A while ago I posed the question: "What I have been wondering is the following: Currently I am using *.rgb textures. I have noticed that the filesize can be reduced by a factor 2 or so by going to *.png textures. However, what is the format which would most efficiently into the scenery? If *.png saves filespace at the expense of time, then there's no point in converting, but if png also loads a factor 2 faster, I would convert all texture sheets."
I have now done some tests myself - and here are the (surprising?) results (I may have to add here that I have no clue what the various dds options and formats actually are...) The test texture: One 1024x1024 texture sheet (altocumulus_textures.rgb), the original is a gimp-created *.rgb file, converted with gimp to a *.png and using nvidia texture tools ./nvcompress -nomips -bc3 altocumulus_textures.png altocumulus_textures.dds into dds format. The test situation: 50.000 ft straight above TNCM, looking down with maximal view angle, 45 km visibility, creating a 50x50 sheet of Altocumulus clouds. The measurement: File size, time till the cloud sheet has appeared in the scenery, framerate after the cloud sheet has appeared in the scenery. The result: rgb: filesize 1.7 MB, time to appear 12 s, framerate for rendering 32 fps png: filesize 0.8 MB, time to appear 135 s (!), framerate for rendering 21 fps dds: filesize 1.1 MB, time to appear 13 s, framerate for rendering 20 fps I have also tried other dds options, some didn't even render properly, and none was better than the bc3 shown here. ... and the winner is: The rgb format. Given than harddisk space is cheap, whereas framerate is not, the larger impact on the framerate makes dds simply not competitive for me - if 0.6 MB space cost 10 fps, then that's a very bad deal. png really seems to be a bad guy - it slows the system down incredibly. So, my answer is, apparently it doesn't help to use a different texture format to speed the system up, rgb is as fast as it gets. Which is disappointing, but that's how it is. If I made a mistake somewhere, please let me know! Cheers, * Thorsten ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
