[PD] How do I squeeze more performance out of Gem?

[John Harrison]

Using Cyrille's test patch for speed which he sent into the list a week or
so ago, I tried creating multiple spheres, gemlists, and models. The sphere
is getting the best performance results, unfortunately. Attached is my test
patch. I just connected [repeat] to either [sphere] [GEMglCallList] or
[model] in the patch. The sphere model I used has probably got way too many
points (just found it on the 'net) but my hope was that as the vertices were
static it wouldn't matter.

http://www.eecs.umich.edu/~guskov/eecs598-1/sphere.obj

maybe one with less vertices will help. I can try...

-John

On Wed, Mar 9, 2011 at 9:48 AM, chris clepper <cgclepper at gmail.com> wrote:

> A model is the way to go since the vertex data is static.  Ideally for
> situations like this there would be one object that loads a single model and
> several clients that just call the display list.  Although there is a lot of
> memory on GPUs now so 200 models of a sphere won't take up that much.
>
> On Wed, Mar 9, 2011 at 10:32 AM, John Harrison <johnharrisonwsu at gmail.com>wrote:
>
>>
>>
>>>> On Wed, Mar 9, 2011 at 1:59 AM, cyrille henry <ch at chnry.net <mailto:
>>>> ch at chnry.net>> wrote:
>>>>
>>>>    hello,
>>>>
>>>>    - try using a display list to render a sphere, so that every point
>>>> don't have to be send for every sphere.
>>>>    see exemple 09.openGL/02.displaylist
>>>>    you can also use a model with a sphere.obj to have the same result.
>>>>
>>>> if the spheres are all moving at once, would a display list still help?
>>>> Seems like recompilation would have to happen for every sphere for every
>>>> frame? I haven't tried the model yet...
>>>>
>>>>  yes, the display list will help to render 1 single sphere.
>>> you have to call it 200 times.
>>>
>>>
>>> Ok I'm seeing a huge performance difference between using 200 of [sphere
>> <size-doesn't-matter> 20] and [sphere <size-doesn't-matter> 30]. Huge. So if
>> I want to keep the sphere with 30 points, I'm thinking gemlist or model are
>> my answer. I'll try both and report back, unless you have a strong
>> recommendation for one or the other to save me time.
>>
>> This list is awesome. Where else could I find help like this? :-)
>>
>> -John
>>
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>


-- 
John
http://alumni.media.mit.edu/~harrison/
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