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JohnWesterman
06-27-2002, 08:39 AM
Hi, Does anyone know if you need a Graphics Card with a Back Buffer to use OpenGL's selection picking. If not, does anyone know of problems with graphics cards such as "Intel(R) 82815" selecting the whole screen instead of where you have clicked?

Relic
06-28-2002, 01:04 AM
glRenderMode(GL_SELECT) does not render any fragments so it doesn't behave different for front or back buffers.
I have no other experience with the i815 drivers than how to get them de-installed for the add-in board I use instead. http://www.opengl.org/discussion_boards/ubb/smile.gif
By "selecting the whole screen instead of where you have clicked" does mean you have a very big rectangle instead of a small one around you mouse? Do you also have additional geometry on the screen which gets selected then? Could it be that your selection buffer is overflown then?
Check the return value of the glRenderMode call. negative is overflown after that absolute hit count and the rest of the selection buffer may contain partial hit records.
To see what you actually render while doing selection you can omit the glRenderMode(GL_SELECT) call. It helps sometimes to find coordinate system (origin placement) errors.