Allegro MacOS X-specific information

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                    MacOS X-specific information.

             See readme.txt for a more general overview.

# MacOS X notes

This is a full featured native MacOS X port.

# Required software

To build Allegro under MacOS X, you need:

- MacOS X 10.2.x or newer
- Apple Developer Tools (December 2002 or newer edition)

If you don't have the Developer Tools installed, you can get the latest release at:

> http://developer.apple.com/tools/download

On the same page you will also find instructions on how to install them. Note that system version 10.2.x is required to compile Allegro, but the library will still work on 10.1.x. (At least that was true once; we haven't gone back and checked it!)

# Installing Allegro

Allegro ships in source code form; this means you need to compile it before you can use it. You do this easily from a terminal window. See the generic documentation in docs/build/cmake.txt.

You may build either Unix-style shared library, or Mac OS X frameworks, or both.

XXX information about universal binaries

# Using Allegro from the command line

The options for linking with Allegro are quite long, expecially for static versions of the library as you need to pull in several different frameworks (Cocoa, QuickTime, etc.) other than Allegro itself. When linking against the shared library version, things are also different. To avoid you having to work out the right linker commands for yourself, the installation creates a script, `allegro-config`, that will print out a suitable commandline. You can use this inside a backtick command substitution, for example:

>           gcc myfile.c -o myprogram `allegro-config --libs`

Or if you want to build a debug version of your program, assuming that you have installed the debug version of Allegro:

>           gcc myfile.c -o myprogram `allegro-config --libs debug`

You can also link against the Allegro framework, providing you previously installed it:

>           gcc myfile.c -o myprogram `allegro-config --frameworks`

Unix newbies, take note that these are ` backticks, not normal ' quotes!

There are also switches for printing out the Allegro version number, overriding the install paths, and selecting between shared and static libraries, in case you installed both. Run `allegro-config` without any arguments for a full list of options.

If you get an error like '`allegro-config: program not found`', and you're sure you have built and installed the library as described above, it probably means that `/usr/local/bin` is not on your path. The method to add it depends on the shell you're using. If you have tcsh, add the following line to the end of the `.cshrc` in your home directory.

>          set path=($path /usr/local/bin)

If you have bash, add the following line to the end of the `.bash_profile` file in your home directory:

>          PATH=${PATH}:/usr/local/bin

If you don't know which, just type `echo $SHELL` on the command line, which will print either `/bin/bash` or `/bin/tcsh`. Newer versions of OSX use bash, older ones use tcsh. You will have to close the Terminal window and open a new one once you have made the changes, so it will have an effect.

# Allegro and application bundles

When you build applications from the command line, you're actually just creating the executable, so you can run it from the command line only, and not also from the finder like a common MacOS X application. In other words, compiling from the command line does not create application bundles.

Allegro ships with a little tool, named fixbundle, which allows to build an application bundle out of an executable. The utility works from the command line and it accepts a variety of options to customize your bundle; the easiest way to use it is:

>           fixbundle executable_name

This will create an application bundle named "`executable_name.app`" that contains your program executable and will appear in the finder with the default application icon. A more complex usage example follows:

>           fixbundle executable_name -m -o bundle_name -v "1.2" icon.bmp

This creates a bundle named "`bundle_name.app`". The executable will be moved instead of copied into the bundle; the application will be marked as version "1.2" and icon.bmp will be converted to an icon for the bundle. You can specify more options and up to 4 differently sized icons (16x16, 32x32, 48x48 and 128x128) to be read from any Allegro supported image files or from datafile objects. Run fixbundle without arguments for the full list of known options.

A special note is required for the "`-e`" switch; this lets you embed the Allegro framework inside the built application bundle, so your app will not require Allegro to be installed into the target machine in order to work. This flag assumes you previously installed the embeddable version of the Allegro framework, and that your executable has been linked to it, either via Project Builder or XCode, either via the allegro-config script. If one of these conditions is not met, the created app may not work on target machines.

Bundles created by fixbundle have this default layout:

>           bundle.app --- Contents --+--- MacOS --- executable
>                                     |
>                                     +--- Resources --+--- (bundle.icns)
>                                     |                |
>                                     |                +--- (executable/...)
>                                     |
>                                     |
>                                     +--- (Frameworks) --- (Allegro.framework/...)
>                                     |
>                                     +--- Info.plist
>                                     |
>                                     +--- PkgInfo

If you are using Project Builder to compile your programs, there is no need to use fixbundle, as the IDE will do the work of generating an application bundle for you.

When an Allegro program starts, it automatically detects if the executable lives inside a bundle or not. The working directory is always set up to be the directory where the standalone executable or application bundle is located, but there is an exception: if the application is a bundle and Allegro finds a directory under the bundle Contents/Resources path with the same name of the executable (note that here we mean the real executable name, not the bundle name), that directory is set to be the working one. This allows to easily package all the application data inside the bundle, and still have a working program without the need to tell your code about the changed location of your files.

# Notes on drivers

This section contains MacOS X-specific notes on the drivers available.

> System:
>   When the system driver is about to be initialized, we already have a working NSApplication object connected to the Window Server. At driver startup, the working directory is changed if inside a bundle with a proper data directory under the Contents/Resources path (see above).

>   Display switching is possible, but only the SWITCH_BACKGROUND mode is supported, so your application will have to deal with it.

> Graphics:
>   The MacOS X windowed graphics mode uses a Cocoa window with a Quartz QuickDraw view as its content view. All combinations of window/desktop color depths are supported; if needed, color conversion will automatically be done transparently to the user.

>   Fullscreen mode uses the CoreGraphics DirectDisplay API; only 8, 15 and 32 bit color depths are supported.

> Sound:
>   The CoreAudio digital/MIDI drivers use V2 AudioUnits, and thus they require MacOS X 10.2.x (Jaguar) or newer to work. If this is not the case, you can fall back to the Carbon Sound Manager and Quicktime MIDI drivers.

> Keyboard:
>   MacOS X Allegro uses the current system keyboard mapping table to map scancodes to characters: the keyboard user settings in allegro.cfg have no effect.

> Mouse:
>   On MacOS X 10.2.x (Jaguar) or newer, Allegro will automatically detect the number of buttons of your mouse at driver initialization. If the 1-button Apple mouse is found, the library will activate an emulation mode that mimics the way MacOS X itself deals with 1-button mice: depending on which key is pressed when the button is clicked, Allegro will report a different mouse button click. (Control + button) emulates a right click and (Option + button) emulates a middle click.

>   On MacOS X 10.1.x, mouse autodetection is not possible, and Allegro will assume an 1-button mouse to always be present, activating buttons emulation accordingly.

# Notes on Threading and Cocoa GUIs

It is possible to include a Cocoa GUI in an Allegro application. If you do this you should be aware that Allegro will run your application's `main()` function in a different thread from the thread that the main OS X event loop runs in. See http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/Multithreading/Introduction/Introduction.html for more information about threading on Mac OS X.

# Final notes

There is a known compatibility problem when using gcc 4 on MacOS X 10.4 that prevents binaries from working on older versions of MacOS X. While it is anticipated that a future update from Apple will fix this problem, you can use gcc 3 to work around it.

As a final note, when coding Allegro programs don't forget that you need to use the `END_OF_MAIN()` macro right after your `main()` function!