I am just watching this tutorial https://www.youtube.com/watch?v=HwUnMy_pR6A and the guy (who seems to be pretty competent) is using a single array to store and access the pixels of his to-be-rendered image.

I was wondering if this really is the best way to do this. The alternative of Multi-Array does have one pointer more, but Arrays do have an O(1) for accessing each index and calculating the index in a single array seems to take one addition and one multiplication operation per pixel.

And if Multi-Arrays really are bad, can't you use something with Hashing to avoid those addition and multiplication operations?