Path: chuka.playstation.co.uk!news From: "K.Wutzke" Newsgroups: scee.yaroze.programming.3d_graphics Subject: Triangles, Quads??? Date: Tue, 13 Oct 1998 18:34:01 +0200 Organization: PlayStation Net Yaroze (SCEE) Lines: 43 Message-ID: <362380F9.EC2420F5@usa.net> NNTP-Posting-Host: dialup6-76.access.nacamar.de Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.05 [en] (Win95; I) What's better? Make the models from triangles or quads? It doesn't make a difference (to me) from an artistic point of view, but what about the performance? I looked at the TMD primitive structures ilen/olen stuff from which I derived, that quads are the faster the more "real" quads, e.g. no simulated triangles there are... The problem is: I'm just guessing around! If I took the TMD structs: G_3T (triangles, gouraud,textured, lights on): ilen 6 - olen 9 and G_4T (quad(r?)angles, gouraud,textured, lights on): ilen 8 - olen 12 Now say I have one torus object each: G_3T: (256 vertices ,) 512 primitives/polygons/triangles G_4T: (256 vertices ,) 256 primitives/polygons/quads Can I calculate or approximate the possible computational work to be done as follows... (no. of prims) * (ilen) + (no. of prims) * (olen) = X G_3T: 512 prims * 6 + 512 prims * 9 = 7680 G_4T: 256 prims * 8 + 256 prims * 12 = 5120 7680 / 5120 = 1.5 -> triangle model ~50% slower??? Hmmm... maybe I should just check the frame rate... Anyway what do you think? What's the playstation doing? Does it convert triangles to quads or quads to triangles ? Does it matter? Can I do the above calculation? Karsten