[vtk-developers] Render Overlay change

[Lisa Avila]

Hi,

I am planning to make a change to the render process. Currently we have 
three passes - RenderOpaqueGeometry, RenderTranslucentGeometry, and 
RenderOverlay. The first two happen before the buffers are swapped in 
double buffering, and the third happens afterwards.

My proposal is to move the RenderOverlay pass before the buffers are swapped.

The reason it is after is historical - VTK used to support X and Win32 
native rendering for text / 2D geometry, which was single buffered. This 
support is now gone, so the need for render overlay to be after the 
swapbuffers is also gone.

The reason I want to make this change is I would like to change 2D 
rendering over to using the RenderOverlay pass. This will make 2D geometry 
render AFTER all opaque and translucent geometry. This means we will be 
able to have, for example, translucent overlays while still seeing volume 
rendering intermixed with opaque geometry behind it.

Any objections?

Lisa