Module trig 

Port of Mojang net.minecraft.util.Mth’s float trig lookup tables.

Carvers, structures, entity physics, and a lot of other gameplay code call Mth.sin(float) / Mth.cos(float), not Math.sin(double). Matching block-level determinism with vanilla requires using the same 65536-entry float table instead of the precise FPU sine.

Vanilla reference

private static final float[] SIN = new float[65536];
static {
    for (int i = 0; i < 65536; i++)
        SIN[i] = (float) Math.sin(i * (Math.PI * 2.0 / 65536.0));
}
public static float sin(double i)  { return SIN[(int)((long)(i * 10430.378350470453) & 65535L)]; }
public static float cos(double i)  { return SIN[(int)((long)(i * 10430.378350470453 + 16384.0) & 65535L)]; }

Note that the multiplier 10430.378350470453 is exactly 65536 / (2π) rounded to a double, and the table is indexed by the low 16 bits of the scaled angle.

Constants

ATAN_TABLE_LEN 🔒

FRAC_BIAS 🔒

INDEX_SCALE 🔒

65536 / (2π) — Mojang’s stored constant.

ONE_SIXTH 🔒

TABLE_LEN 🔒

TABLE_MASK 🔒

Statics

ASIN_TAB 🔒

Arcsine angles in radians for inputs from 0 to 1 in steps of 1/256.

COS_TAB 🔒

Cosines of the angles in ASIN_TAB

SIN_TABLE 🔒

The Mth.SIN table (one entry per 2π / 65536 radians, float-valued).

Functions

atan2

Returns vanilla’s approximate angle in radians for the vector (x, y).

cos

Vanilla Mth.cos(double) — like sin but phase-shifted by +π/2 using the same table.

fast_inv_sqrt 🔒

Approximates 1 / sqrt(value) using a fast inverse square root algorithm.

sin

Vanilla Mth.sin(double) — returns the float from the 65536-entry sine table indexed by the angle’s low-16-bit bucket.