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SLAcer.js/vendor/triangulation.js
8424d63 Mar 18, 2016
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320 lines (186 sloc) 6.83 KB
'use strict';
if ( ! window.THREE ) throw new Error( 'ERROR: three.js not loaded' );
THREE.Triangulation = ( function() {
var timer = false;
var library = 'original';
/**
* Names of the supported libraries
*
* @type {{original: string, earcut: string, poly2tri: string, libtess: string}}
*/
var libraries = {
original: 'original',
earcut: 'earcut',
poly2tri: 'poly2tri',
libtess: 'libtess'
};
/**
* Container object for holding the different library adapters
*
* @type {{}}
*/
var adapters = {};
adapters[ libraries.original ] = {
triangulate: THREE.ShapeUtils.triangulate,
triangulateShape: THREE.ShapeUtils.triangulateShape
};
adapters[ libraries.earcut ] = {
triangulateShape: function( contour, holes ) {
var i, il, dim = 2, array;
var holeIndices = [];
var points = [];
addPoints( contour );
for ( i = 0, il = holes.length; i < il; i ++ ) {
holeIndices.push( points.length / dim );
addPoints( holes[ i ] );
}
array = earcut( points, holeIndices, dim );
var result = [];
for ( i = 0, il = array.length; i < il; i += 3 ) {
result.push( array.slice( i, i + 3 ) );
}
return result;
function addPoints( a ) {
var i, il = a.length;
for ( i = 0; i < il; i ++ ) {
points.push( a[ i ].x, a[ i ].y );
}
}
}
};
adapters[ libraries.poly2tri ] = {
triangulateShape: function( contour, holes ) {
var i, il, object, sweepContext, triangles;
var pointMap = {}, count = 0;
points = makePoints( contour );
sweepContext = new poly2tri.SweepContext( points );
for ( i = 0, il = holes.length; i < il; i ++ ) {
points = makePoints( holes[ i ] );
sweepContext.addHole( points );
points = points.concat( points );
}
object = sweepContext.triangulate();
triangles = object.triangles_;
var a, b, c, points, result = [];
for ( i = 0, il = triangles.length; i < il; i ++ ) {
points = triangles[ i ].points_;
a = pointMap[ points[ 0 ].x + ',' + points[ 0 ].y ];
b = pointMap[ points[ 1 ].x + ',' + points[ 1 ].y ];
c = pointMap[ points[ 2 ].x + ',' + points[ 2 ].y ];
result.push( [ a, b, c ] );
}
return result;
function makePoints( a ) {
var i, il = a.length,
points = [];
for ( i = 0; i < il; i ++ ) {
points.push( new poly2tri.Point( a[ i ].x, a[ i ].y ) );
pointMap[ a[ i ].x + ',' + a[ i ].y ] = count;
count ++;
}
return points;
}
}
};
adapters[ libraries.libtess ] = {
triangulateShape: function( contour, holes ) {
var i, il, triangles = [];
var pointMap = {}, count = 0;
// libtess will take 3d verts and flatten to a plane for tesselation
// since only doing 2d tesselation here, provide z=1 normal to skip
// iterating over verts only to get the same answer.
// comment out to test normal-generation code
tessy.gluTessNormal( 0, 0, 1 );
tessy.gluTessBeginPolygon( triangles );
points = makePoints( contour );
for ( i = 0, il = holes.length; i < il; i ++ ) {
points = makePoints( holes[ i ] );
}
tessy.gluTessEndPolygon();
var a, b, c, points, result = [];
for ( i = 0, il = triangles.length; i < il; i += 6 ) {
a = pointMap[ triangles[ i ] + ',' + triangles[ i + 1 ]];
b = pointMap[ triangles[ i + 2 ] + ',' + triangles[ i + 3 ]];
c = pointMap[ triangles[ i + 4 ] + ',' + triangles[ i + 5 ]];
result.push( [ a, b, c ] );
}
return result;
function makePoints( a ) {
var i, il = a.length,
coordinates;
tessy.gluTessBeginContour();
for ( i = 0; i < il; i ++ ) {
coordinates = [ a[ i ].x, a[ i ].y, 0 ];
tessy.gluTessVertex( coordinates, coordinates );
pointMap[ a[ i ].x + ',' + a[ i ].y ] = count;
count ++;
}
tessy.gluTessEndContour();
return points;
}
}
};
/**
* Initialize the library by attaching the triangulation methods to the three.js API
*/
function init() {
checkDependencies( library );
if ( timer ) {
THREE.ShapeUtils.triangulate = function() {
return adapters[ library ].triangulate.apply( this, arguments );
};
THREE.ShapeUtils.triangulateShape = function() {
console.time( library );
var result = adapters[ library ].triangulateShape.apply( this, arguments );
console.timeEnd( library );
return result;
};
} else {
THREE.ShapeUtils.triangulate = adapters[ library ].triangulate;
THREE.ShapeUtils.triangulateShape = adapters[ library ].triangulateShape;
}
}
/**
* Checks dependencies needed for the current library
*
* @param library
*/
function checkDependencies( library ) {
switch ( library ) {
case libraries.earcut:
if ( ! window.earcut ) throw new Error( 'ERROR: earcut not loaded' );
break;
case libraries.poly2tri:
if ( ! window.poly2tri ) throw new Error( 'ERROR: poly2tri not loaded' );
break;
case libraries.libtess:
if ( ! window.tessy ) throw new Error( 'ERROR: libtess not loaded' );
break;
}
}
/**
* Set the current triangulation library
*
* @param name
*/
function setLibrary( name ) {
if ( ! libraries.hasOwnProperty( name ) ) throw new Error( 'ERROR: unknown library ' + name );
library = name;
init();
}
/**
* Set timer for triangulation on/off
*
* @param boolean
*/
function setTimer( boolean ) {
timer = boolean;
init();
}
init();
return {
libraries: libraries,
setTimer: setTimer,
setLibrary: setLibrary
};
} )();