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/**
* @author zz85 / http://www.lab4games.net/zz85/blog
*/
import { Earcut } from './Earcut.js';
var ShapeUtils = {
// calculate area of the contour polygon
area: function ( contour ) {
var n = contour.length;
var a = 0.0;
for ( var p = n - 1, q = 0; q < n; p = q ++ ) {
a += contour[ p ].x * contour[ q ].y - contour[ q ].x * contour[ p ].y;
}
return a * 0.5;
},
isClockWise: function ( pts ) {
return ShapeUtils.area( pts ) < 0;
},
triangulateShape: function ( contour, holes ) {
var vertices = []; // flat array of vertices like [ x0,y0, x1,y1, x2,y2, ... ]
var holeIndices = []; // array of hole indices
var faces = []; // final array of vertex indices like [ [ a,b,d ], [ b,c,d ] ]
removeDupEndPts( contour );
addContour( vertices, contour );
//
var holeIndex = contour.length;
holes.forEach( removeDupEndPts );
for ( var i = 0; i < holes.length; i ++ ) {
holeIndices.push( holeIndex );
holeIndex += holes[ i ].length;
addContour( vertices, holes[ i ] );
}
//
var triangles = Earcut.triangulate( vertices, holeIndices );
//
for ( var i = 0; i < triangles.length; i += 3 ) {
faces.push( triangles.slice( i, i + 3 ) );
}
return faces;
}
};
function removeDupEndPts( points ) {
var l = points.length;
if ( l > 2 && points[ l - 1 ].equals( points[ 0 ] ) ) {
points.pop();
}
}
function addContour( vertices, contour ) {
for ( var i = 0; i < contour.length; i ++ ) {
vertices.push( contour[ i ].x );
vertices.push( contour[ i ].y );
}
}
export { ShapeUtils };
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