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Re: Looking for huge (mpd) models
avatarMarch 02, 2013 02:02PM
I would like to try that scene, I''ll contact you shortly.

Quote
Ben Supnik
Re: performance, I found a few things with Bricksmith:

* A shader-based pipeline wasn't faster than fixed-function for the same basic work.
* CPU time is proportional to the number of bricks, not the number of vertices.
* When using the programmable pipeline and instancing techniques, BrickSmith is vertex-count bound, not CPU bound. It's not even close -- even with culling and transparent part sorting, I see CPU use of 15-25% while maxed out on fps with 30-40k parts. In this case the interesting number isn't the part count but the vertex count those parts yield. This is with a 4870 - a newer GPU would help the vertex-count bottleneck.

I wrote this up when I finished some perf measurements...

http://www.hacksoflife.blogspot.com/2013/01/instancing-for-bricksmith.html

Very interesting blog post, although I'm not that deep into OpenGL and shaders it gave me some nice pointers to try with the LDCad renderer. I too have an VBO per 'core' brick. which is drawn using drawelements per brick reference. I also do some additional grouping / sorting to limit the state changes though. I can tell you that the flat shading with the unique vertex normal pairs is about 15-20% faster (unique testing is a option in LDCad), almost the same amount as the vertex reduction, confirming the point you making in your text. Although I always use drawelements even when there are no duplicate pairs (haven't tried using drawarrays when the option is disabled yet).

Anyway the main reason I want to try a non fixed approach is to supply nicer lighting (per pixel) and or (better) noticeable differences between rubber, metal and plain plastic. I'm also hoping it would allow for better bfc/culling handling (flipping normals in the shader, to account for submodel mirroring etc) like you suggest on the blog.

It would be a bonus if it's faster too :) Everything will remain optional anyway because LDCad renders on OpenGL as low as 1.1 and I would like to keep it that way.
SubjectAuthorViewsPosted
Looking for huge (mpd) models Roland Melkert1170January 08, 2013 10:15AM
Re: Looking for huge (mpd) models Travis Cobbs462January 08, 2013 10:38AM
Re: Looking for huge (mpd) models Roland Melkert396January 08, 2013 10:53AM
Re: Looking for huge (mpd) models Travis Cobbs393January 08, 2013 12:44PM
Re: Looking for huge (mpd) models Roland Melkert360January 08, 2013 01:15PM
Re: Looking for huge (mpd) models Attachments Michael Heidemann416January 09, 2013 09:00AM
Re: Looking for huge (mpd) models Roland Melkert331January 09, 2013 09:44AM
Re: Looking for huge (mpd) models Michael Heidemann359January 10, 2013 09:19AM
Re: Looking for huge (mpd) models Tim Gould308March 01, 2013 01:12PM
Re: Looking for huge (mpd) models Michael Heidemann273March 01, 2013 01:44PM
Re: Looking for huge (mpd) models Tim Gould283March 01, 2013 01:47PM
Re: Looking for huge (mpd) models Michael Heidemann308March 01, 2013 03:33PM
Re: Looking for huge (mpd) models Attachments Jaco van der Molen330March 01, 2013 05:15AM
Re: Looking for huge (mpd) models Roland Melkert353March 01, 2013 09:20AM
Re: Looking for huge (mpd) models Jaco van der Molen265March 04, 2013 04:56AM
Re: Looking for huge (mpd) models Roland Melkert241March 04, 2013 10:17AM
Re: Looking for huge (mpd) models Ben Supnik286March 02, 2013 12:14PM
Re: Looking for huge (mpd) models Roland Melkert294March 02, 2013 02:02PM
Re: Looking for huge (mpd) models Ben Supnik285March 02, 2013 05:35PM
Re: Looking for huge (mpd) models Roland Melkert262March 03, 2013 10:16AM
Re: Looking for huge (mpd) models Ben Supnik263March 03, 2013 06:00PM
Re: Looking for huge (mpd) models Roland Melkert222March 04, 2013 10:24AM
Re: Looking for huge (mpd) models Travis Cobbs458March 04, 2013 10:47AM



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