[Papervision3D] Optimizing performance: anything else I can do? [UPDATED! 20% performance boost]

[John McCormack]

It looks very good.
Perched above, and hiding, the thumbprint images at the bottom there is 
a segment of a circle showing in grey.
John

Alan Pinstein wrote:
> Just wanted to update everyone as I finally got some positive results, 
> after many, many failures and about 20h down the tubes.
>
> 1. THE SHORT ANSWER: don't use transparent bitmaps!
>
> THE LONG ANSWER
> After hours of grueling research and several different attempts to 
> solve the problem, I happened on a solution that gave me a 20% speed 
> boost, which involved slicing my huge texture into 3 distinct textures 
> and then using a combination of UV Mapping and assigning different 
> materials to different faces to reduce texture size.
>
> So I thought I was really on to something, and set about to optimize 
> the proper # of slices maximize performance. It took me a while, but I 
> ended up with a generic algorithm that given #rows and #cols would 
> "segment" the texture into row*col sections, splice up the "main" 
> texture into smaller BitmapMaterials, and then apply them to the 
> appropriate faces.
>
> After such a big effort I was excited when I finally got this 
> algorithm working to see which slicing pattern provided the best 
> performance. To my surprise, slicing the texture had -0- measurable 
> impact on performance!
>
> This was quite a shocker, and thus I set out to figure out why did my 
> "dirty proof-of-concept" get 20% performance boost when my nice clean 
> implementation had no improvement?
>
> The answer, it turned out, was that I had changed something besides 
> the # of textures in the "dirty proof-of-concept," but I didn't 
> realize it at the time.
>
> We had been using BitmapDataUnlimited to manage our textures since 
> they are bigger than the 2880x2880 limit in Flash 9. I turns out that 
> the default bitmapData.transparent setting used by BitmapDataUnlimited 
> is TRUE, rather than the Flash API default of FALSE. So the renderer 
> was spending a lot of extra time messing with opacity (even though 
> this was an opaque texture).
>
> In the end, adding a single FALSE parameter to a function yielded a 
> 20-25% speed bump!
>
> Fortunately all Flash bitmaps default to transparent=false, but I 
> figured people should be made aware of the implications of transparent 
> bitmaps on performance in case they didn't know, or if anyone else is 
> using BitmapDataUnlimited.
>
> So, thanks to all who chimed in, as ultimately the endeavors 
> undertaken lead me to this fix.
>
> If you want to see the new faster player, check it out here:
>
> http://www.tourbuzz.net/public/vtour/full/2000
>
> I have some other ideas for optimization that I thought of while in 
> the trenches, and will be starting another thread for that...
>
> Thanks & Enjoy,
> Alan
>
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