Vertex pull fullscreen lighting texture shader

shader/lighting/lineShadow.vert

@@ -57,6 +57,7 @@ void main()
   // test if the edge is part of the silhouette
   // that is, if the normals of the faces connected to the edge are in
   // "different directions" wrt the light direction
+  // (first test the "drawbit")
   if (p0.w==1 && dot(n0, lightDir) * dot(n1, lightDir) <= 0 &&
       (dot(lightDir, lightDir) < ru2 || dot(lightDir2, lightDir2) < ru2))
   // using <= rather than < seems to get rid of overlapping shadow