[vtk-developers] Render Overlay change

[Lisa Avila]

No API change. I've already made this change and checked it in. All tests 
pass (well, three fail on my system but they failed before I made the 
change) - but we have pathetically few tests that render 2D geometry.

There are some behavior differences but the new behavior should be more 
desirable.

Lisa

At 03:10 PM 4/11/2002, Lorensen, William E (Research) wrote:
>Will the API change?
>
>-----Original Message-----
>From: Lisa Avila [mailto:lisa.avila at kitware.com]
>Sent: Thursday, April 11, 2002 2:10 PM
>To: vtk-developers
>Subject: [vtk-developers] Render Overlay change
>
>
>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
>
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