add Box2 based on Box3 paradigm.

src/core/Box2.js

@@ -0,0 +1,220 @@
+/**
+ * @author bhouston / http://exocortex.com
+ */
+
+THREE.Box2 = function ( min, max ) {
+
+	if( ! min && ! max ) {			
+		this.min = new THREE.Vector2();
+		this.max = new THREE.Vector2();
+		this.makeEmpty();
+	}
+	else {
+		this.min = min || new THREE.Vector2();
+		this.max = max || new THREE.Vector2().copy( this.min );		// This is done on purpose so you can make a box using a single point and then expand it.
+	}
+};
+
+THREE.Box2.prototype = {
+
+	constructor: THREE.Box2,
+
+	set: function ( min, max ) {
+
+		this.min = min;
+		this.max = max;
+
+		return this;
+	},
+
+	setFromPoints: function ( points ) {
+
+		if( points.length > 0 ) {
+
+			var p = points[0];
+			this.min.copy( p );
+			this.max.copy( p );
+
+			for( var i = 1, numPoints = points.length; i < numPoints; i ++ ) {
+
+				p = points[ v ];
+
+				if ( p.x < this.min.x ) {
+					this.min.x = p.x;
+				}
+				else if ( p.x > this.max.x ) {
+					this.max.x = p.x;
+				}
+
+				if ( p.y < this.min.y ) {
+					this.min.y = p.y;
+				}
+				else if ( p.y > this.max.y ) {
+					this.max.y = p.y;
+				}
+			}
+		}
+		else {
+			this.makeEmpty();
+		}
+
+		return this;
+	},
+
+	setFromCenterAndSize: function ( center, size ) {
+
+		var halfSize = new THREE.Vector2().copy( size ).multiplyScalar( 0.5 );
+		this.min.copy( center ).subSelf( halfSize );
+		this.max.copy( center ).addSelf( halfSize );
+
+		return box;	
+	},
+
+	copy: function ( box ) {
+
+		this.min.copy( box.min );
+		this.max.copy( box.max );
+
+		return this;
+	},
+
+	makeEmpty: function () {
+
+		this.min.x = this.min.y = Number.MAX_VALUE;
+		this.max.x = this.max.y = -Number.MAX_VALUE;
+
+		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 );
+	},
+
+	volume: function () {
+
+		return 
+			( this.max.x - this.min.x ) *
+			( this.max.y - this.min.y );
+	},
+
+	center: function () {
+
+		return new THREE.Vector2().add( this.min, this.max ).multiplyScalar( 0.5 );
+	},
+
+	size: function () {
+
+		return new THREE.Vector2().sub( this.max, this.min );
+	},
+
+	expandByPoint: function ( point ) {
+
+		this.min.minSelf( point );		
+		this.max.maxSelf( point );
+
+		return this;
+	},
+
+	expandByVector: function ( vector ) {
+
+		this.min.subSelf( vector );
+		this.max.addSelf( vector );
+
+		return this;
+	},
+
+	expandByScalar: function ( scalar ) {
+
+		this.min.addScalar( -scalar );
+		this.max.addScalar( scalar );
+		
+		return this;
+	},
+
+	containsPoint: function ( point ) {
+		if( 
+			( this.min.x <= point.x ) && ( point.x <= this.max.x ) &&
+			( this.min.y <= point.y ) && ( point.y <= this.max.y )
+			) {
+			return true;
+		}
+		return false;
+	},
+
+	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 )
+			) {
+			return true;
+		}
+		return false;
+	},
+
+	isIntersection: function ( box ) {
+		// using 6 splitting planes to rule out intersections.
+		if( 
+			( this.max.x < box.min.x ) || ( box.min.x > this.max.x ) ||
+			( this.max.y < box.min.y ) || ( box.min.y > this.max.y )
+			) {
+			return false;
+		}
+		return true;
+	},
+
+	getParameter: function ( point ) {
+		// This can potentially have a divide by zero if the box
+		// has a size dimension of 0.
+		return new THREE.Vector2(
+			( point.x - this.min.x ) / ( this.max.x - this.min.x ),
+			( point.y - this.min.y ) / ( this.max.y - this.min.y )
+			);
+	},
+
+	clampPoint: function ( point ) {
+
+		return new THREE.Vector2().copy( point ).maxSelf( this.min ).minSelf( this.max );
+	},
+
+	distanceToPoint: function ( point ) {
+
+		return this.clampPoint( point ).subSelf( point ).length();
+	},
+
+	intersect: function ( box ) {
+
+		this.min.maxSelf( box.min );
+		this.max.minSelf( box.max );
+		
+		return this;
+	},
+
+	union: function ( box ) {
+
+		this.min.minSelf( box.min );
+		this.max.maxSelf( box.max );
+
+		return this;
+	},
+
+	translate: function ( offset ) {
+
+		this.min.addSelf( offset );
+		this.max.addSelf( offset );
+
+		return this;
+	},
+
+	scale: function ( factor ) {
+
+		var sizeDeltaHalf = this.size().multiplyScalar( ( 1 - factor )  * 0.5 );
+		this.expandByVector( sizeDeltaHalf );
+
+		return this;
+	}
+	
+};

utils/includes/common.json

@@ -5,6 +5,7 @@
 	"../src/core/Vector2.js",
 	"../src/core/Vector3.js",
 	"../src/core/Vector4.js",
+	"../src/core/Box2.js",
 	"../src/core/Box3.js",
 	"../src/core/Matrix3.js",
 	"../src/core/Matrix4.js",