Hi, I was going to start a hobby (i.e. noncommercial) project to simulate an electromechanical coin arcade game. This would include rendering potentially hundres of coins that physically interact (think 500...1000 coins). For the physics simulation I am going for the free bullet physics package. For rendering I intend to use OSG.
One problem with GPUs is that round shapes map badly to triangle meshes. One needs a lot of triangles to make the coins appear sufficiently round. Lots of vertices may conflict with the idea of rendering many coins simultaneously. I could go down the route of using a mesh based 3D model combined with LOD techniques. However this may incur some performance issues on architectures like Intel GMA that have pixel shaders in hardware but do all their vertex processing on the CPU. Also I would really like to include a 3D relief for the coin imprinting (embossment), either by using simple bump mapping or more advanced pixel shader based techniques like parallax mapping or relief mapping. To get simulated (fake) reflections I need to apply some kind of environment mapping. Considering that I will have to use pixels shaders anyway, I was thinking that this can a pixel shader could just as well be used to also render a geometric primitive like for example a cylinder. The pixel shader would have to do some calculatios like "does the view ray intersect with the primitive?" and "what is the surface normal?"... very much like in raytracing. The only vertex based geometry needed would be a billboard that fully covers the visible extents of the geometric primitive (or alternatively a box that wraps around the visible extents of the primitive) To get started with this I could use a few pointers and suggestions. 1) Does anyone here know some open sourced OSG based code that renders primitives like spheres, cylinders, cones or the like within a GLSL pixel shader? I know there have been projects in academia that did just this, but is there anything open sourced? 2) Would anyone know a nicely done (in terms of documentation, clarity) parallax mapping or relief mapping implementation in GLSL and OSG? I've found a lot of conference papers on this (Siggraph etc) but almost no source code. It's often 10 times harder to start something from scratch than to modify someone's existing code. So thanks a lot for any pointers and help, Christian _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
