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+<h1>Frequently Asked Questions</h1>
+Last updated: 19 September 2018
-
-<center>
-<h1>Mesa Frequently Asked Questions</h1>
-Last updated: 21 August 2006
-</center>
-
-<br>
-<br>
<h2>Index</h2>
-<a href="#part1">1. High-level Questions and Answers</a>
-<br>
-<a href="#part2">2. Compilation and Installation Problems</a>
-<br>
-<a href="#part3">3. Runtime / Rendering Problems</a>
-<br>
-<a href="#part4">4. Developer Questions</a>
-<br>
-<br>
-<br>
-
+<ol>
+ <li><a href="#part1">High-level Questions and Answers</a></li>
+ <li><a href="#part2">Compilation and Installation Problems</a></li>
+ <li><a href="#part3">Runtime / Rendering Problems</a></li>
+ <li><a href="#part4">Developer Questions</a></li>
+</ol>
+<h2 id="part1">1. High-level Questions and Answers</h2>
-<a name="part1">
-</a><h1><a name="part1">1. High-level Questions and Answers</a></h1>
-
-<h2><a name="part1">1.1 What is Mesa?</a></h2>
+<h3>1.1 What is Mesa?</h3>
<p>
-<a name="part1">Mesa is an open-source implementation of the OpenGL specification.
+Mesa is an open-source implementation of the OpenGL specification.
OpenGL is a programming library for writing interactive 3D applications.
-See the </a><a href="http://www.opengl.org/">OpenGL website</a> for more
+See the <a href="https://www.opengl.org/">OpenGL website</a> for more
information.
</p>
<p>
-Mesa 6.x supports the OpenGL 1.5 specification.
+Mesa 9.x supports the OpenGL 3.1 specification.
</p>
<h2>1.2 Does Mesa support/use graphics hardware?</h2>
<p>
Yes. Specifically, Mesa serves as the OpenGL core for the open-source DRI
-drivers for XFree86/X.org. See the <a href="http://dri.freedesktop.org/">DRI
-website</a> for more information.
-</p>
-<p>
-There have been other hardware drivers for Mesa over the years (such as
-the 3Dfx Glide/Voodoo driver, an old S3 driver, etc) but the DRI drivers
-are the modern ones.
+drivers for X.org.
</p>
+<ul>
+ <li>See the <a href="https://dri.freedesktop.org/">DRI website</a>
+ for more information.</li>
+ <li>See <a href="https://01.org/linuxgraphics">01.org</a>
+ for more information about Intel drivers.</li>
+ <li>See <a href="https://nouveau.freedesktop.org">nouveau.freedesktop.org</a>
+ for more information about Nouveau drivers.</li>
+ <li>See <a href="https://www.x.org/wiki/RadeonFeature">www.x.org/wiki/RadeonFeature</a>
+ for more information about Radeon drivers.</li>
+</ul>
<h2>1.3 What purpose does Mesa serve today?</h2>
<p>
Still, Mesa serves at least these purposes:
</p>
<ul>
-<li>Mesa is used as the core of the open-source XFree86/X.org DRI
+<li>Mesa is used as the core of the open-source X.org DRI
hardware drivers.
</li>
<li>Mesa is quite portable and allows OpenGL to be used on systems
</ul>
-<h2>1.4 What's the difference between"Stand-Alone" Mesa and the DRI drivers?</h2>
+<h2>1.4 What's the difference between "Stand-Alone" Mesa and the DRI drivers?</h2>
<p>
<em>Stand-alone Mesa</em> is the original incarnation of Mesa.
On systems running the X Window System it does all its rendering through
the Xlib API:
+</p>
<ul>
<li>The GLX API is supported, but it's really just an emulation of the
real thing.
<li>The GLX wire protocol is not supported and there's no OpenGL extension
loaded by the X server.
<li>There is no hardware acceleration.
-<li>The OpenGL library, libGL.so, contains everything (the programming API,
- the GLX functions and all the rendering code).
+<li>The OpenGL library, <code>libGL.so</code>, contains everything (the
+ programming API, the GLX functions and all the rendering code).
</ul>
-</p>
<p>
Alternately, Mesa acts as the core for a number of OpenGL hardware drivers
within the DRI (Direct Rendering Infrastructure):
<ul>
-<li>The libGL.so library provides the GL and GLX API functions, a GLX
- protocol encoder, and a device driver loader.
-<li>The device driver modules (such as r200_dri.so) contain a built-in
- copy of the core Mesa code.
+<li>The <code>libGL.so</code> library provides the GL and GLX API functions,
+ a GLX protocol encoder, and a device driver loader.
+<li>The device driver modules (such as <code>r200_dri.so</code>) contain
+ a built-in copy of the core Mesa code.
<li>The X server loads the GLX module.
The GLX module decodes incoming GLX protocol and dispatches the commands
to a rendering module.
<h2>1.6 Are there other open-source implementations of OpenGL?</h2>
<p>
-Yes, SGI's <a href="http://oss.sgi.com/projects/ogl-sample/index.html"
-target="_parent">
-OpenGL Sample Implemenation (SI)</a> is available.
+Yes, SGI's <a href="http://web.archive.org/web/20171010115110_/http://oss.sgi.com/projects/ogl-sample/index.html">
+OpenGL Sample Implementation (SI)</a> is available.
The SI was written during the time that OpenGL was originally designed.
Unfortunately, development of the SI has stagnated.
Mesa is much more up to date with modern features and extensions.
</p>
<p>
-<a href="http://ogl-es.sourceforge.net" target="_parent">Vincent</a> is
+<a href="https://sourceforge.net/projects/ogl-es/">Vincent</a> is
an open-source implementation of OpenGL ES for mobile devices.
<p>
-<a href="http://www.dsbox.com/minigl.html" target="_parent">miniGL</a>
-is a subset of OpenGL for PalmOS devices.
+<a href="http://web.archive.org/web/20130830162848/http://www.dsbox.com/minigl.html">miniGL</a>
+is a subset of OpenGL for PalmOS devices. The website is gone, but the source
+code can still be found on <a href="https://sourceforge.net/projects/minigl/">sourceforge.net</a>.
<p>
-<a href="http://fabrice.bellard.free.fr/TinyGL/"
-target="_parent">TinyGL</a> is a subset of OpenGL.
+<a href="http://bellard.org/TinyGL/">TinyGL</a>
+is a subset of OpenGL.
</p>
<p>
-<a href="http://softgl.studierstube.org/" target="_parent">SoftGL</a>
+<a href="https://sourceforge.net/projects/softgl/">SoftGL</a>
is an OpenGL subset for mobile devices.
</p>
<p>
-<a href="http://chromium.sourceforge.net/" target="_parent">Chromium</a>
+<a href="http://chromium.sourceforge.net/">Chromium</a>
isn't a conventional OpenGL implementation (it's layered upon OpenGL),
but it does export the OpenGL API. It allows tiled rendering, sort-last
rendering, etc.
</p>
<p>
-<a href="http://www.ticalc.org/archives/files/fileinfo/361/36173.html"
-target="_parent">ClosedGL</a> is an OpenGL subset library for TI
-graphing calculators.
+<a href="http://www.ticalc.org/archives/files/fileinfo/361/36173.html">ClosedGL</a>
+is an OpenGL subset library for TI graphing calculators.
</p>
<p>
</p>
+<h2 id="part2">2. Compilation and Installation Problems</h2>
-<br>
-<br>
-
-
-<a name="part2">
-</a><h1><a name="part2">2. Compilation and Installation Problems</a></h1>
-
-
-<h2><a name="part2">2.1 What's the easiest way to install Mesa?</a></h2>
+<h3>2.1 What's the easiest way to install Mesa?</h3>
<p>
-<a name="part2">If you're using a Linux-based system, your distro CD most likely already
+If you're using a Linux-based system, your distro CD most likely already
has Mesa packages (like RPM or DEB) which you can easily install.
-</a></p>
+</p>
-<h2><a name="part2">2.2 I get undefined symbols such as bgnpolygon, v3f, etc...</a></h2>
+<h3>2.2 I get undefined symbols such as bgnpolygon, v3f, etc...</h3>
<p>
-<a name="part2">You're application is written in IRIS GL, not OpenGL.
+You're application is written in IRIS GL, not OpenGL.
IRIS GL was the predecessor to OpenGL and is a different thing (almost)
entirely.
Mesa's not the solution.
-</a></p>
+</p>
-<h2><a name="part2">2.3 Where is the GLUT library?</a></h2>
+<h3>2.3 Where is the GLUT library?</h3>
<p>
-<a name="part2">GLUT (OpenGL Utility Toolkit) is in the separate MesaGLUT-x.y.z.tar.gz file.
-If you don't already have GLUT installed, you should grab the MesaGLUT
-package and compile it with the rest of Mesa.
-</a></p>
+GLUT (OpenGL Utility Toolkit) is no longer in the separate
+<code>MesaGLUT-x.y.z.tar.gz</code> file.
+If you don't already have GLUT installed, you should grab
+<a href="http://freeglut.sourceforge.net/">freeglut</a>.
+</p>
+<h3>2.4 Where is the GLw library?</h3>
+<p>
+GLw (OpenGL widget library) is now available from a separate <a href="https://gitlab.freedesktop.org/mesa/glw">git repository</a>. Unless you're using very old Xt/Motif applications with OpenGL, you shouldn't need it.
+</p>
+
-<h2><a name="part2">2.4 What's the proper place for the libraries and headers?</a></h2>
+<h2>2.5 What's the proper place for the libraries and headers?</h2>
<p>
-<a name="part2">On Linux-based systems you'll want to follow the
-</a><a href="http://oss.sgi.com/projects/ogl-sample/ABI/index.html"
-target="_parent">Linux ABI</a> standard.
+On Linux-based systems you'll want to follow the
+<a href="https://www.khronos.org/registry/OpenGL/ABI/">Linux ABI</a> standard.
Basically you'll want the following:
</p>
-<ul>
-<li>/usr/include/GL/gl.h - the main OpenGL header
-</li><li>/usr/include/GL/glu.h - the OpenGL GLU (utility) header
-</li><li>/usr/include/GL/glx.h - the OpenGL GLX header
-</li><li>/usr/include/GL/glext.h - the OpenGL extensions header
-</li><li>/usr/include/GL/glxext.h - the OpenGL GLX extensions header
-</li><li>/usr/include/GL/osmesa.h - the Mesa off-screen rendering header
-</li><li>/usr/lib/libGL.so - a symlink to libGL.so.1
-</li><li>/usr/lib/libGL.so.1 - a symlink to libGL.so.1.xyz
-</li><li>/usr/lib/libGL.so.xyz - the actual OpenGL/Mesa library. xyz denotes the
+<dl>
+<dt><code>/usr/include/GL/gl.h</code></dt>
+<dd>the main OpenGL header</dd>
+<dt><code>/usr/include/GL/glu.h</code></dt>
+<dd>the OpenGL GLU (utility) header</dd>
+<dt><code>/usr/include/GL/glx.h</code></dt>
+<dd>the OpenGL GLX header</dd>
+<dt><code>/usr/include/GL/glext.h</code></dt>
+<dd>the OpenGL extensions header</dd>
+<dt><code>/usr/include/GL/glxext.h</code></dt>
+<dd>the OpenGL GLX extensions header</dd>
+<dt><code>/usr/include/GL/osmesa.h</code></dt>
+<dd>the Mesa off-screen rendering header</dd>
+<dt><code>/usr/lib/libGL.so</code></dt>
+<dd>a symlink to <code>libGL.so.1</code></dd>
+<dt><code>/usr/lib/libGL.so.1</code></dt>
+<dd>a symlink to <code>libGL.so.1.xyz</code></dd>
+<dt><code>/usr/lib/libGL.so.xyz</code></dt>
+<dd>the actual OpenGL/Mesa library. xyz denotes the
Mesa version number.
-</li><li>/usr/lib/libGLU.so - a symlink to libGLU.so.1
-</li><li>/usr/lib/libGLU.so.1 - a symlink to libGLU.so.1.3.xyz
-</li><li>/usr/lib/libGLU.so.xyz - the OpenGL Utility library. xyz denotes the Mesa
-version number.
-</li></ul>
+</dd>
+</dl>
<p>
-After installing XFree86/X.org and the DRI drivers, some of these files
-may be symlinks into the /usr/X11R6/ tree.
+When configuring Mesa, there are three meson options that affect the install
+location that you should take care with: <code>--prefix</code>,
+<code>--libdir</code>, and <code>-D dri-drivers-path</code>. To install Mesa
+into the system location where it will be available for all programs to use, set
+<code>--prefix=/usr</code>. Set <code>--libdir</code> to where your Linux
+distribution installs system libraries, usually either <code>/usr/lib</code> or
+<code>/usr/lib64</code>. Set <code>-D dri-drivers-path</code> to the directory
+where your Linux distribution installs DRI drivers. To find your system's DRI
+driver directory, try executing <code>find /usr -type d -name dri</code>. For
+example, if the <code>find</code> command listed <code>/usr/lib64/dri</code>,
+then set <code>-D dri-drivers-path=/usr/lib64/dri</code>.
</p>
<p>
-The old-style Makefile system doesn't install the Mesa libraries; it's
-up to you to copy them (and the headers) to the right place.
+After determining the correct values for the install location, configure Mesa
+with <code>meson configure --prefix=/usr --libdir=xxx -D dri-drivers-path=xxx</code>
+and then install with <code>sudo ninja install</code>.
</p>
-<p>
-The GLUT header and library should go in the same directories.
-</p>
-<br>
-<br>
-<a name="part3">
-</a><h1><a name="part3">3. Runtime / Rendering Problems</a></h1>
+<h2 id="part3">3. Runtime / Rendering Problems</h2>
-<h2><a name="part3">3.1 Rendering is slow / why isn't my graphics hardware being used?</a></h2>
-<p>
-<a name="part3">Stand-alone Mesa (downloaded as MesaLib-x.y.z.tar.gz) doesn't have any
-support for hardware acceleration (with the exception of the 3DFX Voodoo
-driver).
-</a></p>
+<h3>3.1 Rendering is slow / why isn't my graphics hardware being used?</h3>
<p>
-<a name="part3">What you really want is a DRI or NVIDIA (or another vendor's OpenGL) driver
-for your particular hardware.
-</a></p>
+If Mesa can't use its hardware accelerated drivers it falls back on one of its software renderers.
+(eg. classic swrast, softpipe or llvmpipe)
+</p>
<p>
-<a name="part3">You can run the <code>glxinfo</code> program to learn about your OpenGL
+You can run the <code>glxinfo</code> program to learn about your OpenGL
library.
-Look for the GL_VENDOR and GL_RENDERER values.
-That will identify who's OpenGL library you're using and what sort of
+Look for the <code>OpenGL vendor</code> and <code>OpenGL renderer</code> values.
+That will identify who's OpenGL library with which driver you're using and what sort of
hardware it has detected.
-</a></p>
+</p>
<p>
-<a name="part3">If your DRI-based driver isn't working, go to the
-</a><a href="http://dri.sf.net/" target="_parent">DRI website</a> for trouble-shooting information.
+If you're using a hardware accelerated driver you want <code>direct rendering: Yes</code>.
+</p>
+<p>
+If your DRI-based driver isn't working, go to the
+<a href="https://dri.freedesktop.org/">DRI website</a> for trouble-shooting information.
</p>
-<h2>3.2 I'm seeing errors in depth (Z) buffering. Why?</h2>
+<h3>3.2 I'm seeing errors in depth (Z) buffering. Why?</h3>
<p>
Make sure the ratio of the far to near clipping planes isn't too great.
Look
-<a href="http://www.opengl.org/resources/faq/technical/depthbuffer.htm#0040"
-target="_parent"> here</a> for details.
+<a href="https://www.opengl.org/archives/resources/faq/technical/depthbuffer.htm#0040">here</a>
+for details.
</p>
<p>
Mesa uses a 16-bit depth buffer by default which is smaller and faster
to clear than a 32-bit buffer but not as accurate.
If you need a deeper you can modify the parameters to
-<code> glXChooseVisual</code> in your code.
+<code>glXChooseVisual</code> in your code.
</p>
-<h2>3.3 Why Isn't depth buffering working at all?</h2>
+<h3>3.3 Why Isn't depth buffering working at all?</h3>
<p>
-Be sure you're requesting a depth buffered-visual. If you set the MESA_DEBUG
-environment variable it will warn you about trying to enable depth testing
-when you don't have a depth buffer.
+Be sure you're requesting a depth buffered-visual. If you set the
+<code>MESA_DEBUG</code> environment variable it will warn you about trying
+to enable depth testing when you don't have a depth buffer.
</p>
<p>Specifically, make sure <code>glutInitDisplayMode</code> is being called
with <code>GLUT_DEPTH</code> or <code>glXChooseVisual</code> is being
-called with a non-zero value for GLX_DEPTH_SIZE.
+called with a non-zero value for <code>GLX_DEPTH_SIZE</code>.
</p>
<p>This discussion applies to stencil buffers, accumulation buffers and
alpha channels too.
</p>
-<h2>3.4 Why does glGetString() always return NULL?</h2>
+<h3>3.4 Why does <code>glGetString()</code> always return <code>NULL</code>?</h3>
<p>
Be sure you have an active/current OpenGL rendering context before
-calling glGetString.
+calling <code>glGetString</code>.
</p>
-<h2>3.5 GL_POINTS and GL_LINES don't touch the right pixels</h2>
-<p>
-If you're trying to draw a filled region by using GL_POINTS or GL_LINES
-and seeing holes or gaps it's because of a float-to-int rounding problem.
-But this is not a bug.
-See Appendix H of the OpenGL Programming Guide - "OpenGL Correctness Tips".
-Basically, applying a translation of (0.375, 0.375, 0.0) to your coordinates
-will fix the problem.
-</p>
-
-<h2>3.6 How can I change the maximum framebuffer size in Mesa's
-<tt>swrast</tt> backend?</h2>
+<h3>3.5 <code>GL_POINTS</code> and <code>GL_LINES</code> don't touch the
+right pixels</h3>
<p>
-These can be overridden by using the <tt>--with-max-width</tt> and
-<tt>--with-max-height</tt> options. The two need not be equal.
-</p><p>
-Do note that Mesa uses these values to size some internal buffers,
-so increasing these sizes will cause Mesa to require additional
-memory. Furthermore, increasing these limits beyond <tt>4096</tt>
-may introduce rasterization artifacts; see the leading comments in
-<tt>src/mesa/swrast/s_tritemp.h</tt>.
+If you're trying to draw a filled region by using <code>GL_POINTS</code> or
+<code>GL_LINES</code> and seeing holes or gaps it's because of a float-to-int
+rounding problem. But this is not a bug. See Appendix H of the OpenGL
+Programming Guide - "OpenGL Correctness Tips". Basically, applying a
+translation of (0.375, 0.375, 0.0) to your coordinates will fix the problem.
</p>
-<br>
-<br>
-
-<a name="part4">
-</a><h1><a name="part4">4. Developer Questions</a></h1>
+<h2 id="part4">4. Developer Questions</h2>
-<h2>4.1 How can I contribute?</a></h2>
+<h3>4.1 How can I contribute?</h3>
<p>
-First, join the <a href="http://www.mesa3d.org/lists.html">Mesa3d-dev
-mailing list</a>.
+First, join the <a href="lists.html">mesa-dev mailing list</a>.
That's where Mesa development is discussed.
</p>
<p>
-The <a href="http://www.opengl.org/documentation" target="_parent">
-OpenGL Specification</a> is the bible for OpenGL implemention work.
+The <a href="https://www.opengl.org/documentation">
+OpenGL Specification</a> is the bible for OpenGL implementation work.
You should read it.
</p>
<p>Most of the Mesa development work involves implementing new OpenGL
extensions, writing hardware drivers (for the DRI), and code optimization.
</p>
-<h2>4.2 How do I write a new device driver?</h2>
+<h3>4.2 How do I write a new device driver?</h3>
<p>
Unfortunately, writing a device driver isn't easy.
It requires detailed understanding of OpenGL, the Mesa code, and your
<p>
The best way to get started is to use an existing driver as your starting
point.
-For a software driver, the X11 and OSMesa drivers are good examples.
-For a hardware driver, the Radeon and R200 DRI drivers are good examples.
+For a classic hardware driver, the i965 driver is a good example.
+For a Gallium3D hardware driver, the r300g, r600g and the i915g are good examples.
</p>
<p>The DRI website has more information about writing hardware drivers.
The process isn't well document because the Mesa driver interface changes
-over time, and we seldome have spare time for writing documentation.
+over time, and we seldom have spare time for writing documentation.
That being said, many people have managed to figure out the process.
</p>
<p>
</p>
-<h2>4.3 Why isn't GL_EXT_texture_compression_s3tc implemented in Mesa?</h2>
+<h3>4.3 Why isn't <code>GL_EXT_texture_compression_s3tc</code> implemented in
+Mesa?</h3>
<p>
-The <a href="http://oss.sgi.com/projects/ogl-sample/registry/EXT/texture_compression_s3tc.txt" target="_parent">specification for the extension</a>
-indicates that there are intellectual property (IP) and/or patent issues
-to be dealt with.
+Oh but it is! Prior to 2nd October 2017, the Mesa project did not include s3tc
+support due to intellectual property (IP) and/or patent issues around the s3tc
+algorithm.
</p>
-<p>We've been unsucessful in getting a response from S3 (or whoever owns
-the IP nowadays) to indicate whether or not an open source project can
-implement the extension (specifically the compression/decompression
-algorithms).
+<p>
+As of Mesa 17.3.0, Mesa now officially supports s3tc, as the patent has expired.
</p>
<p>
-In the mean time, a 3rd party <a href=
-"http://homepage.hispeed.ch/rscheidegger/dri_experimental/s3tc_index.html"
-target="_parent">plug-in library</a> is available.
+In versions prior to this, a 3rd party <a href="https://dri.freedesktop.org/wiki/S3TC">
+plug-in library</a> was required.
</p>
-
+</div>
</body>
</html>
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