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@micycle1
Created July 20, 2018 20:18
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public static final class Riven {
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 {
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);
}
// Four cardinal directions (credits: Nate)
for (int i = 0; i < 360; i += 90) {
sin[(int) (i * degToIndex) & SIN_MASK] = (float) Math.sin(i * Math.PI / 180.0);
cos[(int) (i * degToIndex) & SIN_MASK] = (float) Math.cos(i * Math.PI / 180.0);
}
}
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];
}
}
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