Re: [GtkGLExt] rubber band effect

[Shane Blackett <s blackett auckland ac nz>]

We have very successfully implemented such a rubber band effect without using overlay planes
(or glLogicOp which I hadn't considered) by rendering our main scene into the back buffer without 
the rubberband, swapping buffers,
and then copying the front buffer to the back buffer.

Then you can draw your rubber band onto the front buffer and as it is dragged just swap again,
copy again and redraw the rubber band.

Yours Sincerely

Shane.