+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.
+
-
-
Environment Variables
+
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)
+
+
+
+
+
Core Mesa environment variables
-
-Mesa supports the following 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.
-If the value of MESA_DEBUG is "FP" floating point arithmetic errors will
-generate exceptions.
-
MESA_NO_DITHER - if set, disables dithering, overriding glEnable(GL_DITHER)
+
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_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
@@ -28,12 +50,32 @@ 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). Valid values are point-separated version numbers,
+such as "3.0". Mesa will not really implement all the features of the given
+version if it's higher than what's normally reported.
+
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)
+
-The following are only applicable to the Xlib software driver.
-See the Xlib software driver page for details.
+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
@@ -43,17 +85,14 @@ See the Xlib software driver page for details.
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_FX - set to either "fullscreen" for full-screen rendering,
- "window" to render into a window, or "disable" to disable the Glide driver.
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.
-
-These environment variables are for the Intel i945/i965 drivers:
-
INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
OpenGL conformance. If set to 2, always use software rendering.
@@ -62,13 +101,68 @@ These environment variables are for the Intel i945/i965 drivers:
+
Radeon driver environment variables (radeon, r200, and r300g)
+
+
+
RADEON_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
+
+
+
+
EGL environment variables
+
-These environment variables are for the Radeon R300 driver:
+Mesa EGL supports different sets of environment variables. See the
+Mesa EGL page for the details.
+
+
+
Gallium environment variables
+
-
R300_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
+
GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
+ variables which are used, and their current values.
+
GALLIUM_NOSSE - if non-zero, do not use SSE runtime code generation for
+ shader execution
+
GALLIUM_NOPPC - if non-zero, do not use PPC runtime code generation for
+ shader execution
+
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.
+
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.
+
+
+
+
+Other Gallium drivers have their own environment variables. These may change
+frequently so the source code should be consulted for details.
+