us and next vertex nodes in a polygon ring this.prev = null; this.next = null; // z-order curve value this.z = 0; // previous and next nodes in z-order this.prevZ = null; this.nextZ = null; // indicates whether this is a steiner point this.steiner = false; } function signedArea( data, start, end, dim ) { let sum = 0; for ( let i = start, j = end - dim; i < end; i += dim ) { sum += ( data[ j ] - data[ i ] ) * ( data[ i + 1 ] + data[ j + 1 ] ); j = i; } return sum; } class ShapeUtils { // calculate area of the contour polygon static area( contour ) { const n = contour.length; let a = 0.0; for ( let 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; } static isClockWise( pts ) { return ShapeUtils.area( pts ) < 0; } static triangulateShape( contour, holes ) { const vertices = []; // flat array of vertices like [ x0,y0, x1,y1, x2,y2, ... ] const holeIndices = []; // array of hole indices const faces = []; // final array of vertex indices like [ [ a,b,d ], [ b,c,d ] ] removeDupEndPts( contour ); addContour( vertices, contour ); // let holeIndex = contour.length; holes.forEach( removeDupEndPts ); for ( let i = 0; i < holes.length; i ++ ) { holeIndices.push( holeIndex ); holeIndex += holes[ i ].length; addContour( vertices, holes[ i ] ); } // const triangles = Earcut.triangulate( vertices, holeIndices ); // for ( let i = 0; i < triangles.length; i += 3 ) { faces.push( triangles.slice( i, i + 3 ) ); } return faces; } } function removeDupEndPts( points ) { const l = points.length; if ( l > 2 && points[ l - 1 ].equals( points[ 0 ] ) ) { points.pop(); } } function addContour( vertices, contour ) { for ( let i = 0; i < contour.length; i ++ ) { vertices.push( contour[ i ].x ); vertices.push( contour[ i ].y ); } } /** * Creates extruded geometry from a path shape. * * parameters = { * * curveSegments: , // number of points on the curves * steps: , // number of points for z-side extrusions / used for subdividing segments of extrude spline too * depth: , // Depth to extrude the shape * * bevelEnabled: , // turn on bevel * bevelThickness: , // how deep into the original shape bevel goes * bevelSize: , // how far from shape outline (including bevelOffset) is bevel * bevelOffset: , // how far from shape outline does bevel start * bevelSegments: , // number of bevel layers * * extrudePath: // curve to extrude shape along * * UVGenerator: