/**
 * @author mr.doob / http://mrdoob.com/
 * based on http://papervision3d.googlecode.com/svn/trunk/as3/trunk/src/org/papervision3d/objects/primitives/Plane.as
 */

THREE.PlaneGeometry = function ( width, height, segmentsWidth, segmentsHeight ) {

	THREE.Geometry.call( this );

	var ix, iy,
	width_half = width / 2,
	height_half = height / 2,
	gridX = segmentsWidth || 1,
	gridY = segmentsHeight || 1,
	gridX1 = gridX + 1,
	gridY1 = gridY + 1,
	segment_width = width / gridX,
	segment_height = height / gridY,
	normal = new THREE.Vector3( 0, 0, 1 );

	for ( iy = 0; iy < gridY1; iy++ ) {

		for ( ix = 0; ix < gridX1; ix++ ) {

			var x = ix * segment_width - width_half;
			var y = iy * segment_height - height_half;

			this.vertices.push( new THREE.Vertex( new THREE.Vector3( x, - y, 0 ) ) );

		}

	}

	for ( iy = 0; iy < gridY; iy++ ) {

		for ( ix = 0; ix < gridX; ix++ ) {

			var a = ix + gridX1 * iy;
			var b = ix + gridX1 * ( iy + 1 );
			var c = ( ix + 1 ) + gridX1 * ( iy + 1 );
			var d = ( ix + 1 ) + gridX1 * iy;

			var face = new THREE.Face4( a, b, c, d );
			face.normal.copy( normal );
			face.vertexNormals.push( normal.clone(), normal.clone(), normal.clone(), normal.clone() );

			this.faces.push( face );
			this.faceVertexUvs[ 0 ].push( [
						new THREE.UV( ix / gridX, iy / gridY ),
						new THREE.UV( ix / gridX, ( iy + 1 ) / gridY ),
						new THREE.UV( ( ix + 1 ) / gridX, ( iy + 1 ) / gridY ),
						new THREE.UV( ( ix + 1 ) / gridX, iy / gridY )
					] );

		}

	}

	this.computeCentroids();

};

THREE.PlaneGeometry.prototype = new THREE.Geometry();
THREE.PlaneGeometry.prototype.constructor = THREE.PlaneGeometry;