mirror of
https://github.com/Doodle3D/Doodle3D-Slicer.git
synced 2024-09-06 12:16:20 +02:00
301 lines
6.0 KiB
JavaScript
301 lines
6.0 KiB
JavaScript
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/**
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* @author mrdoob / http://mrdoob.com/
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* @author alteredq / http://alteredqualia.com/
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*/
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THREE.GeometryUtils = {
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// Merge two geometries or geometry and geometry from object (using object's transform)
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merge: function ( geometry1, geometry2, materialIndexOffset ) {
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console.warn( 'THREE.GeometryUtils: .merge() has been moved to Geometry. Use geometry.merge( geometry2, matrix, materialIndexOffset ) instead.' );
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var matrix;
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if ( geometry2 instanceof THREE.Mesh ) {
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geometry2.matrixAutoUpdate && geometry2.updateMatrix();
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matrix = geometry2.matrix;
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geometry2 = geometry2.geometry;
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}
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geometry1.merge( geometry2, matrix, materialIndexOffset );
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},
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// Get random point in triangle (via barycentric coordinates)
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// (uniform distribution)
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// http://www.cgafaq.info/wiki/Random_Point_In_Triangle
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randomPointInTriangle: function () {
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var vector = new THREE.Vector3();
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return function ( vectorA, vectorB, vectorC ) {
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var point = new THREE.Vector3();
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var a = THREE.Math.random16();
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var b = THREE.Math.random16();
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if ( ( a + b ) > 1 ) {
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a = 1 - a;
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b = 1 - b;
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}
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var c = 1 - a - b;
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point.copy( vectorA );
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point.multiplyScalar( a );
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vector.copy( vectorB );
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vector.multiplyScalar( b );
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point.add( vector );
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vector.copy( vectorC );
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vector.multiplyScalar( c );
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point.add( vector );
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return point;
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};
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}(),
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// Get random point in face (triangle)
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// (uniform distribution)
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randomPointInFace: function ( face, geometry ) {
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var vA, vB, vC;
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vA = geometry.vertices[ face.a ];
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vB = geometry.vertices[ face.b ];
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vC = geometry.vertices[ face.c ];
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return THREE.GeometryUtils.randomPointInTriangle( vA, vB, vC );
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},
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// Get uniformly distributed random points in mesh
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// - create array with cumulative sums of face areas
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// - pick random number from 0 to total area
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// - find corresponding place in area array by binary search
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// - get random point in face
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randomPointsInGeometry: function ( geometry, n ) {
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var face, i,
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faces = geometry.faces,
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vertices = geometry.vertices,
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il = faces.length,
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totalArea = 0,
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cumulativeAreas = [],
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vA, vB, vC;
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// precompute face areas
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for ( i = 0; i < il; i ++ ) {
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face = faces[ i ];
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vA = vertices[ face.a ];
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vB = vertices[ face.b ];
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vC = vertices[ face.c ];
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face._area = THREE.GeometryUtils.triangleArea( vA, vB, vC );
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totalArea += face._area;
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cumulativeAreas[ i ] = totalArea;
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}
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// binary search cumulative areas array
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function binarySearchIndices( value ) {
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function binarySearch( start, end ) {
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// return closest larger index
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// if exact number is not found
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if ( end < start )
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return start;
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var mid = start + Math.floor( ( end - start ) / 2 );
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if ( cumulativeAreas[ mid ] > value ) {
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return binarySearch( start, mid - 1 );
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} else if ( cumulativeAreas[ mid ] < value ) {
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return binarySearch( mid + 1, end );
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} else {
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return mid;
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}
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}
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var result = binarySearch( 0, cumulativeAreas.length - 1 )
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return result;
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}
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// pick random face weighted by face area
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var r, index,
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result = [];
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var stats = {};
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for ( i = 0; i < n; i ++ ) {
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r = THREE.Math.random16() * totalArea;
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index = binarySearchIndices( r );
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result[ i ] = THREE.GeometryUtils.randomPointInFace( faces[ index ], geometry );
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if ( ! stats[ index ] ) {
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stats[ index ] = 1;
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} else {
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stats[ index ] += 1;
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}
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}
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return result;
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},
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randomPointsInBufferGeometry: function ( geometry, n ) {
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var i,
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vertices = geometry.attributes.position.array,
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totalArea = 0,
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cumulativeAreas = [],
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vA, vB, vC;
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// precompute face areas
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vA = new THREE.Vector3();
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vB = new THREE.Vector3();
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vC = new THREE.Vector3();
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// geometry._areas = [];
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var il = vertices.length / 9;
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for ( i = 0; i < il; i ++ ) {
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vA.set( vertices[i * 9 + 0], vertices[i * 9 + 1], vertices[i * 9 + 2] );
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vB.set( vertices[i * 9 + 3], vertices[i * 9 + 4], vertices[i * 9 + 5] );
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vC.set( vertices[i * 9 + 6], vertices[i * 9 + 7], vertices[i * 9 + 8] );
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area = THREE.GeometryUtils.triangleArea( vA, vB, vC );
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totalArea += area;
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cumulativeAreas.push(totalArea);
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}
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// binary search cumulative areas array
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function binarySearchIndices( value ) {
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function binarySearch( start, end ) {
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// return closest larger index
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// if exact number is not found
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if ( end < start )
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return start;
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var mid = start + Math.floor( ( end - start ) / 2 );
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if ( cumulativeAreas[ mid ] > value ) {
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return binarySearch( start, mid - 1 );
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} else if ( cumulativeAreas[ mid ] < value ) {
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return binarySearch( mid + 1, end );
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} else {
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return mid;
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}
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}
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var result = binarySearch( 0, cumulativeAreas.length - 1 )
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return result;
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}
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// pick random face weighted by face area
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var r, index,
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result = [];
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for ( i = 0; i < n; i ++ ) {
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r = THREE.Math.random16() * totalArea;
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index = binarySearchIndices( r );
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// result[ i ] = THREE.GeometryUtils.randomPointInFace( faces[ index ], geometry, true );
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vA.set( vertices[index * 9 + 0], vertices[index * 9 + 1], vertices[index * 9 + 2] );
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vB.set( vertices[index * 9 + 3], vertices[index * 9 + 4], vertices[index * 9 + 5] );
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vC.set( vertices[index * 9 + 6], vertices[index * 9 + 7], vertices[index * 9 + 8] );
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result[ i ] = THREE.GeometryUtils.randomPointInTriangle( vA, vB, vC );
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}
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return result;
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},
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// Get triangle area (half of parallelogram)
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// http://mathworld.wolfram.com/TriangleArea.html
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triangleArea: function () {
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var vector1 = new THREE.Vector3();
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var vector2 = new THREE.Vector3();
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return function ( vectorA, vectorB, vectorC ) {
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vector1.subVectors( vectorB, vectorA );
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vector2.subVectors( vectorC, vectorA );
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vector1.cross( vector2 );
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return 0.5 * vector1.length();
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};
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}(),
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center: function ( geometry ) {
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console.warn( 'THREE.GeometryUtils: .center() has been moved to Geometry. Use geometry.center() instead.' );
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return geometry.center();
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}
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};
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