View Full Version : Opposite of Scissor Test?

12-06-2002, 05:26 AM
Can anyone describe (in detail) how to do the exact opposite of a scissor test? All my drawing is in 2D and I've been trying to work with the Depth buffer, but I cannot get close to what I really need. Basically, I will be drawing on the screen, and then at any given time, I will define a rectangle in which nothing new can be drawn inside even though a line may cross over it. Then, at any given time, I will remove that area and keep drawing over the entire screen before completeing a single frame. Any suggestions?

12-06-2002, 05:33 AM
Look up stencil testing (section 4.1.5 in the spec).

12-06-2002, 07:29 AM
Is there anything other than stencil? When I set GLUT_STENCIL in glutInitDisplayMode, I get the following error when executing the program:
"visual with necessary capabilities not found."
Could this be a problem with the latest nVidia driver for Linux? I tried it with an ATI card on Linux, and that worked, but I am required to get this working with the nVidia card.

12-06-2002, 07:46 AM
Stencil buffering might not be available on 16bit displays.

If you're running a windowed app (I guess you are), you'll have to switch your desktop to 32 bits color depth.

12-06-2002, 08:10 AM
Thanks for the help. 32bit was not supported by the graphics driver, but 24 is and the Stencil Test works now also. Thanks again.