<dl>
<dt><code>LIBGL_DEBUG</code></dt>
<dd>If defined debug information will be printed to stderr.
- If set to 'verbose' additional information will be printed.</dd>
+ If set to <code>verbose</code> additional information will be
+ printed.</dd>
<dt><code>LIBGL_DRIVERS_PATH</code></dt>
<dd>colon-separated list of paths to search for DRI drivers</dd>
<dt><code>LIBGL_ALWAYS_INDIRECT</code></dt>
-<dd>if set to `true`, forces an indirect rendering context/connection.</dd>
+<dd>if set to <code>true</code>, forces an indirect rendering
+ context/connection.</dd>
<dt><code>LIBGL_ALWAYS_SOFTWARE</code></dt>
-<dd>if set to `true`, always use software rendering</dd>
+<dd>if set to <code>true</code>, always use software rendering</dd>
<dt><code>LIBGL_NO_DRAWARRAYS</code></dt>
-<dd>if set to `true`, do not use DrawArrays GLX protocol (for debugging)</dd>
+<dd>if set to <code>true</code>, do not use DrawArrays GLX protocol
+ (for debugging)</dd>
<dt><code>LIBGL_SHOW_FPS</code></dt>
-<dd>print framerate to stdout based on the number of glXSwapBuffers
- calls per second.</dd>
+<dd>print framerate to stdout based on the number of
+ <code>glXSwapBuffers</code> calls per second.</dd>
<dt><code>LIBGL_DRI3_DISABLE</code></dt>
-<dd>disable DRI3 if set to `true`.</dd>
+<dd>disable DRI3 if set to <code>true</code>.</dd>
</dl>
<h2>Core Mesa environment variables</h2>
<dt><code>MESA_NO_SSE</code></dt>
<dd>if set, disables Intel SSE optimizations</dd>
<dt><code>MESA_NO_ERROR</code></dt>
-<dd>if set to 1, error checking is disabled as per KHR_no_error.
+<dd>if set to 1, error checking is disabled as per <code>KHR_no_error</code>.
This will result in undefined behaviour for invalid use of the api, but
can reduce CPU use for apps that are known to be error free.</dd>
<dt><code>MESA_DEBUG</code></dt>
<dd>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 occurred, and possibly why, will be
- printed to stderr. For release builds, MESA_DEBUG defaults to off (no debug
- output). MESA_DEBUG accepts the following comma-separated list of named
- flags, which adds extra behaviour to just set MESA_DEBUG=1:
+ if the application generates a <code>GL_INVALID_ENUM</code> error, a
+ corresponding error message indicating where the error occurred, and
+ possibly why, will be printed to stderr. For release builds,
+ <code>MESA_DEBUG</code> defaults to off (no debug output).
+ <code>MESA_DEBUG</code> accepts the following comma-separated list of
+ named flags, which adds extra behaviour to just set
+ <code>MESA_DEBUG=1</code>:
<dl>
<dt><code>silent</code></dt>
<dd>turn off debug messages. Only useful for debug builds.</dd>
<dt><code>incomplete_fbo</code></dt>
<dd>extra debug messages when a fbo is incomplete</dd>
<dt><code>context</code></dt>
- <dd>create a debug context (see GLX_CONTEXT_DEBUG_BIT_ARB) and print
- error and performance messages to stderr (or MESA_LOG_FILE).</dd>
+ <dd>create a debug context (see <code>GLX_CONTEXT_DEBUG_BIT_ARB</code>)
+ and print error and performance messages to stderr (or
+ <code>MESA_LOG_FILE</code>).</dd>
</dl>
</dd>
<dt><code>MESA_LOG_FILE</code></dt>
<dt><code>MESA_TNL_PROG</code></dt>
<dd>if set, implement conventional vertex transformation operations with
vertex programs (intended for developers only). Setting this variable
- automatically sets the MESA_TEX_PROG variable as well.</dd>
+ automatically sets the <code>MESA_TEX_PROG</code> variable as well.</dd>
<dt><code>MESA_EXTENSION_OVERRIDE</code></dt>
<dd>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.</dd>
+ <code>GL_EXT_foo -GL_EXT_bar</code> will enable the
+ <code>GL_EXT_foo</code> extension and disable the
+ <code>GL_EXT_bar</code> extension.</dd>
<dt><code>MESA_EXTENSION_MAX_YEAR</code></dt>
-<dd>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.
-</dd>
+<dd>The <code>GL_EXTENSIONS</code> 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.</dd>
<dt><code>MESA_GL_VERSION_OVERRIDE</code></dt>
<dd>changes the value returned by
-glGetString(GL_VERSION) and possibly the GL API type.
+<code>glGetString(GL_VERSION)</code> and possibly the GL API type.
<ul>
- <li>The format should be MAJOR.MINOR[FC|COMPAT]
- <li>FC is an optional suffix that indicates a forward compatible
- context. This is only valid for versions >= 3.0.
- <li>COMPAT is an optional suffix that indicates a compatibility
- context or GL_ARB_compatibility support. This is only valid for
- versions >= 3.1.
+ <li>The format should be <code>MAJOR.MINOR[FC|COMPAT]</code>
+ <li><code>FC</code> is an optional suffix that indicates a forward
+ compatible context. This is only valid for versions >= 3.0.
+ <li><code>COMPAT</code> is an optional suffix that indicates a
+ compatibility context or <code>GL_ARB_compatibility</code> support.
+ This is only valid for versions >= 3.1.
<li>GL versions <= 3.0 are set to a compatibility (non-Core)
profile
<li>GL versions = 3.1, depending on the driver, it may or may not
- have the ARB_compatibility extension enabled.
+ have the <code>ARB_compatibility</code> extension enabled.
<li>GL versions >= 3.2 are set to a Core profile
<li>Examples:
<dl>
</ul>
</dd>
<dt><code>MESA_GLES_VERSION_OVERRIDE</code></dt>
-<dd>changes the value returned by glGetString(GL_VERSION) for OpenGL ES.
+<dd>changes the value returned by <code>glGetString(GL_VERSION)</code>
+ for OpenGL ES.
<ul>
-<li> The format should be MAJOR.MINOR
-<li> Examples: 2.0, 3.0, 3.1
+<li> The format should be <code>MAJOR.MINOR</code>
+<li> Examples: <code>2.0</code>, <code>3.0</code>, <code>3.1</code>
<li> Mesa may not really implement all the features of the given version.
(for developers only)
</ul>
</dd>
<dt><code>MESA_GLSL_VERSION_OVERRIDE</code></dt>
-<dd>changes the value returned by glGetString(GL_SHADING_LANGUAGE_VERSION).
+<dd>changes the value returned by
+ <code>glGetString(GL_SHADING_LANGUAGE_VERSION)</code>.
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)
</dd>
<dt><code>MESA_GLSL_CACHE_DISABLE</code></dt>
-<dd>if set to `true`, disables the GLSL shader cache</dd>
+<dd>if set to <code>true</code>, disables the GLSL shader cache</dd>
<dt><code>MESA_GLSL_CACHE_MAX_SIZE</code></dt>
<dd>if set, determines the maximum size of the on-disk cache of compiled GLSL
- programs. Should be set to a number optionally followed by 'K', 'M', or
- 'G' to specify a size in kilobytes, megabytes, or gigabytes. By default,
- gigabytes will be assumed. And if unset, a maximum size of 1GB will be
- used. Note: A separate cache might be created for each architecture that
- Mesa is installed for on your system. For example under the default
- settings you may end up with a 1GB cache for x86_64 and another 1GB cache
- for i386.</dd>
+ programs. Should be set to a number optionally followed by <code>K</code>,
+ <code>M</code>, or <code>G</code> to specify a size in kilobytes,
+ megabytes, or gigabytes. By default, gigabytes will be assumed. And if
+ unset, a maximum size of 1GB will be used. Note: A separate cache might
+ be created for each architecture that Mesa is installed for on your
+ system. For example under the default settings you may end up with a 1GB
+ cache for x86_64 and another 1GB cache for i386.</dd>
<dt><code>MESA_GLSL_CACHE_DIR</code></dt>
<dd>if set, determines the directory to be used for the on-disk cache of
compiled GLSL programs. If this variable is not set, then the cache will
- be stored in $XDG_CACHE_HOME/mesa_shader_cache (if that variable is set),
- or else within .cache/mesa_shader_cache within the user's home directory.
+ be stored in <code>$XDG_CACHE_HOME/mesa_shader_cache</code> (if that
+ variable is set), or else within <code>.cache/mesa_shader_cache</code>
+ within the user's home directory.
</dd>
<dt><code>MESA_GLSL</code></dt>
<dd><a href="shading.html#envvars">shading language compiler options</a></dd>
<dd>see <a href="shading.html#replacement">Experimenting with Shader Replacements</a></dd>
<dt><code>MESA_VK_VERSION_OVERRIDE</code></dt>
<dd>changes the Vulkan physical device version
- as returned in VkPhysicalDeviceProperties::apiVersion.
+ as returned in <code>VkPhysicalDeviceProperties::apiVersion</code>.
<ul>
- <li>The format should be MAJOR.MINOR[.PATCH]</li>
+ <li>The format should be <code>MAJOR.MINOR[.PATCH]</code></li>
<li>This will not let you force a version higher than the driver's
- instance versionas advertised by vkEnumerateInstanceVersion</li>
+ instance versionas advertised by
+ <code>vkEnumerateInstanceVersion</code></li>
<li>This can be very useful for debugging but some features may not be
implemented correctly. (For developers only)</li>
</ul>
<dt><code>MESA_CI_VISUAL</code></dt>
<dd>specifies the X visual and depth for CI mode</dd>
<dt><code>MESA_BACK_BUFFER</code></dt>
-<dd>specifies how to implement the back color buffer, either "pixmap" or
- "ximage"</dd>
+<dd>specifies how to implement the back color buffer, either
+ <code>pixmap</code> or <code>ximage</code></dd>
<dt><code>MESA_GAMMA</code></dt>
<dd>gamma correction coefficients for red, green, blue channels</dd>
<dt><code>MESA_XSYNC</code></dt>
<dt><code>perf</code></dt>
<dd>emit messages about performance issues</dd>
<dt><code>perfmon</code></dt>
- <dd>emit messages about AMD_performance_monitor</dd>
+ <dd>emit messages about <code>AMD_performance_monitor</code></dd>
<dt><code>pix</code></dt>
<dd>emit messages about pixel operations</dd>
<dt><code>prim</code></dt>
<dt><code>GALLIUM_HUD</code></dt>
<dd>draws various information on the screen, like framerate,
cpu load, driver statistics, performance counters, etc.
- Set GALLIUM_HUD=help and run e.g. glxgears for more info.</dd>
+ Set <code>GALLIUM_HUD=help</code> and run e.g. glxgears for more
+ info.</dd>
<dt><code>GALLIUM_HUD_PERIOD</code></dt>
<dd>sets the hud update rate in seconds (float). Use zero
to update every frame. The default period is 1/2 second.</dd>
<dd>toggle visibility via user specified signal.
Especially useful to toggle hud at specific points of application and
disable for unencumbered viewing the rest of the time. For example, set
- GALLIUM_HUD_VISIBLE to false and GALLIUM_HUD_TOGGLE_SIGNAL to 10 (SIGUSR1).
- Use kill -10 <pid> to toggle the hud as desired.</dd>
+ <code>GALLIUM_HUD_VISIBLE</code> to <code>false</code> and
+ <code>GALLIUM_HUD_TOGGLE_SIGNAL</code> to <code>10</code>
+ (<code>SIGUSR1</code>).
+ Use <code>kill -10 <pid></code> to toggle the hud as desired.</dd>
<dt><code>GALLIUM_HUD_DUMP_DIR</code></dt>
<dd>specifies a directory for writing the displayed hud values into files.</dd>
<dt><code>GALLIUM_DRIVER</code></dt>
-<dd>useful in combination with LIBGL_ALWAYS_SOFTWARE=true for choosing one
- of the software renderers "softpipe", "llvmpipe" or "swr".</dd>
+<dd>useful in combination with <code>LIBGL_ALWAYS_SOFTWARE=true</code> for
+ choosing one of the software renderers <code>softpipe</code>,
+ <code>llvmpipe</code> or <code>swr</code>.</dd>
<dt><code>GALLIUM_LOG_FILE</code></dt>
<dd>specifies a file for logging all errors, warnings, etc.
rather than stderr.</dd>
shaders, vertex fetch, etc.</dd>
<dt><code>ST_DEBUG</code></dt>
<dd>controls debug output from the Mesa/Gallium state tracker.
- Setting to "tgsi", for example, will print all the TGSI shaders.
- See src/mesa/state_tracker/st_debug.c for other options.</dd>
+ Setting to <code>tgsi</code>, for example, will print all the TGSI
+ shaders. See <code>src/mesa/state_tracker/st_debug.c</code> for other
+ options.</dd>
</dl>
<h3>Clover state tracker environment variables</h3>
<dt><code>CLOVER_EXTRA_BUILD_OPTIONS</code></dt>
<dd>allows specifying additional compiler and linker
options. Specified options are appended after the options set by the OpenCL
- program in clBuildProgram.</dd>
+ program in <code>clBuildProgram</code>.</dd>
<dt><code>CLOVER_EXTRA_COMPILE_OPTIONS</code></dt>
<dd>allows specifying additional compiler
options. Specified options are appended after the options set by the OpenCL
- program in clCompileProgram.</dd>
+ program in <code>clCompileProgram</code>.</dd>
<dt><code>CLOVER_EXTRA_LINK_OPTIONS</code></dt>
<dd>allows specifying additional linker
options. Specified options are appended after the options set by the OpenCL
- program in clLinkProgram.</dd>
+ program in <code>clLinkProgram</code>.</dd>
</dl>
<h3>WGL environment variables</h3>
<dl>
<dt><code>WGL_SWAP_INTERVAL</code></dt>
-<dd>to set a swap interval, equivalent to calling wglSwapIntervalEXT()
- in an application. If this environment variable is set, application
- calls to wglSwapIntervalEXT() will have no effect.</dd>
+<dd>to set a swap interval, equivalent to calling
+ <code>wglSwapIntervalEXT()</code> in an application. If this
+ environment variable is set, application calls to
+ <code>wglSwapIntervalEXT()</code> will have no effect.</dd>
</dl>
<h3>VA-API state tracker environment variables</h3>