# Environment Variables

Mesa supports the following environment variables:

- MESA_DEBUG - if defined, error messages are printed to stderr
- MESA_NO_DITHER - disable dithering, overriding glEnable(GL_DITHER)
- MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode (X only)
- MESA_CI_VISUAL - specifies the X visual and depth for CI mode (X only)
- MESA_BACK_BUFFER - specifies how to implement the back color buffer (X only)
- MESA_PRIVATE_CMAP - force aux/tk libraries to use private colormaps (X only)
- MESA_GAMMA - gamma correction coefficients (X only)
- MESA_XSYNC - enable synchronous X behavior (for X debugging only)