Richard Smith - Systems Engineer - Melbourne said: > The question was raised about the value of a floating point Z-buffer. > The point here is that for the same number of bits, a fp Z-buffer > uses its bits to distinguish more accurately between near objects > than far objects. As a consequence it should be acceptable to have a > very much greater near/far ratio, particularly for astronomical > objects.
so are you saying that the z buffer on these cards is non linear in precision? > Although some cards e.g. Sun's XVR-1200 have greater than 24 bit > Z-buffer, 32 bits still may not be sufficient. The XVR-1000 and > XVR-4000 (and probably others on the market) use a floating point > Z-buffer. aah, ok, I didn't understand you were talking about hardware changes here. I am making the assumption this was for a game, I could well be wrong. If it is for a game or for 'normal' pc hardware, then this isn't really an option. But if it is a specialist application then it may well be ok to have requirements along these lines. > Another possibility is to use multiple locales separated via > hires coordinates (256 bits), which the Java3D API supports. yes, but you are still limited by the z buffer when it comes to displaying these objects, unless I'm missing something in the way locals work > On the whole it strikes me as inefficient to compute repeatedly > something that cannot physically change rapidly e.g. the stars in > the sky many lightyears away. hence only rendering them on entering a system. > Maybe a better approach is to use a > spherical background geometry as discussed in Daniel Selman's book. cubes are easier to render images for and then apply as textures. Correct me if I got any of that wrong, it's a field i'm still exploring myself. Cheers Jeremy -- Homepage: http://www.computerbooth.com/ Codepage: http://www.newdawnsoftware.com/ =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff JAVA3D-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
