I modeled stadium lights and added environment maps to semi-transparent glass. Since there are several bulbs on each stadium light, several lights for each baseball field, and several baseball fields - the numbers of reflections/transparencies going on start to add up. I'm trying to make the scenery as lean as possible for the CPU, but don't want to sacrifice details if they are GPU-intensive or are have minimal impact. Does anyone know if these are big performance eaters? The cube map is 512x512 btw.  

Transparency is not so much a problem I think as it is a simple check against the z buffer.

 

Specular and environment maps can be more of a hit. I find that when modelling an aircraft changing the textures from plain diffuse to include the bump, spec and env mapped can easily knock off 10% of the framerates. But that is for a whole aircraft with a lot of textures.

 

Make sure your environment map is mipmapped as this will make a big difference and use the smallest possible amount of texture on your glass that you can get away with (less pixels to calculate means better framerates).

 

I use a 512 pixel environment map for my aircraft (so much smaller than the 1024 ones and not much loss of detail) but for scenery you may like to try 256 or even 128 pixels. Depends on how much detail you really need.

 

My personal pet hate is developers who use GMAX, decide they don't want any specular on something so they just set the specular colour to 0,0,0. Ugggh. You still have specular calculations going on even if you can't see them. If you don't want specular select "No Base Material Specular = True".

 

If in doubt you can always do a framerate test, make one model with all your fancy texturing and another with minimal textures. Make sure they have the same guid and switch them in and out of your model library and see what the actual framerate difference is.

Thank you for the feedback. I had to redo the MDL export because of geometry issues so thought I might also reduce the texture demands if it could help (had some low FPS last night testing with stormy ASN weather and the Lancair Legacy). I redid the models without the environment maps and I can't say it was a huge improvement, but there seemed to be a 2-4 fps bump and more smoothness during turns. I think I'm going to leave them out. It was nearly impossible to see the reflections anyway unless I was standing still on the ground right in the middle of a baseball field. In the air, at any kind of speed, even piper cub speed, it was kind of a useless feature.