 = v2.angleBetween(v0);
var max = Math.max(g0, Math.max(g1, g2));
var edge;
if (max > granularity) {
if (g0 === max) {
edge = Math.min(triangle.i0, triangle.i1).toString() + ' ' + Math.max(triangle.i0, triangle.i1).toString();
i = edges[edge];
if (!i) {
subdividedPositions.push(v0.add(v1).multiplyByScalar(0.5));
i = subdividedPositions.length - 1;
edges[edge] = i;
}
triangles.enqueue({
i0 : triangle.i0,
i1 : i,
i2 : triangle.i2
});
triangles.enqueue({
i0 : i,
i1 : triangle.i1,
i2 : triangle.i2
});
} else if (g1 === max) {
edge = Math.min(triangle.i1, triangle.i2).toString() + ' ' + Math.max(triangle.i1, triangle.i2).toString();
i = edges[edge];
if (!i) {
subdividedPositions.push(v1.add(v2).multiplyByScalar(0.5));
i = subdividedPositions.length - 1;
edges[edge] = i;
}
triangles.enqueue({
i0 : triangle.i1,
i1 : i,
i2 : triangle.i0
});
triangles.enqueue({
i0 : i,
i1 : triangle.i2,
i2 : triangle.i0
});
} else if (g2 === max) {
edge = Math.min(triangle.i2, triangle.i0).toString() + ' ' + Math.max(triangle.i2, triangle.i0).toString();
i = edges[edge];
if (!i) {
subdividedPositions.push(v2.add(v0).multiplyByScalar(0.5));
i = subdividedPositions.length - 1;
edges[edge] = i;
}
triangles.enqueue({
i0 : triangle.i2,
i1 : i,
i2 : triangle.i1
});
triangles.enqueue({
i0 : i,
i1 : triangle.i0,
i2 : triangle.i1
});
}
} else {
subdividedIndices.push(triangle.i0);
subdividedIndices.push(triangle.i1);
subdividedIndices.push(triangle.i2);
}
}
// PERFORMANCE_IDEA Rather that waste time re-iterating the entire set of positions
// here, all of the above code can be refactored to flatten as values are added
// Removing the need for this for loop.
var length = subdividedPositions.length;
var flattenedPositions = new Array(length * 3);
var q = 0;
for (i = 0; i < length; i++) {
var item = subdividedPositions[i];
flattenedPositions[q++] = item.x;
flattenedPositions[q++] = item.y;
flattenedPositions[q++] = item.z;
}
return {
attributes : {
position : {
componentDatatype : ComponentDatatype.FLOAT,
componentsPerAttribute : 3,
values : flattenedPositions
}
},
indexLists : [{
primitiveType : PrimitiveType.TRIANGLES,
values : subdividedIndices
}]
};
},
/**
* DOC_TBA
*
* @exception {DeveloperError} ellipsoid is required.
*/
scaleToGeodeticHeight : function(mesh, height, ellipsoid) {
ellipsoid = defaultValue(ellipsoid, Ellipsoid.WGS84);
var n = scaleToGeodeticHeightN;
var p = scaleToGeodeticHeightP;
height = defaultValue(height, 0.0);
if (typeof mesh !== 'undefined' && typeof mesh.attributes !== 'undefined' && typeof mesh.attributes.position !== 'undefined') {
var positions = mesh.attributes.position.values;
var length = positions.length;
for ( var i = 0; i < length; i += 3) {
p.x = positions[i];
p.y = positions[i + 1];
p.z = positions[i + 2];
ellipsoid.scaleToGeodeticSurface(p, p);
ellipsoid.geodeticSurfaceNormal(p, n);
Cartesian3.multiplyByScalar(n, height, n);
Cartesian3.add(p, n, p);
positions[i] = p.x;
positions[i + 1] = p.y;
positions[i + 2] = p.z;
}
}
return mesh;
},
/**
* Given a polygon defined by an outer ring with one or more inner rings (holes), return a single list of points representing
* a polygon defined by the outer ring with the inner holes removed.
*
* @param {Array} outerRing An array of Cartesian points defining the outer boundary of the polygon.
* @param {Array} innerRings An array of arrays of Cartesian points, where each array represents a hole in the polygon.
*
* @return A single list of Cartesian points defining the polygon, including the eliminated inner ring.
*
* @exception {DeveloperError} <code>outerRing</code> is required.
* @exception {DeveloperError} <code>outerRing</code> must not be empty.
* @exception {DeveloperError} <code>innerRings</code> is required.
*
* @example
* // Simplifying a polygon with multiple holes.
* outerRing = PolygonPipeline.eliminateHoles(outerRing, innerRings);
* polygon.setPositions(outerRing);
*/
eliminateHoles : function(outerRing, innerRings, ellipsoid) {
if (typeof outerRing === 'undefined') {
throw new DeveloperError('outerRing is required.');
}
if (outerRing.length === 0) {
throw new DeveloperError('outerRing must not be empty.');
}
if (typeof innerRings === 'undefined') {
throw new DeveloperError('innerRings is required.');
}
ellipsoid = defaultValue(ellipsoid, Ellipsoid.WGS84);
var innerRingsCopy = [];
for ( var i = 0; i < innerRings.length; i++) {
var innerRing = [];
for ( var j = 0; j < innerRings[i].length; j++) {
innerRing.push(Cartesian3.clone(innerRings[i][j]));
}
innerRingsCopy.push(innerRing);
}
var newPolygonVertices = outerRing;
while (innerRingsCopy.length > 0) {
newPolygonVertices = eliminateHole(newPolygonVertices, innerRingsCopy, ellipsoid);
}
return newPolygonVertices;
}
};
return PolygonPipeline;
});