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nk
04-21-2004, 01:04 PM
Is there any connection between Hardware transform and lighting functionality present on NVidia GPUs (like GeForce Mx seris) and OpenGL?
If there is can someone write a small piece of code to show me how to do this?

ZbuffeR
04-21-2004, 01:09 PM
With OpenGL it is automatic, particularly if you use the opengl transformations or glScale/glTranslate/etc. The driver takes care of that. (But I am not sure of the hhardware T&L of mx series...)

Obli
04-23-2004, 01:10 AM
Originally posted by ZbuffeR:
The driver takes care of that.In the sense that if you're rendering on GPU, GL will automatically use HW T&L.
This does not apply if something bad happens and everything rolls back to a software path for some reason.

nk
04-23-2004, 01:08 PM
1. "In the sense that if you're rendering on GPU" - how can I render on GPU? Simply call glTranslate(..) and the required vertex transformation will be calculated by GPU?
How can I be sure that T&L on Nvidia card is REALLY used on OGL?
2. "This does not apply if something bad happens"
Like what?

ZbuffeR
04-24-2004, 02:21 AM
1) glTranslate/etc transformations relies on OpenGL implementation. So it is done by the driver. If the driver knows that the card has T&L capabilities, the T&L work is sent directly to the card. Else, it is computed by the driver in software.
So you can not be SURE. But I would trust nvidia dirvers in this case. If you really want to be sure, maybe try to implement the transformations yourself to compare ? Not sure it is worth the pain though.

2) Old cards (do not remember which ones) only accelerated 1 GL light, so you can test that with a quite higly tesselated sphere, then add GL lights one by one, and see if the frame rate suddendly drops (software fallback). But on my GF3ti200, all 8 lights seem accelerated.

nk
04-24-2004, 05:32 AM
All is much clear now. Thanks.
I have only one more question: do you know any site where it says that T&L engine on NVidia cards is used with OpenGL?(maybe T&L is used only with DirectX).

ZbuffeR
04-26-2004, 01:28 PM
Will you read what I said ?
I you don't trust me, read this :
http://www.delphi3d.net/faq.php?question=8

You can read this thread too, it is not too wrong :
http://www.gamedev.net/community/forums/topic.asp?topic_id=58141

From the horse's mouth :
http://www.nvidia.com/page/search.html?keywords=transform+and+lighting

To sum up, all nvidia cards having 'GeForce' in the name, so since 2000 or so.