webvr js meetup initial commit

node_modules/three/examples/js/utils/GeometryUtils.js

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