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4 |
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5 | import { Earcut } from './Earcut.js';
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6 |
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7 | var ShapeUtils = {
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8 |
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9 |
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10 |
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11 | area: function ( contour ) {
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12 |
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13 | var n = contour.length;
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14 | var a = 0.0;
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15 |
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16 | for ( var p = n - 1, q = 0; q < n; p = q ++ ) {
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17 |
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18 | a += contour[ p ].x * contour[ q ].y - contour[ q ].x * contour[ p ].y;
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19 |
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20 | }
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21 |
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22 | return a * 0.5;
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23 |
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24 | },
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25 |
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26 | isClockWise: function ( pts ) {
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27 |
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28 | return ShapeUtils.area( pts ) < 0;
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29 |
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30 | },
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31 |
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32 | triangulateShape: function ( contour, holes ) {
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33 |
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34 | var vertices = [];
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35 | var holeIndices = [];
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36 | var faces = [];
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37 |
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38 | removeDupEndPts( contour );
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39 | addContour( vertices, contour );
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40 |
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41 |
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42 |
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43 | var holeIndex = contour.length;
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44 |
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45 | holes.forEach( removeDupEndPts );
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46 |
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47 | for ( var i = 0; i < holes.length; i ++ ) {
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48 |
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49 | holeIndices.push( holeIndex );
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50 | holeIndex += holes[ i ].length;
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51 | addContour( vertices, holes[ i ] );
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52 |
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53 | }
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54 |
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55 |
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56 |
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57 | var triangles = Earcut.triangulate( vertices, holeIndices );
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58 |
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59 |
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60 |
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61 | for ( var i = 0; i < triangles.length; i += 3 ) {
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62 |
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63 | faces.push( triangles.slice( i, i + 3 ) );
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64 |
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65 | }
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66 |
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67 | return faces;
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68 |
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69 | }
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70 |
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71 | };
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72 |
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73 | function removeDupEndPts( points ) {
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74 |
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75 | var l = points.length;
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76 |
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77 | if ( l > 2 && points[ l - 1 ].equals( points[ 0 ] ) ) {
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78 |
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79 | points.pop();
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80 |
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81 | }
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82 |
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83 | }
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84 |
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85 | function addContour( vertices, contour ) {
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86 |
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87 | for ( var i = 0; i < contour.length; i ++ ) {
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88 |
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89 | vertices.push( contour[ i ].x );
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90 | vertices.push( contour[ i ].y );
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91 |
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92 | }
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93 |
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94 | }
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95 |
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96 | export { ShapeUtils };
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