/**
* 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.shader;
import ca.eandb.jmist.framework.LightSample;
import ca.eandb.jmist.framework.Painter;
import ca.eandb.jmist.framework.Shader;
import ca.eandb.jmist.framework.ShadingContext;
import ca.eandb.jmist.framework.color.Color;
import ca.eandb.jmist.framework.color.ColorModel;
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.math.Vector3;
/**
* @author Brad Kimmel
*
*/
public final class PhongShader implements Shader {
/** Serialization version ID. */
private static final long serialVersionUID = -7555950836943828911L;
private final Painter diffuse;
private final Painter specular;
private final Painter ambient;
private final Painter exponent;
public PhongShader(Painter kd, Painter ks, Painter ka, Painter n) {
this.diffuse = kd;
this.specular = ks;
this.ambient = ka;
this.exponent = n;
}
public PhongShader(Spectrum kd, Spectrum ks, Spectrum ka, Spectrum n) {
this(new UniformPainter(kd), new UniformPainter(ks), new UniformPainter(ka), new UniformPainter(n));
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.Shader#shade(ca.eandb.jmist.framework.ShadingContext)
*/
public Color shade(ShadingContext sc) {
WavelengthPacket lambda = sc.getWavelengthPacket();
ColorModel cm = sc.getColorModel();
Color kd = diffuse.getColor(sc, lambda);
Color ks = specular.getColor(sc, lambda);
Color ka = ambient.getColor(sc, lambda);
Color n = exponent.getColor(sc, lambda);
Vector3 N = sc.getShadingNormal();
Vector3 V = sc.getIncident().opposite();
Color d = cm.getBlack(lambda);
Color s = d;
Color a = sc.getAmbientLight();
for (LightSample sample : sc.getLightSamples()) {
Vector3 L = sample.getDirToLight();
Vector3 H = L.plus(V).unit();
Color I = sample.getRadiantIntensity();
d = d.plus(I.times(N.dot(L)));
s = s.plus(I.times(cm.getGray(N.dot(H), lambda).pow(n)));
}
d = d.times(kd);
s = s.times(ks);
a = a.times(ka);
return d.plus(s).plus(a);
}
}