README.PicoGUI
author Sam Lantinga <slouken@libsdl.org>
Thu, 02 Apr 2009 04:43:36 +0000
branchSDL-1.2
changeset 4167 a6f635e5eaa6
parent 433 706de3956894
permissions -rw-r--r--
Fixed bug #611

From Tim Angus 2008-08-12 11:18:06

I'm one of the maintainers of ioquake3.org, an updated version of the
Quake 3 engine. Relatively recently, we moved ioq3 to use SDL as a
replacement for 95% of the platform specific code that was there. On the
whole it's doing a great job but unfortunately since the move we've been
getting complaints about the quality of the mouse input on the Windows
platform to the point where for many the game is unplayable. Put in
other terms, the current stable SDL 1.2 is basically not fit for purpose
if you need high quality mouse input as you do in a first person shooter.

Over the weekend I decided to pull my finger out and actually figure out
what's going on. There are basically two major problems. Firstly, when
using the "windib" driver, mouse input is gathered via the WM_MOUSEMOVE
message. Googling for this indicates that often this is known to result
in "spurious" and/or "missing" mouse movement events; this is the
primary cause of the poor mouse input. The second problem is that the
"directx" driver does not work at all in combination with OpenGL meaning
that you can't use DirectInput if your application also uses OpenGL. In
other words you're locked into using the "windib" driver and its poor
mouse input.

In order to address these problems I've done the following:

* Remove WM_MOUSEMOVE based motion event generation and replace with
calls to GetCursorPos which seems much more reliable. In order to
achieve this I've moved mouse motion out into a separate function that
is called once per DIB_PumpEvents.

* Remove the restriction on the "directx" driver being inoperable in
combination with OpenGL. There is a bug for this issues that I've
hijacked to a certain extent
(http://bugzilla.libsdl.org/show_bug.cgi?id=265). I'm the first to admit
I don't really understand why this restriction is there in the first
place. The commit message for the bug fix that introduced this
restriction (r581) isn't very elaborate and I couldn't see any other bug
tracking the issue. If anyone has more information on the bug that was
avoided by r581 it would be helpful as I/someone could then look into
addressing the problem without disabling the "directx" driver.

* I've also removed the restriction on not being allowed to use
DirectInput in windowed mode. I couldn't see any reason for this, at
least not from our perspective. I have my suspicions that it'll be
something like matching up the cursor with the mouse coordinates...

* I bumped up the DirectInput API used to version 7 in order to get
access to mouse buttons 4-7. I've had to inject a little bit of the DX7
headers into SDL there as the MinGW ones aren't up to date in this respect.
slouken@433
     1
 ========================
slouken@433
     2
  Using SDL with PicoGUI
slouken@433
     3
 ========================
slouken@433
     4
slouken@433
     5
- Originally contributed by Micah Dowty <micahjd@users.sourceforge.net>
slouken@433
     6
slouken@433
     7
PicoGUI is a scalable GUI system with a unique architecture, primarily focused
slouken@433
     8
on scalability to various embedded systems. You can find more information
slouken@433
     9
including a FAQ at http://picogui.org
slouken@433
    10
slouken@433
    11
To use the patch:
slouken@433
    12
slouken@433
    13
  1. When compiling, add the "--enable-video-picogui" switch to ./configure
slouken@433
    14
slouken@433
    15
  2. When running your program, ensure that the picogui driver for SDL
slouken@433
    16
     is in use by setting the SDL_VIDEODRIVER environment variable 
slouken@433
    17
     to "picogui".
slouken@433
    18
slouken@433
    19
  3. The program must also be linked to the C client library for PicoGUI
slouken@433
    20
     (libpgui.so). If the program is being compiled with a patched SDL 
slouken@433
    21
     installed this should be done automatically. If you want to use an
slouken@433
    22
     existing binary with PicoGUI, you can set the LD_PRELOAD environment
slouken@433
    23
     variable to the path of your libpgui.so file.
slouken@433
    24
slouken@433
    25
Capabilities:
slouken@433
    26
slouken@433
    27
  So far only basic functionality is provided on true color (linear16/24/32)
slouken@433
    28
  devices. Accessing a memory mapped bitmap, updating the display, and handling
slouken@433
    29
  mouse/keyboard input. This functionality has been tested with several
slouken@433
    30
  applications, including mplayer, Xine, sldroids, and Abuse.
slouken@433
    31
slouken@433
    32
TODO list:
slouken@433
    33
slouken@433
    34
  - YUV overlays will be helpful for watching video on set top boxes or other
slouken@433
    35
    embedded devices that have some graphics acceleration hardware
slouken@433
    36
slouken@433
    37
  - Account for rotated bitmap storage in pgserver
slouken@433
    38
slouken@433
    39
  - Support for hiding or changing the cursor
slouken@433
    40
slouken@433
    41
  - The display should be centered when the SDL application is smaller
slouken@433
    42
    than the PicoGUI panel
slouken@433
    43
slouken@433
    44
  - Fullscreen or any other special modes
slouken@433
    45
slouken@433
    46
  - Support for indexed and grayscale modes
slouken@433
    47
slouken@433
    48
  - Probably much more...
slouken@433
    49
slouken@433
    50
--- The End ---