View Full Version : FPS vegetation increased performance
Jun 6 2008, 00:33
this is a little little tutorial on how to increase your vegetation performance impact on FPS:
Quote[/b] ]I noticed one thing:
What really causes lag is the Pixel shader and Vertex Shader of the _ca texture (the vegetation) and the shadow.
Unfortunately, we can't edit the shadow, since it's hardcoded. But we surely can edit the PS and VS:
for vegetation, you normally use VertexShader: NormalMapSpecularThroughNoFade and PixelShader: NormalMapSpecularThrough.
If instead of that PixelShader, we add the simple PixelShader: NormalMapThrough but with the flag NoAlphaWrite, we will have the SAME effect, but with an increase of FPS and performance http://forums.bistudio.com/oldsmileys/smile_o.gif
Jun 6 2008, 09:02
Interesting Linker Split - did you do large scale tests yet?
Maybe bring the idea to the attention of BI if it works well. http://forums.bistudio.com/oldsmileys/smile_o.gif
By using NormalMapThrough instead of NormalMapSpecularThrough you remove specular highlights on leaves, which makes the computations easier (shader is shorter). I understand this can bring better performance.
As for NoAlphaWrite, I do not see how could it bring any performance. Did you measure it without this flag? I expect NoAlphaWrite to cause significant artifacts when shadows are casted on the tree using it, therefore I suggest avoiding it.
What sort of FPS changes are you seeing in ArmA itself? Buldozer running in a window might not be that representative.
I thought it was mainly the specular setting that would cause the bump in preformance, as we have seen that happens when using the LowPlants mod. I believe that using just that method you would get a performance slightly worse than using the lowplants mod. Just my opinion.
Jun 6 2008, 23:07
I checked also without NoAlphaWrite flag, it's the same result...
Also, seems that what really causes lag is (obviously) shadow casted on both ground and objects.
I got a slightly FPS increased performance when testing this new RVMAT on my HDT island (which got a lot of plants), but if I enable then the shadow setting, then FPS decrease again http://forums.bistudio.com/oldsmileys/sad_o.gif
Can the textures have a performance impact on FPS?
I mean, I saved my vegetation Normal map with _novhq suffix, instead of _non one... but I got no differences.
I also tried to use the normal map parallax (_nopx) and the normal map Fade (_nof), still the same...
Why you BIS left the TexConvert.cfg editable, while even if i try to change the compression method for one class (for example from DXT1 to DXT5), texView 2 still saves the texture with the default compression method?
Jun 6 2008, 23:33
OK, this is of interest to me, as I have large forests of custom trees http://forums.bistudio.com/oldsmileys/smile_o.gif
Jun 7 2008, 01:32
Quote[/b] ]Yes, we found solution how to reduce overdraw about 25%, but this solution need diferent representation of tree surfaces and vertexes (diferent model and binarisation of this model and diferent way, how to switch vegetation lods). So it's not usable for curent vegetation data and will be used in next projects. Alphatextures mean also masked textures (that is 1bit transparency or opacity if you want and we use them)
This is what O'hara said on this forum (I can't find the source)
Basically BI will not implement it until ArmA2... is this still happening? Is this still true?
if so, basically we island makers are screwed. http://forums.bistudio.com/oldsmileys/confused_o.gif
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