looping through all possible colors?

[Kirl]

So I've got three color values (r, g, b) that each range from 0 to 255 and I want to step through them so that every pssible combination is made at least once.

Any bright, loopy ideas on how to achieve this?

[Xetick]

3 nested for loops would be the way to go

[Jim]

Might be a significant saving if you did

Code Select Expand


for (a=0; a < (1<<24); a++)
{
r = a&0xff0000;
g =a&0xff00;
b = a&0xff;
}

Jim

[rain_storm]

Might be a significant saving if you did

Code Select Expand


for (a=0; a < (1<<24); a++)
{
r = a&0xff0000;
g =a&0xff00;
b = a&0xff;
}

Jim

Ever the optimist (optimizer?)

[Xetick]

Might be a significant saving if you did

Code Select Expand


for (a=0; a < (1<<24); a++)
{
r = a&0xff0000;
g =a&0xff00;
b = a&0xff;
}


I would call premature optimization on this one. First of the code wont work as expected since it doesn't shift down the values. This should be more correct

Code Select Expand


for (a=0; a < (1<<24); a++)
{
r = (a&0xff0000)>>16;
g = (a&0xff00)>>8;
b = a&0xff;
}

But since its doing 3 ands and now 2 shifts per color its probably actually slower then the more clearer 3 for loops

But as always, dont assume, if this is your bottleneck then test whats faster

[Jim]

It depends if you need the colour components in the lower 8 bits or if you want colour values you can stick down straight on to the screen, then there'd be no shifting or masking.

Jim

[Kirl]

Thanks for the help! I wanted to try a more random solution and I ended up using kind of a clumsy aproach. I now change r,g and b each with a random speed, which seems to work alright in smoothly shifting through the colors in a randomish manner, Cleaner solutions always welcome.

Code Select Expand


if(r+rv >= 240) rv = -1 + Math.random()*-step;
else if(r+rv <= 20) rv = 1 + Math.random()*step;

if(g+gv >= 240) gv = -1 + Math.random()*-step;
if(g+gv <= 20) gv = 1 + Math.random()*step;

if(b+bv >= 240) bv = -1 + Math.random()*-step;
else if(b+bv <= 20) bv = 1 + Math.random()*step;

r += rv;
g += gv;
b += bv;


[hellfire]

So the question was how to step *smoothly* through all possible colours 
You can probably get better control over your colours by working in HSL.

[elizdaavis]

HSL(hue, saturation, and lightness) and  HSV(hue, saturation, and value) will help you solve the problem..