   Rendering vertex alpha?
  If alpha is stored in the vertex and rendered with glColor4f(), how would you render the scene properly for transparency?Would you still z-sort the faces?  Or would you use some other technique?   
  If you're using additive blending, no sorting is required.If you're using alpha blending, then yes it will look wrong unless the faces are sorted back-to-front.   ;Quote:Original post by HodgmanIf you're using additive blending, no sorting is required.If you're using alpha blending, then yes it will look wrong unless the faces are sorted back-to-front.Thanks for the reply.  However, my question is more of a vertex alpha vs. face alpha issue.  The alpha I'm rendering is stored within the vertex, and not the face.I was just wondering if there are any techniques specifically used for rendering vertex alpha.I was thinking something like this had to be done on a per pixel level.[Edited by - theequal on June 16, 2009 1:57:31 AM];  AFAIK, face alpha is just vertex alpha with all 3 (or N) verts of a face using the same alpha value.When rendering polys with alpha-blending, it doesn't matter where the alpha comes from - just that the polys are sorted.   ;  Well Vertex Alpha and Face Alpha are the same, it's just that Face Alpha applies to all the Vertices of the polygon. Therefore, any issues you will have with Face Alpha will be the with Vertex Alpha and vice versa.So yes, you will still need sort the poly's so they are rendered back-to-front to acheive the correct effect.   ;  Twice in two days someone has gotten there before me, I must be getting old and slow :(   ;  Thanks, for some reason I thought I had to use a specialized shader to get per-pixel transparency.   ;  With vertex-alpha, even though each pixel gets a different interpolated value, it's still usually called "per-vertex", because each pixel can't really choose a value independent of it's neighbours. So if you were going to do this with shaders, you could just use a vertex-shader ;)P.S. Seeing that someone just started a topic about depth peeling - In case you've ever got complex transparent models, there are some techniques for rendering alpha without any sorting first, called 'order independent transparency'.   