source: other-projects/playing-in-the-street/summer-2013/trunk/Playing-in-the-Street-WPF/Content/Web/mrdoob-three.js-4862f5f/src/extras/helpers/SpotLightHelper.js@ 28897

/**
 * @author alteredq / http://alteredqualia.com/
 * @author mrdoob / http://mrdoob.com/
 * @author WestLangley / http://github.com/WestLangley
*/

THREE.SpotLightHelper = function ( light ) {

    THREE.Object3D.call( this );

    this.light = light;
    this.light.updateMatrixWorld();

    this.matrixWorld = light.matrixWorld;
    this.matrixAutoUpdate = false;

    var geometry = new THREE.CylinderGeometry( 0, 1, 1, 8, 1, true );

    geometry.applyMatrix( new THREE.Matrix4().makeTranslation( 0, -0.5, 0 ) );
    geometry.applyMatrix( new THREE.Matrix4().makeRotationX( - Math.PI / 2 ) );

    var material = new THREE.MeshBasicMaterial( { wireframe: true, fog: false } );
    
    this.cone = new THREE.Mesh( geometry, material );
    this.add( this.cone );

    this.update();

};

THREE.SpotLightHelper.prototype = Object.create( THREE.Object3D.prototype );

THREE.SpotLightHelper.prototype.dispose = function () {
    this.cone.geometry.dispose();
    this.cone.material.dispose();
};

THREE.SpotLightHelper.prototype.update = function () {

    var vector = new THREE.Vector3();
    var vector2 = new THREE.Vector3();

    return function () {

        var coneLength = this.light.distance ? this.light.distance : 10000;
        var coneWidth = coneLength * Math.tan( this.light.angle );

        this.cone.scale.set( coneWidth, coneWidth, coneLength );

        vector.setFromMatrixPosition( this.light.matrixWorld );
        vector2.setFromMatrixPosition( this.light.target.matrixWorld );

        this.cone.lookAt( vector2.sub( vector ) );

        this.cone.material.color.copy( this.light.color ).multiplyScalar( this.light.intensity );

    };

}();