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); } }
2009-08-24
FastMath :: sin/cos lookup
Math.sin() is slow. Using a lookup table for sin/cos is roughly 50x faster. The loss of accuracy is minimal, maximum error is roughly 0,001. You can probably get away with it.
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