three.js/src/math/Box3.js

/**
 * @author bhouston / http://exocortex.com
 */

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.extend( THREE.Box3.prototype, {

	constructor: THREE.Box3,

	set: function ( min, max ) {

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

		return this;

	},

	setFromPoints: function ( points ) {

		if ( points.length > 0 ) {

			var point = points[ 0 ];

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

			for ( var i = 1, il = points.length; i < il; i ++ ) {

				point = points[ i ];

				if ( point.x < this.min.x ) {

					this.min.x = point.x;

				} else if ( point.x > this.max.x ) {

					this.max.x = point.x;

				}

				if ( point.y < this.min.y ) {

					this.min.y = point.y;

				} else if ( point.y > this.max.y ) {

					this.max.y = point.y;

				}

				if ( point.z < this.min.z ) {

					this.min.z = point.z;

				} else if ( point.z > this.max.z ) {

					this.max.z = point.z;

				}

			}

		} else {

			this.makeEmpty();

		}

		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;

		};

	}(),

	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;

	},

	empty: 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 ) {

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

		return new THREE.Vector3(
			( 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 )
		);

	},

	isIntersectionBox: 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;

	},

	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 );

		return this;

	},

	union: function ( box ) {

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

		return this;

	},

	transform: 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 ) {

			// 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.makeEmpty();
			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 );

	},

	clone: function () {

		return new THREE.Box3().copy( this );

	}

} );