libs/SDL2/docs/README-directfb.md

+DirectFB
+========
+
+Supports:
+
+- Hardware YUV overlays
+- OpenGL - software only
+- 2D/3D accelerations (depends on directfb driver)
+- multiple displays
+- windows
+
+What you need:
+
+* DirectFB 1.0.1, 1.2.x, 1.3.0
+* Kernel-Framebuffer support: required: vesafb, radeonfb ....
+* Mesa 7.0.x	   - optional for OpenGL
+
+The `/etc/directfbrc` file should contain the following lines to make
+your joystick work and avoid crashes:
+
+```
+disable-module=joystick
+disable-module=cle266
+disable-module=cyber5k
+no-linux-input-grab
+```
+
+To disable to use x11 backend when DISPLAY variable is found use
+
+```
+export SDL_DIRECTFB_X11_CHECK=0
+```
+
+To disable the use of linux input devices, i.e. multimice/multikeyboard support,
+use
+
+```
+export SDL_DIRECTFB_LINUX_INPUT=0
+```
+
+To use hardware accelerated YUV-overlays for YUV-textures, use:
+
+```
+export SDL_DIRECTFB_YUV_DIRECT=1
+```
+
+This is disabled by default. It will only support one
+YUV texture, namely the first. Every other YUV texture will be
+rendered in software.
+
+In addition, you may use (directfb-1.2.x)
+
+```
+export SDL_DIRECTFB_YUV_UNDERLAY=1
+```
+
+to make the YUV texture an underlay. This will make the cursor to
+be shown.
+
+Simple Window Manager
+=====================
+
+The driver has support for a very, very basic window manager you may
+want to use when running with `wm=default`. Use
+
+```
+export SDL_DIRECTFB_WM=1
+```
+
+to enable basic window borders. In order to have the window title rendered,
+you need to have the following font installed:
+
+```
+/usr/share/fonts/truetype/freefont/FreeSans.ttf
+```
+
+OpenGL Support
+==============
+
+The following instructions will give you *software* OpenGL. However this
+works at least on all directfb supported platforms.
+
+As of this writing 20100802 you need to pull Mesa from git and do the following:
+
+```
+git clone git://anongit.freedesktop.org/git/mesa/mesa
+cd mesa
+git checkout 2c9fdaf7292423c157fc79b5ce43f0f199dd753a
+```
+
+Edit `configs/linux-directfb` so that the Directories-section looks like this:
+
+```
+# Directories
+SRC_DIRS     = mesa glu
+GLU_DIRS     = sgi
+DRIVER_DIRS  = directfb
+PROGRAM_DIRS =
+```
+
+Then do the following:
+
+```
+make linux-directfb
+make
+
+echo Installing - please enter sudo pw.
+
+sudo make install INSTALL_DIR=/usr/local/dfb_GL
+cd src/mesa/drivers/directfb
+make
+sudo make install INSTALL_DIR=/usr/local/dfb_GL
+```
+
+To run the SDL - testprograms:
+
+```
+export SDL_VIDEODRIVER=directfb
+export LD_LIBRARY_PATH=/usr/local/dfb_GL/lib
+export LD_PRELOAD=/usr/local/dfb_GL/libGL.so.7
+
+./testgl
+```

libs/SDL2/docs/README-dynapi.md

+# Dynamic API
+
+Originally posted on Ryan's Google+ account.
+
+Background:
+
+- The Steam Runtime has (at least in theory) a really kick-ass build of SDL2,
+  but developers are shipping their own SDL2 with individual Steam games.
+  These games might stop getting updates, but a newer SDL2 might be needed later.
+  Certainly we'll always be fixing bugs in SDL, even if a new video target isn't
+  ever needed, and these fixes won't make it to a game shipping its own SDL.
+- Even if we replace the SDL2 in those games with a compatible one, that is to
+  say, edit a developer's Steam depot (yuck!), there are developers that are
+  statically linking SDL2 that we can't do this for. We can't even force the
+  dynamic loader to ignore their SDL2 in this case, of course.
+- If you don't ship an SDL2 with the game in some form, people that disabled the
+  Steam Runtime, or just tried to run the game from the command line instead of
+  Steam might find themselves unable to run the game, due to a missing dependency.
+- If you want to ship on non-Steam platforms like GOG or Humble Bundle, or target
+  generic Linux boxes that may or may not have SDL2 installed, you have to ship
+  the library or risk a total failure to launch. So now, you might have to have
+  a non-Steam build plus a Steam build (that is, one with and one without SDL2
+  included), which is inconvenient if you could have had one universal build
+  that works everywhere.
+- We like the zlib license, but the biggest complaint from the open source
+  community about the license change is the static linking. The LGPL forced this
+  as a legal, not technical issue, but zlib doesn't care. Even those that aren't
+  concerned about the GNU freedoms found themselves solving the same problems:
+  swapping in a newer SDL to an older game often times can save the day.
+  Static linking stops this dead.
+
+So here's what we did:
+
+SDL now has, internally, a table of function pointers. So, this is what SDL_Init
+now looks like:
+
+```c
+UInt32 SDL_Init(Uint32 flags)
+{
+    return jump_table.SDL_Init(flags);
+}
+```
+
+Except that is all done with a bunch of macro magic so we don't have to maintain
+every one of these.
+
+What is jump_table.SDL_init()? Eventually, that's a function pointer of the real
+SDL_Init() that you've been calling all this time. But at startup, it looks more
+like this:
+
+```c
+Uint32 SDL_Init_DEFAULT(Uint32 flags)
+{
+    SDL_InitDynamicAPI();
+    return jump_table.SDL_Init(flags);
+}
+```
+
+SDL_InitDynamicAPI() fills in jump_table with all the actual SDL function
+pointers, which means that this `_DEFAULT` function never gets called again.
+First call to any SDL function sets the whole thing up.
+
+So you might be asking, what was the value in that? Isn't this what the operating
+system's dynamic loader was supposed to do for us? Yes, but now we've got this
+level of indirection, we can do things like this:
+
+```bash
+export SDL_DYNAMIC_API=/my/actual/libSDL-2.0.so.0
+./MyGameThatIsStaticallyLinkedToSDL2
+```
+
+And now, this game that is statically linked to SDL, can still be overridden
+with a newer, or better, SDL. The statically linked one will only be used as
+far as calling into the jump table in this case. But in cases where no override
+is desired, the statically linked version will provide its own jump table,
+and everyone is happy.
+
+So now:
+- Developers can statically link SDL, and users can still replace it.
+  (We'd still rather you ship a shared library, though!)
+- Developers can ship an SDL with their game, Valve can override it for, say,
+  new features on SteamOS, or distros can override it for their own needs,
+  but it'll also just work in the default case.
+- Developers can ship the same package to everyone (Humble Bundle, GOG, etc),
+  and it'll do the right thing.
+- End users (and Valve) can update a game's SDL in almost any case,
+  to keep abandoned games running on newer platforms.
+- Everyone develops with SDL exactly as they have been doing all along.
+  Same headers, same ABI. Just get the latest version to enable this magic.
+
+
+A little more about SDL_InitDynamicAPI():
+
+Internally, InitAPI does some locking to make sure everything waits until a
+single thread initializes everything (although even SDL_CreateThread() goes
+through here before spinning a thread, too), and then decides if it should use
+an external SDL library. If not, it sets up the jump table using the current
+SDL's function pointers (which might be statically linked into a program, or in
+a shared library of its own). If so, it loads that library and looks for and
+calls a single function:
+
+```c
+SInt32 SDL_DYNAPI_entry(Uint32 version, void *table, Uint32 tablesize);
+```
+
+That function takes a version number (more on that in a moment), the address of
+the jump table, and the size, in bytes, of the table.
+Now, we've got policy here: this table's layout never changes; new stuff gets
+added to the end. Therefore SDL_DYNAPI_entry() knows that it can provide all
+the needed functions if tablesize <= sizeof its own jump table. If tablesize is
+bigger (say, SDL 2.0.4 is trying to load SDL 2.0.3), then we know to abort, but
+if it's smaller, we know we can provide the entire API that the caller needs.
+
+The version variable is a failsafe switch.
+Right now it's always 1. This number changes when there are major API changes
+(so we know if the tablesize might be smaller, or entries in it have changed).
+Right now SDL_DYNAPI_entry gives up if the version doesn't match, but it's not
+inconceivable to have a small dispatch library that only supplies this one
+function and loads different, otherwise-incompatible SDL libraries and has the
+right one initialize the jump table based on the version. For something that
+must generically catch lots of different versions of SDL over time, like the
+Steam Client, this isn't a bad option.
+
+Finally, I'm sure some people are reading this and thinking,
+"I don't want that overhead in my project!"
+
+To which I would point out that the extra function call through the jump table
+probably wouldn't even show up in a profile, but lucky you: this can all be
+disabled. You can build SDL without this if you absolutely must, but we would
+encourage you not to do that. However, on heavily locked down platforms like
+iOS, or maybe when debugging, it makes sense to disable it. The way this is
+designed in SDL, you just have to change one #define, and the entire system
+vaporizes out, and SDL functions exactly like it always did. Most of it is
+macro magic, so the system is contained to one C file and a few headers.
+However, this is on by default and you have to edit a header file to turn it
+off. Our hopes is that if we make it easy to disable, but not too easy,
+everyone will ultimately be able to get what they want, but we've gently
+nudged everyone towards what we think is the best solution.

libs/SDL2/docs/README-emscripten.md

+# Emscripten
+
+(This documentation is not very robust; we will update and expand this later.)
+
+## A quick note about audio
+
+Modern web browsers will not permit web pages to produce sound before the
+user has interacted with them; this is for several reasons, not the least
+of which being that no one likes when a random browser tab suddenly starts
+making noise and the user has to scramble to figure out which and silence
+it.
+
+To solve this, most browsers will refuse to let a web app use the audio
+subsystem at all before the user has interacted with (clicked on) the page
+in a meaningful way. SDL-based apps also have to deal with this problem; if
+the user hasn't interacted with the page, SDL_OpenAudioDevice will fail.
+
+There are two reasonable ways to deal with this: if you are writing some
+sort of media player thing, where the user expects there to be a volume
+control when you mouseover the canvas, just default that control to a muted
+state; if the user clicks on the control to unmute it, on this first click,
+open the audio device. This allows the media to play at start, the user can
+reasonably opt-in to listening, and you never get access denied to the audio
+device.
+
+Many games do not have this sort of UI, and are more rigid about starting
+audio along with everything else at the start of the process. For these, your
+best bet is to write a little Javascript that puts up a "Click here to play!"
+UI, and upon the user clicking, remove that UI and then call the Emscripten
+app's main() function. As far as the application knows, the audio device was
+available to be opened as soon as the program started, and since this magic
+happens in a little Javascript, you don't have to change your C/C++ code at
+all to make it happen.
+
+Please see the discussion at https://github.com/libsdl-org/SDL/issues/6385
+for some Javascript code to steal for this approach.
+
+
+## Building SDL/emscripten
+
+SDL currently requires at least Emscripten 3.1.35 to build. Newer versions
+are likely to work, as well.
+
+
+Build:
+
+    $ mkdir build
+    $ cd build
+    $ emconfigure ../configure --host=asmjs-unknown-emscripten --disable-assembly --disable-threads --disable-cpuinfo CFLAGS="-O2"
+    $ emmake make
+
+Or with cmake:
+
+    $ mkdir build
+    $ cd build
+    $ emcmake cmake ..
+    $ emmake make
+
+To build one of the tests:
+
+    $ cd test/
+    $ emcc -O2 --js-opts 0 -g4 testdraw2.c -I../include ../build/.libs/libSDL2.a ../build/libSDL2_test.a -o a.html
+
+Uses GLES2 renderer or software
+
+Some other SDL2 libraries can be easily built (assuming SDL2 is installed somewhere):
+
+SDL_mixer (http://www.libsdl.org/projects/SDL_mixer/):
+
+    $ EMCONFIGURE_JS=1 emconfigure ../configure
+    build as usual...
+
+SDL_gfx (http://cms.ferzkopp.net/index.php/software/13-sdl-gfx):
+
+    $ EMCONFIGURE_JS=1 emconfigure ../configure --disable-mmx
+    build as usual...

libs/SDL2/docs/README-gdk.md

+GDK
+=====
+
+This port allows SDL applications to run via Microsoft's Game Development Kit (GDK).
+
+Windows (GDK) and  Xbox One/Xbox Series (GDKX) are supported. Although most of the Xbox code is included in the public SDL source code, NDA access is required for a small number of source files. If you have access to GDKX, these required Xbox files are posted on the GDK forums [here](https://forums.xboxlive.com/questions/130003/).
+
+
+Requirements
+------------
+
+* Microsoft Visual Studio 2022 (in theory, it should also work in 2017 or 2019, but this has not been tested)
+* Microsoft GDK June 2022 or newer (public release [here](https://github.com/microsoft/GDK/releases/tag/June_2022))
+* To publish a package or successfully authenticate a user, you will need to create an app id/configure services in Partner Center. However, for local testing purposes (without authenticating on Xbox Live), the identifiers used by the GDK test programs in the included solution will work.
+
+
+Windows GDK Status
+------
+
+The Windows GDK port supports the full set of Win32 APIs, renderers, controllers, input devices, etc., as the normal Windows x64 build of SDL.
+
+* Additionally, the GDK port adds the following:
+  * Compile-time platform detection for SDL programs. The `__GDK__` is `#define`d on every GDK platform, and the  `__WINGDK__` is `#define`d on Windows GDK, specifically. (This distinction exists because other GDK platforms support a smaller subset of functionality. This allows you to mark code for "any" GDK separate from Windows GDK.)
+  * GDK-specific setup:
+    * Initializing/uninitializing the game runtime, and initializing Xbox Live services
+    * Creating a global task queue and setting it as the default for the process. When running any async operations, passing in `NULL` as the task queue will make the task get added to the global task queue.
+
+  * An implementation on `WinMain` that performs the above GDK setup (you should link against SDL2main.lib, as in Windows x64). If you are unable to do this, you can instead manually call `SDL_GDKRunApp` from your entry point, passing in your `SDL_main` function and `NULL` as the parameters.
+  * Global task queue callbacks are dispatched during `SDL_PumpEvents` (which is also called internally if using `SDL_PollEvent`).
+  * You can get the handle of the global task queue through `SDL_GDKGetTaskQueue`, if needed. When done with the queue, be sure to use `XTaskQueueCloseHandle` to decrement the reference count (otherwise it will cause a resource leak).
+
+* What doesn't work:
+  * Compilation with anything other than through the included Visual C++ solution file
+
+## VisualC-GDK Solution
+
+The included `VisualC-GDK/SDL.sln` solution includes the following targets for the Gaming.Desktop.x64 configuration:
+
+* SDL2 (DLL) - This is the typical SDL2.dll, but for Gaming.Desktop.x64.
+* SDL2main (lib) - This contains a drop-in implementation of `WinMain` that is used as the entry point for GDK programs.
+* tests/testgamecontroller - Standard SDL test program demonstrating controller functionality.
+* tests/testgdk - GDK-specific test program that demonstrates using the global task queue to login a user into Xbox Live.
+  *NOTE*: As of the June 2022 GDK, you cannot test user logins without a valid Title ID and MSAAppId. You will need to manually change the identifiers in the `MicrosoftGame.config` to your valid IDs from Partner Center if you wish to test this.
+* tests/testsprite2 - Standard SDL test program demonstrating sprite drawing functionality.
+
+If you set one of the test programs as a startup project, you can run it directly from Visual Studio.
+
+Windows GDK Setup, Detailed Steps
+---------------------
+
+These steps assume you already have a game using SDL that runs on Windows x64 along with a corresponding Visual Studio solution file for the x64 version. If you don't have this, it's easiest to use one of the test program vcxproj files in the `VisualC-GDK` directory as a starting point, though you will still need to do most of the steps below.
+
+### 1. Add a Gaming.Desktop.x64 Configuration ###
+
+In your game's existing Visual Studio Solution, go to Build > Configuration Manager. From the "Active solution platform" drop-down select "New...". From the drop-down list, select Gaming.Desktop.x64 and copy the settings from the x64 configuration.
+
+### 2. Build SDL2 and SDL2main for GDK ###
+
+Open `VisualC-GDK/SDL.sln` in Visual Studio, you need to build the SDL2 and SDL2main targets for the Gaming.Desktop.x64 platform (Release is recommended). You will need to copy/keep track of the `SDL2.dll`, `XCurl.dll` (which is output by Gaming.Desktop.x64), `SDL2.lib`, and `SDL2main.lib` output files for your game project.
+
+*Alternatively*, you could setup your solution file to instead reference the SDL2/SDL2main project file targets from the SDL source, and add those projects as a dependency. This would mean that SDL2 and SDL2main would both be built when your game is built.
+
+### 3. Configuring Project Settings ###
+
+While the Gaming.Desktop.x64 configuration sets most of the required settings, there are some additional items to configure for your game project under the Gaming.Desktop.x64 Configuration:
+
+*  Under C/C++ > General > Additional Include Directories, make sure the `SDL/include` path is referenced
+* Under Linker > General > Additional Library Directories, make sure to reference the path where the newly-built SDL2.lib and SDL2main.lib are
+* Under Linker > Input > Additional Dependencies, you need the following:
+  * `SDL2.lib`
+  * `SDL2main.lib` (unless not using)
+  * `xgameruntime.lib`
+  * `../Microsoft.Xbox.Services.141.GDK.C.Thunks.lib`
+* Note that in general, the GDK libraries depend on the MSVC C/C++ runtime, so there is no way to remove this dependency from a GDK program that links against GDK.
+
+### 4. Setting up SDL_main ###
+
+Rather than using your own implementation of `WinMain`, it's recommended that you instead `#include "SDL_main.h"` and declare a standard main function. If you are unable to do this, you can instead manually call `SDL_GDKRunApp` from your entry point, passing in your `SDL_main` function and `NULL` as the parameters.
+
+### 5. Required DLLs ###
+
+The game will not launch in the debugger unless required DLLs are included in the directory that contains the game's .exe file. You need to make sure that the following files are copied into the directory:
+
+* Your SDL2.dll
+* "$(Console_GRDKExtLibRoot)Xbox.Services.API.C\DesignTime\CommonConfiguration\Neutral\Lib\Release\Microsoft.Xbox.Services.141.GDK.C.Thunks.dll"
+* XCurl.dll
+
+You can either copy these in a post-build step, or you can add the dlls into the project and set its Configuration Properties > General > Item type to "Copy file," which will also copy them into the output directory.
+
+### 6. Setting up MicrosoftGame.config ###
+
+You can copy `VisualC-GDK/tests/testgdk/MicrosoftGame.config` and use that as a starting point in your project. Minimally, you will want to change the Executable Name attribute, the DefaultDisplayName, and the Description.
+
+This file must be copied into the same directory as the game's .exe file. As with the DLLs, you can either use a post-build step or the "Copy file" item type.
+
+For basic testing, you do not need to change anything else in `MicrosoftGame.config`. However, if you want to test any Xbox Live services (such as logging in users) _or_ publish a package, you will need to setup a Game app on Partner Center.
+
+Then, you need to set the following values to the values from Partner Center:
+
+* Identity tag - Name and Publisher attributes
+* TitleId
+* MSAAppId
+
+### 7. Adding Required Logos
+
+Several logo PNG files are required to be able to launch the game, even from the debugger. You can use the sample logos provided in `VisualC-GDK/logos`. As with the other files, they must be copied into the same directory as the game's .exe file.
+
+
+### 8. Copying any Data Files ###
+
+When debugging GDK games, there is no way to specify a working directory. Therefore, any required game data must also be copied into the output directory, likely in a post-build step.
+
+
+### 9. Build and Run from Visual Studio ###
+
+At this point, you should be able to build and run your game from the Visual Studio Debugger. If you get any linker errors, make sure you double-check that you referenced all the required libs.
+
+If you are testing Xbox Live functionality, it's likely you will need to change to the Sandbox for your title. To do this:
+
+1. Run "Desktop VS 2022 Gaming Command Prompt" from the Start Menu
+2. Switch the sandbox name with:
+   `XblPCSandbox SANDBOX.#`
+3. (To switch back to the retail sandbox):
+   `XblPCSandbox RETAIL`
+
+### 10. Packaging and Installing Locally
+
+You can use one of the test program's `PackageLayout.xml` as a starting point. Minimally, you will need to change the exe to the correct name and also reference any required game data. As with the other data files, it's easiest if you have this copy to the output directory, although it's not a requirement as you can specify relative paths to files.
+
+To create the package:
+
+1. Run "Desktop VS 2022 Gaming Command Prompt" from the Start Menu
+2. `cd` to the directory containing the `PackageLayout.xml` with the correct paths (if you use the local path as in the sample package layout, this would be from your .exe output directory)
+3. `mkdir Package` to create an output directory
+4. To package the file into the `Package` directory, use:
+    `makepkg pack /f PackageLayout.xml /lt /d . /nogameos /pc /pd Package`
+5. To install the package, use:
+   `wdapp install PACKAGENAME.msixvc`
+6. Once the package is installed, you can run it from the start menu.
+7. As with when running from Visual Studio, if you need to test any Xbox Live functionality you must switch to the correct sandbox.
+
+
+Troubleshooting
+---------------
+
+#### Xbox Live Login does not work
+
+As of June 2022 GDK, you must have a valid Title Id and MSAAppId in order to test Xbox Live functionality such as user login. Make sure these are set correctly in the `MicrosoftGame.config`. This means that even testgdk will not let you login without setting these properties to valid values.
+
+Furthermore, confirm that your PC is set to the correct sandbox.
+
+
+#### "The current user has already installed an unpackaged version of this app. A packaged version cannot replace this." error when installing
+
+Prior to June 2022 GDK, running from the Visual Studio debugger would still locally register the app (and it would appear on the start menu). To fix this, you have to uninstall it (it's simplest to right click on it from the start menu to uninstall it).

libs/SDL2/docs/README-gesture.md

+Dollar Gestures
+===========================================================================
+SDL provides an implementation of the $1 gesture recognition system. This allows for recording, saving, loading, and performing single stroke gestures.
+
+Gestures can be performed with any number of fingers (the centroid of the fingers must follow the path of the gesture), but the number of fingers must be constant (a finger cannot go down in the middle of a gesture). The path of a gesture is considered the path from the time when the final finger went down, to the first time any finger comes up.
+
+Dollar gestures are assigned an Id based on a hash function. This is guaranteed to remain constant for a given gesture. There is a (small) chance that two different gestures will be assigned the same ID. In this case, simply re-recording one of the gestures should result in a different ID.
+
+Recording:
+----------
+To begin recording on a touch device call:
+SDL_RecordGesture(SDL_TouchID touchId), where touchId is the id of the touch device you wish to record on, or -1 to record on all connected devices.
+
+Recording terminates as soon as a finger comes up. Recording is acknowledged by an SDL_DOLLARRECORD event.
+A SDL_DOLLARRECORD event is a dgesture with the following fields:
+
+* event.dgesture.touchId   - the Id of the touch used to record the gesture.
+* event.dgesture.gestureId - the unique id of the recorded gesture.
+
+
+Performing:
+-----------
+As long as there is a dollar gesture assigned to a touch, every finger-up event will also cause an SDL_DOLLARGESTURE event with the following fields:
+
+* event.dgesture.touchId    - the Id of the touch which performed the gesture.
+* event.dgesture.gestureId  - the unique id of the closest gesture to the performed stroke.
+* event.dgesture.error      - the difference between the gesture template and the actual performed gesture. Lower error is a better match.
+* event.dgesture.numFingers - the number of fingers used to draw the stroke.
+
+Most programs will want to define an appropriate error threshold and check to be sure that the error of a gesture is not abnormally high (an indicator that no gesture was performed).
+
+
+
+Saving:
+-------
+To save a template, call SDL_SaveDollarTemplate(gestureId, dst) where gestureId is the id of the gesture you want to save, and dst is an SDL_RWops pointer to the file where the gesture will be stored.
+
+To save all currently loaded templates, call SDL_SaveAllDollarTemplates(dst) where dst is an SDL_RWops pointer to the file where the gesture will be stored.
+
+Both functions return the number of gestures successfully saved.
+
+
+Loading:
+--------
+To load templates from a file, call SDL_LoadDollarTemplates(touchId,src) where touchId is the id of the touch to load to (or -1 to load to all touch devices), and src is an SDL_RWops pointer to a gesture save file.
+
+SDL_LoadDollarTemplates returns the number of templates successfully loaded.
+
+
+
+===========================================================================
+Multi Gestures
+===========================================================================
+SDL provides simple support for pinch/rotate/swipe gestures.
+Every time a finger is moved an SDL_MULTIGESTURE event is sent with the following fields:
+
+* event.mgesture.touchId - the Id of the touch on which the gesture was performed.
+* event.mgesture.x       - the normalized x coordinate of the gesture. (0..1)
+* event.mgesture.y       - the normalized y coordinate of the gesture. (0..1)
+* event.mgesture.dTheta  - the amount that the fingers rotated during this motion.
+* event.mgesture.dDist   - the amount that the fingers pinched during this motion.
+* event.mgesture.numFingers - the number of fingers used in the gesture.
+
+
+===========================================================================
+Notes
+===========================================================================
+For a complete example see test/testgesture.c
+
+Please direct questions/comments to:
+   jim.tla+sdl_touch@gmail.com

libs/SDL2/docs/README-git.md

+git
+=========
+
+The latest development version of SDL is available via git.
+Git allows you to get up-to-the-minute fixes and enhancements;
+as a developer works on a source tree, you can use "git" to mirror that
+source tree instead of waiting for an official release. Please look
+at the Git website ( https://git-scm.com/ ) for more
+information on using git, where you can also download software for
+macOS, Windows, and Unix systems.
+
+    git clone https://github.com/libsdl-org/SDL
+
+If you are building SDL via configure, you will need to run autogen.sh
+before running configure.
+
+There is a web interface to the Git repository at:
+	http://github.com/libsdl-org/SDL/
+

libs/SDL2/docs/README-hg.md

+We are no longer hosted in Mercurial. Please see README-git.md for details.
+
+Thanks!
+

libs/SDL2/docs/README-ios.md

+iOS
+======
+
+Building the Simple DirectMedia Layer for iOS 9.0+
+==============================================================================
+
+Requirements: Mac OS X 10.9 or later and the iOS 9.0 or newer SDK.
+
+Instructions:
+
+1. Open SDL.xcodeproj (located in Xcode/SDL) in Xcode.
+2. Select your desired target, and hit build.
+
+
+Using the Simple DirectMedia Layer for iOS
+==============================================================================
+
+1. Run Xcode and create a new project using the iOS Game template, selecting the Objective C language and Metal game technology.
+2. In the main view, delete all files except for Assets and LaunchScreen
+3. Right click the project in the main view, select "Add Files...", and add the SDL project, Xcode/SDL/SDL.xcodeproj
+4. Select the project in the main view, go to the "Info" tab and under "Custom iOS Target Properties" remove the line "Main storyboard file base name"
+5. Select the project in the main view, go to the "Build Settings" tab, select "All", and edit "Header Search Path" and drag over the SDL "Public Headers" folder from the left
+6. Select the project in the main view, go to the "Build Phases" tab, select "Link Binary With Libraries", and add SDL2.framework from "Framework-iOS"
+7. Select the project in the main view, go to the "General" tab, scroll down to "Frameworks, Libraries, and Embedded Content", and select "Embed & Sign" for the SDL library.
+8. In the main view, expand SDL -> Library Source -> main -> uikit and drag SDL_uikit_main.c into your game files
+9. Add the source files that you would normally have for an SDL program, making sure to have #include "SDL.h" at the top of the file containing your main() function.
+10. Add any assets that your application needs.
+11. Enjoy!
+
+
+TODO: Add information regarding App Store requirements such as icons, etc.
+
+
+Notes -- Retina / High-DPI and window sizes
+==============================================================================
+
+Window and display mode sizes in SDL are in "screen coordinates" (or "points",
+in Apple's terminology) rather than in pixels. On iOS this means that a window
+created on an iPhone 6 will have a size in screen coordinates of 375 x 667,
+rather than a size in pixels of 750 x 1334. All iOS apps are expected to
+size their content based on screen coordinates / points rather than pixels,
+as this allows different iOS devices to have different pixel densities
+(Retina versus non-Retina screens, etc.) without apps caring too much.
+
+By default SDL will not use the full pixel density of the screen on
+Retina/high-dpi capable devices. Use the SDL_WINDOW_ALLOW_HIGHDPI flag when
+creating your window to enable high-dpi support.
+
+When high-dpi support is enabled, SDL_GetWindowSize() and display mode sizes
+will still be in "screen coordinates" rather than pixels, but the window will
+have a much greater pixel density when the device supports it, and the
+SDL_GL_GetDrawableSize() or SDL_GetRendererOutputSize() functions (depending on
+whether raw OpenGL or the SDL_Render API is used) can be queried to determine
+the size in pixels of the drawable screen framebuffer.
+
+Some OpenGL ES functions such as glViewport expect sizes in pixels rather than
+sizes in screen coordinates. When doing 2D rendering with OpenGL ES, an
+orthographic projection matrix using the size in screen coordinates
+(SDL_GetWindowSize()) can be used in order to display content at the same scale
+no matter whether a Retina device is used or not.
+
+
+Notes -- Application events
+==============================================================================
+
+On iOS the application goes through a fixed life cycle and you will get
+notifications of state changes via application events. When these events
+are delivered you must handle them in an event callback because the OS may
+not give you any processing time after the events are delivered.
+
+e.g.
+
+    int HandleAppEvents(void *userdata, SDL_Event *event)
+    {
+        switch (event->type)
+        {
+        case SDL_APP_TERMINATING:
+            /* Terminate the app.
+               Shut everything down before returning from this function.
+            */
+            return 0;
+        case SDL_APP_LOWMEMORY:
+            /* You will get this when your app is paused and iOS wants more memory.
+               Release as much memory as possible.
+            */
+            return 0;
+        case SDL_APP_WILLENTERBACKGROUND:
+            /* Prepare your app to go into the background.  Stop loops, etc.
+               This gets called when the user hits the home button, or gets a call.
+            */
+            return 0;
+        case SDL_APP_DIDENTERBACKGROUND:
+            /* This will get called if the user accepted whatever sent your app to the background.
+               If the user got a phone call and canceled it, you'll instead get an SDL_APP_DIDENTERFOREGROUND event and restart your loops.
+               When you get this, you have 5 seconds to save all your state or the app will be terminated.
+               Your app is NOT active at this point.
+            */
+            return 0;
+        case SDL_APP_WILLENTERFOREGROUND:
+            /* This call happens when your app is coming back to the foreground.
+               Restore all your state here.
+            */
+            return 0;
+        case SDL_APP_DIDENTERFOREGROUND:
+            /* Restart your loops here.
+               Your app is interactive and getting CPU again.
+            */
+            return 0;
+        default:
+            /* No special processing, add it to the event queue */
+            return 1;
+        }
+    }
+
+    int main(int argc, char *argv[])
+    {
+        SDL_SetEventFilter(HandleAppEvents, NULL);
+
+        ... run your main loop
+
+        return 0;
+    }
+
+
+Notes -- Accelerometer as Joystick
+==============================================================================
+
+SDL for iPhone supports polling the built in accelerometer as a joystick device.  For an example on how to do this, see the accelerometer.c in the demos directory.
+
+The main thing to note when using the accelerometer with SDL is that while the iPhone natively reports accelerometer as floating point values in units of g-force, SDL_JoystickGetAxis() reports joystick values as signed integers.  Hence, in order to convert between the two, some clamping and scaling is necessary on the part of the iPhone SDL joystick driver.  To convert SDL_JoystickGetAxis() reported values BACK to units of g-force, simply multiply the values by SDL_IPHONE_MAX_GFORCE / 0x7FFF.
+
+
+Notes -- OpenGL ES
+==============================================================================
+
+Your SDL application for iOS uses OpenGL ES for video by default.
+
+OpenGL ES for iOS supports several display pixel formats, such as RGBA8 and RGB565, which provide a 32 bit and 16 bit color buffer respectively. By default, the implementation uses RGB565, but you may use RGBA8 by setting each color component to 8 bits in SDL_GL_SetAttribute().
+
+If your application doesn't use OpenGL's depth buffer, you may find significant performance improvement by setting SDL_GL_DEPTH_SIZE to 0.
+
+Finally, if your application completely redraws the screen each frame, you may find significant performance improvement by setting the attribute SDL_GL_RETAINED_BACKING to 0.
+
+OpenGL ES on iOS doesn't use the traditional system-framebuffer setup provided in other operating systems. Special care must be taken because of this:
+
+- The drawable Renderbuffer must be bound to the GL_RENDERBUFFER binding point when SDL_GL_SwapWindow() is called.
+- The drawable Framebuffer Object must be bound while rendering to the screen and when SDL_GL_SwapWindow() is called.
+- If multisample antialiasing (MSAA) is used and glReadPixels is used on the screen, the drawable framebuffer must be resolved to the MSAA resolve framebuffer (via glBlitFramebuffer or glResolveMultisampleFramebufferAPPLE), and the MSAA resolve framebuffer must be bound to the GL_READ_FRAMEBUFFER binding point, before glReadPixels is called.
+
+The above objects can be obtained via SDL_GetWindowWMInfo() (in SDL_syswm.h).
+
+
+Notes -- Keyboard
+==============================================================================
+
+The SDL keyboard API has been extended to support on-screen keyboards:
+
+void SDL_StartTextInput()
+	-- enables text events and reveals the onscreen keyboard.
+
+void SDL_StopTextInput()
+	-- disables text events and hides the onscreen keyboard.
+
+SDL_bool SDL_IsTextInputActive()
+	-- returns whether or not text events are enabled (and the onscreen keyboard is visible)
+
+
+Notes -- Mouse
+==============================================================================
+
+iOS now supports Bluetooth mice on iPad, but by default will provide the mouse input as touch. In order for SDL to see the real mouse events, you should set the key UIApplicationSupportsIndirectInputEvents to true in your Info.plist
+
+
+Notes -- Reading and Writing files
+==============================================================================
+
+Each application installed on iPhone resides in a sandbox which includes its own Application Home directory.  Your application may not access files outside this directory.
+
+Once your application is installed its directory tree looks like:
+
+    MySDLApp Home/
+        MySDLApp.app
+        Documents/
+        Library/
+            Preferences/
+        tmp/
+
+When your SDL based iPhone application starts up, it sets the working directory to the main bundle (MySDLApp Home/MySDLApp.app), where your application resources are stored.  You cannot write to this directory.  Instead, I advise you to write document files to "../Documents/" and preferences to "../Library/Preferences".
+
+More information on this subject is available here:
+http://developer.apple.com/library/ios/#documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/Introduction/Introduction.html
+
+
+Notes -- xcFramework
+==============================================================================
+
+The SDL.xcodeproj file now includes a target to build SDL2.xcframework. An xcframework is a new (Xcode 11) uber-framework which can handle any combination of processor type and target OS platform.
+
+In the past, iOS devices were always an ARM variant processor, and the simulator was always i386 or x86_64, and thus libraries could be combined into a single framework for both simulator and device. With the introduction of the Apple Silicon ARM-based machines, regular frameworks would collide as CPU type was no longer sufficient to differentiate the platform. So Apple created the new xcframework library package.
+
+The xcframework target builds into a Products directory alongside the SDL.xcodeproj file, as SDL2.xcframework. This can be brought in to any iOS project and will function properly for both simulator and device, no matter their CPUs. Note that Intel Macs cannot cross-compile for Apple Silicon Macs. If you need AS compatibility, perform this build on an Apple Silicon Mac.
+
+This target requires Xcode 11 or later. The target will simply fail to build if attempted on older Xcodes.
+
+In addition, on Apple platforms, main() cannot be in a dynamically loaded library. This means that iOS apps which used the statically-linked libSDL2.lib and now link with the xcframwork will need to define their own main() to call SDL_UIKitRunApp(), like this:
+
+#ifndef SDL_MAIN_HANDLED
+#ifdef main
+#undef main
+#endif
+
+int
+main(int argc, char *argv[])
+{
+	return SDL_UIKitRunApp(argc, argv, SDL_main);
+}
+#endif /* !SDL_MAIN_HANDLED */
+
+Using an xcFramework is similar to using a regular framework. However, issues have been seen with the build system not seeing the headers in the xcFramework. To remedy this, add the path to the xcFramework in your app's target ==> Build Settings ==> Framework Search Paths and mark it recursive (this is critical). Also critical is to remove "*.framework" from Build Settings ==> Sub-Directories to Exclude in Recursive Searches. Clean the build folder, and on your next build the build system should be able to see any of these in your code, as expected:
+
+#include "SDL_main.h"
+#include <SDL.h>
+#include <SDL_main.h>
+
+
+Notes -- iPhone SDL limitations
+==============================================================================
+
+Windows:
+	Full-size, single window applications only.  You cannot create multi-window SDL applications for iPhone OS.  The application window will fill the display, though you have the option of turning on or off the menu-bar (pass SDL_CreateWindow() the flag SDL_WINDOW_BORDERLESS).
+
+Textures:
+	The optimal texture formats on iOS are SDL_PIXELFORMAT_ABGR8888, SDL_PIXELFORMAT_ABGR8888, SDL_PIXELFORMAT_BGR888, and SDL_PIXELFORMAT_RGB24 pixel formats.
+
+Loading Shared Objects:
+	This is disabled by default since it seems to break the terms of the iOS SDK agreement for iOS versions prior to iOS 8. It can be re-enabled in SDL_config_iphoneos.h.
+
+
+Notes -- CoreBluetooth.framework
+==============================================================================
+
+SDL_JOYSTICK_HIDAPI is disabled by default. It can give you access to a lot
+more game controller devices, but it requires permission from the user before
+your app will be able to talk to the Bluetooth hardware. "Made For iOS"
+branded controllers do not need this as we don't have to speak to them
+directly with raw bluetooth, so many apps can live without this.
+
+You'll need to link with CoreBluetooth.framework and add something like this
+to your Info.plist:
+
+<key>NSBluetoothPeripheralUsageDescription</key>
+<string>MyApp would like to remain connected to nearby bluetooth Game Controllers and Game Pads even when you're not using the app.</string>
+
+
+Game Center
+==============================================================================
+
+Game Center integration might require that you break up your main loop in order to yield control back to the system. In other words, instead of running an endless main loop, you run each frame in a callback function, using:
+
+    int SDL_iPhoneSetAnimationCallback(SDL_Window * window, int interval, void (*callback)(void*), void *callbackParam);
+
+This will set up the given function to be called back on the animation callback, and then you have to return from main() to let the Cocoa event loop run.
+
+e.g.
+
+    extern "C"
+    void ShowFrame(void*)
+    {
+        ... do event handling, frame logic and rendering ...
+    }
+
+    int main(int argc, char *argv[])
+    {
+        ... initialize game ...
+
+    #if __IPHONEOS__
+        // Initialize the Game Center for scoring and matchmaking
+        InitGameCenter();
+
+        // Set up the game to run in the window animation callback on iOS
+        // so that Game Center and so forth works correctly.
+        SDL_iPhoneSetAnimationCallback(window, 1, ShowFrame, NULL);
+    #else
+        while ( running ) {
+            ShowFrame(0);
+            DelayFrame();
+        }
+    #endif
+        return 0;
+    }
+
+
+Deploying to older versions of iOS
+==============================================================================
+
+SDL supports deploying to older versions of iOS than are supported by the latest version of Xcode, all the way back to iOS 8.0
+
+In order to do that you need to download an older version of Xcode:
+https://developer.apple.com/download/more/?name=Xcode
+
+Open the package contents of the older Xcode and your newer version of Xcode and copy over the folders in Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport
+
+Then open the file Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/SDKSettings.plist and add the versions of iOS you want to deploy to the key Root/DefaultProperties/DEPLOYMENT_TARGET_SUGGESTED_VALUES
+
+Open your project and set your deployment target to the desired version of iOS
+
+Finally, remove GameController from the list of frameworks linked by your application and edit the build settings for "Other Linker Flags" and add -weak_framework GameController

libs/SDL2/docs/README-kmsbsd.md

+KMSDRM on *BSD
+==================================================
+
+KMSDRM is supported on FreeBSD and OpenBSD. DragonFlyBSD works but requires being a root user. NetBSD isn't supported yet because the application will crash when creating the KMSDRM screen.
+
+WSCONS support has been brought back, but only as an input backend. It will not be brought back as a video backend to ease maintenance.
+
+OpenBSD note: Note that the video backend assumes that the user has read/write permissions to the /dev/drm* devices.
+
+
+SDL2 WSCONS input backend features
+===================================================
+1. It is keymap-aware; it will work properly with different keymaps.
+2. It has mouse support.
+3. Accent input is supported.
+4. Compose keys are supported.
+5. AltGr and Meta Shift keys work as intended.
+
+Partially working or no input on OpenBSD/NetBSD.
+==================================================
+
+The WSCONS input backend needs read/write access to the /dev/wskbd* devices, without which it will not work properly. /dev/wsmouse must also be read/write accessible, otherwise mouse input will not work.
+
+Partially working or no input on FreeBSD.
+==================================================
+
+The evdev devices are only accessible to the root user by default. Edit devfs rules to allow access to such devices. The /dev/kbd* devices are also only accessible to the root user by default. Edit devfs rules to allow access to such devices.

libs/SDL2/docs/README-linux.md

+Linux
+================================================================================
+
+By default SDL will only link against glibc, the rest of the features will be
+enabled dynamically at runtime depending on the available features on the target
+system. So, for example if you built SDL with XRandR support and the target
+system does not have the XRandR libraries installed, it will be disabled
+at runtime, and you won't get a missing library error, at least with the
+default configuration parameters.
+
+
+Build Dependencies
+--------------------------------------------------------------------------------
+
+Ubuntu 18.04, all available features enabled:
+
+    sudo apt-get install build-essential git make autoconf automake libtool \
+    pkg-config cmake ninja-build gnome-desktop-testing libasound2-dev libpulse-dev \
+    libaudio-dev libjack-dev libsndio-dev libsamplerate0-dev libx11-dev libxext-dev \
+    libxrandr-dev libxcursor-dev libxfixes-dev libxi-dev libxss-dev libwayland-dev \
+    libxkbcommon-dev libdrm-dev libgbm-dev libgl1-mesa-dev libgles2-mesa-dev \
+    libegl1-mesa-dev libdbus-1-dev libibus-1.0-dev libudev-dev fcitx-libs-dev
+
+Ubuntu 22.04+ can also add `libpipewire-0.3-dev libdecor-0-dev` to that command line.
+
+Fedora 35, all available features enabled:
+
+    sudo yum install gcc git-core make cmake autoconf automake libtool \
+    alsa-lib-devel pulseaudio-libs-devel nas-devel pipewire-devel \
+    libX11-devel libXext-devel libXrandr-devel libXcursor-devel libXfixes-devel \
+    libXi-devel libXScrnSaver-devel dbus-devel ibus-devel fcitx-devel \
+    systemd-devel mesa-libGL-devel libxkbcommon-devel mesa-libGLES-devel \
+    mesa-libEGL-devel vulkan-devel wayland-devel wayland-protocols-devel \
+    libdrm-devel mesa-libgbm-devel libusb-devel libdecor-devel \
+    libsamplerate-devel pipewire-jack-audio-connection-kit-devel \
+
+NOTES:
+- This includes all the audio targets except arts and esd, because Ubuntu
+  (and/or Debian) pulled their packages, but in theory SDL still supports them.
+  The sndio audio target is also unavailable on Fedora.
+- libsamplerate0-dev lets SDL optionally link to libresamplerate at runtime
+  for higher-quality audio resampling. SDL will work without it if the library
+  is missing, so it's safe to build in support even if the end user doesn't
+  have this library installed.
+- DirectFB isn't included because the configure script (currently) fails to find
+  it at all. You can do "sudo apt-get install libdirectfb-dev" and fix the
+  configure script to include DirectFB support. Send patches.  :)
+
+
+Joystick does not work
+--------------------------------------------------------------------------------
+
+If you compiled or are using a version of SDL with udev support (and you should!)
+there's a few issues that may cause SDL to fail to detect your joystick. To
+debug this, start by installing the evtest utility. On Ubuntu/Debian:
+
+    sudo apt-get install evtest
+
+Then run:
+
+    sudo evtest
+
+You'll hopefully see your joystick listed along with a name like "/dev/input/eventXX"
+Now run:
+
+    cat /dev/input/event/XX
+
+If you get a permission error, you need to set a udev rule to change the mode of
+your device (see below)
+
+Also, try:
+
+    sudo udevadm info --query=all --name=input/eventXX
+
+If you see a line stating ID_INPUT_JOYSTICK=1, great, if you don't see it,
+you need to set up an udev rule to force this variable.
+
+A combined rule for the Saitek Pro Flight Rudder Pedals to fix both issues looks
+like:
+
+    SUBSYSTEM=="input", ATTRS{idProduct}=="0763", ATTRS{idVendor}=="06a3", MODE="0666", ENV{ID_INPUT_JOYSTICK}="1"
+    SUBSYSTEM=="input", ATTRS{idProduct}=="0764", ATTRS{idVendor}=="06a3", MODE="0666", ENV{ID_INPUT_JOYSTICK}="1"
+
+You can set up similar rules for your device by changing the values listed in
+idProduct and idVendor. To obtain these values, try:
+
+    sudo udevadm info -a --name=input/eventXX | grep idVendor
+    sudo udevadm info -a --name=input/eventXX | grep idProduct
+
+If multiple values come up for each of these, the one you want is the first one of each.
+
+On other systems which ship with an older udev (such as CentOS), you may need
+to set up a rule such as:
+
+    SUBSYSTEM=="input", ENV{ID_CLASS}=="joystick", ENV{ID_INPUT_JOYSTICK}="1"
+

libs/SDL2/docs/README-macos.md

+# Mac OS X (aka macOS).
+
+These instructions are for people using Apple's Mac OS X (pronounced
+"ten"), which in newer versions is just referred to as "macOS".
+
+From the developer's point of view, macOS is a sort of hybrid Mac and
+Unix system, and you have the option of using either traditional
+command line tools or Apple's IDE Xcode.
+
+# Command Line Build
+
+To build SDL using the command line, use the standard configure and make
+process:
+
+```bash
+mkdir build
+cd build
+../configure
+make
+sudo make install
+```
+
+CMake is also known to work, although it continues to be a work in progress:
+
+```bash
+mkdir build
+cd build
+cmake -DCMAKE_BUILD_TYPE=Release ..
+make
+sudo make install
+```
+
+
+You can also build SDL as a Universal library (a single binary for both
+64-bit Intel and ARM architectures), by using the build-scripts/clang-fat.sh
+script.
+
+```bash
+mkdir build
+cd build
+CC=$PWD/../build-scripts/clang-fat.sh ../configure
+make
+sudo make install
+```
+
+This script builds SDL with 10.9 ABI compatibility on 64-bit Intel and 11.0
+ABI compatibility on ARM64 architectures.  For best compatibility you
+should compile your application the same way.
+
+Please note that building SDL requires at least Xcode 6 and the 10.9 SDK.
+PowerPC support for macOS has been officially dropped as of SDL 2.0.2.
+32-bit Intel and macOS 10.8 runtime support has been officially dropped as
+of SDL 2.24.0.
+
+To use the library once it's built, you essential have two possibilities:
+use the traditional autoconf/automake/make method, or use Xcode.
+
+
+# Caveats for using SDL with Mac OS X
+
+If you register your own NSApplicationDelegate (using [NSApp setDelegate:]),
+SDL will not register its own. This means that SDL will not terminate using
+SDL_Quit if it receives a termination request, it will terminate like a
+normal app, and it will not send a SDL_DROPFILE when you request to open a
+file with the app. To solve these issues, put the following code in your
+NSApplicationDelegate implementation:
+
+
+```objc
+- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication *)sender
+{
+    if (SDL_GetEventState(SDL_QUIT) == SDL_ENABLE) {
+        SDL_Event event;
+        event.type = SDL_QUIT;
+        SDL_PushEvent(&event);
+    }
+
+    return NSTerminateCancel;
+}
+
+- (BOOL)application:(NSApplication *)theApplication openFile:(NSString *)filename
+{
+    if (SDL_GetEventState(SDL_DROPFILE) == SDL_ENABLE) {
+        SDL_Event event;
+        event.type = SDL_DROPFILE;
+        event.drop.file = SDL_strdup([filename UTF8String]);
+        return (SDL_PushEvent(&event) > 0);
+    }
+
+    return NO;
+}
+```
+
+# Using the Simple DirectMedia Layer with a traditional Makefile
+
+An existing autoconf/automake build system for your SDL app has good chances
+to work almost unchanged on macOS. However, to produce a "real" Mac binary
+that you can distribute to users, you need to put the generated binary into a
+so called "bundle", which is basically a fancy folder with a name like
+"MyCoolGame.app".
+
+To get this build automatically, add something like the following rule to
+your Makefile.am:
+
+```make
+bundle_contents = APP_NAME.app/Contents
+APP_NAME_bundle: EXE_NAME
+	mkdir -p $(bundle_contents)/MacOS
+	mkdir -p $(bundle_contents)/Resources
+	echo "APPL????" > $(bundle_contents)/PkgInfo
+	$(INSTALL_PROGRAM) $< $(bundle_contents)/MacOS/
+```
+
+You should replace `EXE_NAME` with the name of the executable. `APP_NAME` is
+what will be visible to the user in the Finder. Usually it will be the same
+as `EXE_NAME` but capitalized. E.g. if `EXE_NAME` is "testgame" then `APP_NAME`
+usually is "TestGame". You might also want to use `@PACKAGE@` to use the
+package name as specified in your configure.ac file.
+
+If your project builds more than one application, you will have to do a bit
+more. For each of your target applications, you need a separate rule.
+
+If you want the created bundles to be installed, you may want to add this
+rule to your Makefile.am:
+
+```make
+install-exec-hook: APP_NAME_bundle
+	rm -rf $(DESTDIR)$(prefix)/Applications/APP_NAME.app
+	mkdir -p $(DESTDIR)$(prefix)/Applications/
+	cp -r $< /$(DESTDIR)$(prefix)Applications/
+```
+
+This rule takes the Bundle created by the rule from step 3 and installs them
+into "$(DESTDIR)$(prefix)/Applications/".
+
+Again, if you want to install multiple applications, you will have to augment
+the make rule accordingly.
+
+But beware! That is only part of the story! With the above, you end up with
+a barebones .app bundle, which is double-clickable from the Finder. But
+there are some more things you should do before shipping your product...
+
+1. The bundle right now probably is dynamically linked against SDL. That
+   means that when you copy it to another computer, *it will not run*,
+   unless you also install SDL on that other computer. A good solution
+   for this dilemma is to static link against SDL. On OS X, you can
+   achieve that by linking against the libraries listed by
+
+   ```bash
+   sdl-config --static-libs
+   ```
+
+   instead of those listed by
+
+   ```bash
+   sdl-config --libs
+   ```
+
+   Depending on how exactly SDL is integrated into your build systems, the
+   way to achieve that varies, so I won't describe it here in detail
+
+2. Add an 'Info.plist' to your application. That is a special XML file which
+   contains some meta-information about your application (like some copyright
+   information, the version of your app, the name of an optional icon file,
+   and other things). Part of that information is displayed by the Finder
+   when you click on the .app, or if you look at the "Get Info" window.
+   More information about Info.plist files can be found on Apple's homepage.
+
+
+As a final remark, let me add that I use some of the techniques (and some
+variations of them) in [Exult](https://github.com/exult/exult) and
+[ScummVM](https://github.com/scummvm/scummvm); both are available in source on
+the net, so feel free to take a peek at them for inspiration!
+
+
+# Using the Simple DirectMedia Layer with Xcode
+
+These instructions are for using Apple's Xcode IDE to build SDL applications.
+
+## First steps
+
+The first thing to do is to unpack the Xcode.tar.gz archive in the
+top level SDL directory (where the Xcode.tar.gz archive resides).
+Because Stuffit Expander will unpack the archive into a subdirectory,
+you should unpack the archive manually from the command line:
+
+```bash
+cd [path_to_SDL_source]
+tar zxf Xcode.tar.gz
+```
+
+This will create a new folder called Xcode, which you can browse
+normally from the Finder.
+
+## Building the Framework
+
+The SDL Library is packaged as a framework bundle, an organized
+relocatable folder hierarchy of executable code, interface headers,
+and additional resources. For practical purposes, you can think of a
+framework as a more user and system-friendly shared library, whose library
+file behaves more or less like a standard UNIX shared library.
+
+To build the framework, simply open the framework project and build it.
+By default, the framework bundle "SDL.framework" is installed in
+/Library/Frameworks. Therefore, the testers and project stationary expect
+it to be located there. However, it will function the same in any of the
+following locations:
+
+* ~/Library/Frameworks
+* /Local/Library/Frameworks
+* /System/Library/Frameworks
+
+## Build Options
+
+There are two "Build Styles" (See the "Targets" tab) for SDL.
+"Deployment" should be used if you aren't tweaking the SDL library.
+"Development" should be used to debug SDL apps or the library itself.
+
+## Building the Testers
+
+Open the SDLTest project and build away!
+
+## Using the Project Stationary
+
+Copy the stationary to the indicated folders to access it from
+the "New Project" and "Add target" menus. What could be easier?
+
+## Setting up a new project by hand
+
+Some of you won't want to use the Stationary so I'll give some tips:
+
+(this is accurate as of Xcode 12.5.)
+
+* Click "File" -> "New" -> "Project...
+* Choose "macOS" and then "App" from the "Application" section.
+* Fill out the options in the next window. User interface is "XIB" and
+  Language is "Objective-C".
+* Remove "main.m" from your project
+* Remove "MainMenu.xib" from your project
+* Remove "AppDelegates.*" from your project
+* Add "\$(HOME)/Library/Frameworks/SDL.framework/Headers" to include path
+* Add "\$(HOME)/Library/Frameworks" to the frameworks search path
+* Add "-framework SDL -framework Foundation -framework AppKit" to "OTHER_LDFLAGS"
+* Add your files
+* Clean and build
+
+## Building from command line
+
+Use `xcode-build` in the same directory as your .pbxproj file
+
+## Running your app
+
+You can send command line args to your app by either invoking it from
+the command line (in *.app/Contents/MacOS) or by entering them in the
+Executables" panel of the target settings.
+
+# Implementation Notes
+
+Some things that may be of interest about how it all works...
+
+## Working directory
+
+In SDL 1.2, the working directory of your SDL app is by default set to its
+parent, but this is no longer the case in SDL 2.0. SDL2 does change the
+working directory, which means it'll be whatever the command line prompt
+that launched the program was using, or if launched by double-clicking in
+the finger, it will be "/", the _root of the filesystem_. Plan accordingly!
+You can use SDL_GetBasePath() to find where the program is running from and
+chdir() there directly.
+
+
+## You have a Cocoa App!
+
+Your SDL app is essentially a Cocoa application. When your app
+starts up and the libraries finish loading, a Cocoa procedure is called,
+which sets up the working directory and calls your main() method.
+You are free to modify your Cocoa app with generally no consequence
+to SDL. You cannot, however, easily change the SDL window itself.
+Functionality may be added in the future to help this.
+
+# Bug reports
+
+Bugs are tracked at [the GitHub issue tracker](https://github.com/libsdl-org/SDL/issues/).
+Please feel free to report bugs there!
+

libs/SDL2/docs/README-n3ds.md

+# Nintendo 3DS
+
+SDL port for the Nintendo 3DS [Homebrew toolchain](https://devkitpro.org/) contributed by:
+
+-   [Pierre Wendling](https://github.com/FtZPetruska)
+
+Credits to:
+
+-   The awesome people who ported SDL to other homebrew platforms.
+-   The Devkitpro team for making all the tools necessary to achieve this.
+
+## Building
+
+To build for the Nintendo 3DS, make sure you have devkitARM and cmake installed and run:
+
+```bash
+cmake -S. -Bbuild -DCMAKE_TOOLCHAIN_FILE="$DEVKITPRO/cmake/3DS.cmake" -DCMAKE_BUILD_TYPE=Release
+cmake --build build
+cmake --install build
+```
+
+## Notes
+
+-   Currently only software rendering is supported.
+-   SDL2main should be used to ensure ROMFS is enabled.
+-   By default, the extra L2 cache and higher clock speeds of the New 2/3DS lineup are enabled. If you wish to turn it off, use `osSetSpeedupEnable(false)` in your main function.
+-   `SDL_GetBasePath` returns the romfs root instead of the executable's directory.
+-   The Nintendo 3DS uses a cooperative threading model on a single core, meaning a thread will never yield unless done manually through the `SDL_Delay` functions, or blocking waits (`SDL_LockMutex`, `SDL_SemWait`, `SDL_CondWait`, `SDL_WaitThread`). To avoid starving other threads, `SDL_SemTryWait` and `SDL_SemWaitTimeout` will yield if they fail to acquire the semaphore, see https://github.com/libsdl-org/SDL/pull/6776 for more information.

libs/SDL2/docs/README-nacl.md

+Native Client
+================================================================================
+
+Requirements:
+
+* Native Client SDK (https://developer.chrome.com/native-client),
+  (tested with Pepper version 33 or higher).
+
+The SDL backend for Chrome's Native Client has been tested only with the PNaCl
+toolchain, which generates binaries designed to run on ARM and x86_32/64
+platforms. This does not mean it won't work with the other toolchains!
+
+================================================================================
+Building SDL for NaCl
+================================================================================
+
+Set up the right environment variables (see naclbuild.sh), then configure SDL with:
+
+    configure --host=pnacl --prefix some/install/destination
+
+Then "make".
+
+As an example of how to create a deployable app a Makefile project is provided
+in test/nacl/Makefile, which includes some monkey patching of the common.mk file
+provided by NaCl, without which linking properly to SDL won't work (the search
+path can't be modified externally, so the linker won't find SDL's binaries unless
+you dump them into the SDK path, which is inconvenient).
+Also provided in test/nacl is the required support file, such as index.html,
+manifest.json, etc.
+SDL apps for NaCl run on a worker thread using the ppapi_simple infrastructure.
+This allows for blocking calls on all the relevant systems (OpenGL ES, filesystem),
+hiding the asynchronous nature of the browser behind the scenes...which is not the
+same as making it disappear!
+
+
+================================================================================
+Running tests
+================================================================================
+
+Due to the nature of NaCl programs, building and running SDL tests is not as
+straightforward as one would hope. The script naclbuild.sh in build-scripts
+automates the process and should serve as a guide for users of SDL trying to build
+their own applications.
+
+Basic usage:
+
+    ./naclbuild.sh path/to/pepper/toolchain (i.e. ~/naclsdk/pepper_35)
+
+This will build testgles2.c by default.
+
+If you want to build a different test, for example testrendercopyex.c:
+
+    SOURCES=~/sdl/SDL/test/testrendercopyex.c ./naclbuild.sh ~/naclsdk/pepper_35
+
+Once the build finishes, you have to serve the contents with a web server (the
+script will give you instructions on how to do that with Python).
+
+================================================================================
+RWops and nacl_io
+================================================================================
+
+SDL_RWops work transparently with nacl_io. Two functions control the mount points:
+
+    int mount(const char* source, const char* target,
+                      const char* filesystemtype,
+                      unsigned long mountflags, const void *data);
+    int umount(const char *target);
+
+    For convenience, SDL will by default mount an httpfs tree at / before calling
+the app's main function. Such setting can be overridden by calling:
+
+    umount("/");
+
+And then mounting a different filesystem at /
+
+It's important to consider that the asynchronous nature of file operations on a
+browser is hidden from the application, effectively providing the developer with
+a set of blocking file operations just like you get in a regular desktop
+environment, which eases the job of porting to Native Client, but also introduces
+a set of challenges of its own, in particular when big file sizes and slow
+connections are involved.
+
+For more information on how nacl_io and mount points work, see:
+
+    https://developer.chrome.com/native-client/devguide/coding/nacl_io
+    https://src.chromium.org/chrome/trunk/src/native_client_sdk/src/libraries/nacl_io/nacl_io.h
+
+To be able to save into the directory "/save/" (like backup of game) :
+
+    mount("", "/save", "html5fs", 0, "type=PERSISTENT");
+
+And add to manifest.json :
+
+    "permissions": [
+        "unlimitedStorage"
+    ]
+
+================================================================================
+TODO - Known Issues
+================================================================================
+* Testing of all systems with a real application (something other than SDL's tests)
+* Key events don't seem to work properly
+

libs/SDL2/docs/README-ngage.md

+Nokia N-Gage
+============
+
+SDL2 port for Symbian S60v1 and v2 with a main focus on the Nokia N-Gage
+(Classic and QD) by [Michael Fitzmayer](https://github.com/mupfdev).
+
+Compiling
+---------
+
+SDL is part of the [N-Gage SDK.](https://github.com/ngagesdk) project.
+The library is included in the
+[toolchain](https://github.com/ngagesdk/ngage-toolchain) as a
+sub-module.
+
+A complete example project based on SDL2 can be found in the GitHub
+account of the SDK: [Wordle](https://github.com/ngagesdk/wordle).
+
+Current level of implementation
+-------------------------------
+
+The video driver currently provides full screen video support with
+keyboard input.
+
+At the moment only the software renderer works.
+
+Audio is not yet implemented.
+
+Acknowledgements
+----------------
+
+Thanks to Hannu Viitala, Kimmo Kinnunen and Markus Mertama for the
+valuable insight into Symbian programming.  Without the SDL 1.2 port
+which was specially developed for CDoom (Doom for the Nokia 9210), this
+adaptation would not have been possible.
+
+I would like to thank my friends
+[Razvan](https://twitter.com/bewarerazvan) and [Dan
+Whelan](https://danwhelan.ie/), for their continuous support.  Without
+you and the [N-Gage community](https://discord.gg/dbUzqJ26vs), I would
+have lost my patience long ago.
+
+Last but not least, I would like to thank the development team of
+[EKA2L1](https://12z1.com/) (an experimental Symbian OS emulator). Your
+patience and support in troubleshooting helped me a lot.

libs/SDL2/docs/README-os2.md

+Simple DirectMedia Layer 2 for OS/2 & eComStation
+================================================================================
+SDL port for OS/2, authored by Andrey Vasilkin <digi@os2.snc.ru>, 2016
+
+
+OpenGL not supported by this port.
+
+Additional optional environment variables:
+
+SDL_AUDIO_SHARE
+  Values: 0 or 1, default is 0
+  Initializes the device as shareable or exclusively acquired.
+
+SDL_VIDEODRIVER
+  Values: DIVE or VMAN, default is DIVE
+  Use video subsystem: Direct interface video extensions (DIVE) or
+  Video Manager (VMAN).
+
+You may significantly increase video output speed with OS4 kernel and patched
+files vman.dll and dive.dll or with latest versions of ACPI support and video
+driver Panorama.
+
+Latest versions of OS/4 kernel:
+  http://gus.biysk.ru/os4/
+ (Info: https://www.os2world.com/wiki/index.php/Phoenix_OS/4)
+
+Patched files vman.dll and dive.dll:
+  http://gus.biysk.ru/os4/test/pached_dll/PATCHED_DLL.RAR
+
+
+Compiling:
+----------
+
+Open Watcom 1.9 or newer is tested. For the new Open Watcom V2 fork, see:
+https://github.com/open-watcom/ and https://open-watcom.github.io
+WATCOM environment variable must to be set to the Open Watcom install
+directory. To compile, run: wmake -f Makefile.os2
+
+
+Installing:
+-----------
+
+- eComStation:
+
+  If you have previously installed SDL2, make a Backup copy of SDL2.dll
+  located in D:\ecs\dll (where D: is disk on which installed eComStation).
+  Stop all programs running with SDL2. Copy SDL2.dll to D:\ecs\dll
+
+- OS/2:
+
+  Copy SDL2.dll to any directory on your LIBPATH.  If you have a previous
+  version installed, close all SDL2 applications before replacing the old
+  copy.  Also make sure that any other older versions of DLLs are removed
+  from your system.
+
+
+Joysticks in SDL2:
+------------------
+
+The joystick code in SDL2 is a direct forward-port from the SDL-1.2 version.
+Here is the original documentation from SDL-1.2:
+
+The Joystick detection only works for standard joysticks (2 buttons, 2 axes
+and the like). Therefore, if you use a non-standard joystick, you should
+specify its features in the SDL_OS2_JOYSTICK environment variable in a batch
+file or CONFIG.SYS, so SDL applications can provide full capability to your
+device. The syntax is:
+
+SET SDL_OS2_JOYSTICK=[JOYSTICK_NAME] [AXES] [BUTTONS] [HATS] [BALLS]
+
+So, it you have a Gravis GamePad with 4 axes, 2 buttons, 2 hats and 0 balls,
+the line should be:
+
+SET SDL_OS2_JOYSTICK=Gravis_GamePad 4 2 2 0
+
+If you want to add spaces in your joystick name, just surround it with
+quotes or double-quotes:
+
+SET SDL_OS2_JOYSTICK='Gravis GamePad' 4 2 2 0
+
+or
+
+SET SDL_OS2_JOYSTICK="Gravis GamePad" 4 2 2 0
+
+   Note however that Balls and Hats are not supported under OS/2, and the
+value will be ignored... but it is wise to define these correctly because
+in the future those can be supported.
+
+   Also the number of buttons is limited to 2 when using two joysticks,
+4 when using one joystick with 4 axes, 6 when using a joystick with 3 axes
+and 8 when using a joystick with 2 axes. Notice however these are limitations
+of the Joystick Port hardware, not OS/2.

libs/SDL2/docs/README-pandora.md

+Pandora
+=====================================================================
+
+( http://openpandora.org/ )
+- A pandora specific video driver was written to allow SDL 2.0 with OpenGL ES
+support to work on the pandora under the framebuffer. This driver do not have
+input support for now, so if you use it you will have to add your own control code.
+The video driver name is "pandora" so if you have problem running it from
+the framebuffer, try to set the following variable before starting your application :
+"export SDL_VIDEODRIVER=pandora"
+
+- OpenGL ES support was added to the x11 driver, so it's working like the normal
+x11 driver one with OpenGLX support, with SDL input event's etc..
+
+
+David Carré (Cpasjuste)
+cpasjuste@gmail.com

libs/SDL2/docs/README-platforms.md

+Platforms
+=========
+
+We maintain the list of supported platforms on our wiki now, and how to
+build and install SDL for those platforms:
+
+    https://wiki.libsdl.org/Installation
+

libs/SDL2/docs/README-porting.md

+Porting
+=======
+
+* Porting To A New Platform
+
+  The first thing you have to do when porting to a new platform, is look at
+include/SDL_platform.h and create an entry there for your operating system.
+The standard format is "__PLATFORM__", where PLATFORM is the name of the OS.
+Ideally SDL_platform.h will be able to auto-detect the system it's building
+on based on C preprocessor symbols.
+
+There are two basic ways of building SDL at the moment:
+
+1. The "UNIX" way:  ./configure; make; make install
+
+   If you have a GNUish system, then you might try this.  Edit configure.ac,
+   take a look at the large section labelled:
+
+	"Set up the configuration based on the host platform!"
+
+   Add a section for your platform, and then re-run autogen.sh and build!
+
+2. Using an IDE:
+
+   If you're using an IDE or other non-configure build system, you'll probably
+   want to create a custom SDL_config.h for your platform.  Edit SDL_config.h,
+   add a section for your platform, and create a custom SDL_config_{platform}.h,
+   based on SDL_config_minimal.h and SDL_config.h.in
+
+   Add the top level include directory to the header search path, and then add
+   the following sources to the project:
+
+	src/*.c
+	src/atomic/*.c
+	src/audio/*.c
+	src/cpuinfo/*.c
+	src/events/*.c
+	src/file/*.c
+	src/haptic/*.c
+	src/joystick/*.c
+	src/power/*.c
+	src/render/*.c
+	src/render/software/*.c
+	src/stdlib/*.c
+	src/thread/*.c
+	src/timer/*.c
+	src/video/*.c
+	src/audio/disk/*.c
+	src/audio/dummy/*.c
+	src/filesystem/dummy/*.c
+	src/video/dummy/*.c
+	src/haptic/dummy/*.c
+	src/joystick/dummy/*.c
+	src/main/dummy/*.c
+	src/thread/generic/*.c
+	src/timer/dummy/*.c
+	src/loadso/dummy/*.c
+
+
+Once you have a working library without any drivers, you can go back to each
+of the major subsystems and start implementing drivers for your platform.
+
+If you have any questions, don't hesitate to ask on the SDL mailing list:
+	http://www.libsdl.org/mailing-list.php
+
+Enjoy!
+	Sam Lantinga				(slouken@libsdl.org)
+

libs/SDL2/docs/README-ps2.md

+PS2
+======
+SDL2 port for the Sony Playstation 2 contributed by:
+- Francisco Javier Trujillo Mata
+
+
+Credit to
+   - The guys that ported SDL to PSP & Vita because I'm taking them as reference.
+   - David G. F. for helping me with several issues and tests.
+
+## Building
+To build SDL2 library for the PS2, make sure you have the latest PS2Dev status and run:
+```bash
+cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=$PS2DEV/ps2sdk/ps2dev.cmake
+cmake --build build
+cmake --install build
+```
+
+## Hints
+The PS2 port has a special Hint for having a dynamic VSYNC. The Hint is `SDL_HINT_PS2_DYNAMIC_VSYNC`.
+If you enabled the dynamic vsync having as well `SDL_RENDERER_PRESENTVSYNC` enabled, then if the app is not able to run at 60 FPS, automatically the `vsync` will be disabled having a better performance, instead of droping FPS to 30.
+
+## Notes
+If you trying to debug a SDL app through [ps2client](https://github.com/ps2dev/ps2client) you need to avoid the IOP reset, otherwise you will lose the conection with your computer.
+So to avoid the reset of the IOP CPU, you need to call to the macro `SDL_PS2_SKIP_IOP_RESET();`.
+It could be something similar as:
+```c
+.....
+
+SDL_PS2_SKIP_IOP_RESET();
+
+int main(int argc, char *argv[])
+{
+.....
+```
+For a release binary is recommendable to reset the IOP always.
+
+Remember to do a clean compilation everytime you enable or disable the `SDL_PS2_SKIP_IOP_RESET` otherwise the change won't be reflected.
+
+## Getting PS2 Dev
+[Installing PS2 Dev](https://github.com/ps2dev/ps2dev)
+
+## Running on PCSX2 Emulator
+[PCSX2](https://github.com/PCSX2/pcsx2)
+
+[More PCSX2 information](https://pcsx2.net/)
+
+## To Do
+- PS2 Screen Keyboard
+- Dialogs
+- Others

libs/SDL2/docs/README-psp.md

+PSP
+======
+SDL2 port for the Sony PSP contributed by:
+- Captian Lex
+- Francisco Javier Trujillo Mata
+- Wouter Wijsman
+
+
+Credit to
+   Marcus R.Brown,Jim Paris,Matthew H for the original SDL 1.2 for PSP
+   Geecko for his PSP GU lib "Glib2d"
+
+## Building
+To build SDL2 library for the PSP, make sure you have the latest PSPDev status and run:
+```bash
+cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=$PSPDEV/psp/share/pspdev.cmake
+cmake --build build
+cmake --install build
+```
+
+
+## Getting PSP Dev
+[Installing PSP Dev](https://github.com/pspdev/pspdev)
+
+## Running on PPSSPP Emulator
+[PPSSPP](https://github.com/hrydgard/ppsspp)
+
+[Build Instructions](https://github.com/hrydgard/ppsspp/wiki/Build-instructions)
+
+
+## Compiling a HelloWorld
+[PSP Hello World](https://psp-dev.org/doku.php?id=tutorial:hello_world)
+
+## To Do
+- PSP Screen Keyboard
+- Dialogs