Wow, thanks for all of the suggestions. How many of these tips are
implemented in OSG::Particles? In particular using few or one draw call and
disabling display lists? If I were to roll my own would it be best to start
by extending a Drawable? Is that difficult, and if so is there an easier
way. I've pretty much been using stock OpenSG classes up to this point.
Again, thanks for all the help :-)
-jesse
On 10/18/07, Eric Maslowski <[EMAIL PROTECTED]> wrote:
>
> You could try some form of "imposter rendering" to handle the wheat in the
> distance, but I would say this should be tried after moving things onto
> the
> GPU and seeing what kind of performance you get. Imposters are a useful
> technique but have their own cost which really needs to be taken into
> account since it could slow things down if used improperly.
>
> If you're fillrate limited you can opt for alpha testing instead of
> blending
> for your textures which will help speed things up. On modern hardware you
> can get this to look very nice with some transparency anti-aliasing.
>
> Good luck
>
> E.
>
> ---
> Eric Maslowski
> Research Computer Specialist
> University of Michigan 3D Lab
>
> Autodesk 3D Studio Max Certified Trainer
>
> email: [EMAIL PROTECTED]
> office: 734-615-9699
> mobile: 734-730-9904
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Jesse
> Lane
> Sent: Thursday, October 18, 2007 00:58
> To: [email protected]
> Subject: Re: [Opensg-users] Particle tricks
>
> Thanks. We'll be viewing the wheat from the viewpoint of a combine or
> tractor so from the ground. We are batching the wheat into "cells" of
> about
> a meter or so wide, so quite a large bunch. I have the GPU Gems books and
> have read that particular article and may try to implement some of the
> ideas
> there. My only problem with putting entire rows on a single object is
> that
> the wheat is harvestable so I'd have to recalculate the different LODs all
> the time. Is this done often? Is it reasonable(possible)? Thanks again.
>
> -jesse
>
>
> On 10/17/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
>
> Hi Jesse,
> How will you be viewing the fields of wheat? Will you be viewing
> it
> from above, on the ground, or both? Generally speaking, try to
> batch
> your strands of wheat if possible. Avoid one stalk per particle
> for
> everything. Try putting multiple stalks on a single particle. For
> particles in the distance, try putting entire rows on a single
> object
> instead of keeping individual particles. This works particularly
> well
> with distance LODs that "fade" between levels. If you animate the
> foreground then the switch is rarely noticed.
>
> There's an article in the first GPU Gems Book (and on NVIDIA's
> website
> I believe) entitled "Rendering Countless Blades of Waving Grass"
> by
> Kurt Pelzer. It a great article and would be a good place to
> start.
> :)
>
> Best,
>
> E.
>
>
> Quoting Jesse Lane < [EMAIL PROTECTED]
> <mailto:[EMAIL PROTECTED]> >:
>
> > Hello all. I'm currently working on a project that simulates a
> large field
> > of wheat that is harvestable. I'm currently using particles to
> represent
> > the wheat. I need to be able to render quite a lot of pieces.
> Right now my
> > frame rate is dropping to about 5fps when rendering 10,000
> particles, and if
> > possible we'd like to push this up to another order of magnitude
> (or even
> > 2). I'm not an expert in particle systems, or graphics for that
> matter, and
> > I could use any suggestions, tips, or tricks that can be tossed
> my
> way for
> > optimizing this field. I'm contemplating pushing some of the
> work
> out to
> > shaders, especially since I'd like to add some effects like wind
> and noise.
> > I've done some rudimentary profiling and the lion's share of the
> time is
> > being spent in the render call (I'm using VRJuggler and my
> application is a
> > cannabilized version of OpenSGApp so the render call is in
> draw()). Thanks
> > in advance.
> >
> > Jesse Lane
> >
>
>
>
>
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