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# Could you guys test my c-buffer algorithm??

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Hi guys I''m implementing a bsp/c-buffer, into my engine, and i would need that you guys test to see the speed you guys get on your machines. This test program (61kb) troughs 10.000 textured polygons to the screen with a z space distance of 0.1 between each quad. I would like to see, how much fps you people get with opengl z-buffer and with the c-buffer.. The c-buffer still has some bugs, but it''s just to see the performance. The test program is at www.geocities.com/brunomtc/test.zip Thanks Bruno

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hm

we wanna play, not watch the pictures

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With my lousy win2k GeForce drivers:

OpenGL z-buffer: 45 fps
c-buffer: 71 fps

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Humm, but you''re loosing some visible polys

Win 98 with MP3 on the background
PIII 500(P3BF) + GeForce DDR
Windowed
ZBUFFER (textured) : 62 fps
CBUFFER (textured) : 120 fps

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on the ati rage 128, with p3 500 and win98 se in fullscreen, textured mode
z: 17fps
c: 45fps

hope you could correct the errors, would be nice

we wanna play, not watch the pictures

Edited by - davepermen on October 8, 2000 2:08:40 PM

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nice one now all u have to do is have the ability for the viewer to change positions

http://members.xoom.com/myBollux

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z-buffer: 46 FPS [textured]
c-buffer: 35 FPS [textured]

system:

PIII 500
64MB
Win98SE
GeForce2 MX (Hercules)

I''ve had GetRight (d''loading a big zip), CrashGuard, Anti-virus, FireWall & CPU cooler (win98SE doesn''t do HLT''s ) on the background while testing your program.
I''ll test it later without all those programs because I think they''re hogging the CPU a bit

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richardve, you got me worried, i know i have to make some optimizations, but c-buffer slower than z-buffer

Bruno

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z-buffer: 53 FPS
c-buffer: 41 FPS

As you can see the Z-buffer with 10.000 quads is faster again (don''t ask me why.. )

I think it''s a good idea to make an option to use a Z or C-buffer.

btw. I''ve noticed that my GeForce2 MX from Hercules is very, very fast in OpenGL

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richardve:
What the hell..., that is strange..
I don''t understand how do the performance is slower with the c-buffer..
As i can see skyslayer, is also using a PIII(500), but with a GeForce DDR, instead of a GeForce MX.

Do you know if the GeForce DDR is much diferent than you geforce? I don''t have a clue on the performance of the boards.
thanks for the test

Bruno

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61 z-buffer
61 c-buffer

Geforce 256 DDR 32
800 AMD Althon
256 megs ram

----
Eurosprt1
--

Pilot Extrodinaire

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quote:
Original post by Bruno

richardve:
What the hell..., that is strange..
I don''t understand how do the performance is slower with the c-buffer..
As i can see skyslayer, is also using a PIII(500), but with a GeForce DDR, instead of a GeForce MX.

Do you know if the GeForce DDR is much diferent than you geforce? I don''t have a clue on the performance of the boards.
thanks for the test

Bruno

AFAIK the GeForce DDR is a little faster than the GeForce2 MX (GF2 MX = halve speed of GF2)

I can''t help you much with the c-buffer problem but if you''ve got another demo that you want to test just sent it to me.

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ok.., thanks richardve, and eveyone
I guess, i will have to mess with the code., everyone that tests this with a GeForce, don''t have such a speed optimization, or even have a loss of speed (like you )..

thanks mate

Bruno

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I found some interesting stuff in the newest documents about hardware T&L from nVidia.
Have a look at this snippet:

 Other optimizations: Culling* View Frustum  * Sphere, AABB, OBB, Cone, Cylinder* Occlusion  * Don't use span buffers or C-buffer -- too much CPU work

I think it would be better to detect wich card is used (with glGet(GL_RENDERER))
and switch to the c-buffer when a TNT or other card w/out hw-T&L is detected...

Hope that helped you

Edited by - richardve on October 11, 2000 5:48:22 AM

Edited by - richardve on October 11, 2000 5:49:11 AM

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celeron2 600@900MHz, diamond viper550 TNT

z buffer: 27fps
c buffer: 62fps

i think it would be useful to include both methods - one for fast processors & 1 for fast gfx cards

alistair

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pIII 700
geForce2 (running at 1x agp *groan* *damn mother board*)

z with tex = 43
c with tex = 88

-------------------------------------------------
Don't take life too seriously, you''ll never get out of it alive. -Bugs Bunny

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Celeron-300A, 64 MB RAM, Geforce256, 6.18 Detonator 3

Z-buffer
Line = 39
Tex = 60

C-buffer
Line = 42
Tex = 42

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I know what some of *our* problems are: V-Sync. Pre-disabling it, I got 51 fps on both. After disabling V-Sync, I noticed a 40% increase using c-buffer. Good algorithim. Where''d you learn about using a c-Buffer?

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The C-buffer algorithm is going to depend more heavily on available CPU and memory access speeds; the z-buffer on modern cards is going to dependent more on card power and onboard vs mainboard memory usage.

''Raw'' speed in a graphics technique is handy, the higher speed of a given technique, the greater the chances of throughput success for a total project. Note, however, that these statements are generally relative and will also relate to a given machine state.

A high-speed c-buffer alg is nice, but if 100% CPU is being used while, a hardware supported z-buffer is only using 12%, the overall throughput of a given application is likely to be higher with the z-buffer than the c-buffer!

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quote:
Original post by skyfire360

I know what some of *our* problems are: V-Sync. Pre-disabling it, I got 51 fps on both. After disabling V-Sync, I noticed a 40% increase using c-buffer. Good algorithim. Where''d you learn about using a c-Buffer?

My V-sync is always disabled...

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I''m sorry anon, but i have to disagree with you.,
anon, if a c-buffer is slower than a z-buffer, then why the c-buffer was invented ?? I know Crystal Space uses C-buffers, and CS is a high performance engine ..

You can check on tutorials on s-buffer and c-buffer at flipcode.., Jaap Sutter, is also giving me a hand

Bruno

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