docs/envvars.html

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  11   <h1>The Mesa 3D Graphics Library</h1>
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  16
  17 <h1>Environment Variables</h1>
  18
  19 <p>
  20 Normally, no environment variables need to be set.  Most of the environment
  21 variables used by Mesa/Gallium are for debugging purposes, but they can
  22 sometimes be useful for debugging end-user issues.
  23 </p>
  24
  25
  26 <h2>LibGL environment variables</h2>
  27
  28 <ul>
  29 <li>LIBGL_DEBUG - If defined debug information will be printed to stderr.
  30    If set to 'verbose' additional information will be printed.
  31 <li>LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers
  32 <li>LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.
  33 <li>LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering
  34 <li>LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)
  35 </ul>
  36
  37
  38
  39 <h2>Core Mesa environment variables</h2>
  40
  41 <ul>
  42 <li>MESA_NO_ASM - if set, disables all assembly language optimizations
  43 <li>MESA_NO_MMX - if set, disables Intel MMX optimizations
  44 <li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
  45 <li>MESA_NO_SSE - if set, disables Intel SSE optimizations
  46 <li>MESA_DEBUG - if set, error messages are printed to stderr.  For example,
  47    if the application generates a GL_INVALID_ENUM error, a corresponding error
  48    message indicating where the error occured, and possibly why, will be
  49    printed to stderr.<br>
  50    If the value of MESA_DEBUG is 'FP' floating point arithmetic errors will
  51    generate exceptions.
  52 <li>MESA_LOG_FILE - specifies a file name for logging all errors, warnings,
  53 etc., rather than stderr
  54 <li>MESA_TEX_PROG - if set, implement conventional texture env modes with
  55 fragment programs (intended for developers only)
  56 <li>MESA_TNL_PROG - if set, implement conventional vertex transformation
  57 operations with vertex programs (intended for developers only).
  58 Setting this variable automatically sets the MESA_TEX_PROG variable as well.
  59 <li>MESA_EXTENSION_OVERRIDE - can be used to enable/disable extensions.
  60 A value such as "GL_EXT_foo -GL_EXT_bar" will enable the GL_EXT_foo extension
  61 and disable the GL_EXT_bar extension.
  62 <li>MESA_EXTENSION_MAX_YEAR - The GL_EXTENSIONS string returned by Mesa is sorted
  63 by extension year.
  64 If this variable is set to year X, only extensions defined on or before year
  65 X will be reported.
  66 This is to work-around a bug in some games where the extension string is
  67 copied into a fixed-size buffer without truncating.
  68 If the extension string is too long, the buffer overrun can cause the game
  69 to crash.
  70 This is a work-around for that.
  71 <li>MESA_GL_VERSION_OVERRIDE - changes the value returned by
  72 glGetString(GL_VERSION). Valid values are point-separated version numbers,
  73 such as "3.0". Mesa will not really implement all the features of the given
  74 version if it's higher than what's normally reported.
  75 <li>MESA_GLSL_VERSION_OVERRIDE - changes the value returned by
  76 glGetString(GL_SHADING_LANGUAGE_VERSION). Valid values are integers, such as
  77 "130".  Mesa will not really implement all the features of the given language version
  78 if it's higher than what's normally reported. (for developers only)
  79 <li>MESA_GLSL - <a href="shading.html#envvars">shading language compiler options</a>
  80 </ul>
  81
  82
  83 <h2>Mesa Xlib driver environment variables</h2>
  84
  85 <p>
  86 The following are only applicable to the Mesa Xlib software driver.
  87 See the <a href="xlibdriver.html">Xlib software driver page</a> for details.
  88 </p>
  89 <ul>
  90 <li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
  91 <li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
  92 <li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
  93     either "pixmap" or "ximage"
  94 <li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
  95 <li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
  96 <li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
  97 <li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
  98 <li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
  99 <li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
 100 </ul>
 101
 102
 103 <h2>i945/i965 driver environment variables (non-Gallium)</h2>
 104
 105 <ul>
 106 <li>INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
 107     OpenGL conformance.  If set to 2, always use software rendering.
 108 <li>INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,
 109     glCopyPixels, glDrawPixels.
 110 </ul>
 111
 112
 113 <h2>Radeon driver environment variables (radeon, r200, and r300g)</h2>
 114
 115 <ul>
 116 <li>RADEON_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
 117 </ul>
 118
 119
 120 <h2>EGL environment variables</h2>
 121
 122 <p>
 123 Mesa EGL supports different sets of environment variables.  See the
 124 <a href="egl.html">Mesa EGL</a> page for the details.
 125 </p>
 126
 127
 128 <h2>Gallium environment variables</h2>
 129
 130 <ul>
 131 <li>GALLIUM_LOG_FILE - specifies a file for logging all errors, warnings, etc.
 132     rather than stderr.
 133 <li>GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
 134     variables which are used, and their current values.
 135 <li>GALLIUM_NOSSE - if non-zero, do not use SSE runtime code generation for
 136     shader execution
 137 <li>GALLIUM_NOPPC - if non-zero, do not use PPC runtime code generation for
 138     shader execution
 139 <li>GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up
 140 <li>TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and
 141     print any errors to stderr.
 142 <LI>DRAW_FSE - ???
 143 <LI>DRAW_NO_FSE - ???
 144 <li>DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute
 145     shaders, vertex fetch, etc.
 146 </ul>
 147
 148 <h3>Softpipe driver environment variables</h3>
 149 <ul>
 150 <li>SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders
 151     to stderr
 152 <li>SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders
 153     to stderr
 154 <li>SOFTPIPE_NO_RAST - if set, rasterization is no-op'd.  For profiling purposes.
 155 <li>SOFTPIPE_USE_LLVM - if set, the softpipe driver will try to use LLVM JIT for
 156     vertex shading procesing.
 157 </ul>
 158
 159
 160 <h3>LLVMpipe driver environment variables</h3>
 161 <ul>
 162 <li>LP_NO_RAST - if set LLVMpipe will no-op rasterization
 163 <li>LP_DEBUG - a comma-separated list of debug options is acceptec.  See the
 164     source code for details.
 165 <li>LP_PERF - a comma-separated list of options to selectively no-op various
 166     parts of the driver.  See the source code for details.
 167 <li>LP_NUM_THREADS - an integer indicating how many threads to use for rendering.
 168     Zero turns of threading completely.  The default value is the number of CPU
 169     cores present.
 170 </ul>
 171
 172
 173 <p>
 174 Other Gallium drivers have their own environment variables.  These may change
 175 frequently so the source code should be consulted for details.
 176 </p>
 177
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