function pointInTriangle(p, a, b, c) {
    c.vsub(a,v0);
    b.vsub(a,v1);
    p.vsub(a,v2);

    var dot00 = v0.dot( v0 );
    var dot01 = v0.dot( v1 );
    var dot02 = v0.dot( v2 );
    var dot11 = v1.dot( v1 );
    var dot12 = v1.dot( v2 );

    var u,v;

    return  ( (u = dot11 * dot02 - dot01 * dot12) >= 0 ) &&
            ( (v = dot00 * dot12 - dot01 * dot02) >= 0 ) &&
            ( u + v < ( dot00 * dot11 - dot01 * dot01 ) );
}
Do itersection against all bodies in the given World.
@method intersectWorld
@param  {World} world
@param  {object} options
@return {Boolean} True if the ray hit anything, otherwise false.