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/*
* The MIT License
*
* Copyright (c) 2016-2021 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;
import org.joml.Random;
/**
* 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 seed.
*
* @param seed
* the seed to initialize the random number generator with
*/
public SpiralSampling(long seed) {
rnd = new Random(seed);
}
/**
* Create numSamples number of samples on a spiral with maximum radius radius around the center using numRotations number of rotations
* along the spiral, and call the given callback for each sample generated.
*
* 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 numSamples number of samples on a spiral with maximum radius radius around the center using numRotations number of rotations
* along the spiral, and call the given callback for each sample generated.
*
* The generated sample points are distributed with equal angle differences around the spiral, so they concentrate towards the center.
*
* Additionally, the radius of each sample point is jittered by the given jitter 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 [0..1]
* @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);
}
}
}