Hi Alex, Long time no read 
@Santeri
I use Alex' excellent approach in my LDCad, you can see the shader code in the resources folder of it's installation.
The geometry shader approach is the most efficient on paper but on older cards/drivers it's actually slower then the vs one.
The vs approach works on almost any gl platform, but it takes a whopping 5 attributes (incl pos) per vertex, and as a result wastes quite some memory and completely messes up your index re usage, But the performance you get is all all worth it
@Santeri
I use Alex' excellent approach in my LDCad, you can see the shader code in the resources folder of it's installation.
The geometry shader approach is the most efficient on paper but on older cards/drivers it's actually slower then the vs one.
The vs approach works on almost any gl platform, but it takes a whopping 5 attributes (incl pos) per vertex, and as a result wastes quite some memory and completely messes up your index re usage, But the performance you get is all all worth it