View Full Version : Blending, pixel format, FPS, ...

Ehsan Kamrani
08-29-2006, 08:48 AM
1)When i move near the objects, the frame rate start to decrease.Note that i have not written a function to increase the vertex counts of the objects. I have written a class that cull the objects that are not in frustum . Why it happens?

2)Also when i optimize my program in releasing the program( not debugging ), i see an increase in frame rate specially when blending is enabled( the frame rate does not change when i draw the lens flares with blending ).However when debugging the program, blending decreases the frame rate.What does happen in releasing the application?Does it force the hardware to do blending for me?

3)In one program, I removed all the objects and started FRAPS. the maximum frame rate reported by fraps was different in different times.Soemtimes it's about 85 FPS and sometimes it's about 60 FPS. Why?

4)Something about the WGL extension.Does wglChoosePixelFormatARB() increases the performance?
I have used from the function ChoosePixelFormat() to choose the appropriate pixel format. Should i replace this function with wglChoosePixelFormatARB()?

5)I have written a class to play the AVI files. My colleague said that he should specify the FPS of the AVI files that are generated with 3DS Max. What value is appropriate? ( 30, 60, etc. )

6)Do old graphic cards support the GL_BGR_EXT or GL_BGRA_EXT extensions?

7) How can i detect the amount of texture memory in my program?


08-29-2006, 09:38 AM
Is this a joke?

Ehsan Kamrani
08-29-2006, 10:53 AM
These are not jokes.These are questions.Note that i had edited my reply before.However as i said in another tpoic, some features of the OpenGL Message Board don't work correctly for me!

08-29-2006, 11:56 AM
OK quick ansvers

1. it may be because you might increase the total rendered fragments, thus making it run slower.

2. Debug mode often runs slower.

3. Could be vsync.

4. no it doesn't matter.

5. 25-30 is good, anything faster takes up a lot of data rate, anything slower and it's a bit choppy.

6. No, that is if you mean with old a 3DFX Voodoo 2 or lower, all the rest support it.

7. this is impossible, but you would have known this if you would have searched the forums a little, there has been at least one of these posts within the last 24 hours.

Ehsan Kamrani
08-29-2006, 03:02 PM
Thank you.
Can you explain more about question 3?
...And about question 6, i mean Nvidia TNT2 or ATI Radeon 7000.

08-29-2006, 08:05 PM
Ehsan Kamrani,
About question 6, I am very positive that TNT2 and Radeon 7000 support GL_BGR and GL_BGRA, because they are introduced in OpenGL version 1.2.

08-30-2006, 02:19 AM
Ehsan, about extension support, here is a good place to start checking :