/**
* 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.light;
import java.io.Serializable;
import ca.eandb.jmist.framework.Illuminable;
import ca.eandb.jmist.framework.Random;
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.path.LightNode;
import ca.eandb.jmist.framework.path.LightTerminalNode;
import ca.eandb.jmist.framework.path.PathInfo;
import ca.eandb.jmist.framework.random.RandomUtil;
import ca.eandb.jmist.math.HPoint3;
import ca.eandb.jmist.math.Point3;
import ca.eandb.jmist.math.Ray3;
import ca.eandb.jmist.math.Vector3;
/**
* A <code>Light</code> that emits from a single point.
* @author Brad Kimmel
*/
public final class PointLight extends AbstractLight implements Serializable {
/**
* Creates a new <code>PointLight</code>.
* @param position The <code>Point3</code> where the light is to emit from.
* @param emittedPower The <code>Spectrum</code> representing the emitted
* power of the light.
* @param shadows A value indicating whether the light should be affected
* by shadows.
*/
public PointLight(Point3 position, Spectrum emittedPower, boolean shadows) {
this.position = position;
this.emittedPower = emittedPower;
this.shadows = shadows;
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.Light#illuminate(ca.eandb.jmist.framework.SurfacePoint, ca.eandb.jmist.framework.color.WavelengthPacket, ca.eandb.jmist.framework.Random, ca.eandb.jmist.framework.Illuminable)
*/
public void illuminate(SurfacePoint x, WavelengthPacket lambda, Random rng, Illuminable target) {
Vector3 lightIn = x.getPosition().vectorTo(this.position);
double dSquared = lightIn.squaredLength();
lightIn = lightIn.divide(Math.sqrt(dSquared));
double ndotl = x.getShadingNormal().dot(lightIn);
double attenuation = Math.abs(ndotl) / (4.0 * Math.PI * dSquared);
target.addLightSample(new PointLightSample(x, position, emittedPower.sample(lambda).times(attenuation), shadows));
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.Light#sample(ca.eandb.jmist.framework.path.PathInfo, double, double, double)
*/
public LightNode sample(PathInfo pathInfo, double ru, double rv, double rj) {
return new Node(pathInfo, ru, rv, rj);
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.Light#getSamplePDF(ca.eandb.jmist.framework.SurfacePoint, ca.eandb.jmist.framework.path.PathInfo)
*/
public double getSamplePDF(SurfacePoint x, PathInfo pathInfo) {
return 0;
}
private final class Node extends LightTerminalNode {
public Node(PathInfo pathInfo, double ru, double rv, double rj) {
super(pathInfo, ru, rv, rj);
}
public double getCosine(Vector3 v) {
return 1.0;
}
public double getPDF() {
return 1.0;
}
public HPoint3 getPosition() {
return position;
}
public boolean isSpecular() {
return true;
}
public ScatteredRay sample(double ru, double rv, double rj) {
Vector3 v = RandomUtil.uniformOnSphere(ru, rv).toCartesian();
Ray3 ray = new Ray3(position, v);
return ScatteredRay.diffuse(ray, sample(emittedPower),
1.0 / (4.0 * Math.PI));
}
public Color scatter(Vector3 v) {
return sample(emittedPower).divide(4.0 * Math.PI);
}
public double getPDF(Vector3 v) {
return 1.0 / (4.0 * Math.PI);
}
}
/** The <code>Point3</code> where the light is to emit from. */
private final Point3 position;
/** The emission <code>Spectrum</code> of the light. */
private final Spectrum emittedPower;
/** A value indicating whether the light should be affected by shadows. */
private final boolean shadows;
/**
* Serialization version ID.
*/
private static final long serialVersionUID = -5220350307274318220L;
}