/**
* Java Modular Image Synthesis Toolkit (JMIST)
* Copyright (C) 2008-2013 Bradley W. Kimmel
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
package ca.eandb.jmist.framework.material.biospec;
import ca.eandb.jmist.framework.ScatteredRay;
import ca.eandb.jmist.framework.SurfacePoint;
import ca.eandb.jmist.framework.color.Color;
import ca.eandb.jmist.framework.color.Spectrum;
import ca.eandb.jmist.framework.color.WavelengthPacket;
import ca.eandb.jmist.framework.material.OpaqueMaterial;
import ca.eandb.jmist.math.Ray3;
import ca.eandb.jmist.math.Vector3;
/**
* A <code>Material</code> representing a absorptive layer with sieve effects
* in the ABM-B/ABM-U light transport models.
* @author Brad Kimmel
* @see ABMMaterial
*/
public final class ABMSieveAbsorbingMaterial extends OpaqueMaterial {
/** Serialization version ID. */
private static final long serialVersionUID = -2192497635802551618L;
/** The absorption coefficient of the medium (in m<sup>-1</sup>). */
private final Spectrum absorptionCoefficient;
/** The thickness of the medium (in meters). */
private final double thickness;
/**
* Creates a new <code>AbsorbingSurfaceScatterer</code>.
* @param absorptionCoefficient The absorption coefficient of the medium
* (in m<sup>-1</sup>).
* @param thickness The thickness of the medium (in meters).
*/
public ABMSieveAbsorbingMaterial(Spectrum absorptionCoefficient,
double thickness) {
this.absorptionCoefficient = absorptionCoefficient;
this.thickness = thickness;
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.material.AbstractMaterial#scatter(ca.eandb.jmist.framework.SurfacePoint, ca.eandb.jmist.math.Vector3, boolean, ca.eandb.jmist.framework.color.WavelengthPacket, double, double, double)
*/
@Override
public ScatteredRay scatter(SurfacePoint x, Vector3 v, boolean adjoint,
WavelengthPacket lambda, double ru, double rv, double rj) {
Color col = absorptionCoefficient.sample(lambda);
// double abs = ColorUtil.getMeanChannelValue(col);
//
// if (abs > MathUtil.EPSILON) {
// double p = -Math.log(1.0 - rnd.next()) * Math.cos(Math.abs(x.getNormal().dot(v))) / abs;
//
// col = col.times(-thickness).exp();
// col = col.divide(ColorUtil.getMeanChannelValue(col));
//
// if (p > thickness) {
// return ScatteredRay.transmitSpecular(new Ray3(x.getPosition(), v), col, 1.0);
// }
// }
//
// return null;
col = col.times(-thickness / Math.cos(Math.abs(x.getNormal().dot(v)))).exp();
return ScatteredRay.transmitSpecular(new Ray3(x.getPosition(), v), col, 1.0);
}
}