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Border/lasso select + occlude geometry on = out of rectangle selected vertices
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Description

Starting with the default scene, delete the cube, and add Suzanne instead.

Switch occlude geometry on, and border (or lasso) select the ear.

Some vertices outside are selected. Notice in the attached png that some in the eyes are selected!

This issue doesn't appear when occlude geometry is set to off, and is independent of anti-aliasing.

Macbook Pro 5,1 nvidia 9400M used
It has been reproduced by Moguri on his win32 system.

svn 25830

Event Timeline

I can confirm the problem on Linux/Nvidia as well. This should either be fixed very soon, or AA should be disabled again, since box/lasso selection is really a critical tool. I'm not going to fix this bug, no time for it...

My guess is GL_SELECT is not working well with sample buffers in the Nvidia drivers. Blender has two backbuffer selection methods, one uses GL_SELECT, the other use color coding. The former is not well supported anymore and the intention is to move to color coded drawing, but will require quite some work.

Alternatively, there may be something else causing it, or a simple workaround may be possible, but I can't think of anything at the moment.

On NVidia (at least), GL_SELECT is not working well when the GL context is initialized with an AA enabled pixel format, even if the multisampling is not used for the selection drawing.
So AA is disabled again until the selection method is changed to color coded drawing.

Fixed in svn 25835

Damien Plisson (damien78) changed the task status from Unknown Status to Resolved.Jan 8 2010, 4:02 PM

Investigating closer showed that when FSAA is enabled in pixel format, "some" AA artifacts still exist, even if multisample is deactivated locally (using the glDisable method).

The backbuf_AAon.png file shows the issue of the backbuffer drawing. Notice the artifacts in at least the line circled in blue (zoom 200% for best viewing).
Googling for this issue also revealed that color coding can't be used from the moment FSAA is enabled.

So as color coding is the algorithm used in Blender for vertices selection when occlude geometry is on, and GL_SELECT is deprecated, FSAA seems to be bound to remain a BGE feature, at least for the short term.