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[Untelligent]

Thanks to Steelion in this topic, I discovered two, maybe three rather interesting effects of setting color values to something higher than 7.


Values 8-15

Setting the value of the foreground or background color to anything from 8 to 15, with the brightness value at Zero, appears to set it to the same colors of the "standard" values of 0-7, in the same order. However, the brightness value will effectively be Nonzero. Although this may not seem very interesting at first, it also applies to background color, meaning that you can use this trick to give the background a "bright" color, which is not possible using the standard values.

Setting the foreground or background color to 8-15 and setting the brightness to Nonzero has unusual effects that appear to affect both colors, even if one of them is a "standard" value. I'm not sure of the specifics yet (although the colors appear to be constant, as opposed to the higher values I'll get to in a few seconds), and I will continue to research that later. Secondly:


Values higher than 15:

Setting the foreground value to anything higher than 15 has an odd effect. At first, I thought the creature was cycling through several colors, almost always green and occaisonally gray. After a minute or two of careful examination, I realized that the creature's color depended on the corresponding color of the tile it was standing on. Xenomorph has a more technical explanation in the topic I mentioned earlier.

Setting the background value has the same effect, but since almost all (if not all) walkable tiles have a black background, the creature's background will probably be black in all cases except on the unit list.


Note: setting the brightness value to anything other than 0 or 1 appears to act as 1. This is probably because it only checks for zero or nonzero numbers.

My to-do list:

- find the exact effect of setting a color to 8-15 and setting the brightness to nonzero
- check for effects of negative values

[Mephansteras]

Huh. Very cool. Keep us posted.

the creature's color depended on the corresponding color of the tile it was standing on.

Oooh, I should mod in a chameleon creature using this trick!

[Jifodus]

If you want the technical spoiler...

Spoiler (click to show/hide)

There are 15 colors internally defined (in an array).

In slots 0-7 are the standard colors.
In slots 8-15 are the brighter colors.

When DF is converting a bright foreground color, it adds 8 to the color number, thus causing it to access the colors, which is the behavior you have pointed out. When the input number falls outside the range of 0 - 15, then it'll ignore the attempt to change the color, hence causing the chameleon effect.

Note: DF uses signed 8-bit integers to index colors, making the possible value range [-128, 127] or [0, 255]. However, only [0, 15] are actually used.

More specifically the code used is:

Code: [Select]

// enabler.cpp, lines 1188 - 1197, BC windows source code
void convert_to_rgb(float &r,float &g,float &b,char col,char bright)
{
short ci=col+(bright!=0)*8;
if(ci>=0&&ci<16)
{
r=enabler.ccolor[ci][0];
g=enabler.ccolor[ci][1];
b=enabler.ccolor[ci][2];
}
}


[Steelion]

Well, I guess I'm proud to have discovered this quirk. It was awfully weird when I saw it first. Didn't occur to me that it was taking the ground tile color. 

[Neoskel]

This means we can have actual black objects instead of always dark gray. Cool.

[i2amroy]

This is awesome! Can you say, chameleon beast.