Vertex colors

Vertex color channel

R= control ambient occlusion of the model during night, most (except for night lights) will have it topped to 255 so it gets very dark at night

G= Artificial light, topping this to 255 will give a self emissive power to the object. Used for objects near to lamposts or light sources to simulate ambiental lightning

B= Moonlight illumination, how much the object reflects of the moonlight. Rockstar uses this at very frequent situations to avoid a fully dark atmosphere

Painting leaves using shaders for tree or with _um param. (these shaders will make object move on wind):
RED - every part painted on red will move on wind
GREEN - every part painted on green will not move on wind
Illum channel

Black (0, 0, 0): Texture slot1
Blue (0, 0, 255): Texture slot2
Green (0, 255, 0): Texture slot3
Light Blue(0, 255, 255): Texture slot4

Alpha channel

Green - makes lookup visible
Red - makes illumination color visible