SEVdemo: why does it eat up 100% cpu?

[BBegemott]

1. Start taskmanager.
2. Open SEVd game. ALT+TAB from it.
3. Open Space Empires V Demo/Data/DebugSettings.txt
4. Set TRUE to 'Generate Game Debug Log' and 'Debug Section Main Drawing Loop'.
5. ALT+TAB into the game. Wait for 10 secs doing nothing. Dont move the mouse or press any key.
6. ALT+TAB from it.
7. Go to taskamanager. You should notice your processor has just been at 100% cpu. Why? You did nothing.
8. Go to Space Empires V Demo/Backup/SE5Game_Log.txt
9. Count, how many strings 'Adjust camera position' does this log file have?
10. Mine has got several thousand.
11. So here is the answer. The game moves the camera, though you dont.

[Arralen]

Turn off loging and debugging routines and you'll be fine

[NullAshton]

Most games take up 100% CPU even at the menu. It's nothing much.

[Baron Munchausen]

It'll use 100 percent of CPU even without the debug settings. This is true of all 3D 'real time' games. They are designed to go for maximum performance in all situations. Every bit of available CPU will be claimed to keep those frames updating as fast as possible. And yes, the main display is a real-time 3D image. If you zoom in you can see the planets rotating.

[PDF]

NullAshton said:
Most games take up 100% CPU even at the menu. It's nothing much.

Yep, that's the reason : they can't eat up *more* than 100%, else they'll do !

[Raapys]

Does it change if Vsync is on?

[NullAshton]

No... it's just where it's rendering your beautiful 3D graphics! Try that on any game. You'll find that it still takes up 100% of your CPU doing nothing. That's because the CPU is processing the data for the next frame to send to the GPU once it's done with the current frame. Something like that, I think.

[Arralen]

It does not always run at 100%.
I'm running the demo on my Athlon64 3GHz with 1GB RAM, 6600GT graphic, detonator 91.31 under W2k and it does only uses 90% CPU on average, rendering 75 fps in 1152x864x32 .

ButI think there's a missunderstanding: That windows reports 100% CPU in task manager does not mean the CPU is really working hard all the time.
Look at the se5 interface - it runs basically in front of everything, in fullscreen, as most games do. To do that, it creates its own "drawing surface" and does not rely on the explorer to generate its windows/menues.
Same with the event loop: to maximize responsiveness, it uses its own complete with its own 'idling' .. . If the actual workload from player input or AI calculations is low, first the FPS go up as the game can render more frames - up to some limit set by the programmer. After that, the program uses its own idling routines, therefore the win taskmanager can never realise that the CPU is in fact doing nothing.