On Friday 09 June 2006 17:03, Frederic Bouvier wrote: > Graphic cards are optimized to texture objects. The greatest penalty is > when you do state changes. A state is all attributes that affect the > rendering of a primitive ( point, line or triangle ). A color change is > heavy as well as a texture change. The new Paris Scenery can display lots > of identical building just because they use the same texture. That way, you > can draw hundreds of building with a single state change. If these > buildings where designed using 2 textures, there will be 2 state changes > for each building, so hundreds of state changes, and that wouldn't be > playable. > > Texture size has a litle impact on filtering time and a huge one when card > memory is completely filled. In that situation, swapping begins and very > low fps are encountered. > > > There's another question. I am used to creating high detailed objects for > > low distance view and a second low detailed copy for high distance view. > > That speeds up the simulator when the object is distant but ... does FGFS > > unload the unused high detailed 3d object (and its texture file) from the > > graphic cards memory? > > The complete model stay in memory, as well as textures. There is a gain > because less primitives and less state changes are processed by the GPU. > LOD has also an effect on the visual because displaying sub pixel features > usually creates flickers. > > Using Shared models helps saving memory. That way, only one model is > loaded, and it is displayed multiple times. With static objects, every > instance is loaded in memory, with duplicates on geometry and textures. > Changing OBJECT_STATIC to OBJECT_SHARED helped having a decent fps over > Paris, as well as reducing texture size to avoid GPU memory saturation.
Well, all that Fred writes is true as long as the sum of all textures used for the scene fits into texture memory of your graphics card. So using many huge textures will hurt users of small graphics cards. So, looking at the size of the textures used for the models might be a good idea anyway. Also unused areas of testures should be avoided since this also takes memory on the graphics card even if that is not mapped to triangles. ... just don't waste graphics card memory for textures not really required. Mathias -- Mathias Fröhlich, email: [EMAIL PROTECTED] _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
