Storing Colors in Lua

[Aezay]

The most commen way to store colors in Lua is using tables, like this

local color = { r = 1, b = 0.5, g = 0.75 }

Although I prefer this way, because it works with unpack()

local color = { 1, 0.5, 0.75 }

But I've been thinking, wouldn't storing colors in a single number be more efficient, as that would use no tables. Then you just have to throw them through a function like this to get the rgb values.

function DecodeColor(color)
	local r = bit.band(bit.rshift(color,16),255);
	local g = bit.band(bit.rshift(color,8),255);
	local b = bit.band(color,255);
	return r / 255, g / 255, b / 255;
end

print(DecodeColor(0xff80c0))

[Seerah]

I'm confused.... Wouldn't you be doing more work there? I'm a beginner, so please enlighten me on why having a function with three bit.band calls (referencing another function) be better. I thought lua was very efficient with table lookups?

[Slakah]

I very much doubt it would make enough difference to be worthwhile.

[Akryn]

You gain a bit of memory efficiency at the expense of a bit of CPU time. It won't matter either way most of the time, but generally it's better to be CPU efficient. Still, if you're transmitting a lot of data to other users, quickly, or storing huge amounts, then there's a point where this kind of compression will be useful.

[Aezay]

Yes, there would be times where this is not the ideal solution, but lets make a scenario where you just have to keep a lot of user defined colors which are stored between sessions, and all you do is to apply them when variables has been loaded. In such a case, wouldn't this be ideal, rather than loads of tables?

[Exawatt]

Originally Posted by Aezay Yes, there would be times where this is not the ideal solution, but lets make a scenario where you just have to keep a lot of user defined colors which are stored between sessions, and all you do is to apply them when variables has been loaded. In such a case, wouldn't this be ideal, rather than loads of tables?

Depending on how they're going to be accessed, you could try using one table, like so

colors = {
	[1] = 255, --1r
	[2] = 0, --1g
	[3] = 0, --1b
	[4] = 255, --2r
	[5] = 255, --2g
	[6] = 0, --2b
}

Then use something like this to get your colors out:

whichColor = 2

r = colors[3 * whichColor - 2]
g = colors[3 * whichColor - 1]
b = colors[3 * whichColor]

Or something like that. That way, you're only using one table for all your colors.

[Aezay]

Exawatt
That is a good alternative, didn't even think of that, thanks for the suggestion.