docs/README-winrt.md
author David Ludwig
Thu, 27 Nov 2014 09:55:34 -0500
changeset 9242 f4d353bd5d16
parent 9224 bc074eca6597
child 9247 eddb899239fe
permissions -rw-r--r--
WinRT: added SDL_HINT_WINRT_PREF_PATH_ROOT

SDL_HINT_WINRT_PREF_PATH_ROOT allows WinRT apps to alter the path that
SDL_GetPrefPath() returns. Setting it to "local" uses the app's
OS-defined Local folder, setting it to "roaming" uses the app's OS-defined
Roaming folder.

Roaming folder support is not available in Windows Phone 8.0. Attempts to
make SDL_GetPrefPath() return a Roaming folder on this OS will be ignored.

Various bits of documentation on this were added to SDL_hints.h, and to
README-winrt.md
     1 WinRT
     2 =====
     3 
     4 This port allows SDL applications to run on Microsoft's platforms that require
     5 use of "Windows Runtime", aka. "WinRT", APIs.  WinRT apps are currently
     6 full-screen only, and run in what Microsoft sometimes refers to as their
     7 "Modern" (formerly, "Metro"), environment.  For Windows 8.x, Microsoft may also
     8 refer to them as "Windows Store" apps, due to them being distributed,
     9 primarily, via a Microsoft-run online store (of the same name).
    10 
    11 Some of the operating systems that include WinRT, are:
    12 
    13 * Windows 8.x
    14 * Windows RT 8.x (aka. Windows 8.x for ARM processors)
    15 * Windows Phone 8.x
    16 
    17 
    18 Requirements
    19 ------------
    20 
    21 * Microsoft Visual C++ (aka Visual Studio), either 2013 or 2012 versions
    22   - Free, "Community" or "Express" editions may be used, so long as they
    23     include  support for either "Windows Store" or "Windows Phone" apps.
    24     "Express" versions marked as supporting "Windows Desktop" development
    25     typically do not include support for creating WinRT apps, to note.
    26     (The "Community" edition of Visual C++ 2013 does, however, support both
    27     desktop/Win32 and WinRT development).
    28   - Visual C++ 2012 can only build apps that target versions 8.0 of Windows,
    29     or  Windows Phone.  8.0-targetted apps will run on devices running 8.1
    30     editions of Windows, however they will not be able to take advantage of
    31     8.1-specific features.
    32   - Visual C++ 2013 cannot create app projects that target Windows 8.0.
    33     Visual C++ 2013 Update 4, can create app projects for Windows Phone 8.0,
    34     Windows Phone 8.1, and Windows 8.1, but not Windows 8.0.  An optional
    35     Visual Studio add-in, "Tools for Maintaining Store apps for Windows 8",
    36     allows Visual C++ 2013 to load and build Windows 8.0 projects that were
    37     created with Visual C++ 2012, so long as Visual C++ 2012 is installed
    38     on the same machine.  More details on targeting different versions of
    39     Windows can found at the following web pages:
    40       - [Develop apps by using Visual Studio 2013](http://msdn.microsoft.com/en-us/library/windows/apps/br211384.aspx)
    41       - [To add the Tools for Maintaining Store apps for Windows 8](http://msdn.microsoft.com/en-us/library/windows/apps/dn263114.aspx#AddMaintenanceTools)
    42 * A valid Microsoft account - This requirement is not imposed by SDL, but
    43   rather by Microsoft's Visual C++ toolchain.  This is required to launch or 
    44   debug apps.
    45 
    46 
    47 Status
    48 ------
    49 
    50 Here is a rough list of what works, and what doens't:
    51 
    52 * What works:
    53   * compilation via Visual C++ 2012 and 2013
    54   * compile-time platform detection for SDL programs.  The C/C++ #define,
    55     `__WINRT__`, will be set to 1 (by SDL) when compiling for WinRT.
    56   * GPU-accelerated 2D rendering, via SDL_Renderer.
    57   * software rendering, via either SDL_Surface (optionally in conjunction with
    58     SDL_GetWindowSurface() and SDL_UpdateWindowSurface()) or via the
    59     SDL_Renderer APIs
    60   * threads.  Significant chunks of Win32's threading APIs are not available in
    61     WinRT.  A new, SDL threading backend was built using C++11's threading APIs
    62     (std::thread, std::mutex, std::condition_variable, etc.), which C or C++
    63     programs alike can access via SDL's threading APIs.  Support for thread
    64     priorities is not, however, currently available, due to restrictions in
    65     WinRT's own API set.
    66   * timers (via SDL_GetTicks(), SDL_AddTimer(), SDL_GetPerformanceCounter(),
    67     SDL_GetPerformanceFrequency(), etc.)
    68   * file I/O via SDL_RWops
    69   * mouse input  (unsupported on Windows Phone)
    70   * audio, via a modified version of SDL's XAudio2 backend
    71   * .DLL file loading.  Libraries must be packaged inside applications.  Loading
    72     anything outside of the app is not supported.
    73   * system path retrieval via SDL's filesystem APIs
    74   * game controllers.  Support is provided via the SDL_Joystick and
    75     SDL_GameController APIs, and is backed by Microsoft's XInput API.
    76   * multi-touch input
    77   * app events.  SDL_APP_WILLENTER* and SDL_APP_DIDENTER* events get sent out as
    78     appropriate.
    79   * window events.  SDL_WINDOWEVENT_MINIMIZED and SDL_WINDOWEVENT_RESTORED are
    80     sent out on app suspend and resume, respectively.  SDL_WINDOWEVENT_SHOWN and
    81     SDL_WINDOWEVENT_HIDDEN are also sent, but not necessarily on app suspend or
    82     resume, as WinRT treats these two concepts differently..
    83   * using Direct3D 11.x APIs outside of SDL.  Non-XAML / Direct3D-only apps can
    84     choose to render content directly via Direct3D, using SDL to manage the
    85     internal WinRT window, as well as input and audio.  (Use
    86     SDL_GetWindowWMInfo() to get the WinRT 'CoreWindow', and pass it into
    87     IDXGIFactory2::CreateSwapChainForCoreWindow() as appropriate.)
    88 
    89 * What partially works:
    90   * keyboard input.  Most of WinRT's documented virtual keys are supported, as
    91     well as many keys with documented hardware scancodes.
    92   * OpenGL.  Experimental support for OpenGL ES 2 is available via the ANGLE
    93     project, using either MS Open Technologies' repository, at 
    94     https://github.com/msopentech/angle (both the "winrt" and "future-dev"
    95     branches are supported), or the official ANGLE repository, at
    96     https://chromium.googlesource.com/angle/angle
    97   * SDLmain.  WinRT uses a different signature for each app's main() function.
    98     SDL-based apps that use this port must compile in SDL_winrt_main_NonXAML.cpp
    99     (in `SDL\src\main\winrt\`) directly in order for their C-style main()
   100     functions to be called.
   101   * XAML interoperability.  This feature is currently experimental (there are
   102     **many** known bugs in this, at present!), preliminary, and only for
   103     Windows 8.x/RT at the moment.  Windows Phone + XAML support is still
   104     pending.
   105 
   106 * What doesn't work:
   107   * compilation with anything other than Visual C++ 2012 or 2013
   108   * programmatically-created custom cursors.  These don't appear to be supported
   109     by WinRT.  Different OS-provided cursors can, however, be created via
   110     SDL_CreateSystemCursor() (unsupported on Windows Phone)
   111   * SDL_WarpMouseInWindow() or SDL_WarpMouseGlobal().  This are not currently
   112     supported by WinRT itself.
   113   * joysticks and game controllers that aren't supported by Microsoft's XInput
   114     API.
   115   * probably anything else that's not listed as supported
   116 
   117 
   118 
   119 Caveats
   120 -------
   121 
   122 #### SDL_GetPrefPath() usage
   123 
   124 SDL_GetPrefPath() is available for use in WinRT apps, however the following
   125 should be noted:
   126 
   127 1. It will return different path types, by default, depending on the WinRT
   128    platform.  Windows Phone apps will default to using the app's "local" path,
   129    whereas Windows Store (i.e. non-Phone) apps will default to using the app's
   130    "roaming" path.  This behavior can be changed by calling SDL_SetHint() with
   131    the key, SDL_HINT_WINRT_PREF_PATH_ROOT, and a value of either "local" or
   132    "roaming".
   133 
   134 2. Windows Phone 8.0 does not provide apps access to a "roaming" folder.
   135    Attempts to make SDL_GetPrefPath() return a roaming folder on Windows
   136    Phone 8.0 will be ignored (and a path inside the "local" folder will be
   137    used instead).
   138 
   139 Further details on this can be found in the documentation for
   140 SDL_HINT_WINRT_PREF_PATH_ROOT, in SDL_hints.h, as well as the docs for
   141 SDL_WinRT_Path, SDL_WinRTGetFSPathUNICODE, and SDL_WinRTGetFSPathUTF8,
   142 in SDL_system.h.
   143 
   144 
   145 
   146 Setup, High-Level Steps
   147 -----------------------
   148 
   149 The steps for setting up a project for an SDL/WinRT app looks like the
   150 following, at a high-level:
   151 
   152 1. create a new Visual C++ project using Microsoft's template for a,
   153    "Direct3D App".
   154 2. remove most of the files from the project.
   155 3. make your app's project directly reference SDL/WinRT's own Visual C++
   156    project file, via use of Visual C++'s "References" dialog.  This will setup
   157    the linker, and will copy SDL's .dll files to your app's final output.
   158 4. adjust your app's build settings, at minimum, telling it where to find SDL's
   159    header files.
   160 5. add a file that contains a WinRT-appropriate main function.
   161 6. add SDL-specific app code.
   162 7. build and run your app.
   163 
   164 
   165 Setup, Detailed Steps
   166 ---------------------
   167 
   168 ### 1. Create a new project ###
   169 
   170 Create a new project using one of Visual C++'s templates for a plain, non-XAML,
   171 "Direct3D App" (XAML support for SDL/WinRT is not yet ready for use).  If you
   172 don't see one of these templates, in Visual C++'s 'New Project' dialog, try
   173 using the textbox titled, 'Search Installed Templates' to look for one.
   174 
   175 
   176 ### 2. Remove unneeded files from the project ###
   177 
   178 In the new project, delete any file that has one of the following extensions:
   179 
   180 - .cpp
   181 - .h
   182 - .hlsl
   183 
   184 When you are done, you should be left with a few files, each of which will be a
   185 necessary part of your app's project.  These files will consist of:
   186 
   187 - an .appxmanifest file, which contains metadata on your WinRT app.  This is
   188   similar to an Info.plist file on iOS, or an AndroidManifest.xml on Android.
   189 - a few .png files, one of which is a splash screen (displayed when your app
   190   launches), others are app icons.
   191 - a .pfx file, used for code signing purposes.
   192 
   193 
   194 ### 3. Add references to SDL's project files ###
   195 
   196 SDL/WinRT can be built in multiple variations, spanning across three different
   197 CPU architectures (x86, x64, and ARM) and two different configurations
   198 (Debug and Release).  WinRT and Visual C++ do not currently provide a means
   199 for combining multiple variations of one library into a single file.
   200 Furthermore, it does not provide an easy means for copying pre-built .dll files
   201 into your app's final output (via Post-Build steps, for example).  It does,
   202 however, provide a system whereby an app can reference the MSVC projects of
   203 libraries such that, when the app is built:
   204 
   205 1. each library gets built for the appropriate CPU architecture(s) and WinRT
   206    platform(s).
   207 2. each library's output, such as .dll files, get copied to the app's build 
   208    output.
   209 
   210 To set this up for SDL/WinRT, you'll need to run through the following steps:
   211 
   212 1. open up the Solution Explorer inside Visual C++ (under the "View" menu, then
   213    "Solution Explorer")
   214 2. right click on your app's solution.
   215 3. navigate to "Add", then to "Existing Project..."
   216 4. find SDL/WinRT's Visual C++ project file and open it.  Different project
   217    files exist for different WinRT platforms.  All of them are in SDL's
   218    source distribution, in the following directories:
   219     * `VisualC-WinRT/WinPhone80_VS2012/` - for Windows Phone 8.0 apps
   220     * `VisualC-WinRT/WinPhone81_VS2013/` - for Windows Phone 8.1 apps
   221     * `VisualC-WinRT/WinRT80_VS2012/` - for Windows 8.0 apps
   222     * `VisualC-WinRT/WinRT81_VS2013/` - for Windows 8.1 apps
   223 5. once the project has been added, right-click on your app's project and
   224    select, "References..."
   225 6. click on the button titled, "Add New Reference..."
   226 7. check the box next to SDL
   227 8. click OK to close the dialog
   228 9. SDL will now show up in the list of references.  Click OK to close that
   229    dialog.
   230 
   231 Your project is now linked to SDL's project, insofar that when the app is
   232 built, SDL will be built as well, with its build output getting included with
   233 your app.
   234 
   235 
   236 ### 4. Adjust Your App's Build Settings ###
   237 
   238 Some build settings need to be changed in your app's project.  This guide will
   239 outline the following:
   240 
   241 - making sure that the compiler knows where to find SDL's header files
   242 - **Optional for C++, but NECESSARY for compiling C code:** telling the
   243   compiler not to use Microsoft's C++ extensions for WinRT development.
   244 - **Optional:** telling the compiler not generate errors due to missing
   245   precompiled header files.
   246 
   247 To change these settings:
   248 
   249 1. right-click on the project
   250 2. choose "Properties"
   251 3. in the drop-down box next to "Configuration", choose, "All Configurations"
   252 4. in the drop-down box next to "Platform", choose, "All Platforms"
   253 5. in the left-hand list, expand the "C/C++" section
   254 6. select "General"
   255 7. edit the "Additional Include Directories" setting, and add a path to SDL's
   256    "include" directory
   257 8. **Optional: to enable compilation of C code:** change the setting for
   258    "Consume Windows Runtime Extension" from "Yes (/ZW)" to "No".  If you're 
   259    working with a completely C++ based project, this step can usually be 
   260    omitted.
   261 9. **Optional: to disable precompiled headers (which can produce 
   262    'stdafx.h'-related build errors, if setup incorrectly:** in the left-hand 
   263    list, select "Precompiled Headers", then change the setting for "Precompiled 
   264    Header" from "Use (/Yu)" to "Not Using Precompiled Headers".
   265 10. close the dialog, saving settings, by clicking the "OK" button
   266 
   267 
   268 ### 5. Add a WinRT-appropriate main function to the app. ###
   269 
   270 C/C++-based WinRT apps do contain a `main` function that the OS will invoke when 
   271 the app starts launching. The parameters of WinRT main functions are different 
   272 than those found on other platforms, Win32 included.  SDL/WinRT provides a 
   273 platform-appropriate main function that will perform these actions, setup key 
   274 portions of the app, then invoke a classic, C/C++-style main function (that take 
   275 in "argc" and "argv" parameters).  The code for this file is contained inside 
   276 SDL's source distribution, under `src/main/winrt/SDL_winrt_main_NonXAML.cpp`.  
   277 You'll need to add this file, or a copy of it, to your app's project, and make 
   278 sure it gets compiled using a Microsoft-specific set of C++ extensions called 
   279 C++/CX.
   280 
   281 **NOTE: C++/CX compilation is currently required in at least one file of your 
   282 app's project.  This is to make sure that Visual C++'s linker builds a 'Windows 
   283 Metadata' file (.winmd) for your app.  Not doing so can lead to build errors.**
   284 
   285 To include `SDL_winrt_main_NonXAML.cpp`:
   286 
   287 1. right-click on your project (again, in Visual C++'s Solution Explorer), 
   288    navigate to "Add", then choose "Existing Item...".
   289 2. open `SDL_winrt_main_NonXAML.cpp`, which is found inside SDL's source 
   290    distribution, under `src/main/winrt/`.  Make sure that the open-file dialog 
   291    closes, either by double-clicking on the file, or single-clicking on it and 
   292    then clicking Add.
   293 3. right-click on the file (as listed in your project), then click on 
   294    "Properties...".
   295 4. in the drop-down box next to "Configuration", choose, "All Configurations"
   296 5. in the drop-down box next to "Platform", choose, "All Platforms"
   297 6. in the left-hand list, click on "C/C++"
   298 7. change the setting for "Consume Windows Runtime Extension" to "Yes (/ZW)".
   299 8. click the OK button.  This will close the dialog.
   300 
   301 
   302 ### 6. Add app code and assets ###
   303 
   304 At this point, you can add in SDL-specific source code.  Be sure to include a 
   305 C-style main function (ie: `int main(int argc, char *argv[])`).  From there you 
   306 should be able to create a single `SDL_Window` (WinRT apps can only have one 
   307 window, at present), as well as an `SDL_Renderer`.  Direct3D will be used to 
   308 draw content.  Events are received via SDL's usual event functions 
   309 (`SDL_PollEvent`, etc.)  If you have a set of existing source files and assets, 
   310 you can start adding them to the project now.  If not, or if you would like to 
   311 make sure that you're setup correctly, some short and simple sample code is 
   312 provided below.
   313 
   314 
   315 #### 6.A. ... when creating a new app ####
   316 
   317 If you are creating a new app (rather than porting an existing SDL-based app), 
   318 or if you would just like a simple app to test SDL/WinRT with before trying to 
   319 get existing code working, some working SDL/WinRT code is provided below.  To 
   320 set this up:
   321 
   322 1. right click on your app's project
   323 2. select Add, then New Item.  An "Add New Item" dialog will show up.
   324 3. from the left-hand list, choose "Visual C++"
   325 4. from the middle/main list, choose "C++ File (.cpp)"
   326 5. near the bottom of the dialog, next to "Name:", type in a name for your 
   327 source file, such as, "main.cpp".
   328 6. click on the Add button.  This will close the dialog, add the new file to 
   329 your project, and open the file in Visual C++'s text editor.
   330 7. Copy and paste the following code into the new file, then save it.
   331 
   332 
   333     #include <SDL.h>
   334     
   335     int main(int argc, char **argv)
   336     {
   337         SDL_DisplayMode mode;
   338         SDL_Window * window = NULL;
   339         SDL_Renderer * renderer = NULL;
   340         SDL_Event evt;
   341     
   342         if (SDL_Init(SDL_INIT_VIDEO) != 0) {
   343             return 1;
   344         }
   345     
   346         if (SDL_GetCurrentDisplayMode(0, &mode) != 0) {
   347             return 1;
   348         }
   349     
   350         if (SDL_CreateWindowAndRenderer(mode.w, mode.h, SDL_WINDOW_FULLSCREEN, &window, &renderer) != 0) {
   351             return 1;
   352         }
   353     
   354         while (1) {
   355             while (SDL_PollEvent(&evt)) {
   356             }
   357     
   358             SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
   359             SDL_RenderClear(renderer);
   360             SDL_RenderPresent(renderer);
   361         }
   362     }
   363 
   364 
   365 #### 6.B. Adding code and assets ####
   366 
   367 If you have existing code and assets that you'd like to add, you should be able 
   368 to add them now.  The process for adding a set of files is as such.
   369 
   370 1. right click on the app's project
   371 2. select Add, then click on "New Item..."
   372 3. open any source, header, or asset files as appropriate.  Support for C and 
   373 C++ is available.
   374 
   375 Do note that WinRT only supports a subset of the APIs that are available to 
   376 Win32-based apps.  Many portions of the Win32 API and the C runtime are not 
   377 available.
   378 
   379 A list of unsupported C APIs can be found at 
   380 <http://msdn.microsoft.com/en-us/library/windows/apps/jj606124.aspx>
   381 
   382 General information on using the C runtime in WinRT can be found at 
   383 <http://msdn.microsoft.com/en-us/LIBRARY/hh972425(v=vs.110).aspx>
   384 
   385 A list of supported Win32 APIs for Windows 8/RT apps can be found at 
   386 <http://msdn.microsoft.com/en-us/library/windows/apps/br205757.aspx>.  To note, 
   387 the list of supported Win32 APIs for Windows Phone 8 development is different.  
   388 That list can be found at 
   389 <http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj662956(v=vs.105).aspx>
   390 
   391 
   392 ### 7. Build and run your app ###
   393 
   394 Your app project should now be setup, and you should be ready to build your app.  
   395 To run it on the local machine, open the Debug menu and choose "Start 
   396 Debugging".  This will build your app, then run your app full-screen.  To switch 
   397 out of your app, press the Windows key.  Alternatively, you can choose to run 
   398 your app in a window.  To do this, before building and running your app, find 
   399 the drop-down menu in Visual C++'s toolbar that says, "Local Machine".  Expand 
   400 this by clicking on the arrow on the right side of the list, then click on 
   401 Simulator.  Once you do that, any time you build and run the app, the app will 
   402 launch in window, rather than full-screen.
   403 
   404 
   405 #### 7.A. Running apps on ARM-based devices ####
   406 
   407 To build and run the app on ARM-based, "Windows RT" devices, you'll need to:
   408 
   409 - install Microsoft's "Remote Debugger" on the device.  Visual C++ installs and 
   410   debugs ARM-based apps via IP networks.
   411 - change a few options on the development machine, both to make sure it builds 
   412   for ARM (rather than x86 or x64), and to make sure it knows how to find the 
   413   Windows RT device (on the network).
   414 
   415 Microsoft's Remote Debugger can be found at 
   416 <http://msdn.microsoft.com/en-us/library/vstudio/bt727f1t.aspx>.  Please note 
   417 that separate versions of this debugger exist for different versions of Visual 
   418 C++, one for debugging with MSVC 2012, another for debugging with MSVC 2013.
   419 
   420 To setup Visual C++ to launch your app on an ARM device:
   421 
   422 1. make sure the Remote Debugger is running on your ARM device, and that it's on 
   423    the same IP network as your development machine.
   424 2. from Visual C++'s toolbar, find a drop-down menu that says, "Win32".  Click 
   425    it, then change the value to "ARM".
   426 3. make sure Visual C++ knows the hostname or IP address of the ARM device.  To 
   427    do this:
   428     1. open the app project's properties
   429     2. select "Debugging"
   430     3. next to "Machine Name", enter the hostname or IP address of the ARM 
   431        device
   432     4. if, and only if, you've turned off authentication in the Remote Debugger,
   433        then change the setting for "Require Authentication" to No
   434     5. click "OK"
   435 4. build and run the app (from Visual C++).  The first time you do this, a 
   436    prompt will show up on the ARM device, asking for a Microsoft Account.  You 
   437    do, unfortunately, need to log in here, and will need to follow the 
   438    subsequent registration steps in order to launch the app.  After you do so, 
   439    if the app didn't already launch, try relaunching it again from within Visual 
   440    C++.
   441 
   442 
   443 Troubleshooting
   444 ---------------
   445 
   446 #### Build fails with message, "error LNK2038: mismatch detected for 'vccorlib_lib_should_be_specified_before_msvcrt_lib_to_linker'"
   447 
   448 Try adding the following to your linker flags.  In MSVC, this can be done by
   449 right-clicking on the app project, navigating to Configuration Properties ->
   450 Linker -> Command Line, then adding them to the Additional Options
   451 section.
   452 
   453 * For Release builds / MSVC-Configurations, add:
   454 
   455     /nodefaultlib:vccorlib /nodefaultlib:msvcrt vccorlib.lib msvcrt.lib
   456 
   457 * For Debug builds / MSVC-Configurations, add:
   458 
   459     /nodefaultlib:vccorlibd /nodefaultlib:msvcrtd vccorlibd.lib msvcrtd.lib
   460