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View Full Version : Any info about GL_NV_timer_query?



yooyo
07-12-2005, 04:58 AM
I was looking into extension set of new beta (leaked) drivers 80.40 and found two new extensions (ARB_pixel_buffer_objects NV_timer_query). First extension is already known, but second one is unknown for me.

I do some investiogation and I didn't found new entry points. So I suppose it must be able to query something using glGetXXX functions.

Any idea what it sholud do?

yooyo

Obli
07-12-2005, 08:29 AM
By the way, are there any news on NV_conditional_render?

Eric Lengyel
07-12-2005, 11:14 AM
I would bet that the NV_timer_query extension just defines a new target enum for the glBeginQuery/glEndQuery mechanism.

Jan
07-12-2005, 12:09 PM
Originally posted by Obli:
By the way, are there any news on NV_conditional_render?Yeah, we already asked that, err... 2 years ago? At least one!

yooyo
07-13-2005, 04:46 AM
Originally posted by Eric Lengyel:
I would bet that the NV_timer_query extension just defines a new target enum for the glBeginQuery/glEndQuery mechanism.I just check for new targets for glBeginQuery (looping from 0 to 0xffff and call glBeginQuery) found new query target: 0x88bf. I'll continue investigation...

Maybe it can be used for measure rendering performances? Some internal GPU timers?

yooyo

yooyo
07-13-2005, 05:20 AM
Seems that glBeginQuery/glEndQuery works!
I do some basic tests:


#define GL_TIMER_QUERY_NV 0x88bf

GLuint TimeElapsed=0;

glBeginQueryARB(GL_TIMER_QUERY_NV, m_TimerQuery);
RenderGrid(1.0f);
glEndQuery(GL_TIMER_QUERY_NV);
glGetQueryObjectuivARB(m_TimerQuery, GL_QUERY_RESULT_ARB, &TimeElapsed);Depending on amount of rendering primitives TimeElapsed has change. If I do not render anything on screen TimeElapsed is close to 1.

Im not sure in which units is this value? GPU clock-tics or nano-sec or micro-sec?

yooyo

knackered
07-13-2005, 11:36 PM
This may be something to do with getting the nvPerfHUD to work in opengl, maybe. Perhaps we're seeing some of the benefits of nvidia working with sony on the ps3.

Pentagram
07-14-2005, 06:48 AM
I think it's more likely the perfkit timers (instead of perfhud). I hope so as using that "performance data helper" windows api is kindof annoying :D
They will then probably only have this in the extension string of the instrumented drivers.

Charles