Hi all, There was a thread recently about rendering many instances of spheres (I didn't want to hijack the thread so I created a new one). Many methods were proposed among which there were opengl pseudo instancing and the draw_instanced extension. First I would like to know the main differences between these two (both in the principle and in terms of efficiency).
just for the record, I've read the Nvidia paper given by Christian, http://download.nvidia.com/developer/SDK/Individual_Samples/DEMOS/OpenGL/src/glsl_pseudo_instancing/docs/glsl_pseudo_instancing.pdf and it seems that the pseudo instancing methods will be worth only when each instance contains few vertices (less than 50). This constraint won't cause any trouble for a sphere, I guess. Is it the same with the draw_instanced extension? And then what would be the best approach to render many instances of a big geometry (eg thousands of vertices per instance)? Last, are those instancing methods worth even if the geometry is static, or is it more efficient to use DisplayList or VBO? I know there must not be general answers depending on many aspects (as the Graphics card, the driver, etc.) but I am looking forward to get a bit of your expertise in that matter. Thanks in advance. Loïc PS: I'm not very skilled in openGL so don't hesitate to explain things that seems very basic about all those concepts ( like instancing, VBO, displayList). Hopefully this will be also useful for other osg newbies like me.
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