docs/envvars.html

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  10 <h1>Environment Variables</h1>
  11
  12 <p>
  13 Normally, no environment variables need to be set.  Most of the environment
  14 variables used by Mesa/Gallium are for debugging purposes, but they can
  15 sometimes be useful for debugging end-user issues.
  16 </p>
  17
  18
  19 <H2>LibGL environment variables</H2>
  20
  21 <ul>
  22 <li>LIBGL_DEBUG - If defined debug information will be printed to stderr.
  23    If set to 'verbose' additional information will be printed.
  24 <li>LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers
  25 <li>LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.
  26 <li>LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering
  27 <li>LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)
  28 </ul>
  29
  30
  31
  32 <H2>Core Mesa environment variables</H2>
  33
  34 <ul>
  35 <li>MESA_NO_ASM - if set, disables all assembly language optimizations
  36 <li>MESA_NO_MMX - if set, disables Intel MMX optimizations
  37 <li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
  38 <li>MESA_NO_SSE - if set, disables Intel SSE optimizations
  39 <li>MESA_DEBUG - if set, error messages are printed to stderr.  For example,
  40    if the application generates a GL_INVALID_ENUM error, a corresponding error
  41    message indicating where the error occured, and possibly why, will be
  42    printed to stderr.<br>
  43    If the value of MESA_DEBUG is 'FP' floating point arithmetic errors will
  44    generate exceptions.
  45 <li>MESA_TEX_PROG - if set, implement conventional texture env modes with
  46 fragment programs (intended for developers only)
  47 <li>MESA_TNL_PROG - if set, implement conventional vertex transformation
  48 operations with vertex programs (intended for developers only).
  49 Setting this variable automatically sets the MESA_TEX_PROG variable as well.
  50 <li>MESA_EXTENSION_OVERRIDE - can be used to enable/disable extensions.
  51 A value such as "GL_EXT_foo -GL_EXT_bar" will enable the GL_EXT_foo extension
  52 and disable the GL_EXT_bar extension.
  53 <li>MESA_EXTENSION_MAX_YEAR - The GL_EXTENSIONS string returned by Mesa is sorted
  54 by extension year.
  55 If this variable is set to year X, only extensions defined on or before year
  56 X will be reported.
  57 This is to work-around a bug in some games where the extension string is
  58 copied into a fixed-size buffer without truncating.
  59 If the extension string is too long, the buffer overrun can cause the game
  60 to crash.
  61 This is a work-around for that.
  62 <li>MESA_GL_VERSION_OVERRIDE - changes the value returned by
  63 glGetString(GL_VERSION). Valid values are point-separated version numbers,
  64 such as "3.0". Mesa will not really implement all the features of the given
  65 version if it's higher than what's normally reported.
  66 <li>MESA_GLSL_VERSION_OVERRIDE - changes the value returned by
  67 glGetString(GL_SHADING_LANGUAGE_VERSION). Valid values are integers, such as
  68 "130".  Mesa will not really implement all the features of the given language version
  69 if it's higher than what's normally reported. (for developers only)
  70 <li>MESA_GLSL - <a href="shading.html#envvars">shading language compiler options</a>
  71 </ul>
  72
  73
  74 <H2>Mesa Xlib driver environment variables</H2>
  75
  76 <p>
  77 The following are only applicable to the Mesa Xlib software driver.
  78 See the <A HREF="xlibdriver.html">Xlib software driver page</A> for details.
  79 </p>
  80 <ul>
  81 <li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
  82 <li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
  83 <li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
  84     either "pixmap" or "ximage"
  85 <li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
  86 <li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
  87 <li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
  88 <li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
  89 <li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
  90 <li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
  91 </ul>
  92
  93
  94 <h2>i945/i965 driver environment variables (non-Gallium)</h2>
  95
  96 <ul>
  97 <li>INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
  98     OpenGL conformance.  If set to 2, always use software rendering.
  99 <li>INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,
 100     glCopyPixels, glDrawPixels.
 101 </ul>
 102
 103
 104 <h2>Radeon driver environment variables (radeon, r200, and r300g)</h2>
 105
 106 <ul>
 107 <li>RADEON_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
 108 </ul>
 109
 110
 111 <h2>EGL environment variables</h2>
 112
 113 <p>
 114 Mesa EGL supports different sets of environment variables.  See the
 115 <a href="egl.html">Mesa EGL</a> page for the details.
 116 </p>
 117
 118
 119 <h2>Gallium environment variables</h2>
 120
 121 <ul>
 122 <li>GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
 123     variables which are used, and their current values.
 124 <li>GALLIUM_NOSSE - if non-zero, do not use SSE runtime code generation for
 125     shader execution
 126 <li>GALLIUM_NOPPC - if non-zero, do not use PPC runtime code generation for
 127     shader execution
 128 <li>GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up
 129 <li>TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and
 130     print any errors to stderr.
 131 <LI>DRAW_FSE - ???
 132 <LI>DRAW_NO_FSE - ???
 133 <li>DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute
 134     shaders, vertex fetch, etc.
 135 </ul>
 136
 137 <h3>Softpipe driver environment variables</h3>
 138 <ul>
 139 <li>SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders
 140     to stderr
 141 <li>SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders
 142     to stderr
 143 <li>SOFTPIPE_NO_RAST - if set, rasterization is no-op'd.  For profiling purposes.
 144 <li>SOFTPIPE_USE_LLVM - if set, the softpipe driver will try to use LLVM JIT for
 145     vertex shading procesing.
 146 </ul>
 147
 148
 149 <h3>LLVMpipe driver environment variables</h3>
 150 <ul>
 151 <li>LP_NO_RAST - if set LLVMpipe will no-op rasterization
 152 <li>LP_DEBUG - a comma-separated list of debug options is acceptec.  See the
 153     source code for details.
 154 <li>LP_PERF - a comma-separated list of options to selectively no-op various
 155     parts of the driver.  See the source code for details.
 156 <li>LP_NUM_THREADS - an integer indicating how many threads to use for rendering.
 157     Zero turns of threading completely.  The default value is the number of CPU
 158     cores present.
 159 </ul>
 160
 161
 162 <p>
 163 Other Gallium drivers have their own environment variables.  These may change
 164 frequently so the source code should be consulted for details.
 165 </p>
 166
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