/**
* 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 ca.eandb.jmist.framework.DirectionalTexture3;
import ca.eandb.jmist.framework.Illuminable;
import ca.eandb.jmist.framework.Random;
import ca.eandb.jmist.framework.SurfacePoint;
import ca.eandb.jmist.framework.color.WavelengthPacket;
import ca.eandb.jmist.framework.random.RandomUtil;
import ca.eandb.jmist.math.Basis3;
import ca.eandb.jmist.math.Vector3;
/**
* A <code>Light</code> that illuminates from all directions in the specified
* hemisphere.
* @author Brad Kimmel
*/
public final class HemisphericalLight extends AbstractLight {
/** Serialization version ID. */
private static final long serialVersionUID = 7440635665736022550L;
/**
* A <code>DirectionalTexture3</code> representing the incident radiance.
*/
private final DirectionalTexture3 environment;
/**
* The <code>Basis3</code> representing the coordinate system of the
* illuminating hemisphere.
*/
private final Basis3 basis;
/** A value indicating whether shadows should be computed. */
private final boolean shadows;
/**
* Creates a new <code>HemisphericalLight</code>.
* @param environment A <code>DirectionalTexture3</code> representing the
* distribution of incoming radiance.
* @param zenith A <code>Vector3</code> indicating the direction toward the
* center of the illuminating hemisphere.
*/
public HemisphericalLight(DirectionalTexture3 environment, Vector3 zenith) {
this(environment, zenith, true);
}
/**
* Creates a new <code>HemisphericalLight</code>.
* @param environment A <code>DirectionalTexture3</code> representing the
* distribution of incoming radiance.
* @param zenith A <code>Vector3</code> indicating the direction toward the
* center of the illuminating hemisphere.
* @param shadows A value indicating whether shadows should be computed.
*/
public HemisphericalLight(DirectionalTexture3 environment, Vector3 zenith, boolean shadows) {
this.environment = environment;
this.basis = Basis3.fromW(zenith);
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 source = RandomUtil.uniformOnUpperHemisphere(rng).toCartesian(basis);
double dot = x.getShadingNormal().dot(source);
target.addLightSample(new DirectionalLightSample(x, source, environment.evaluate(source, lambda).times(dot), shadows));
}
}