/**
* 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;
import ca.eandb.jmist.framework.Painter;
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.painter.UniformPainter;
import ca.eandb.jmist.framework.random.RandomUtil;
import ca.eandb.jmist.math.Ray3;
import ca.eandb.jmist.math.SphericalCoordinates;
import ca.eandb.jmist.math.Vector3;
/**
* A <code>Material</code> that reflects light equally in all directions in
* the upper hemisphere.
* @author Brad Kimmel
*/
public final class LambertianMaterial extends OpaqueMaterial {
/**
* Creates a new <code>LambertianMaterial</code> that does not emit light.
* @param reflectance The reflectance <code>Painter</code>.
*/
public LambertianMaterial(Painter reflectance) {
this(reflectance, null);
}
/**
* Creates a new <code>LambertianMaterial</code> that emits light.
* @param reflectance The reflectance <code>Painter</code>.
* @param emittance The emission <code>Painter</code>.
*/
public LambertianMaterial(Painter reflectance, Painter emittance) {
this.reflectance = reflectance;
this.emittance = emittance;
}
/**
* Creates a new <code>LambertianMaterial</code> that does not emit light.
* @param reflectance The reflectance <code>Spectrum</code>.
*/
public LambertianMaterial(Spectrum reflectance) {
this(reflectance != null ? new UniformPainter(reflectance) : null);
}
/**
* Creates a new <code>LambertianMaterial</code> that emits light.
* @param reflectance The reflectance <code>Spectrum</code>.
* @param emittance The emission <code>Spectrum</code>.
*/
public LambertianMaterial(Spectrum reflectance, Spectrum emittance) {
this(reflectance != null ? new UniformPainter(reflectance) : null, emittance != null ? new UniformPainter(emittance) : null);
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.AbstractMaterial#isEmissive()
*/
@Override
public boolean isEmissive() {
return (this.emittance != null);
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.material.AbstractMaterial#emission(ca.eandb.jmist.framework.SurfacePoint, ca.eandb.jmist.math.Vector3, ca.eandb.jmist.framework.color.WavelengthPacket)
*/
@Override
public Color emission(SurfacePoint x, Vector3 out, WavelengthPacket lambda) {
if (this.emittance != null && x.getNormal().dot(out) > 0.0) {
return emittance.getColor(x, lambda).divide(Math.PI);
} else {
return lambda.getColorModel().getBlack(lambda);
}
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.material.AbstractMaterial#emit(ca.eandb.jmist.framework.SurfacePoint, ca.eandb.jmist.framework.color.WavelengthPacket, double, double, double)
*/
@Override
public ScatteredRay emit(SurfacePoint x, WavelengthPacket lambda, double ru, double rv, double rj) {
if (this.emittance != null) {
SphericalCoordinates out = RandomUtil.diffuse(ru, rv);
Ray3 ray = new Ray3(x.getPosition(), out.toCartesian(x.getShadingBasis()));
if (x.getNormal().dot(ray.direction()) > 0.0) {
return ScatteredRay.diffuse(ray, emittance.getColor(x, lambda), 1.0 / Math.PI);
}
}
return null;
}
/* (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, ca.eandb.jmist.framework.Random)
*/
@Override
public ScatteredRay scatter(SurfacePoint x, Vector3 v, boolean adjoint,
WavelengthPacket lambda, double ru, double rv, double rj) {
if (this.reflectance != null) {
boolean fromFront = x.getNormal().dot(v) < 0.0;
SphericalCoordinates out = RandomUtil.diffuse(ru, rv);
if (!fromFront) {
out = out.opposite();
}
Ray3 ray = new Ray3(x.getPosition(), out.toCartesian(x.getShadingBasis()));
boolean toFront = ray.direction().dot(x.getNormal()) > 0.0;
if (fromFront == toFront) {
return ScatteredRay.diffuse(ray, reflectance.getColor(x, lambda), 1.0 / Math.PI);
}
}
return null;
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.material.AbstractMaterial#bsdf(ca.eandb.jmist.framework.SurfacePoint, ca.eandb.jmist.math.Vector3, ca.eandb.jmist.math.Vector3, ca.eandb.jmist.framework.color.WavelengthPacket)
*/
@Override
public Color bsdf(SurfacePoint x, Vector3 in, Vector3 out, WavelengthPacket lambda) {
Vector3 n = x.getNormal();
boolean fromFront = (n.dot(in) < 0.0);
boolean toFront = (n.dot(out) > 0.0);
Vector3 n1 = x.getShadingNormal();
boolean fromFront1 = (n1.dot(in) < 0.0);
if (this.reflectance != null && (toFront == fromFront) && (toFront == fromFront1)) {
return reflectance.getColor(x, lambda).divide(Math.PI);
} else {
return lambda.getColorModel().getBlack(lambda);
}
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.material.AbstractMaterial#getEmissionPDF(ca.eandb.jmist.framework.SurfacePoint, ca.eandb.jmist.math.Vector3, ca.eandb.jmist.framework.color.WavelengthPacket)
*/
@Override
public double getEmissionPDF(SurfacePoint x, Vector3 out,
WavelengthPacket lambda) {
return emittance != null ? 1.0 / Math.PI : 0.0;
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.material.AbstractMaterial#getScatteringPDF(ca.eandb.jmist.framework.SurfacePoint, ca.eandb.jmist.math.Vector3, ca.eandb.jmist.math.Vector3, boolean, ca.eandb.jmist.framework.color.WavelengthPacket)
*/
@Override
public double getScatteringPDF(SurfacePoint x, Vector3 in, Vector3 out,
boolean adjoint, WavelengthPacket lambda) {
return reflectance != null ? 1.0 / Math.PI : 0.0;
}
/** The reflectance <code>Painter</code> of this <code>Material</code>. */
private final Painter reflectance;
/** The emittance <code>Painter</code> of this <code>Material</code>. */
private final Painter emittance;
/**
* Serialization version ID.
*/
private static final long serialVersionUID = 485410070543495668L;
}