org.apache.batik.ext.awt.image.DistantLight Maven / Gradle / Ivy
/*
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this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
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http://www.apache.org/licenses/LICENSE-2.0
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See the License for the specific language governing permissions and
limitations under the License.
*/
package org.apache.batik.ext.awt.image;
import java.awt.Color;
/**
* A light source placed at the infinity, such that the light angle is
* constant over the whole surface.
*
* @author Vincent Hardy
* @version $Id: DistantLight.java 1733416 2016-03-03 07:07:13Z gadams $
*/
public class DistantLight extends AbstractLight {
/**
* The azimuth of the distant light, i.e., the angle of the light vector
* on the (X, Y) plane
*/
private double azimuth;
/**
* The elevation of the distant light, i.e., the angle of the light
* vector on the (X, Z) plane.
*/
private double elevation;
/**
* Light vector
*/
private double Lx, Ly, Lz;
/**
* @return the DistantLight's azimuth
*/
public double getAzimuth(){
return azimuth;
}
/**
* @return the DistantLight's elevation
*/
public double getElevation(){
return elevation;
}
public DistantLight(double azimuth, double elevation, Color color){
super(color);
this.azimuth = azimuth;
this.elevation = elevation;
Lx = Math.cos( Math.toRadians( azimuth ) ) * Math.cos( Math.toRadians( elevation ) );
Ly = Math.sin( Math.toRadians( azimuth ) ) * Math.cos( Math.toRadians( elevation ) );
Lz = Math.sin( Math.toRadians( elevation ));
}
/**
* @return true if the light is constant over the whole surface
*/
public boolean isConstant(){
return true;
}
/**
* Computes the light vector in (x, y)
*
* @param x x-axis coordinate where the light should be computed
* @param y y-axis coordinate where the light should be computed
* @param L array of length 3 where the result is stored
*/
public void getLight(final double x, final double y, final double z,
final double[] L){
L[0] = Lx;
L[1] = Ly;
L[2] = Lz;
}
/**
* Returns a row of the light map, starting at (x, y) with dx
* increments, a given width, and z elevations stored in the
* fourth component on the N array.
*
* @param x x-axis coordinate where the light should be computed
* @param y y-axis coordinate where the light should be computed
* @param dx delta x for computing light vectors in user space
* @param width number of samples to compute on the x axis
* @param z array containing the z elevation for all the points
* @param lightRow array to store the light info to, if null it will
* be allocated for you and returned.
*
* @return an array width columns where each element
* is an array of three components representing the x, y and z
* components of the light vector. */
public double[][] getLightRow(double x, double y,
final double dx, final int width,
final double[][] z,
final double[][] lightRow) {
double [][] ret = lightRow;
if (ret == null) {
// If we are allocating then use the same light vector for
// all entries.
ret = new double[width][];
double[] CL = new double[3];
CL[0]=Lx;
CL[1]=Ly;
CL[2]=Lz;
for(int i=0; i