[gl4java-usergroup] Re: animation stutters

[Alban <aco...@wa...>]

Hi Peter,

Here is a little checklist that might help you solving your problem :

Your animation may be stuttering because of frequent runs of the garbage
collector. This can happen if you create and destroy a lot of objects per
frame. To avoid this, make sure you never create any temporary objects in
your rendering loop, having a preference using values that are global to
your classes.
Running your program using the option -Xincgc will smooth the garbage
collection over time (but also reduce performance) and this can help you
figure out if the gc is responsible of your problem.
-> java -Xincgc yourclass

You don't need to compile arrays into display lists (this is really useless=
,
I have not noticed any percent of performance increase testing this
feature), but it is always good to lock your vertex arrays. It allows the
driver to optimize the vertex data access in memory and thus gain
performance.

Make sure you don't recompile your display lists at each frame (this a
stupid advice, but we never know...)

Make sure your hard disk drive is not swapping during the rendering, this
would explain the poor / unregular access to the vertex data in memory.
If so, add more RAM to your computer.

Allocate more RAM than needed to the virtual machine, I've had the feeling
it was increasing a bit the performance. For this, use the flag -Xmx
-> java -Xmx256000000 yourclass  (to allocate 256Megs of memory to the
program)

Make sure you don't have 3dsMax or any third party openGL application
launched in the background when you execute your program. In some cases,
3dsMAX make me loose up 70% of my application performance, and I hask mysel=
f
"what the f%% is going on ?"..."oh max is running in the background..."

Don't use too small arrays. Small counts of polygons like 50-200 won't make
you benefit of a real performance increase. Prefer having several thousand
faces per array if possible.

I'm personnaly using vertex arrays having very good and smooth performance
under a geForce2MX. What 3d card do you have ?

Regards,

Alban Cousini=E9
Mind2Machine