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README.QNX by Mike Gorchak <>, <>
Last changed at 24 Apr 2004.
Table of Contents:
1. OpenGL.
2. Wheel and multi-button mouses.
3. CDROM handling issues.
4. Hardware video overlays.
5. Shared library building.
6. Some building issues.
7. Environment variables.
1. OpenGL:
OpenGL works well and is stable, but fullscreen mode has not been
heavily tested yet.
If you have QNX RtP version 6.1.0 or above you must download the
Photon3D runtime from or install it from the
public repository or from the public CD, available with QNX. OS versi-
ons below 6.1.0 are not supported.
When creating an OpenGL context, software renderer mode is artifi-
cially selected (QSSL made acceleration only for Voodoo boards in
fullscreen mode, sorry but I don't have this board to test OpenGL -
maybe it works or maybe not :)). If you want acceleration - you can
remove one line in the source code: find the file SDL_ph_image.c and
remove the following
line in the ph_SetupOpenGLContext() function or change the argument to
2. Wheel and multi-button mouses:
Photon emits keyboard events (key up and down) when the mouse
wheel is moved. The key_scan field appears valid, and it contains zero.
That is a basic method of detecting mouse wheel events under Photon.
It looks like a hack, but it works for me :) on various PC configura-
I've tested it on:
1. Genius Optical NetScroll/+ PS/2 (1 wheel)
2. A4Tech Optical GreatEye WheelMouse PS/2, model: WOP-35. (2 wheels
+ 2 additional buttons). The wheel for vertical scrolling works as
usual, but the second wheel for horizontal scrolling emits two se-
quential events up or down, so it can provide faster scrolling than
the first wheel. Additional buttons don't emit any events, but it
looks like they're handled by photon in an unusual way - like click
to front, but works not with any window, looks like a fun bug-o-fe-
ature :).
3. CDROM handling issues:
Access to CDROM can only be provided with 'root' privileges. I
can't do anything about that, /dev/cd0 has brw------- permissions and
root:root rights.
4. Hardware video overlays:
Overlays can flicker during window movement, resizing, etc. It
happens because the photon driver updates the real window contents be-
hind the overlay, then draws the temporary chroma key color over the
window contents. It can be done without using the chroma key but that
causes the overlay to always be on top. So flickering during window
movement is preferred instead.
Double buffering code is temporarily disabled in the photon driver
code, because on my GF2-MX it can accidentally cause a buffer switch,
which causes the old frame to show. S3 Savage4 has the same problem,
but ATI Rage 128 doesn't. I think it can be fixed later. Current code
works very well, so maybe double buffering is not needed right now.
Something strange happens when you try to move the window with the
overlay beyond the left border of the screen. The overlay tries to
stay at position x=0, but when attempting to move it a bit more it
jumps to position x=-60 (on GF2-MX, on ATI Rage128 this value a bit
smaller). It's really strange, looks like the overlay doesn't like
negative coordinates.
5. Shared library building:
A shared library can be built, but before running the
script you must manually delete the libtool.m4 stuff from the acinclu-
de.m4 file (it comes after the ESD detection code up to the end of the
file), because the libtool stuff in the acinclude.m4 file was very old
in SDL distribution before the version 1.2.7 and doesn't knew anything
about QNX. SDL 1.2.7 distribution contains the new libtool.m4 script,
but anyway it is broken :), Just remove it, then run "libtoolize
--force --copy", delete the file aclocal.m4 if it is exists and after
that run the script. SDL 1.2.8 contains fixed libtool.m4, and config.sub files, so you can just run the
6. Some building issues:
Feel free to not use the --disable-shared configure option if you'
ve read the above comment about 'Shared library building'. Otherwise
this option is strongly recommended, as without it the sdl-config
script will be broken.
Run the configure script without x11 support, e.g.:
a) for OpenGL support:
./configure --prefix=/usr \
--disable-video-x11 \
b) without OpenGL support:
./configure --prefix=/usr \
--disable-video-x11 \
--disable-shared \
And of course dont forget to specify --disable-debug, which is on
by default, to disable debug and enable the expensive optimizations.
In the test directory also run the ./configure script without
x11 support, e.g.:
./configure --with-sdl-prefix=/usr \
--with-sdl-exec-prefix=/usr \
--prefix=/usr --without-x
7. Environment variables:
Please note that the photon driver is sensible to the following
environmental variables:
* SDL_PHOTON_FULLSCREEN_REFRESH - this environment variable controls
the refresh rate in all fullscreen modes. Be carefull !!! Photon
drivers usually do not checking the maximum refresh rate, which video
adapter or monitor supports.
* SDL_VIDEO_WINDOW_POS - can be set in the "X,Y" format. If X and Y
coordinates are bigger than the current desktop resolution, then win-
dow positioning across virtual consoles is activated. If X and Y are
smaller than the desktop resolution then window positioning in the
current console is activated. The word "center" can be used instead of
coordinates, it produces the same behavior as SDL_VIDEO_CENTERED
environmental variable.
* SDL_VIDEO_CENTERED - if this environmental variable exists then the
window centering is perfomed in the current virtual console.
Notes: The SDL_VIDEO_CENTERED enviromental variable has greater pri-
ority than the SDL_VIDEO_WINDOW_POS in case if both variables are sup-
plied to the application.
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