@woosh/meep-engine/src/core/geom/3d/mat4/compose_matrix4_array.js

Pure JavaScript game engine. Fully featured and production ready.

/**
 *
 * @param {number[]|Float32Array|mat4} result
 * @param { { x:number, y:number, z:number } } position
 * @param { { x:number, y:number, z:number, w:number } } rotation
 * @param { { x:number, y:number, z:number } } scale
 */
export function compose_matrix4_array(result, position, rotation, scale) {
    const x = rotation.x;
    const y = rotation.y;
    const z = rotation.z;
    const w = rotation.w;

    const x2 = x + x;
    const y2 = y + y;
    const z2 = z + z;

    const xx = x * x2;
    const xy = x * y2;
    const xz = x * z2;

    const yy = y * y2;
    const yz = y * z2;
    const zz = z * z2;

    const wx = w * x2;
    const wy = w * y2;
    const wz = w * z2;

    const sx = scale.x;
    const sy = scale.y;
    const sz = scale.z;

    result[0] = (1 - (yy + zz)) * sx;
    result[1] = (xy + wz) * sx;
    result[2] = (xz - wy) * sx;
    result[3] = 0;

    result[4] = (xy - wz) * sy;
    result[5] = (1 - (xx + zz)) * sy;
    result[6] = (yz + wx) * sy;
    result[7] = 0;

    result[8] = (xz + wy) * sz;
    result[9] = (yz - wx) * sz;
    result[10] = (1 - (xx + yy)) * sz;
    result[11] = 0;

    result[12] = position.x;
    result[13] = position.y;
    result[14] = position.z;
    result[15] = 1;
}