docs/envvars.html

   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
   2 <html lang="en">
   3 <head>
   4   <meta http-equiv="content-type" content="text/html; charset=utf-8">
   5   <title>Environment Variables</title>
   6   <link rel="stylesheet" type="text/css" href="mesa.css">
   7 </head>
   8 <body>
   9
  10 <div class="header">
  11   <h1>The Mesa 3D Graphics Library</h1>
  12 </div>
  13
  14 <iframe src="contents.html"></iframe>
  15 <div class="content">
  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) and possibly the GL API type.
  73 <ul>
  74 <li> The format should be MAJOR.MINOR[FC]
  75 <li> FC is an optional suffix that indicates a forward compatible context.
  76 This is only valid for versions &gt;= 3.0.
  77 <li> GL versions &lt; 3.0 are set to a compatibility (non-Core) profile
  78 <li> GL versions = 3.0, see below
  79 <li> GL versions &gt; 3.0 are set to a Core profile
  80 <li> Examples: 2.1, 3.0, 3.0FC, 3.1, 3.1FC
  81 <ul>
  82 <li> 2.1 - select a compatibility (non-Core) profile with GL version 2.1
  83 <li> 3.0 - select a compatibility (non-Core) profile with GL version 3.0
  84 <li> 3.0FC - select a Core+Forward Compatible profile with GL version 3.0
  85 <li> 3.1 - select a Core profile with GL version 3.1
  86 <li> 3.1FC - select a Core+Forward Compatible profile with GL version 3.1
  87 </ul>
  88 <li> Mesa may not really implement all the features of the given version.
  89 (for developers only)
  90 </ul>
  91 <li>MESA_GLSL_VERSION_OVERRIDE - changes the value returned by
  92 glGetString(GL_SHADING_LANGUAGE_VERSION). Valid values are integers, such as
  93 "130".  Mesa will not really implement all the features of the given language version
  94 if it's higher than what's normally reported. (for developers only)
  95 <li>MESA_GLSL - <a href="shading.html#envvars">shading language compiler options</a>
  96 </ul>
  97
  98
  99 <h2>Mesa Xlib driver environment variables</h2>
 100
 101 <p>
 102 The following are only applicable to the Mesa Xlib software driver.
 103 See the <a href="xlibdriver.html">Xlib software driver page</a> for details.
 104 </p>
 105 <ul>
 106 <li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
 107 <li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
 108 <li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
 109     either "pixmap" or "ximage"
 110 <li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
 111 <li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
 112 <li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
 113 <li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
 114 <li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
 115 <li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
 116 </ul>
 117
 118
 119 <h2>i945/i965 driver environment variables (non-Gallium)</h2>
 120
 121 <ul>
 122 <li>INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
 123     OpenGL conformance.  If set to 2, always use software rendering.
 124 <li>INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,
 125     glCopyPixels, glDrawPixels.
 126 </ul>
 127
 128
 129 <h2>Radeon driver environment variables (radeon, r200, and r300g)</h2>
 130
 131 <ul>
 132 <li>RADEON_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
 133 </ul>
 134
 135
 136 <h2>EGL environment variables</h2>
 137
 138 <p>
 139 Mesa EGL supports different sets of environment variables.  See the
 140 <a href="egl.html">Mesa EGL</a> page for the details.
 141 </p>
 142
 143
 144 <h2>Gallium environment variables</h2>
 145
 146 <ul>
 147 <li>GALLIUM_LOG_FILE - specifies a file for logging all errors, warnings, etc.
 148     rather than stderr.
 149 <li>GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
 150     variables which are used, and their current values.
 151 <li>GALLIUM_NOSSE - if non-zero, do not use SSE runtime code generation for
 152     shader execution
 153 <li>GALLIUM_NOPPC - if non-zero, do not use PPC runtime code generation for
 154     shader execution
 155 <li>GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up
 156 <li>TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and
 157     print any errors to stderr.
 158 <LI>DRAW_FSE - ???
 159 <LI>DRAW_NO_FSE - ???
 160 <li>DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute
 161     shaders, vertex fetch, etc.
 162 </ul>
 163
 164 <h3>Softpipe driver environment variables</h3>
 165 <ul>
 166 <li>SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders
 167     to stderr
 168 <li>SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders
 169     to stderr
 170 <li>SOFTPIPE_NO_RAST - if set, rasterization is no-op'd.  For profiling purposes.
 171 <li>SOFTPIPE_USE_LLVM - if set, the softpipe driver will try to use LLVM JIT for
 172     vertex shading procesing.
 173 </ul>
 174
 175
 176 <h3>LLVMpipe driver environment variables</h3>
 177 <ul>
 178 <li>LP_NO_RAST - if set LLVMpipe will no-op rasterization
 179 <li>LP_DEBUG - a comma-separated list of debug options is acceptec.  See the
 180     source code for details.
 181 <li>LP_PERF - a comma-separated list of options to selectively no-op various
 182     parts of the driver.  See the source code for details.
 183 <li>LP_NUM_THREADS - an integer indicating how many threads to use for rendering.
 184     Zero turns of threading completely.  The default value is the number of CPU
 185     cores present.
 186 </ul>
 187
 188
 189 <p>
 190 Other Gallium drivers have their own environment variables.  These may change
 191 frequently so the source code should be consulted for details.
 192 </p>
 193
 194 </div>
 195 </body>
 196 </html>