The true nature of surfacelight/lightimage? (shader)

[FarbrorGnur]

I've noticed that when using surfacelight and lightimage in textures, it creates a weird inconsistent effect. Round lights are showing up on the surface that emits light. Makes it hard to find the right mood!

 

Here are two screenshots with an exaggerated surfacelight value, to show it.

 

https://dl.dropboxusercontent.com/u/58757568/surfacelight1.jpg

 

https://dl.dropboxusercontent.com/u/58757568/surfacelight2.jpg

 

Shader (non-exaggerated version):

 

textures/Bootland/ceiling1
{
qer_editorimage textures/Bootland/ceiling1.tga
q3map_lightimage textures/Bootland/ceiling1.tga
q3map_surfaceLight 30
{
map $lightmap
rgbGen identity
}
{
map textures/Bootland/ceiling1
blendFunc filter
rgbGen identity
}
}

 

Non-exaggerated screenshot: https://dl.dropboxusercontent.com/u/58757568/surfacelight3.jpg

 

 

I'm aware that it uses itself as a lightimage. This is so that the texture that is emitting will be affected by the light in the same degree as its surroundings (ideally..!)

 

Any ideas?