free forum make a forum for free message boards free forum hosting free phpbb forum phpbb create free forum

bphelps · Joined: 07 Sep 2008 Posts: 1

Hi Pete,

I'm in gamedevz and tried your game out (finally). Unfortunately I had poor performance on my laptop. The specs are dual core 2GHZ, 2GB Ram, and ATI X1400 running Vista.

When a level wasn't loaded, I had 60 FPS, however, when I loaded a map, my frames dropped to between 4-6 FPS. I thought perhaps it was fill rate limited, but I managed to get away from the level and look away and still had low FPS. PIX confirmed that fill rate was not the issue as the pixel shader is very simple (PS 1.1, <5 instructions)

I used the HUD in PIX to get an idea of where the performance bottleneck is to help you debug, and I found the following measures:
~150 SetRenderState calls
~225 SetVertexShader/SetPixelShader calls
~122 SetTexture calls
~227 DIP calls

It is likely that all these state changes are causing the bottleneck. Ideally you could render the level with much less state changes. IE, put the entire map in a static vertex buffer, set the render state once, set the effect once, and draw the level in one pass. This would likely yield better performance on lower-end hardware.

I ran it through NProf to get a better idea of the perf bottleneck and it spent a lot of time in Present(). This suggests that it is GPU bound, but its pretty meaningless, because since it is running in a Window, the app is sharing the GPU with Vista, so it'd have to run in fullscreen mode (where it has exclusive access to the GPU) to know for sure... I couldn't find a fullscreen command to try it

My intuition says that having less DIP and less state changes would greatly increase the performance on my card (and in general)

Just some ideas for helping it run on lower-end hardware Smile

If you need any other perf ideas just holla back. I would like to give it a real try, it looks like a neat project!

FYI, my laptop runs Counter-Strike : Source and Battlefield 2142 ok, so it isn't a terrible card, but definitely no 8800 either Smile

Again best of luck! Its very impressive !
-Bryan

Ubrasaur · Site Admin Joined: 20 Jul 2008 Posts: 25

Thanks a lot for all the diagnostics! This does seem to be a common problem right now for laptops.

Actually I've been working the last couple days to rearrange things so that I can go easier on the GPU, so I have hopes this will fix this problem with laptops. (The version that is up right now is very inefficient, it is changing the shader for every object in the world, and every map 'chunk', so I think there is tons of room for improvement on that). So far for my local version I have the map rendering fixed up, and I was about to start the object rendering when I checked this board. Thanks again for all the diagnostics!

Free Forum