ZDoom

is there any way for us to have access to them for this type of situation, or rather, is there any reason why that shouldn't be incorporated into the engine? With the recent advent of the awesome material system, it would be fantastic to be able to apply those to any surface that the author deems necessary.

Keep in mind that camera textures are not normal textures because they aren't created from some image but from the result of a render pass. They are set up differently than anything else and even though they appear to work as a brightmap in your example, even that is more or less a side effect of how the material definition uses textures and not an intended effect.

material texture "ATEX"
{
    specular materials/specular/ATEX.png
    normal materials/normal/ATEX.png
    brightmap "CAMTEX"
    glossiness 32
    specularlevel 1
}

material texture "CAMTEX"
{
    specular materials/specular/ATEX.png
    normal materials/normal/ATEX.png
    brightmap materials/brightmap/ATEX.png
    glossiness 32
    specularlevel 1
}

I am able to write a material definition like the following:
[code]material texture "ATEX"
{
specular materials/specular/ATEX.png
normal materials/normal/ATEX.png
brightmap "CAMTEX"
glossiness 32
specularlevel 1
}[/code]

The camera texture works as a brightmap for texture ATEX:
[imgur]https://imgur.com/evIBmbn[/imgur]

However if I try the following code:

[code]material texture "CAMTEX"
{
specular materials/specular/ATEX.png
normal materials/normal/ATEX.png
brightmap materials/brightmap/ATEX.png
glossiness 32
specularlevel 1
}[/code]

This whole material defintion is completely ignored and the camera texture is displayed in game as if it were just a plain texture.
[imgur]https://imgur.com/5qEelLn[/imgur]

Is this a bug or a feature or something that was just overlooked? It would be beyond amazing to have the ability to assign material definitions to Camera Textures.