/*
* (C) Copyright 2016-2017 JOML
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 org.joml.sampling;
/**
* Creates samples on a spiral around a center point.
*
* @author Kai Burjack
*/
public class SpiralSampling {
private final Random rnd;
/**
* Create a new instance of {@link SpiralSampling} and initialize the random number generator with the given <code>seed</code>.
*
* @param seed
* the seed to initialize the random number generator with
*/
public SpiralSampling(long seed) {
rnd = new Random(seed);
}
/**
* Create <code>numSamples</code> number of samples on a spiral with maximum radius <code>radius</code> around the center using <code>numRotations</code> number of rotations
* along the spiral, and call the given <code>callback</code> for each sample generated.
* <p>
* The generated sample points are distributed with equal angle differences around the spiral, so they concentrate towards the center.
*
* @param radius
* the maximum radius of the spiral
* @param numRotations
* the number of rotations of the spiral
* @param numSamples
* the number of samples to generate
* @param callback
* will be called for each sample generated
*/
public void createEquiAngle(float radius, int numRotations, int numSamples, Callback2d callback) {
for (int sample = 0; sample < numSamples; sample++) {
float angle = 2.0f * (float) Math.PI * (sample * numRotations) / numSamples;
float r = radius * sample / (numSamples - 1);
float x = (float) Math.sin_roquen_9(angle + 0.5f * (float) Math.PI) * r;
float y = (float) Math.sin_roquen_9(angle) * r;
callback.onNewSample(x, y);
}
}
/**
* Create <code>numSamples</code> number of samples on a spiral with maximum radius <code>radius</code> around the center using <code>numRotations</code> number of rotations
* along the spiral, and call the given <code>callback</code> for each sample generated.
* <p>
* The generated sample points are distributed with equal angle differences around the spiral, so they concentrate towards the center.
* <p>
* Additionally, the radius of each sample point is jittered by the given <code>jitter</code> factor.
*
* @param radius
* the maximum radius of the spiral
* @param numRotations
* the number of rotations of the spiral
* @param numSamples
* the number of samples to generate
* @param jitter
* the factor by which the radius of each sample point is jittered. Possible values are <tt>[0..1]</tt>
* @param callback
* will be called for each sample generated
*/
public void createEquiAngle(float radius, int numRotations, int numSamples, float jitter, Callback2d callback) {
float spacing = radius / numRotations;
for (int sample = 0; sample < numSamples; sample++) {
float angle = 2.0f * (float) Math.PI * (sample * numRotations) / numSamples;
float r = radius * sample / (numSamples - 1) + (rnd.nextFloat() * 2.0f - 1.0f) * spacing * jitter;
float x = (float) Math.sin_roquen_9(angle + 0.5f * (float) Math.PI) * r;
float y = (float) Math.sin_roquen_9(angle) * r;
callback.onNewSample(x, y);
}
}
}