TrigLUT.java

package com.artemis.utils;

// Thanks to Riven
// From: http://riven8192.blogspot.com/2009/08/fastmath-sincos-lookup-tables.html
public class TrigLUT {
	public static void main(String[] args) {
		System.out.println(cos((float) Math.PI));
		System.out.println(cosDeg(180f));
	}

	public static final float sin(float rad) {
		return sin[(int) (rad * radToIndex) & SIN_MASK];
	}

	public static final float cos(float rad) {
		return cos[(int) (rad * radToIndex) & SIN_MASK];
	}

	public static final float sinDeg(float deg) {
		return sin[(int) (deg * degToIndex) & SIN_MASK];
	}

	public static final float cosDeg(float deg) {
		return cos[(int) (deg * degToIndex) & SIN_MASK];
	}

	private static final float RAD, DEG;
	private static final int SIN_BITS, SIN_MASK, SIN_COUNT;
	private static final float radFull, radToIndex;
	private static final float degFull, degToIndex;
	private static final float[] sin, cos;

	static {
		RAD = (float) Math.PI / 180.0f;
		DEG = 180.0f / (float) Math.PI;

		SIN_BITS = 12;
		SIN_MASK = ~(-1 << SIN_BITS);
		SIN_COUNT = SIN_MASK + 1;

		radFull = (float) (Math.PI * 2.0);
		degFull = (float) (360.0);
		radToIndex = SIN_COUNT / radFull;
		degToIndex = SIN_COUNT / degFull;

		sin = new float[SIN_COUNT];
		cos = new float[SIN_COUNT];

		for (int i = 0; i < SIN_COUNT; i++) {
			sin[i] = (float) Math.sin((i + 0.5f) / SIN_COUNT * radFull);
			cos[i] = (float) Math.cos((i + 0.5f) / SIN_COUNT * radFull);
		}
	}
}