gistfile1.txt

Average Error 0.00060 / Largest Error 0.00224 - Performance   7.306 ns/op
AMD FX-8350

sincos.java

  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];
  }