Detail Texture Method

[Gildoran]

I think I've found a good way of doing detail textures... it has the advantage over regular modulation that it usually keeps the average color of the texture the same, whereas modulation must darken the average color. (this means you could turn the detail passes off for distant entities to save on fill-rate, and the player wouldn't notice a change in their brightness) The disadvantage is that the intensity of the detail depends on the detail texture, and can't be scaled by the material.

 

The way it works is as follows:

1. Create a greyscale detail texture with an average color of 50%. Parts of the detail texture that have middle-grey will keep the material the same color. Darker parts of the image will darken the material, lighter parts of the image will lighten it.
   
2. Add the following render pass at the end of your material shader:

   {
   blend gl_dst_color, gl_src_color
   map your/detail/texture
   scale 4, 4 // or however much you want.. you can also rotate it
   }

   You can add as many detail passes as you like, but keep in mind they use fill-rate.
   

[OrbWeaver]

Interesting idea, this is basically a modulate scaled by 2 as far as I can see. As you say, this will have the advantage of not being forced to darken the result.

[Gildoran]

Yeah... I got the idea as a way to simplify the blending used in the TDM main menu's background (it consists of two separate passes; one to modulate and one to scale), which was intended to look similar to "soft light" blending in image editing programs.

[Gildoran]

Ok, I've come up with a variation of this method that allows you to scale the intensity of the detail texture, but it requires two passes and an inverted detail texture. (though most would probably look just fine without being inverted)

 

{
blend gl_zero, gl_one_minus_src_color
map your/detail/texture
rgb detailAlpha
scale 2, 2 // or whatever
}
{
blend gl_dst_color, gl_one
map _white
rgb detailAlpha/(2-detailAlpha)
}

In the above example, replace detailAlpha with whatever you're using to determine detail intensity. (for example, parm3 might be good, as would a constant)

[Gildoran]

Ok, I've added this to the wiki.