I got it. We need a normalized lightness texture.
Lab colorspace Lightness channel + normalize:
@MirceaKitsune
Do you mind to update the color textures. Extract lightness channel. Normalize it. Store as lightness.png.
Looking at the normalized lightness texture right now. What we need is actually an ambient occlusion texture.
edit:
The rendering would go like:
1. Alpha blend color with skin.
2. Multiply by ambient occlusion.
Any volunteers to bake ambient occlusion textures for our cars?
@joe
How fit are you in fixed function OpenGL? Alpha + multiply blend should be possible without shaders too I think.
Yeah. I just converted the current skins to a grayscale png and renamed them to color.png, then made a copy of it the body01 with the parts that musn't be colored. Hope it is ok and working now.
I checked in the color selection gui (rev 2708). It is non functional for the moment. Comments are welcomed.
I've got the skins ready (needed some fixes here and there).
Should I overwrite the current body textures with the new ones or give them another name, body-00.png instead of body00.png?
I would tend to overwrite the existing ones and point last release users to the previous vdrift-data revision and update cars.vdrift.net accordingly.
The new skins are in trunk(r554).
There are still a number of cars using old skins, need some more work to get them ready for coloring: G4, M3, M3D, NS, TC, XM, Z06. Volunteers are welcomed.