@woosh/meep-engine/src/core/geom/mat2/m2_multiply.js

Pure JavaScript game engine. Fully featured and production ready.

/**
 * Multiplication of 2x2 matrices
 * @param {number[]} result
 * @param {number[]} a
 * @param {number[]} b
 */
export function m2_multiply(result, a, b) {
    const v0 = a[0] * b[0] + a[1] * b[2];
    const v1 = a[0] * b[1] + a[1] * b[3];
    const v2 = a[2] * b[0] + a[3] * b[2];
    const v3 = a[2] * b[1] + a[3] * b[3];

    result[0] = v0;
    result[1] = v1;
    result[2] = v2;
    result[3] = v3;
}