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[Bug Update - Repost to beta: 481] Sliding/Collision performance (Community)
[Bug Update - Repost to beta: 481] Sliding/Collision performance // CommunityubermonkeyApr 26, 2003, 10:26pm
Recent experimentation has shown that a massive performance drop related to
collision detection/sliding ONLY takes place (on my system) while in D3D (T&L or no). Tests with D3D indicate that colliding with an object, even if no movement is being made (face a flat surface at a 90 degree angle), FPS can often be cut in half (60 drops to 30) The same test with OpenGL and software indicate that no more than 1 FPS is ever lost while colliding. I also noticed that sliding is generally much smoother in OpenGL, even though OGL is mostly useless as far as speed and accuracy of rendering. This seems to indicate that the glitch which causes the FPS to plummet is not actually in the collision code but (somehow?) related to the rendering. Anyone able to confirm or deny these results? UberMonkey dionApr 26, 2003, 11:10pm
How did you conduct these "tests"?
I don't think rendering can cause anything of the sort. The rendering simply shows your view and the objects and everything whereas the programming determines if you can or can't move forward any longer and such. I don't think the rendering engine really gives any ouput to the programming code, either, except if there is an error and for the frame rate. -Dion [View Quote] Tests with D3D indicate that colliding with an object, even if no movement is being made (face a flat surface at a 90 degree angle), FPS can often be cut in half (60 drops to 30) The same test with OpenGL and software indicate that no more than 1 FPS is ever lost while colliding. I also noticed that sliding is generally much smoother in OpenGL, even though OGL is mostly useless as far as speed and accuracy of rendering. This seems to indicate that the glitch which causes the FPS to plummet is not actually in the collision code but (somehow?) related to the rendering. Anyone able to confirm or deny these results? UberMonkey ubermonkeyApr 27, 2003, 5:45am
[View Quote]
I'll tell you exactly how. I teleported myself directly in front of a flat
object (in this case table2.rwx) facing at an exact 90 degree angle. I then proceeded to walk directly towards the table until colliding with it. I then stopped holding the forward key and waited for the FPS meter to stabilize. standing FPS: 60 I then held the move forward key, which resulted in absolutely no movement since I was at a 90 degree angle to the object, and waited for the FPS meter to stabilize. standing FPS while holding move forward: 30 Then I tried it with other objects. Always similar results. I then repeated the test in all other video modes. I found that it occurs more severely in D3D (regardless of T&L). While in OpenGL, colliding with an object does not appear to affect FPS to as severe a degree (often losing no more than 20% of fps) (though the overall FPS is lower and there are a number of horrible z-buffering problems). The same appears true in software, though an accurate determination here is difficult considering the low FPS (6). I'm not necessarily implying that the rendering has caused this glitch, however there must be some reason why the OpenGL engine does not display this issue, yes? Or else the percent lost decreases as the FPS decreases, due to the program taking less samples per second and therefore doing less collision calculations overall. ... confirmed, D3D also loses less at lower FPS. However testing 60fps in OpenGL drops to 45, while D3D still drops to 30. I dunno. Monkey ubermonkeyApr 27, 2003, 5:49am
Oi!
Here's an interesting one. In D3D, starting at 93FPS, still drops directly to 30 and sits there. Tried others between 60 and 100, still goes to exactly 30 fps. kahApr 27, 2003, 9:06am
"ubermonkey" <henry at wcalliance.com> wrote in news:3eab8b6f$1
at server1.Activeworlds.com: > Oi! > Here's an interesting one. > In D3D, starting at 93FPS, still drops directly to 30 and sits there. > Tried others between 60 and 100, still goes to exactly 30 fps. Probably because of the setting to keep framerate above $foo FPS. KAH ubermonkeyApr 27, 2003, 3:27pm
However I was under the impression that this setting only affects the
visibility, which in all tests I have locked to 100m. I just now tried setting it to 10 fps, however the browser's FPS still drops to exactly 30 as long as it's over 30 to begin with (otherwise, it displays similar behaviour to OpenGL, losing about 25% fps on collision) [View Quote] ubermonkeyApr 27, 2003, 3:35pm
A quick intall of 3.3 and a repeat of the same tests gives the same results.
IOW, this has nothing to do with 3.4 specifically.. whatever the problem is, it most likely comes from an original botched sliding implementation that has not been altered in 3.4. (as a note to those complaining about sliding in 3.4 being unreliable on terrain, try 3.3... it's even worse.) goober kingApr 27, 2003, 3:54pm
Negative. On my system, the collision detection lag occurs in all video
modes except software. It's quite noticeable for me, since I almost never get framerates above 20FPS unless I'm out in the open. Goober Specs -- Pentium III 700MHz 384MB RAM at 66MHz GeForce2 MX 32MB VRAM 56K Dialup modem Windows 98 SE DirectX 9.0 DirectX w/ T&L mode [View Quote] -- Goober King Lagging like a mosquito in amber... gooberking at utn.cjb.net wingApr 27, 2003, 7:06pm
I just did a repeat of these tests, and I lose no more than .1FPS (From a
starting point of 64.1) in D3d/T&L both while sliding along the object at varying angles and pushing up against it perpendicularly. See the chart for my full results. Sliding count is the LOWEST that I see, not constant. Mode Standing Still Pushing Sliding D3D/T&L 64.1 64.1 64.0 D3D 64.1 64.1 64.0 OpenGL 64.1 64.1 49.9 Software 12.1 11.8 11.8 Vis locked at 200 - pushing up against boardh4m rotated 90 degrees around the X axis to act like a "wall". looking towards directional light source over user defined light sources, over animated water, under a 3-layer sky and pushing upwards on a hill. No performance hit to speak of. What's your system configuration? Test platform: WinXP Pro w/ SP1 GeForce 4 Ti4200 128mb Asus A7n8x Deluxe motherboard AMD Athlon XP 1900+ (1.6GHz) 256mb DDR single channel at 133MHz 56k Winmodem DirectX 8.1 (WinXP stock) Running software: WinXP StyleXP service w/ custom WingCorp skin mIRC PC-cillin 2002 WinZip Quick Pick PowerStrip InterVideo WinCinema Manager Winamp Agent Daemon Tools w/ 4 virtual drives enabled CloneCD w/ 8 virtual drives enabled 3Com network diagnostic tool nForce Tray Options Winamp 2.90 (Playing a variety of songs - framerate fluctuated during track change, so those results were thrown out) Outlook Express AOL Instant Messenger Windows Messenger not running - removed from system. [View Quote] wingApr 28, 2003, 5:18pm
And Shamus just made a post in Beta saying that the slowdowns may be caused
by debug logging being turned on - which I do not have enabled. [View Quote] |