glPointSize not working with glRenderMode( GL_SELECT )

Blake
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Post: #1
I am having a problem with glPointSize not working with glRenderMode( GL_SELECT ). I can only get the point to be selected if I click on the very center of the point. glGetError returns 0.
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Moderator
Posts: 1,560
Joined: 2003.10
Post: #2
I think I know what's happening here... As I recall, a point is culled if its center lies outside the viewing volume, even if it "should" be visible due to a glPointSize > 1. When you use gluPickMatrix, it sets up the projection to only include the small space around the point you specify, so regardless of your point size, your point gets culled, and subsequently doesn't get added to the selection buffer.
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Luminary
Posts: 5,143
Joined: 2002.04
Post: #3
solutions -- use a picking viewport as large as the point size, draw your points as billboarded quads instead, or use analytical intersection detection rather than relying on GL's horrible selection stuff.
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Blake
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Post: #4
Thanks for the help, I just made the gluPickMatrix size bigger and the points a bit smaller.
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