Since according to the newsletter Stuart's current ongoing quest is to get better performance for 3d clouds, here are some of my observation:
* I've noticed that when I use the relatively lowres Altocumulus texture sheet (3x3 on one sheet) I can basically use a ridiculous number of sprites without performance deterioration, whereas when I use the hires Cumulus sheets (1x2 plus 1x3) the number of sprites I can show before performance takes a nosedive goes down substantially. The high resolution is however only needed for the small amount of clouds which are relatively close, but what makes a real difference is the amount of distant clouds, because there are so much more. So my guess is that using lowres textures for distant clouds would do just fine and improve performance. I've been wondering if dds sheets with the mipmaps would not automatically address that problem. The other option to test would be to scale down the resolution of the Cu cloud textures and see if the result is still acceptable (I know it isn't perfect, there was a reason I went to high resolution in the first place, but maybe the flaws can be hidden by the right mixture with other texture types). * There seems still to be stuff computed in the shaders per vertex that is actually an uniform per frame - eyepos for instance. I wonder if the computations could be speeded up significantly by consequently pulling all things that are really uniforms out of the shaders. * We're likewise fond of computing stuff per frame that changes more like per minute. The orientation of faraway clouds doesn't have to be computed per frame, because it can't change much per frame. If there'd be a way to store the value used last time, then (based on a distance criterion), one could assign clouds into n task groups and recompute a task group only every nth frame and use the last stored value otherwise. Back when I rotated clouds from Nasal, this did work and improved performance by a factor 5 or 6 - not sure how much it could do with a Shader setup, not sure how to do it technically, but my guess is that it would speed things up. Maybe some of this helps! Cheers, * Thorsten ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
