That game looks like fun Hey, thanks for the earlier compliments. Sorry it didn't solve the problem but i think that i can tweak the code to look more like you want. It's almost there from what i can see - the beam does just look like two 8-sided cylinders with normal face culling (like you said). The impact point is definitely just a billboard sprite facing the camera and that's real easy to achieve - you could either:
  • use a TGLSprite which is purely 2D and won't go too well with the 3D space atmosphere
  • use a TGLQuad with the following IIRC:


[pascal]
GLQuad1.Pointto(GLCamera1.absolutePosition, YHMGVector); // assuming YAxis is up
[/pascal]

It's either PointTo or PointToObject (i'll double check when i'm playing in delphi again)

[thinking out loud]
As for the tapering, that's not a problem at all. If i make the phase a class, then each "node" can also have a radius as well as position (like TGLPipe).

Also, it's not a big leap from there to get some pulsating animation. The phase is a direct line so interpolating several nodes along the path is do-able, then just sine wave the radii of all nodes over time. But i'm getting WAY ahead of myself back to the orignal problem ... the glow seems to be using additive textures (which i can't help with as my artist skills are beyond laughable ) i'll try the image you posted above.
[/thinking out loud]

Now that i have an idea of the desired result, i'll (try and) post something soon