/**
* 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.pixel;
import ca.eandb.jmist.framework.PixelShader;
import ca.eandb.jmist.framework.color.Color;
import ca.eandb.jmist.math.Box2;
/**
* A pixel shader decorator that averages stratified samples from the
* decorated pixel shader.
* @author Brad Kimmel
*/
public final class StratifyingPixelShader implements PixelShader {
/**
* Serialization version ID.
*/
private static final long serialVersionUID = 1059443381015930105L;
/**
* Initializes the number of rows and columns to divide each pixel
* into as well as the underlying decorated pixel shader.
* @param columns The number of columns to divide each pixel into.
* @param rows The number of rows to divide each pixel into.
* @param pixelShader The decorated pixel shader.
*/
public StratifyingPixelShader(int columns, int rows, PixelShader pixelShader) {
this.columns = columns;
this.rows = rows;
this.pixelShader = pixelShader;
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.PixelShader#shadePixel(ca.eandb.jmist.math.Box2)
*/
public Color shadePixel(Box2 bounds) {
double x0, x1, y0, y1;
Color pixel = null;
Color sample;
Box2 subpixel;
for (int i = 0; i < this.rows; i++) {
x0 = bounds.interpolateX((double) i / (double) this.rows);
x1 = bounds.interpolateX((double) (i + 1) / (double) this.rows);
for (int j = 0; j < this.columns; j++) {
y0 = bounds.interpolateY((double) j / (double) this.columns);
y1 = bounds.interpolateY((double) (j + 1) / (double) this.columns);
subpixel = new Box2(x0, y0, x1, y1);
sample = pixelShader.shadePixel(subpixel);
pixel = add(pixel, sample);
}
}
return pixel.divide(this.rows * this.columns);
}
/**
* Adds two <code>Color</code>s.
* @param a The first <code>Color</code> (may be null).
* @param b The second <code>Color</code>.
* @return The sum of the two <code>Color</code>s.
*/
public Color add(Color a, Color b) {
return (a != null) ? a.plus(b) : b;
}
/** The number of columns to divide each pixel into. */
private final int columns;
/** The number of rows to divide each pixel into. */
private final int rows;
/** The pixel shader to average the results from. */
private final PixelShader pixelShader;
}