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Comment by ridaj | Hacker News Reader

I think the real space saver is not necessarily "hexadecimal system" per se but the "bitmapped graphics" technique that they seem to be referring to. Nowadays, graphics information doesn't tend to be packed in bitmaps, either manually or otherwise. It's pretty inconvenient for processing to have everything bitmapped (compositing, collision detection, etc.) and they probably wouldn't do it if it weren't for the space savings

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Yes you are correct. Take something like the Super Nintendo, it typically displayed hundreds of colors on screen, however each graphical element could have a maximum of 16 colors (4 bits).

The way they solved this was by having CLUTs (color lookup tables), so for the Super Nintendo (if my memory serves me) you had 16 different CLUTs that you could assign to a graphical object, each able to contain 16 unique colors.

This is what made something like the Super Nintendo graphics look so much better than say the Amiga 500, both used bitmap graphics, but the Amiga did not have a CLUT solution, so you were stuck with 32 colors except for more advanced graphic modes which weren't really usable for games.

Bitmaps do not save space relative to, say, a vector representation -- but they do save CPU time. And they were hella convenient to work with for compositing and collision detection because there was specialized hardware to do just that. The sprite hardware in the video unit of most game consoles could draw bitmaps with transparency just as the electron beam arrived at the affected pixels. And it would signal an interrupt when two sprites collided (and often alert the CPU via registers which two sprites collided).

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