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Antialiasing

Started by QWERTY 26 replies 950+ views
Original Post
QWERTY
QWERTY
Hello guys! I''m trying to set up full scene antialiasing on my GeForce 2 but I have problems to find suitable pixel format supporting multisample buffer. I''m using WGL_ARB_pixel_format extension but it seems no one of 46 different pixel formats support multisample buffer. I don''t know what I am doing wrong. I have quite good experiences with OpenGL. It would be very appreciated if someone could point me on an article or source code of a demo showing how to use antialiasing with OpenGL. Please help.
QWERTY
QWERTY
Ok, I missed the previous post that was about the same topic. Sorry. If you know about some code example about antialiasing please let me know. Thanks in advance.
vincoof
vincoof
Do you have the latest, 40.7X drivers from NVIDIA ?
QWERTY
QWERTY
It''s a beta relesa though. So I have downloaded the latest non beta release that is vesion 30.82 because I had preblems with NVidia beta drivers on my Manli card in the past. Maybe it has changed so I will try to use that one recommended by you. Thank for your reply.
vincoof
vincoof
No, please don''t download 40.7X drivers ! I just asked because there is a known bug in multisample with 40.7X drivers. If that the drivers you were using, it could have been the reason why you pixel formats failed.
QWERTY
QWERTY
I have been using version 30.82 and there was no ARB_multisample extension supported. Today I have dowloaded new 40.7x driver and because it is a beta release I have some problems with it but even in this version there is no multisample extension available. Despite of this fact I can enable or disable FSAA via control panel''s display settings however not in my application as I want though. The ARB_multisample extension is not listed in supported extensions of the driver and there is none pixel format with a sample buffer available. In the old driver from Manli the manufacturer of my card there was multisample extension supported but none appropriate pixel format available too.
vincoof
vincoof
Well IMO the best you can do is crossing your fingers while multisample bugs are being fixed in the current beta drivers. According to the fact that you "can enable or disable FSAA via control panel''s display settings", I''m assuming there is a way to provide the OpenGL functionality.

btw, do you notice a significant framerate/fps drop when you enable FSAA ? By "significant", I mean is it 2x slower, 10x slower or 100x slower ?
Compiler Fiend
Compiler Fiend
QWERTY:

nVidia''s extension info:
http://www.nvidia.com/dev_content/nvopenglspecs/GL_ARB_multisample.txt

ATi''s extension info:
http://www.3dlabs.com/support/developer/EXTmanpages/multisample.txt

Link to the other thread about AntiAliasing:
http://www.gamedev.net/community/forums/topic.asp?topic_id=118970

vincoof:

AntiAliasing doesn''t have that much of an impact on current-generation technology (Geforce 4/Radeon 9000/9700).

The Geforce 2 series of cards takes a HEAVY hit because FSAA is mapped to non-specialized HW registers (unlike current-gen hardware.)
QWERTY
QWERTY
I have discovered that I neglected the fact I can enable FSAA manually in display settings only in non beta release of the driver (v30.82). In beta release (v40.7x) I am unable to do it even manually. And yes, the drop down in fps was significant. A Quake3 scene was rendered about 2x slower with FSAA enabled.
I hope that NVidia will do a bugfix and in the next release there will be FSAA fully supported. I would like to implement this feature in my engine. Thank you guys for your replys again.
vincoof
vincoof
The 2x drop is not that much for a GeForce2 ! It is reasonable to think that FSAA is done in hardware, otherwise it would have been even worse. That means that yes definately you can use the multisample extension, be it sooner or later. Have you tried to query the pixel formats with the non-beta drivers ? Supposedly you tried already and failed to find a suitable pixel format, but I''m just wondering anyhow...

The "bugfix" is a bit of a complex problem. Not that the bug is complex, but the willing to fix the bug is not certain ! I recommend you to follow the topic at opengl.org forums where profesionals from NVIDIA recently posted about it.
(I can post a few links to the threads if you don''t find them)
QWERTY
QWERTY
As you supposed I have tried to query a pixel format for all three versions of the driver I have ever installed even a non-beta release but there was no one with sample buffer and there was no multisample extension either. I have recently found at opengl.org forum that multisample extension is available only for Geforce3 and above. I don''t know why. I don''t see any problem here especially if Geforce2 supports FSAA in hardware. So why it is available only for manual configuration from control panel? I am confused.
QWERTY
QWERTY
Ok, I have made much deeper search in the forum at opengl.org and I found interesting informations. It seems that multisampling can be controlled by application only on non MX cards. The only way how to enable FSAA on MX version of cards is to use control panel''s display settings. I still don''t understand why it is so though.
vincoof
vincoof
I''m not that much suprised. That may be an interface problem.
Enabling multisampling with their control panel allows them to "use their own multisampling method", whereas if they supported OpenGL multisampling they would have to support all the WGL_ARB_multisample requirements (as well as WGL_ARB_pixel_format and such) which is less easy for them.

Moreover GF2MX is a bit old now, and I think they''d rather concentrate their work on GF4MX drivers for instance.
QWERTY
QWERTY
I thought the only difference between MX and non MX version is a frequency of the core, memory and bandwidth of the memory bus. So when Geforce2 supports FSAA I thought Geforce2MX do so. Probably I was wrong. Maybe it is time to look for another card. I will never by a MX version anymore.
vincoof
vincoof
GeForce MX still remain way cheaper than GeForce Ti. You get what you want. Quality = Ti. Economy = MX.

BTW, does your extensions strings (both OpenGL and WGL strings) support all necessary extensions for multisampling ?
QWERTY
QWERTY
I think I have alredy written it. The latest driver from NVidia, v40.72 - beta release, doesn''t support WGL_ARB_multisample extension required for FSAA. My latest driver from Manli supports it but I was unable to find a suitable pixel format. And yes, WGL_ARB_pixel_format is supported by all the drivers. AFAIK those two are the only extensions required for doing FSAA. I am wondering if this driver issue related to MX cards is specific only for NVidia or it is cocerned with ATI''s "cheap" versions of their Radeon gfx cards too.
vincoof
vincoof
If you haven''t done it yet, you could take a look at delphi3D.net 3D hardware info database. Get the list of all cards/drivers that support the extension WGL_ARB_multisample. You''ll see a few different driver versions that support it with the GeForce2MX card. Maybe in this list of drivers there will be one that will be ok for you.

I can''t help more, sorry.
QWERTY
QWERTY
Thank for your help vincoof. You have helped me a lot. Now I am wondering where can I obtain any older driver versions.
vincoof
vincoof
NVIDIA may have archives hosted in their site. Otherwise you still can download some versions in other sites that hosted the drivers when once they were the "latest" drivers and since were not removed from the site (yet).

[edited by - vincoof on October 24, 2002 4:59:23 AM]
bakery2k1
bakery2k1
NVidia definitely have archives of (some) old drivers on their ftp site, download.nvidia.com

http://users.ox.ac.uk/~univ1234

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