M4x4.mul = function M4x4_mul(a, b, r) { //MathUtils_assert(a.length == 16, "a.length == 16"); //MathUtils_assert(b.length == 16, "b.length == 16"); //MathUtils_assert(r == undefined || r.length == 16, "r == undefined || r.length == 16"); //MathUtils_assert(a != r && b != r, "a != r && b != r");

if (r == undefined)
    r = new MJS_FLOAT_ARRAY_TYPE(16);
var a0 = a[0], a1 = a[1], a2 = a[2], a3 = a[3], a4 = a[4], a5 = a[5],

a6 = a[6], a7 = a[7], a8 = a[8], a9 = a[9], a10 = a[10], a11 = a[11], a12 = a[12], a13 = a[13], a14 = a[14], a15 = a[15], b0 = b[0], b1 = b[1], b2 = b[2], b3 = b[3], b4 = b[4], b5 = b[5], b6 = b[6], b7 = b[7], b8 = b[8], b9 = b[9], b10 = b[10], b11 = b[11], b12 = b[12], b13 = b[13], b14 = b[14], b15 = b[15]; r[0] = b0 * a0 + b1 * a4 + b2 * a8 + b3 * a12; r[1] = b0 * a1 + b1 * a5 + b2 * a9 + b3 * a13; r[2] = b0 * a2 + b1 * a6 + b2 * a10 + b3 * a14; r[3] = b0 * a3 + b1 * a7 + b2 * a11 + b3 * a15; r[4] = b4 * a0 + b5 * a4 + b6 * a8 + b7 * a12; r[5] = b4 * a1 + b5 * a5 + b6 * a9 + b7 * a13; r[6] = b4 * a2 + b5 * a6 + b6 * a10 + b7 * a14; r[7] = b4 * a3 + b5 * a7 + b6 * a11 + b7 * a15; r[8] = b8 * a0 + b9 * a4 + b10 * a8 + b11 * a12; r[9] = b8 * a1 + b9 * a5 + b10 * a9 + b11 * a13; r[10] = b8 * a2 + b9 * a6 + b10 * a10 + b11 * a14; r[11] = b8 * a3 + b9 * a7 + b10 * a11 + b1 * a15; r[12] = b12 * a0 + b13 * a4 + b14 * a8 + b15 * a12; r[13] = b12 * a1 + b13 * a5 + b14 * a9 + b15 * a13; r[14] = b12 * a2 + b13 * a6 + b14 * a10 + b15 * a14; r[15] = b12 * a3 + b13 * a7 + b14 * a11 + b15 * a15; return r; };

Is ~10-20% faster.

Also, this way r === a || r === b works fine.

This issue was closed by revision b8ec95f90d.