finding neighbour faces in a large mesh

vicviper · 2003-07-09T14:02:08

Hi! I have a little big problem, I want to compute normals of a mesh with a large amount of triangles(+20000) , and they have to be computed in a way that every vertex shares the normal of all its neightbour triangles (so triangles will be rendered smoothed). I already have the loop running, the problem is that it is painfully slow, it takes near 15min to go. I''m not using that for computing terrain normals, but to compute normals of typical 3D meshes. So far, I noticed that most of the time what the loop does is to try to find the neighbour triangles of every vertex, since the triangle table is +20000, the loops are painfully slow... after finding the triangles I have no problem computing the normals. So, the question is: is there any way to rearrange the triangles of a mesh, or any other trick (like building a tree, a lookup table, whatever), to find the triangles that share a vertex in a large table?

Graphics and GPU Programming Programming

Started by vicviper July 07, 2003 06:10 AM

9 comments, last by vicviper 20 years, 9 months ago

blue_knight

194

July 09, 2003 02:02 PM

If you split vertices based on texcoords, materials or whatever calculate your normals BEFORE you split your vertices that way you can use the fast method.