/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "stdosl.h"
#include "oslutil.h"

shader node_wireframe(
	string bump_offset = "center",
	int use_pixel_size = 0,
	float Size = 0.01,
	output float Fac = 0.0)
{
	Fac = wireframe("triangles", Size, use_pixel_size);
	/* TODO(sergey): Since we can't use autodiff here we do algebraic
	 * calculation of derivatives by definition. We could probably
	 * optimize this a bit by doing some extra calculation in wireframe().
	 */
	if (bump_offset == "dx") {
		point dx = Dx(P);
		P -= dx;
		Fac += (Fac - wireframe("triangles", Size, use_pixel_size)) / length(dx);
	}
	else if (bump_offset == "dy") {
		point dy = Dy(P);
		P -= dy;
		Fac += (Fac - wireframe("triangles", Size, use_pixel_size)) / length(dy);
	}
}