112 lines
3.9 KiB
HTML
112 lines
3.9 KiB
HTML
<HTML>
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<TITLE>Mesa glFBDev Driver</TITLE>
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<link rel="stylesheet" type="text/css" href="mesa.css"></head>
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<BODY>
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<center><H1>Mesa glFBDev Driver</H1></center>
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<H1>1. Introduction</H1>
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<p>
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The GLFBDev driver interface allows one to do OpenGL rendering into a
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framebuffer managed with the Linux's fbdev interface.
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</p>
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<p>
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Basically, the programmer uses the fbdev functions to initialize the
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graphics hardware and setup the framebuffer.
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Then, using a calls to Mesa's glFBDev API functions, one can render
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into the framebuffer with the OpenGL API functions.
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</p>
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<p>
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Note, only software rendering is supported; there is no hardware
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acceleration.
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</p>
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<p>
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The GL/glfbdev.h header file defines the glFBDev interface.
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</p>
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<p>
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The progs/fbdev/glfbdevtest.c demonstrates how to use the glFBDev interface.
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</p>
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<p>
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For more information about fbdev, see the
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<a href="http://www.tldp.org/HOWTO/Framebuffer-HOWTO.html" target="_parent">
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Framebuffer Howto</a>
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</p>
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<p>
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You will need at minimum, a framebuffer device, check /dev/fb0
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</p>
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<h1>2. Compilation</h1>
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<p>
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To compile Mesa with support for the glFBDev interface:
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<pre>
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make realclean
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make linux-fbdev
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</pre>
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<p>
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When compilation is finished look in progs/glfbdev/ for the glfbdevtest demo.
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</p>
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<h1>3. Permissions</h1>
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<p>
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Typically /dev/fb/0 is grouped to the video group. It may be useful to add
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your user to the video group so the demos will not have to be run as root.
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To use fbdevglut with the prefered tty input, you should add the user to the
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tty group as well
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<p>
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<h1>4. Using fbdevglut</h1>
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Almost all of the programs in the progs directory use glut, and they compile with fbdevglut.
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<p>
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To compile the redbook sample programs:
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<pre>
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cd progs/redbook
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make
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</pre>
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</p>
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<p>glut features not supported:
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<li>Overlays
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<li>Subwindows
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<li>Input devices other than Keyboard/Mouse
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<li>No support for GLUT_MULTISAMPLE, GLUT_STEREO, or GLUT_LUMINANCE
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<li>Cursor and Menu Support will flicker in GLUT_SINGLE mode
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<p>Keyboard input is read by opening /dev/tty and reading keycodes in medium raw mode.
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<p>Mouse input is read from env var MOUSE, or /dev/gpmdata and should be in ms3 format.
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To forward data in this format to /dev/gpmdata, run gpm with the -Rms3 option.
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<p> glutInit allows glut programs to pass parameters to the glut library, currently the
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following options are supported for fbdevglut:
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<p><li>-geometry widthxheight -- This will force the resolution to be widthxheight instead of autodetecting.
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The modes are read from /etc/fb.modes
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<p><li>-bpp -- This will force the bitdepth to the one specified
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<p><li>-vt -- This allows you to specify the virtual terminal to attach keyboard input to. It is useful to specify when running inside screen.
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<p><li>-mousespeed -- A floating point multiplication factor to increase mouse speed
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<p><li>-nomouse -- Disable mouse support
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<p><li>-nokeyboard -- Disable keyboard support (this will probably break mouse support as well)
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<p><li>-stdin -- Use stdin for input instead of attaching to kbd in medium-raw mode.
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This will make it impossible to detect keypresses like Shift+Tab, you will also need to specify -gpmmouse for mouse support. This option can be used with a debugger, and it is possible to single step a program with gdb and set the FRAMEBUFFER environment variable to a different framebuffer for display. The program will not be able to handle vt switching on it's own, so it will always display.
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<p><li>-gpmmouse -- This will attempt to connect to the /dev/gpmctl socket using liblow
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for mouse data. Gpm does not provide this data when in graphics mode, so vt switching
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will briefly display text. This mode typically has no initial mouse delay.
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<p><li>-- Ignore any additional arguments
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<p>Notes:
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<p>
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1. The mouse pointer flickers in single buffering mode, as it must be rendered in software. Hopefully in the future there will be a way to access hardware cursors in fbdev devices.
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</p>
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</body>
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</html>
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