normal averaging

[Julio]

hi,
for a water mesh, what is the proper way to average normals to make the surface look smooth? I have glShadeModel(GL_SMOOTH); enable, I'm using triangle strips, and I'm currently calculating the normal for each triangle. the term normal averaging has come up, but I'm not exactly sure what this entails.
thanks,
Joe

[Julio]

nevermind, I think I got it working.

[peter.vullings]

If you havent got it yet:

Only specifiying face normals doesnt give the smoothest effect. For the smoothest effect you should specifiy a vertex normal for each 'corner'.

A vertex normal is calculated by averaging all the face normals that share that vertex as one of their 'corners'.

To average a bunch of normals, simply add them together and then normalise the result. Adding vectors (a normal is a vector) goes as follows:

v1= x1,y1,z1
v2= x2,y1,z1

v3= x1+x2,y1+y2,z1+z2

Hope someone finds this useful (and I hope its correct!)

[Julio]

thanks, I'll have to give it a try. so to clarify what you're saying; you take the average of the three face normals that are touching the vertex, and to do this for each vertex?