Here is an example use case:


I created a 3D model of a Half-Life style health station based on LossForWords textures. The screens utilize canvas textures to draw the status of the station. All that works fine, the problem is the contents of the screen should be rendered full bright, but even with bright maps, the brightness is directly dependent on sector light level. I could make the model's actor full bright but the whole model shouldn't be full bright so that won't work either.
I can only think of two workarounds, neither of which is appealing or ideal.
1: Create a seperate non-canvas texture for every possible output the screen can display and use A_ChangeModel to display them on the station. This would require me to create hundreds of entries in Textures and GLDEFS.
2: Create the station out of map geometry and set the lines brightness to 256. Then use the Dim function to darken all the parts of the texture that should not be full bright. This method is what I'm currently using in my mod, having to create tons of dim zones all over the texture is far from ideal and I still haven't figured out the math to get the dimmed parts to appear exactly right at different sector light levels. On top of that, dimmed parts of the texture do not appear right when lit up by dynamic lights.