README.WinCE
author Sam Lantinga <slouken@libsdl.org>
Thu, 02 Apr 2009 04:43:36 +0000
branchSDL-1.2
changeset 4167 a6f635e5eaa6
parent 1251 86d0d01290ea
child 5894 414b2fa01526
child 6430 48d519500f7e
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@453
     1
icculus@1251
     2
Project files for embedded Visual C++ 3.0, 4.0 and 
icculus@1251
     3
Visual Studio 2005 can be found in VisualCE.zip
icculus@1251
     4
icculus@1251
     5
SDL supports GAPI and WinDib output for Windows CE.
icculus@1251
     6
icculus@1251
     7
GAPI driver supports:
icculus@1251
     8
icculus@1251
     9
- all possible WinCE devices (Pocket PC, Smartphones, HPC)
icculus@1251
    10
  with different orientations of video memory and resolutions.
icculus@1251
    11
- 4, 8 and 16 bpp devices
icculus@1251
    12
- special handling of 8bpp on 8bpp devices
icculus@1251
    13
- VGA mode, you can even switch between VGA and GAPI in runtime
icculus@1251
    14
  (between 240x320 and 480x640 for example). On VGA devices you can
icculus@1251
    15
  use either GAPI or VGA.
icculus@1251
    16
- Landscape mode and automatic rotation of buttons and stylus coordinates.
icculus@1251
    17
  To enable landscape mode make width of video screen bigger than height.
icculus@1251
    18
  For example: 
icculus@1251
    19
    SDL_SetVideoMode(320,240,16,SDL_FULLSCREEN)
icculus@1251
    20
- WM2005
icculus@1251
    21
- SDL_ListModes
slouken@0
    22
slouken@0
    23
NOTE:
slouken@0
    24
There are several SDL features not available in the WinCE port of SDL.
slouken@0
    25
slouken@0
    26
- DirectX is not yet available
slouken@0
    27
- Semaphores are not available
slouken@0
    28
- Joystick support is not available
slouken@0
    29
- CD-ROM control is not available
slouken@0
    30
slouken@0
    31
In addition, there are several features that run in "degraded" mode:
slouken@0
    32
slouken@0
    33
Preprocessor Symbol		Effect
slouken@0
    34
===================		=================================
slouken@0
    35
slouken@0
    36
SDL_systimer.c:
slouken@0
    37
USE_GETTICKCOUNT		Less accurate values for SDL time functions
slouken@0
    38
USE_SETTIMER			Use only a single marginally accurate timer
slouken@0
    39
slouken@0
    40
SDL_syswm.c:
slouken@0
    41
DISABLE_ICON_SUPPORT		Can't set the runtime window icon
slouken@0
    42
slouken@0
    43
SDL_sysmouse.c:
slouken@0
    44
USE_STATIC_CURSOR		Only the arrow cursor is available
slouken@0
    45
slouken@0
    46
SDL_sysevents.c:
slouken@0
    47
NO_GETKEYBOARDSTATE		Can't get modifier state on keyboard focus
slouken@0
    48
slouken@0
    49
SDL_dibevents.c:
slouken@0
    50
NO_GETKEYBOARDSTATE		Very limited keycode translation
slouken@0
    51
slouken@0
    52
SDL_dibvideo.c:
slouken@0
    53
NO_GETDIBITS			Can't distinguish between 15 bpp and 16 bpp
slouken@0
    54
NO_CHANGEDISPLAYSETTINGS	No fullscreen support
slouken@0
    55
NO_GAMMA_SUPPORT		Gamma correction not available