In an effort to get a bunch of numbers on how well Moviesandbox performs as a renderer (while still being super-unoptimized) I ran a quick test drawing 3.3 million particles.
This is done through a simple cloud picture created in Photoshop with 512×512 resolution. (note that I am filling in missing particles for high variance in depth, which is why it’s such a high particle count!) resulting in a 1.1 million Vertex Buffer Object is being drawn three times with a super-simple vertex shader to make it wave around.
Framerates with Deferred Lighting (1 shadow casting light) and Ambient Occlusion (SSAO) go down to 10fps, without SSAO, we get 15 fps and without lighting at all
we get 20 fps. Recorded with awesome FRAPS on a Macbook Pro with a Geforce 9600.

I noticed that there’s a definite need for some sort of occlusion culling, as the particles right now are drawn independently from the viewport rotation. So even if I don’t see any, the framerate stays the same. Not very good. But not too hard to implement either. In addition, importing the 512×512 image took ages and actually crashed the program. I guess there’s a need for a binary filetype at some point…

I am however very pleased with the general performance, knowing that there’s more to get once optimizations start. And the image quality was quite decent.