Tonfilms particles patch (nice!) brought an issue back to my mind which I discussed with Oschatz a few weeks ago.
Instead of using spheres one could easily use point sprites of spheres with alpha masks. That would save lots of computing power but a basic problem with billboarding always remains: The z-sorting.
Extracting the position data from the vertex buffer, then sorting polygons by their z-value and reassembling the buffer is far too slow as a discreet patch.
Any suggestions from the developers, how to solve this task within one single node?
As this issue comes up almost regularly when working with alpha textures I would really appreciate a proper solution here.