mirror of
https://github.com/Doodle3D/Doodle3D-Slicer.git
synced 2024-11-30 01:14:57 +01:00
343 lines
7.9 KiB
JavaScript
Executable File
343 lines
7.9 KiB
JavaScript
Executable File
/*
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* @author zz85 / http://twitter.com/blurspline / http://www.lab4games.net/zz85/blog
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*
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* Subdivision Geometry Modifier
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* using Loop Subdivision Scheme
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*
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* References:
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* http://graphics.stanford.edu/~mdfisher/subdivision.html
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* http://www.holmes3d.net/graphics/subdivision/
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* http://www.cs.rutgers.edu/~decarlo/readings/subdiv-sg00c.pdf
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*
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* Known Issues:
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* - currently doesn't handle UVs
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* - currently doesn't handle "Sharp Edges"
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*
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*/
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THREE.SubdivisionModifier = function ( subdivisions ) {
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this.subdivisions = (subdivisions === undefined ) ? 1 : subdivisions;
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};
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// Applies the "modify" pattern
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THREE.SubdivisionModifier.prototype.modify = function ( geometry ) {
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var repeats = this.subdivisions;
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while ( repeats -- > 0 ) {
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this.smooth( geometry );
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}
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delete geometry.__tmpVertices;
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geometry.computeFaceNormals();
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geometry.computeVertexNormals();
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};
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(function() {
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// Some constants
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var WARNINGS = !true; // Set to true for development
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var ABC = [ 'a', 'b', 'c' ];
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function getEdge( a, b, map ) {
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var vertexIndexA = Math.min( a, b );
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var vertexIndexB = Math.max( a, b );
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var key = vertexIndexA + "_" + vertexIndexB;
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return map[ key ];
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}
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function processEdge( a, b, vertices, map, face, metaVertices ) {
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var vertexIndexA = Math.min( a, b );
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var vertexIndexB = Math.max( a, b );
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var key = vertexIndexA + "_" + vertexIndexB;
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var edge;
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if ( key in map ) {
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edge = map[ key ];
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} else {
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var vertexA = vertices[ vertexIndexA ];
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var vertexB = vertices[ vertexIndexB ];
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edge = {
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a: vertexA, // pointer reference
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b: vertexB,
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newEdge: null,
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// aIndex: a, // numbered reference
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// bIndex: b,
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faces: [] // pointers to face
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};
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map[ key ] = edge;
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}
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edge.faces.push( face );
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metaVertices[ a ].edges.push( edge );
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metaVertices[ b ].edges.push( edge );
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}
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function generateLookups( vertices, faces, metaVertices, edges ) {
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var i, il, face, edge;
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for ( i = 0, il = vertices.length; i < il; i ++ ) {
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metaVertices[ i ] = { edges: [] };
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}
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for ( i = 0, il = faces.length; i < il; i ++ ) {
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face = faces[ i ];
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processEdge( face.a, face.b, vertices, edges, face, metaVertices );
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processEdge( face.b, face.c, vertices, edges, face, metaVertices );
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processEdge( face.c, face.a, vertices, edges, face, metaVertices );
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}
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}
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function newFace( newFaces, a, b, c ) {
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newFaces.push( new THREE.Face3( a, b, c ) );
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}
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/////////////////////////////
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// Performs one iteration of Subdivision
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THREE.SubdivisionModifier.prototype.smooth = function ( geometry ) {
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var tmp = new THREE.Vector3();
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var oldVertices, oldFaces;
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var newVertices, newFaces; // newUVs = [];
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var n, l, i, il, j, k;
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var metaVertices, sourceEdges;
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// new stuff.
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var sourceEdges, newEdgeVertices, newSourceVertices
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oldVertices = geometry.vertices; // { x, y, z}
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oldFaces = geometry.faces; // { a: oldVertex1, b: oldVertex2, c: oldVertex3 }
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/******************************************************
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*
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* Step 0: Preprocess Geometry to Generate edges Lookup
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*
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*******************************************************/
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metaVertices = new Array( oldVertices.length );
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sourceEdges = {}; // Edge => { oldVertex1, oldVertex2, faces[] }
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generateLookups(oldVertices, oldFaces, metaVertices, sourceEdges);
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/******************************************************
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*
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* Step 1.
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* For each edge, create a new Edge Vertex,
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* then position it.
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*
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*******************************************************/
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newEdgeVertices = [];
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var other, currentEdge, newEdge, face;
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var edgeVertexWeight, adjacentVertexWeight, connectedFaces;
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for ( i in sourceEdges ) {
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currentEdge = sourceEdges[ i ];
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newEdge = new THREE.Vector3();
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edgeVertexWeight = 3 / 8;
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adjacentVertexWeight = 1 / 8;
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connectedFaces = currentEdge.faces.length;
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// check how many linked faces. 2 should be correct.
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if ( connectedFaces != 2 ) {
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// if length is not 2, handle condition
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edgeVertexWeight = 0.5;
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adjacentVertexWeight = 0;
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if ( connectedFaces != 1 ) {
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if (WARNINGS) console.warn('Subdivision Modifier: Number of connected faces != 2, is: ', connectedFaces, currentEdge);
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}
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}
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newEdge.addVectors( currentEdge.a, currentEdge.b ).multiplyScalar( edgeVertexWeight );
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tmp.set( 0, 0, 0 );
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for ( j = 0; j < connectedFaces; j ++ ) {
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face = currentEdge.faces[ j ];
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for ( k = 0; k < 3; k ++ ) {
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other = oldVertices[ face[ ABC[k] ] ];
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if (other !== currentEdge.a && other !== currentEdge.b ) break;
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}
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tmp.add( other );
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}
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tmp.multiplyScalar( adjacentVertexWeight );
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newEdge.add( tmp );
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currentEdge.newEdge = newEdgeVertices.length;
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newEdgeVertices.push(newEdge);
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// console.log(currentEdge, newEdge);
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}
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/******************************************************
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*
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* Step 2.
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* Reposition each source vertices.
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*
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*******************************************************/
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var beta, sourceVertexWeight, connectingVertexWeight;
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var connectingEdge, connectingEdges, oldVertex, newSourceVertex;
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newSourceVertices = [];
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for ( i = 0, il = oldVertices.length; i < il; i ++ ) {
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oldVertex = oldVertices[ i ];
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// find all connecting edges (using lookupTable)
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connectingEdges = metaVertices[ i ].edges;
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n = connectingEdges.length;
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beta;
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if ( n == 3 ) {
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beta = 3 / 16;
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} else if ( n > 3 ) {
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beta = 3 / ( 8 * n ); // Warren's modified formula
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}
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// Loop's original beta formula
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// beta = 1 / n * ( 5/8 - Math.pow( 3/8 + 1/4 * Math.cos( 2 * Math. PI / n ), 2) );
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sourceVertexWeight = 1 - n * beta;
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connectingVertexWeight = beta;
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if ( n <= 2 ) {
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// crease and boundary rules
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// console.warn('crease and boundary rules');
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if ( n == 2 ) {
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if (WARNINGS) console.warn('2 connecting edges', connectingEdges);
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sourceVertexWeight = 3 / 4;
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connectingVertexWeight = 1 / 8;
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// sourceVertexWeight = 1;
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// connectingVertexWeight = 0;
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} else if ( n == 1 ) {
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if (WARNINGS) console.warn('only 1 connecting edge');
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} else if ( n == 0 ) {
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if (WARNINGS) console.warn('0 connecting edges');
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}
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}
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newSourceVertex = oldVertex.clone().multiplyScalar( sourceVertexWeight );
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tmp.set( 0, 0, 0 );
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for ( j = 0; j < n; j ++ ) {
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connectingEdge = connectingEdges[ j ];
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other = connectingEdge.a !== oldVertex ? connectingEdge.a : connectingEdge.b;
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tmp.add( other );
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}
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tmp.multiplyScalar( connectingVertexWeight );
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newSourceVertex.add( tmp );
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newSourceVertices.push( newSourceVertex );
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}
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/******************************************************
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*
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* Step 3.
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* Generate Faces between source vertecies
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* and edge vertices.
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*
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*******************************************************/
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newVertices = newSourceVertices.concat( newEdgeVertices );
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var sl = newSourceVertices.length, edge1, edge2, edge3;
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newFaces = [];
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for ( i = 0, il = oldFaces.length; i < il; i ++ ) {
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face = oldFaces[ i ];
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// find the 3 new edges vertex of each old face
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edge1 = getEdge( face.a, face.b, sourceEdges ).newEdge + sl;
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edge2 = getEdge( face.b, face.c, sourceEdges ).newEdge + sl;
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edge3 = getEdge( face.c, face.a, sourceEdges ).newEdge + sl;
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// create 4 faces.
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newFace( newFaces, edge1, edge2, edge3 );
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newFace( newFaces, face.a, edge1, edge3 );
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newFace( newFaces, face.b, edge2, edge1 );
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newFace( newFaces, face.c, edge3, edge2 );
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}
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// Overwrite old arrays
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geometry.vertices = newVertices;
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geometry.faces = newFaces;
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// console.log('done');
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};
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})(); |