public void toVertexUV(ThreadContext context, IRubyObject[] args) {
Arity.checkArgumentCount(context.getRuntime(), args, 3, 3);
double u = (Double) args[1].toJava(Double.class);
double v = (Double) args[2].toJava(Double.class);
JRender renderer = (JRender) args[0].toJava(JRender.class);
renderer.vertex(jx, jy, jz, u, v);
}