Math

Utility math functions compatible with the Allegro 4 math API.

Constants

const PI = 3.14159265;
const PI2 = 2 * PI; // full circle in radians
const PI_2 = PI / 2; // 90°
const PI_3 = PI / 3; // 60°
const PI_4 = PI / 4; // 45°

Random numbers

function rand(): number; // integer 0–65535
function AL_RAND(): number; // alias for rand()
function rand32(): number; // integer –2147483648 to 2147483647
function frand(): number; // float 0.0–1.0

// Roll a d6
const die = (rand() % 6) + 1;

// Random float in 0.0–10.0
const value = frand() * 10;

Basic math

function abs(a: number): number; // absolute value
function floor(num: number): number; // Math.floor
function scaleclamp(value, min, max, newMin, newMax): number;

scaleclamp maps value from the range [min, max] to [newMin, newMax] and clamps the result to the new range.

// Map health 0–100 to bar width 0–200px
const barWidth = scaleclamp(health, 0, 100, 0, 200);

Fixed-point angles

Allegro 4 uses a fixed-point angle system where 256 = full circle (360°). allegro-ts uses this convention in all rotation functions.

function fix_to_rad(d: number): number;

Converts an Allegro fixed-point angle to radians (used internally by the rotation functions).

Allegro angle	Degrees	radians
0	0°	0
64	90°	π/2
128	180°	π
192	270°	3π/2
256	360°	2π