Is this a mistake in grad()?

[akriegman]

I either found a mistake in the code or there's something I don't understand here:

static float grad(int32_t hash, float x, float y) {
    const int32_t h = hash & 0x3F;  // Convert low 3 bits of hash code
    const float u = h < 4 ? x : y;  // into 8 simple gradient directions,
    const float v = h < 4 ? y : x;
    return ((h & 1) ? -u : u) + ((h & 2) ? -2.0f * v : 2.0f * v); // and compute the dot product with (x,y).
}

in this case isn't h the low 6 bits of hash, and isn't h < 4 false most of the time?

[SRombauts]

Yes, it has been years but I see that the code isn't in sync with the comment so I'll have to fix and test, and also read back thé reference code

[devoh747]

Any update?