three.js/src/math/Box3.js

/**
 * @author bhouston / http://clara.io
 * @author WestLangley / http://github.com/WestLangley
 */

THREE.Box3 = function ( min, max ) {

	this.min = ( min !== undefined ) ? min : new THREE.Vector3( + Infinity, + Infinity, + Infinity );
	this.max = ( max !== undefined ) ? max : new THREE.Vector3( - Infinity, - Infinity, - Infinity );

};

THREE.Box3.prototype = {

	constructor: THREE.Box3,

	set: function ( min, max ) {

		this.min.copy( min );
		this.max.copy( max );

		return this;

	},

	setFromArray: function ( array ) {

		this.makeEmpty();

		var minX = + Infinity;
		var minY = + Infinity;
		var minZ = + Infinity;

		var maxX = - Infinity;
		var maxY = - Infinity;
		var maxZ = - Infinity;

		for ( var i = 0, il = array.length; i < il; i += 3 ) {

			var x = array[ i ];
			var y = array[ i + 1 ];
			var z = array[ i + 2 ];

			if ( x < minX ) minX = x;
			if ( y < minY ) minY = y;
			if ( z < minZ ) minZ = z;

			if ( x > maxX ) maxX = x;
			if ( y > maxY ) maxY = y;
			if ( z > maxZ ) maxZ = z;

		}

		this.min.set( minX, minY, minZ );
		this.max.set( maxX, maxY, maxZ );

	},

	setFromPoints: function ( points ) {

		this.makeEmpty();

		for ( var i = 0, il = points.length; i < il; i ++ ) {

			this.expandByPoint( points[ i ] );

		}

		return this;

	},

	setFromCenterAndSize: function () {

		var v1 = new THREE.Vector3();

		return function ( center, size ) {

			var halfSize = v1.copy( size ).multiplyScalar( 0.5 );

			this.min.copy( center ).sub( halfSize );
			this.max.copy( center ).add( halfSize );

			return this;

		};

	}(),

	setFromObject: function () {

		// Computes the world-axis-aligned bounding box of an object (including its children),
		// accounting for both the object's, and children's, world transforms

		var v1 = new THREE.Vector3();

		return function ( object ) {

			var scope = this;

			object.updateMatrixWorld( true );

			this.makeEmpty();

			object.traverse( function ( node ) {

				var geometry = node.geometry;

				if ( geometry !== undefined ) {

					if ( geometry instanceof THREE.Geometry ) {

						var vertices = geometry.vertices;

						for ( var i = 0, il = vertices.length; i < il; i ++ ) {

							v1.copy( vertices[ i ] );
							v1.applyMatrix4( node.matrixWorld );

							scope.expandByPoint( v1 );

						}

					} else if ( geometry instanceof THREE.BufferGeometry && geometry.attributes[ 'position' ] !== undefined ) {

						var positions = geometry.attributes[ 'position' ].array;

						for ( var i = 0, il = positions.length; i < il; i += 3 ) {

							v1.fromArray( positions, i );
							v1.applyMatrix4( node.matrixWorld );

							scope.expandByPoint( v1 );

						}

					}

				}

			} );

			return this;

		};

	}(),

	clone: function () {

		return new this.constructor().copy( this );

	},

	copy: function ( box ) {

		this.min.copy( box.min );
		this.max.copy( box.max );

		return this;

	},

	makeEmpty: function () {

		this.min.x = this.min.y = this.min.z = + Infinity;
		this.max.x = this.max.y = this.max.z = - Infinity;

		return this;

	},

	isEmpty: function () {

		// this is a more robust check for empty than ( volume <= 0 ) because volume can get positive with two negative axes

		return ( this.max.x < this.min.x ) || ( this.max.y < this.min.y ) || ( this.max.z < this.min.z );

	},

	center: function ( optionalTarget ) {

		var result = optionalTarget || new THREE.Vector3();
		return result.addVectors( this.min, this.max ).multiplyScalar( 0.5 );

	},

	size: function ( optionalTarget ) {

		var result = optionalTarget || new THREE.Vector3();
		return result.subVectors( this.max, this.min );

	},

	expandByPoint: function ( point ) {

		this.min.min( point );
		this.max.max( point );

		return this;

	},

	expandByVector: function ( vector ) {

		this.min.sub( vector );
		this.max.add( vector );

		return this;

	},

	expandByScalar: function ( scalar ) {

		this.min.addScalar( - scalar );
		this.max.addScalar( scalar );

		return this;

	},

	containsPoint: function ( point ) {

		if ( point.x < this.min.x || point.x > this.max.x ||
				 point.y < this.min.y || point.y > this.max.y ||
				 point.z < this.min.z || point.z > this.max.z ) {

			return false;

		}

		return true;

	},

	containsBox: function ( box ) {

		if ( ( this.min.x <= box.min.x ) && ( box.max.x <= this.max.x ) &&
			 ( this.min.y <= box.min.y ) && ( box.max.y <= this.max.y ) &&
			 ( this.min.z <= box.min.z ) && ( box.max.z <= this.max.z ) ) {

			return true;

		}

		return false;

	},

	getParameter: function ( point, optionalTarget ) {

		// This can potentially have a divide by zero if the box
		// has a size dimension of 0.

		var result = optionalTarget || new THREE.Vector3();

		return result.set(
			( point.x - this.min.x ) / ( this.max.x - this.min.x ),
			( point.y - this.min.y ) / ( this.max.y - this.min.y ),
			( point.z - this.min.z ) / ( this.max.z - this.min.z )
		);

	},

	intersectsBox: function ( box ) {

		// using 6 splitting planes to rule out intersections.

		if ( box.max.x < this.min.x || box.min.x > this.max.x ||
				 box.max.y < this.min.y || box.min.y > this.max.y ||
				 box.max.z < this.min.z || box.min.z > this.max.z ) {

			return false;

		}

		return true;

	},

	intersectsSphere: ( function () {

		var closestPoint;

		return function intersectsSphere( sphere ) {

			if ( closestPoint === undefined ) closestPoint = new THREE.Vector3();

			// Find the point on the AABB closest to the sphere center.
			this.clampPoint( sphere.center, closestPoint );

			// If that point is inside the sphere, the AABB and sphere intersect.
			return closestPoint.distanceToSquared( sphere.center ) <= ( sphere.radius * sphere.radius );

		};

	} )(),

	intersectsPlane: function ( plane ) {

		// We compute the minimum and maximum dot product values. If those values
		// are on the same side (back or front) of the plane, then there is no intersection.

		var min, max;

		if ( plane.normal.x > 0 ) {

			min = plane.normal.x * this.min.x;
			max = plane.normal.x * this.max.x;

		} else {

			min = plane.normal.x * this.max.x;
			max = plane.normal.x * this.min.x;

		}

		if ( plane.normal.y > 0 ) {

			min += plane.normal.y * this.min.y;
			max += plane.normal.y * this.max.y;

		} else {

			min += plane.normal.y * this.max.y;
			max += plane.normal.y * this.min.y;

		}

		if ( plane.normal.z > 0 ) {

			min += plane.normal.z * this.min.z;
			max += plane.normal.z * this.max.z;

		} else {

			min += plane.normal.z * this.max.z;
			max += plane.normal.z * this.min.z;

		}

		return ( min <= plane.constant && max >= plane.constant );

	},

	clampPoint: function ( point, optionalTarget ) {

		var result = optionalTarget || new THREE.Vector3();
		return result.copy( point ).clamp( this.min, this.max );

	},

	distanceToPoint: function () {

		var v1 = new THREE.Vector3();

		return function ( point ) {

			var clampedPoint = v1.copy( point ).clamp( this.min, this.max );
			return clampedPoint.sub( point ).length();

		};

	}(),

	getBoundingSphere: function () {

		var v1 = new THREE.Vector3();

		return function ( optionalTarget ) {

			var result = optionalTarget || new THREE.Sphere();

			result.center = this.center();
			result.radius = this.size( v1 ).length() * 0.5;

			return result;

		};

	}(),

	intersect: function ( box ) {

		this.min.max( box.min );
		this.max.min( box.max );

		// ensure that if there is no overlap, the result is fully empty, not slightly empty with non-inf/+inf values that will cause subsequence intersects to erroneously return valid values.
		if( this.isEmpty() ) this.makeEmpty();

		return this;

	},

	union: function ( box ) {

		this.min.min( box.min );
		this.max.max( box.max );

		return this;

	},

	applyMatrix4: function () {

		var points = [
			new THREE.Vector3(),
			new THREE.Vector3(),
			new THREE.Vector3(),
			new THREE.Vector3(),
			new THREE.Vector3(),
			new THREE.Vector3(),
			new THREE.Vector3(),
			new THREE.Vector3()
		];

		return function ( matrix ) {

			// transform of empty box is an empty box.
			if( this.isEmpty() ) return this;

			// NOTE: I am using a binary pattern to specify all 2^3 combinations below
			points[ 0 ].set( this.min.x, this.min.y, this.min.z ).applyMatrix4( matrix ); // 000
			points[ 1 ].set( this.min.x, this.min.y, this.max.z ).applyMatrix4( matrix ); // 001
			points[ 2 ].set( this.min.x, this.max.y, this.min.z ).applyMatrix4( matrix ); // 010
			points[ 3 ].set( this.min.x, this.max.y, this.max.z ).applyMatrix4( matrix ); // 011
			points[ 4 ].set( this.max.x, this.min.y, this.min.z ).applyMatrix4( matrix ); // 100
			points[ 5 ].set( this.max.x, this.min.y, this.max.z ).applyMatrix4( matrix ); // 101
			points[ 6 ].set( this.max.x, this.max.y, this.min.z ).applyMatrix4( matrix ); // 110
			points[ 7 ].set( this.max.x, this.max.y, this.max.z ).applyMatrix4( matrix );	// 111

			this.setFromPoints( points );

			return this;

		};

	}(),

	translate: function ( offset ) {

		this.min.add( offset );
		this.max.add( offset );

		return this;

	},

	equals: function ( box ) {

		return box.min.equals( this.min ) && box.max.equals( this.max );

	}

};