The Mesa 3D Graphics Library

Environment Variables

Normally, no environment variables need to be set.  Most of the environment

variables used by Mesa/Gallium are for debugging purposes, but they can

sometimes be useful for debugging end-user issues.

LibGL environment variables

LIBGL_DEBUG - If defined debug information will be printed to stderr.

   If set to 'verbose' additional information will be printed.

LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers

LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.

LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering

LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)

LIBGL_SHOW_FPS - print framerate to stdout based on the number of glXSwapBuffers

    calls per second.

Core Mesa environment variables

MESA_NO_ASM - if set, disables all assembly language optimizations

MESA_NO_MMX - if set, disables Intel MMX optimizations

MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations

MESA_NO_SSE - if set, disables Intel SSE optimizations

MESA_DEBUG - if set, error messages are printed to stderr.  For example,

   if the application generates a GL_INVALID_ENUM error, a corresponding error

   message indicating where the error occured, and possibly why, will be

   printed to stderr.

   If the value of MESA_DEBUG is 'FP' floating point arithmetic errors will

   generate exceptions.

MESA_LOG_FILE - specifies a file name for logging all errors, warnings,

etc., rather than stderr

MESA_TEX_PROG - if set, implement conventional texture env modes with

fragment programs (intended for developers only)

MESA_TNL_PROG - if set, implement conventional vertex transformation

operations with vertex programs (intended for developers only).

Setting this variable automatically sets the MESA_TEX_PROG variable as well.

MESA_EXTENSION_OVERRIDE - can be used to enable/disable extensions.

A value such as "GL_EXT_foo -GL_EXT_bar" will enable the GL_EXT_foo extension

and disable the GL_EXT_bar extension.

MESA_EXTENSION_MAX_YEAR - The GL_EXTENSIONS string returned by Mesa is sorted

by extension year.

If this variable is set to year X, only extensions defined on or before year

X will be reported.

This is to work-around a bug in some games where the extension string is

copied into a fixed-size buffer without truncating.

If the extension string is too long, the buffer overrun can cause the game

to crash.

This is a work-around for that.

MESA_GL_VERSION_OVERRIDE - changes the value returned by

glGetString(GL_VERSION) and possibly the GL API type.

 The format should be MAJOR.MINOR[FC]

 FC is an optional suffix that indicates a forward compatible context.

This is only valid for versions >= 3.0.

 GL versions < 3.0 are set to a compatibility (non-Core) profile

 GL versions = 3.0, see below

 GL versions > 3.0 are set to a Core profile

 Examples: 2.1, 3.0, 3.0FC, 3.1, 3.1FC

 2.1 - select a compatibility (non-Core) profile with GL version 2.1

 3.0 - select a compatibility (non-Core) profile with GL version 3.0

 3.0FC - select a Core+Forward Compatible profile with GL version 3.0

 3.1 - select a Core profile with GL version 3.1

 3.1FC - select a Core+Forward Compatible profile with GL version 3.1

 Mesa may not really implement all the features of the given version.

(for developers only)

MESA_GLSL_VERSION_OVERRIDE - changes the value returned by

glGetString(GL_SHADING_LANGUAGE_VERSION). Valid values are integers, such as

"130".  Mesa will not really implement all the features of the given language version

if it's higher than what's normally reported. (for developers only)

MESA_GLSL - shading language compiler options

Mesa Xlib driver environment variables

The following are only applicable to the Mesa Xlib software driver.

See the Xlib software driver page for details.

MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode

MESA_CI_VISUAL - specifies the X visual and depth for CI mode

MESA_BACK_BUFFER - specifies how to implement the back color buffer,

    either "pixmap" or "ximage"

MESA_GAMMA - gamma correction coefficients for red, green, blue channels

MESA_XSYNC - enable synchronous X behavior (for debugging only)

MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals

MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.

MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.

MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.

i945/i965 driver environment variables (non-Gallium)

INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve

    OpenGL conformance.  If set to 2, always use software rendering.

INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,

    glCopyPixels, glDrawPixels.

Radeon driver environment variables (radeon, r200, and r300g)

RADEON_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.

EGL environment variables

Mesa EGL supports different sets of environment variables.  See the

Mesa EGL page for the details.

Gallium environment variables

GALLIUM_HUD - draws various information on the screen, like framerate,

    cpu load, driver statistics, performance counters, etc.

    Set GALLIUM_HUD=help and run e.g. glxgears for more info.

GALLIUM_LOG_FILE - specifies a file for logging all errors, warnings, etc.

    rather than stderr.

GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment

    variables which are used, and their current values.

GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up

TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and

    print any errors to stderr.

DRAW_FSE - ???

DRAW_NO_FSE - ???

DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute

    shaders, vertex fetch, etc.

ST_DEBUG - controls debug output from the Mesa/Gallium state tracker.

Setting to "tgsi", for example, will print all the TGSI shaders.

See src/mesa/state_tracker/st_debug.c for other options.

Softpipe driver environment variables

SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders

    to stderr

SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders

    to stderr

SOFTPIPE_NO_RAST - if set, rasterization is no-op'd.  For profiling purposes.

SOFTPIPE_USE_LLVM - if set, the softpipe driver will try to use LLVM JIT for

    vertex shading procesing.

LLVMpipe driver environment variables

LP_NO_RAST - if set LLVMpipe will no-op rasterization

LP_DEBUG - a comma-separated list of debug options is acceptec.  See the

    source code for details.

LP_PERF - a comma-separated list of options to selectively no-op various

    parts of the driver.  See the source code for details.

LP_NUM_THREADS - an integer indicating how many threads to use for rendering.

    Zero turns of threading completely.  The default value is the number of CPU

    cores present.

VMware SVGA driver environment variables

SVGA_FORCE_SWTNL - force use of software vertex transformation

SVGA_NO_SWTNL - don't allow software vertex transformation fallbacks

(will often result in incorrect rendering).

SVGA_DEBUG - for dumping shaders, constant buffers, etc.  See the code

for details.

See the driver code for other, lesser-used variables.

Other Gallium drivers have their own environment variables.  These may change

frequently so the source code should be consulted for details.