org.joml.sampling.Math Maven / Gradle / Ivy
/*
* The MIT License
*
* Copyright (c) 2016-2019 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;
/**
* Internal Math class used by the sampling package.
*
* @author Kai Burjack
*/
class Math {
static final double PI = java.lang.Math.PI;
static final double PI2 = PI * 2.0;
static final double PIHalf = PI * 0.5;
static final double PI_INV = 1.0 / PI;
private static final double s5 = Double.longBitsToDouble(4523227044276562163L);
private static final double s4 = Double.longBitsToDouble(-4671934770969572232L);
private static final double s3 = Double.longBitsToDouble(4575957211482072852L);
private static final double s2 = Double.longBitsToDouble(-4628199223918090387L);
private static final double s1 = Double.longBitsToDouble(4607182418589157889L);
/**
* Reference: http://www.java-gaming.org/
*
* @author roquendm
*/
static double sin_roquen_9(double v) {
double i = java.lang.Math.rint(v * PI_INV);
double x = v - i * Math.PI;
double qs = 1 - 2 * ((int) i & 1);
double x2 = x * x;
double r;
x = qs * x;
r = s5;
r = r * x2 + s4;
r = r * x2 + s3;
r = r * x2 + s2;
r = r * x2 + s1;
return x * r;
}
static double acos(double a) {
//return java.lang.Math.acos(a);
/*
* http://stackoverflow.com/questions/3380628/fast-arc-cos-algorithm#answer-3380723
*/
return (-0.69813170079773212 * a * a - 0.87266462599716477) * a + 1.5707963267948966;
}
/* Other math functions not yet approximated */
static double sqrt(double r) {
return java.lang.Math.sqrt(r);
}
static float min(float a, float b) {
return a < b ? a : b;
}
static int min(int a, int b) {
return a < b ? a : b;
}
static int max(int a, int b) {
return a > b ? a : b;
}
static float max(float a, float b) {
return a > b ? a : b;
}
static float abs(float r) {
return java.lang.Math.abs(r);
}
}