Posted by Martin on Aug 01, 2022; 10:55am
URL: https://forum.jogamp.org/Swing-panel-displays-pixels-of-previous-frame-where-pixels-of-current-frame-have-alpha-1-tp4041804.html

Hi,

I got a surprising bug with GLJPanel (Swing) which does not occur with GLCanvas (AWT).

To summarize my issue : I display translucent polygons which let appear content of the previous image exactly where the alpha is < 1 (see image below).

Would someone have a suggestion to solve this, given that I already verified the bellow ideas :
- Changing GLCapabilities.setBackgroundOpaque(true/false)
- Changing GLCapabilities.setDoubledBuffer(true/false)
- Changing setAutoSwapBuffer(true/false)
- Changing the depth buffer clear value (tried 1, 10, 10000, -1, -10)
- Changing the clear color to a copy of default clear color to ensure its alpha channel was not modified accidentally. Also verified that the clear color alpha channel is 1.
- The fact that AWT works proves that there is no OpenGL misconfiguration (e.g. no reason to think that the depth buffer is not cleared)