Occlusion and BSP

[Idiot_stupid_head]

I'm making a map for U1 and UT1 which both use the same BSP and occlusion methods. Here is what I've found so far:

I cannot use more than 150 BSP polies on screen on wide open areas, it's the safe max limit for low end PCs. Indoor I can go for 300 or so.

Textures under the same resolution renders nearly 2x as fast if they are s3tc compressed, I belive that my shit MX440 has a increbly low fillrate to gain that much performance just by compressing texture as s3tc over palletized. Also, upscaling textures seems to give me nearly the same boost in fps. In contrast, downscaling textures seems to give slow down rendering by the same ammount as upscaling does speed up rendering.

UT2 BSP doesn't occlude, why did Epic choose to drop BSP self occlusion?

UT2k7 seems to have no zone portals nor antiportals, how is that auto occlusion possible?

 

[Idiot_stupid_head]

It seems that one 512 wide brush with one 512 wide texture renders faster than the same texture split in two 256 wide pieces on two 256 wide brushes.

 

[Idiot_stupid_head]

I'm comming to the conclusion that using larger textures and fewer brushes, thus, fewers polies on screen is better, at least in UT1 engine.

 

[Idiot_stupid_head]

shit! 1024 x 256 palletized textures look blury.

 

[Simon F]

0 has a increbly low fillrate to gain that much performance just by compressing texture as s3tc over palletized.

Palette-based textures are unpleasant to support in hardware so are you sure they are even available? I would think it's more likely that the palette is expanded to a full 24/32-bit texture.

 

[ERP]

Palette-based textures are unpleasant to support in hardware so are you sure they are even available? I would think it's more likely that the palette is expanded to a full 24/32-bit texture.

On that period NVidia card they were "available" but the run at half speed for the obvious reason.
Current cards don't support them at all.

 

[ERP]

UT2 BSP doesn't occlude, why did Epic choose to drop BSP self occlusion?

Because its not worth the CPU cycles on modern hardware .

 

[Idiot_stupid_head]

Because its not worth the CPU cycles on modern hardware .

Is UE3 occlusion done on the GPU?

 

[Idiot_stupid_head]

On that period NVidia card they were "available" but the run at half speed for the obvious reason.
Current cards don't support them at all.

Oh my bad... Then this explains why a voodoo 3 card runs UT in glide with detail textures at 1024 x 768 x 16bits at over 50fps, whereas the mx440 is running at 32bits at much better max fps but with a stupidly unstable fps.

 

[ERP]

Is UE3 occlusion done on the GPU?

UE3 renders front to back.
They submit conservative bounding volumes, and use the occlusion result to decide whether to submit the actual objects.
They may do something different on PC.