To: sdl@libsdl.org From: Christian Walther <cwalther@gmx.ch> Date: Thu, 15 Dec 2005 21:19:53 +0100 Subject: [SDL] More mouse enhancements for Mac OS X The attached patch brings two more enhancements to mouse handling on Mac OS X (Quartz): 1. Currently, after launching an SDL application, SDL's notion of the mouse position is stuck in the top left corner (0,0) until the first time the mouse is moved. That's because the UpdateMouse() function isn't implemented in the Quartz driver. This patch adds it. 2. When grabbing input while the mouse cursor is hidden, the function CGAssociateMouseAndMouseCursorPosition(0) is called, which prevents the system's notion of the mouse location from moving (and therefore leaving the SDL window) even when the mouse is moved. However, apparently the Wacom tablet driver (and maybe other special pointing device drivers) doesn't care about that setting and still allows the mouse location to go outside of the window. Interestingly, the system cursor, which is made visible by the existing code in SDL in that case, does not follow the mouse location, but appears in the middle of the SDL window. The mouse location being outside of the window however means that mouse button events go to background applications (or the dock or whatever is there), which is very confusing to the user who sees no cursor outside of the SDL window. I have not found any way of intercepting these events (and that's probably by design, as "normal" applications shouldn't prevent the user from bringing other applications' windows to the front by clicking on them). An idea would be placing a fully transparent, screen-filling window in front of everything, but I fear that this might affect rendering performance (by doing unnecessary compositing, using up memory, or whatever). The deluxe solution to the problem would be talking to the tablet driver using AppleEvents to tell it to constrain its mapped area to the window (see Wacom's "TabletEventDemo" sample app, http://www.wacomeng.com/devsupport/mac/downloads.html), but I think that the bloat that solution would add to SDL would outweigh its usefulness. What I did instead in my patch is reassociating mouse and cursor when the mouse leaves the window while an invisible grab is in effect, and restoring the grab when the window is entered. That way, the grab can still be effectively broken by a tablet, but at least it's obvious to the user that it is broken. That change is minimal - it doesn't affect operation with a mouse (or a trackpad), and the code that it adds is not executed on every PumpEvents() call, only when entering and leaving the window. Unless there are any concerns about the patch, please apply. Feel free to shorten the lengthy comment in SDL_QuartzEvents.m if you think it's too verbose. Thanks -Christian

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Using the Simple DirectMedia Layer with MacOS 7,8,9 on PPC
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These instructions are for people using the Apple MPW environment:
http://developer.apple.com/tools/mpw-tools/

CodeWarrior projects are available in the CWprojects directory.

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I.  Building the Simple DirectMedia Layer libraries:
    (This step isn't necessary if you have the SDL binary distribution)

  First, unpack the MPWmake.sea.hqx archive and move SDL.make into the
  SDL directory.

  Start MPW

  Set the current directory within MPW to the SDL toplevel directory.

  Build "SDL"  (Type Command-B and enter "SDL" in the dialog)

  If everything compiles successfully, you now have the PPC libraries
  "SDL" and "SDLmain.o" in the 'lib' subdirectory.

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II. Building the Simple DirectMedia Layer test programs:

  First, unpack the MPWmake.sea.hqx archive, move the new rsrc directory to
  the main SDL directory, and move the makefiles in the new test subdirectory
  to the SDL 'test' subdirectory.

  Start MPW

  Set the current directory within MPW to the SDL 'test' subdirectory.

  Build the programs that have an associated MPW makefile (file ending
  with .make), including "testwin", "testalpha", and "graywin".

  Copy the SDL library file into the test directory, and run!

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III. Building the Simple DirectMedia Layer demo programs:

  Copy one of the test program Makefiles to the demo directory
  and modify it to match the sources in the demo.

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IV.  Enjoy! :)

  If you have a project you'd like me to know about, or want to ask questions,
  go ahead and join the SDL developer's mailing list by sending e-mail to:

	sdl-request@libsdl.org

  and put "subscribe" into the subject of the message. Or alternatively you
  can use the web interface:

	http://www.libsdl.org/mailman/listinfo/sdl
  
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