docs/envvars.html

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   9 <H1>Environment Variables</H1>
  10
  11 <p>
  12 Normally, no environment variables need to be set.  Most of the environment
  13 variables used by Mesa/Gallium are for debugging purposes, but they can
  14 sometimes be useful for debugging end-user issues.
  15 </p>
  16
  17
  18 <H2>LibGL environment variables</H2>
  19
  20 <ul>
  21 <li>LIBGL_DEBUG - If defined debug information will be printed to stderr.
  22    If set to 'verbose' additional information will be printed.
  23 <li>LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers
  24 <li>LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.
  25 <li>LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering
  26 <li>LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)
  27 </ul>
  28
  29
  30
  31 <H2>Core Mesa environment variables</H2>
  32
  33 <ul>
  34 <li>MESA_NO_ASM - if set, disables all assembly language optimizations
  35 <li>MESA_NO_MMX - if set, disables Intel MMX optimizations
  36 <li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
  37 <li>MESA_NO_SSE - if set, disables Intel SSE optimizations
  38 <li>MESA_DEBUG - if set, error messages are printed to stderr.  For example,
  39    if the application generates a GL_INVALID_ENUM error, a corresponding error
  40    message indicating where the error occured, and possibly why, will be
  41    printed to stderr.<br>
  42    If the value of MESA_DEBUG is 'FP' floating point arithmetic errors will
  43    generate exceptions.
  44 <li>MESA_TEX_PROG - if set, implement conventional texture env modes with
  45 fragment programs (intended for developers only)
  46 <li>MESA_TNL_PROG - if set, implement conventional vertex transformation
  47 operations with vertex programs (intended for developers only).
  48 Setting this variable automatically sets the MESA_TEX_PROG variable as well.
  49 <li>MESA_EXTENSION_OVERRIDE - can be used to enable/disable extensions.
  50 A value such as "GL_EXT_foo -GL_EXT_bar" will enable the GL_EXT_foo extension
  51 and disable the GL_EXT_bar extension.
  52 <li>MESA_EXTENSION_MAX_YEAR - The GL_EXTENSIONS string returned by Mesa is sorted
  53 by extension year.
  54 If this variable is set to year X, only extensions defined on or before year
  55 X will be reported.
  56 This is to work-around a bug in some games where the extension string is
  57 copied into a fixed-size buffer without truncating.
  58 If the extension string is too long, the buffer overrun can cause the game
  59 to crash.
  60 This is a work-around for that.
  61 <li>MESA_GLSL - <a href="shading.html#envvars">shading language compiler options</a>
  62 </ul>
  63
  64
  65 <H2>Mesa Xlib driver environment variables</H2>
  66
  67 <p>
  68 The following are only applicable to the Mesa Xlib software driver.
  69 See the <A HREF="xlibdriver.html">Xlib software driver page</A> for details.
  70 </p>
  71 <ul>
  72 <li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
  73 <li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
  74 <li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
  75     either "pixmap" or "ximage"
  76 <li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
  77 <li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
  78 <li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
  79 <li>MESA_GLX_FX - set to either "fullscreen" for full-screen rendering,
  80   "window" to render into a window, or "disable" to disable the Glide driver.
  81 <li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
  82 <li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
  83 <li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
  84 </ul>
  85
  86
  87 <h2>i945/i965 driver environment variables (non-Gallium)</h2>
  88
  89 <ul>
  90 <li>INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
  91     OpenGL conformance.  If set to 2, always use software rendering.
  92 <li>INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,
  93     glCopyPixels, glDrawPixels.
  94 </ul>
  95
  96
  97 <h2>Radeon R300 driver environment variables (non-Gallium)</h2>
  98
  99 <ul>
 100 <li>R300_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
 101 </ul>
 102
 103
 104 <h2>EGL environment variables</h2>
 105
 106 <p>
 107 Mesa EGL supports different sets of environment variables.  See the
 108 <a href="egl.html">Mesa EGL</a> page for the details.
 109 </p>
 110
 111
 112 <h2>Gallium environment variables</h2>
 113
 114 <ul>
 115 <li>GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
 116     variables which are used, and their current values.
 117 <li>GALLIUM_NOSSE - if non-zero, do not use SSE runtime code generation for
 118     shader execution
 119 <li>GALLIUM_NOPPC - if non-zero, do not use PPC runtime code generation for
 120     shader execution
 121 <li>GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up
 122 <li>TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and
 123     print any errors to stderr.
 124 <LI>DRAW_FSE - ???
 125 <LI>DRAW_NO_FSE - ???
 126 <li>DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute
 127     shaders, vertex fetch, etc.
 128 </ul>
 129
 130 <h3>Softpipe driver environment variables</h3>
 131 <ul>
 132 <li>SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders
 133     to stderr
 134 <li>SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders
 135     to stderr
 136 <li>SOFTPIPE_NO_RAST - if set, rasterization is no-op'd.  For profiling purposes.
 137 </ul>
 138
 139
 140 <h3>LLVMpipe driver environment variables</h3>
 141 <ul>
 142 <li>LP_NO_RAST - if set LLVMpipe will no-op rasterization
 143 <li>LP_DEBUG - a comma-separated list of debug options is acceptec.  See the
 144     source code for details.
 145 <li>LP_PERF - a comma-separated list of options to selectively no-op various
 146     parts of the driver.  See the source code for details.
 147 <li>LP_NUM_THREADS - an integer indicating how many threads to use for rendering.
 148     Zero turns of threading completely.  The default value is the number of CPU
 149     cores present.
 150 </ul>
 151
 152
 153 <p>
 154 Other Gallium drivers have their own environment variables.  These may change
 155 frequently so the source code should be consulted for details.
 156 </p>
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