/*
 * Copyright 2011, Blender Foundation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "stdosl.h"

shader node_geometry(
	normal NormalIn = N,
	string bump_offset = "center",

	output point Position = point(0.0, 0.0, 0.0),
	output normal Normal = normal(0.0, 0.0, 0.0),
	output normal Tangent = normal(0.0, 0.0, 0.0),
	output normal TrueNormal = normal(0.0, 0.0, 0.0),
	output vector Incoming = vector(0.0, 0.0, 0.0),
	output point Parametric = point(0.0, 0.0, 0.0),
	output float Backfacing = 0.0)
{
	Position = P;
	Normal = NormalIn;
	TrueNormal = Ng;
	Incoming = I;
	Parametric = point(u, v, 0.0);
	Backfacing = backfacing();

	if (bump_offset == "dx") {
		Position += Dx(Position);
		Parametric += Dx(Parametric);
	}
	else if (bump_offset == "dy") {
		Position += Dy(Position);
		Parametric += Dy(Parametric);
	}

	/* first try to get tangent attribute */
	point generated;

	/* try to create spherical tangent from generated coordinates */
	if (getattribute("geom:generated", generated)) {
		vector T = vector(-(generated[1] - 0.5), (generated[0] - 0.5), 0.0);
		T = transform("object", "world", T);
		Tangent = cross(Normal, normalize(cross(T, Normal)));
	}
	else {
		/* otherwise use surface derivatives */
		Tangent = normalize(dPdu);
	}
}