- -

Mesa Frequently Asked Questions

-Last updated: 19 September 2012 - +

Frequently Asked Questions

+Last updated: 19 September 2018 -
-

Index

-1. High-level Questions and Answers -
-2. Compilation and Installation Problems -
-3. Runtime / Rendering Problems -
-4. Developer Questions -
-
-
+

High-level Questions and Answers
Compilation and Installation Problems
Runtime / Rendering Problems
Developer Questions

1. High-level Questions and Answers

- -

1. High-level Questions and Answers

- -

1.1 What is Mesa?

Mesa is an open-source implementation of the OpenGL specification. OpenGL is a programming library for writing interactive 3D applications. -See the OpenGL website for more +See the OpenGL website for more information.

@@ -52,14 +42,18 @@ Mesa 9.x supports the OpenGL 3.1 specification.

1.2 Does Mesa support/use graphics hardware?

Yes. Specifically, Mesa serves as the OpenGL core for the open-source DRI -drivers for XFree86/X.org. See the DRI -website for more information. -

-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.

See the DRI website + for more information.
See 01.org + for more information about Intel drivers.
See nouveau.freedesktop.org + for more information about Nouveau drivers.
See www.x.org/wiki/RadeonFeature + for more information about Radeon drivers.

1.3 What purpose does Mesa serve today?

@@ -68,7 +62,7 @@ operating systems today. Still, Mesa serves at least these purposes:

Mesa is used as the core of the open-source XFree86/X.org DRI +
Mesa is used as the core of the open-source X.org DRI hardware drivers.
Mesa is quite portable and allows OpenGL to be used on systems @@ -102,17 +96,17 @@ the Xlib API:
The GLX wire protocol is not supported and there's no OpenGL extension loaded by the X server.
There is no hardware acceleration. -
The OpenGL library, libGL.so, contains everything (the programming API, - the GLX functions and all the rendering code). +
The OpenGL library, libGL.so, contains everything (the + programming API, the GLX functions and all the rendering code).

Alternately, Mesa acts as the core for a number of OpenGL hardware drivers within the DRI (Direct Rendering Infrastructure):

The libGL.so library provides the GL and GLX API functions, a GLX - protocol encoder, and a device driver loader. -
The device driver modules (such as r200_dri.so) contain a built-in - copy of the core Mesa code. +
The libGL.so library provides the GL and GLX API functions, + a GLX protocol encoder, and a device driver loader. +
The device driver modules (such as r200_dri.so) contain + a built-in copy of the core Mesa code.
The X server loads the GLX module. The GLX module decodes incoming GLX protocol and dispatches the commands to a rendering module. @@ -132,28 +126,29 @@ Just follow the Mesa compilation instructions.
1.6 Are there other open-source implementations of OpenGL?

-Yes, SGI's -OpenGL Sample Implemenation (SI) is available. +Yes, SGI's +OpenGL Sample Implementation (SI) 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.

-Vincent is +Vincent is an open-source implementation of OpenGL ES for mobile devices.
-miniGL -is a subset of OpenGL for PalmOS devices. +miniGL +is a subset of OpenGL for PalmOS devices. The website is gone, but the source +code can still be found on sourceforge.net.
-TinyGL +TinyGL is a subset of OpenGL.

-SoftGL +SoftGL is an OpenGL subset for mobile devices.
@@ -175,22 +170,16 @@ popular and feature-complete.
+
2. Compilation and Installation Problems
-
-
- - -
2. Compilation and Installation Problems
- - -
2.1 What's the easiest way to install Mesa?
+
2.1 What's the easiest way to install Mesa?

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.
-
2.2 I get undefined symbols such as bgnpolygon, v3f, etc...
+
2.2 I get undefined symbols such as bgnpolygon, v3f, etc...

You're application is written in IRIS GL, not OpenGL. IRIS GL was the predecessor to OpenGL and is a different thing (almost) @@ -199,159 +188,157 @@ Mesa's not the solution.
-
2.3 Where is the GLUT library?
+
2.3 Where is the GLUT library?

-GLUT (OpenGL Utility Toolkit) is no longer in the separate MesaGLUT-x.y.z.tar.gz file. +GLUT (OpenGL Utility Toolkit) is no longer in the separate +MesaGLUT-x.y.z.tar.gz file. If you don't already have GLUT installed, you should grab freeglut.
-
2.4 Where is the GLw library?
+
2.4 Where is the GLw library?

-GLw (OpenGL widget library) is now available from a separate git repository. Unless you're using very old Xt/Motif applications with OpenGL, you shouldn't need it. +GLw (OpenGL widget library) is now available from a separate git repository. Unless you're using very old Xt/Motif applications with OpenGL, you shouldn't need it.

2.5 What's the proper place for the libraries and headers?

On Linux-based systems you'll want to follow the -Linux ABI standard. +Linux ABI standard. Basically you'll want the following:
-
- /usr/include/GL/gl.h - the main OpenGL header -
- /usr/include/GL/glu.h - the OpenGL GLU (utility) header -
- /usr/include/GL/glx.h - the OpenGL GLX header -
- /usr/include/GL/glext.h - the OpenGL extensions header -
- /usr/include/GL/glxext.h - the OpenGL GLX extensions header -
- /usr/include/GL/osmesa.h - the Mesa off-screen rendering header -
- /usr/lib/libGL.so - a symlink to libGL.so.1 -
- /usr/lib/libGL.so.1 - a symlink to libGL.so.1.xyz -
- /usr/lib/libGL.so.xyz - the actual OpenGL/Mesa library. xyz denotes the +
  +
  /usr/include/GL/gl.h
  +
  the main OpenGL header
  +
  /usr/include/GL/glu.h
  +
  the OpenGL GLU (utility) header
  +
  /usr/include/GL/glx.h
  +
  the OpenGL GLX header
  +
  /usr/include/GL/glext.h
  +
  the OpenGL extensions header
  +
  /usr/include/GL/glxext.h
  +
  the OpenGL GLX extensions header
  +
  /usr/include/GL/osmesa.h
  +
  the Mesa off-screen rendering header
  +
  /usr/lib/libGL.so
  +
  a symlink to libGL.so.1
  +
  /usr/lib/libGL.so.1
  +
  a symlink to libGL.so.1.xyz
  +
  /usr/lib/libGL.so.xyz
  +
  the actual OpenGL/Mesa library. xyz denotes the Mesa version number. -
+ +
-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: --prefix, +--libdir, and -D dri-drivers-path. To install Mesa +into the system location where it will be available for all programs to use, set +--prefix=/usr. Set --libdir to where your Linux +distribution installs system libraries, usually either /usr/lib or +/usr/lib64. Set -D dri-drivers-path to the directory +where your Linux distribution installs DRI drivers. To find your system's DRI +driver directory, try executing find /usr -type d -name dri. For +example, if the find command listed /usr/lib64/dri, +then set -D dri-drivers-path=/usr/lib64/dri.

-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 meson configure --prefix=/usr --libdir=xxx -D dri-drivers-path=xxx +and then install with sudo ninja install.
-
-The GLUT header and library should go in the same directories. -
-
-
-
3. Runtime / Rendering Problems
+
3. Runtime / Rendering Problems
-
3.1 Rendering is slow / why isn't my graphics hardware being used?
-
-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). -
+
3.1 Rendering is slow / why isn't my graphics hardware being used?

-What you really want is a DRI or NVIDIA (or another vendor's OpenGL) driver -for your particular hardware. +If Mesa can't use its hardware accelerated drivers it falls back on one of its software renderers. +(eg. classic swrast, softpipe or llvmpipe)

You can run the glxinfo 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 OpenGL vendor and OpenGL renderer values. +That will identify who's OpenGL library with which driver you're using and what sort of hardware it has detected.

+If you're using a hardware accelerated driver you want direct rendering: Yes. +
+
If your DRI-based driver isn't working, go to the -DRI website for trouble-shooting information. +DRI website for trouble-shooting information.
-
3.2 I'm seeing errors in depth (Z) buffering. Why?
+
3.2 I'm seeing errors in depth (Z) buffering. Why?

Make sure the ratio of the far to near clipping planes isn't too great. Look -here +here for details.

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 - glXChooseVisual in your code. +glXChooseVisual in your code.
-
3.3 Why Isn't depth buffering working at all?
+
3.3 Why Isn't depth buffering working at all?

-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 +MESA_DEBUG environment variable it will warn you about trying +to enable depth testing when you don't have a depth buffer.

Specifically, make sure glutInitDisplayMode is being called with GLUT_DEPTH or glXChooseVisual is being -called with a non-zero value for GLX_DEPTH_SIZE. +called with a non-zero value for GLX_DEPTH_SIZE.

This discussion applies to stencil buffers, accumulation buffers and alpha channels too.
-
3.4 Why does glGetString() always return NULL?
+
3.4 Why does glGetString() always return NULL?

Be sure you have an active/current OpenGL rendering context before -calling glGetString. +calling glGetString.
-
3.5 GL_POINTS and GL_LINES don't touch the right pixels
+
3.5 GL_POINTS and GL_LINES don't touch the +right pixels

-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. +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.
-
3.6 How can I change the maximum framebuffer size in Mesa's -swrast backend?
-
-These can be overridden by using the --with-max-width and ---with-max-height options. The two need not be equal. -
-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 4096 -may introduce rasterization artifacts; see the leading comments in -src/mesa/swrast/s_tritemp.h. -
- -
-
+
4. Developer Questions
-
4. Developer Questions
- -
4.1 How can I contribute?
+
4.1 How can I contribute?

First, join the mesa-dev mailing list. That's where Mesa development is discussed.

-The -OpenGL Specification is the bible for OpenGL implemention work. +The +OpenGL Specification is the bible for OpenGL implementation work. You should read it.

Most of the Mesa development work involves implementing new OpenGL extensions, writing hardware drivers (for the DRI), and code optimization.
-
4.2 How do I write a new device driver?
+
4.2 How do I write a new device driver?

Unfortunately, writing a device driver isn't easy. It requires detailed understanding of OpenGL, the Mesa code, and your @@ -361,12 +348,12 @@ target hardware/operating system.
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.

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.

@@ -375,20 +362,19 @@ the archives) is a good way to get information.
-
4.3 Why isn't GL_EXT_texture_compression_s3tc implemented in Mesa?
+
4.3 Why isn't GL_EXT_texture_compression_s3tc implemented in +Mesa?

-The specification for the extension -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.
-
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). +
+As of Mesa 17.3.0, Mesa now officially supports s3tc, as the patent has expired.

-In the mean time, a 3rd party -plug-in library is available. +In versions prior to this, a 3rd party +plug-in library was required.

The Mesa 3D Graphics Library

Mesa Frequently Asked Questions

Frequently Asked Questions

Index

1. High-level Questions and Answers

1. High-level Questions and Answers

1.1 What is Mesa?

1.1 What is Mesa?

1.2 Does Mesa support/use graphics hardware?

1.3 What purpose does Mesa serve today?

1.6 Are there other open-source implementations of OpenGL?

2. Compilation and Installation Problems

2. Compilation and Installation Problems

2.1 What's the easiest way to install Mesa?

2.1 What's the easiest way to install Mesa?

2.2 I get undefined symbols such as bgnpolygon, v3f, etc...

2.2 I get undefined symbols such as bgnpolygon, v3f, etc...

2.3 Where is the GLUT library?

2.3 Where is the GLUT library?

2.4 Where is the GLw library?

2.4 Where is the GLw library?

2.5 What's the proper place for the libraries and headers?

3. Runtime / Rendering Problems

3. Runtime / Rendering Problems

3.1 Rendering is slow / why isn't my graphics hardware being used?

3.1 Rendering is slow / why isn't my graphics hardware being used?

3.2 I'm seeing errors in depth (Z) buffering. Why?

3.2 I'm seeing errors in depth (Z) buffering. Why?

3.3 Why Isn't depth buffering working at all?

3.3 Why Isn't depth buffering working at all?

3.4 Why does glGetString() always return NULL?

3.4 Why does glGetString() always return NULL?

3.5 GL_POINTS and GL_LINES don't touch the right pixels

3.5 GL_POINTS and GL_LINES don't touch the +right pixels

3.6 How can I change the maximum framebuffer size in Mesa's -swrast backend?

4. Developer Questions

4. Developer Questions

4.1 How can I contribute?

4.1 How can I contribute?

4.2 How do I write a new device driver?

4.2 How do I write a new device driver?

4.3 Why isn't GL_EXT_texture_compression_s3tc implemented in Mesa?

4.3 Why isn't GL_EXT_texture_compression_s3tc implemented in +Mesa?

3.4 Why does `glGetString()` always return `NULL`?

3.5 `GL_POINTS` and `GL_LINES` don't touch the +right pixels

3.6 How can I change the maximum framebuffer size in Mesa's -`swrast` backend?

4.3 Why isn't `GL_EXT_texture_compression_s3tc` implemented in +Mesa?