SDL  2.0
docs/README-winrt.md
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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 10, via its Universal Windows Platform (UWP) APIs
14 * Windows 8.x
15 * Windows RT 8.x (aka. Windows 8.x for ARM processors)
16 * Windows Phone 8.x
17 
18 
19 Requirements
20 ------------
21 
22 * Microsoft Visual C++ (aka Visual Studio), either 2015, 2013, or 2012
23  - Free, "Community" or "Express" editions may be used, so long as they
24  include support for either "Windows Store" or "Windows Phone" apps.
25  "Express" versions marked as supporting "Windows Desktop" development
26  typically do not include support for creating WinRT apps, to note.
27  (The "Community" editions of Visual C++ do, however, support both
28  desktop/Win32 and WinRT development).
29  - Visual C++ 2012 can only build apps that target versions 8.0 of Windows,
30  or Windows Phone. 8.0-targetted apps will run on devices running 8.1
31  editions of Windows, however they will not be able to take advantage of
32  8.1-specific features.
33  - Visual C++ 2013 cannot create app projects that target Windows 8.0.
34  Visual C++ 2013 Update 4, can create app projects for Windows Phone 8.0,
35  Windows Phone 8.1, and Windows 8.1, but not Windows 8.0. An optional
36  Visual Studio add-in, "Tools for Maintaining Store apps for Windows 8",
37  allows Visual C++ 2013 to load and build Windows 8.0 projects that were
38  created with Visual C++ 2012, so long as Visual C++ 2012 is installed
39  on the same machine. More details on targeting different versions of
40  Windows can found at the following web pages:
41  - [Develop apps by using Visual Studio 2013](http://msdn.microsoft.com/en-us/library/windows/apps/br211384.aspx)
42  - [To add the Tools for Maintaining Store apps for Windows 8](http://msdn.microsoft.com/en-us/library/windows/apps/dn263114.aspx#AddMaintenanceTools)
43 * A valid Microsoft account - This requirement is not imposed by SDL, but
44  rather by Microsoft's Visual C++ toolchain. This is required to launch or
45  debug apps.
46 
47 
48 Status
49 ------
50 
51 Here is a rough list of what works, and what doens't:
52 
53 * What works:
54  * compilation via Visual C++ 2012 through 2015
55  * compile-time platform detection for SDL programs. The C/C++ #define,
56  `__WINRT__`, will be set to 1 (by SDL) when compiling for WinRT.
57  * GPU-accelerated 2D rendering, via SDL_Renderer.
58  * OpenGL ES 2, via the ANGLE library (included separately from SDL)
59  * software rendering, via either SDL_Surface (optionally in conjunction with
60  SDL_GetWindowSurface() and SDL_UpdateWindowSurface()) or via the
61  SDL_Renderer APIs
62  * threads
63  * timers (via SDL_GetTicks(), SDL_AddTimer(), SDL_GetPerformanceCounter(),
64  SDL_GetPerformanceFrequency(), etc.)
65  * file I/O via SDL_RWops
66  * mouse input (unsupported on Windows Phone)
67  * audio, via a modified version of SDL's XAudio2 backend
68  * .DLL file loading. Libraries *MUST* be packaged inside applications. Loading
69  anything outside of the app is not supported.
70  * system path retrieval via SDL's filesystem APIs
71  * game controllers. Support is provided via the SDL_Joystick and
72  SDL_GameController APIs, and is backed by Microsoft's XInput API.
73  * multi-touch input
74  * app events. SDL_APP_WILLENTER* and SDL_APP_DIDENTER* events get sent out as
75  appropriate.
76  * window events
77  * using Direct3D 11.x APIs outside of SDL. Non-XAML / Direct3D-only apps can
78  choose to render content directly via Direct3D, using SDL to manage the
79  internal WinRT window, as well as input and audio. (Use
80  SDL_GetWindowWMInfo() to get the WinRT 'CoreWindow', and pass it into
81  IDXGIFactory2::CreateSwapChainForCoreWindow() as appropriate.)
82 
83 * What partially works:
84  * keyboard input. Most of WinRT's documented virtual keys are supported, as
85  well as many keys with documented hardware scancodes.
86  * SDLmain. WinRT uses a different signature for each app's main() function.
87  SDL-based apps that use this port must compile in SDL_winrt_main_NonXAML.cpp
88  (in `SDL\src\main\winrt\`) directly in order for their C-style main()
89  functions to be called.
90 
91 * What doesn't work:
92  * compilation with anything other than Visual C++
93  * programmatically-created custom cursors. These don't appear to be supported
94  by WinRT. Different OS-provided cursors can, however, be created via
95  SDL_CreateSystemCursor() (unsupported on Windows Phone)
96  * SDL_WarpMouseInWindow() or SDL_WarpMouseGlobal(). This are not currently
97  supported by WinRT itself.
98  * joysticks and game controllers that aren't supported by Microsoft's XInput
99  API.
100  * turning off VSync when rendering on Windows Phone. Attempts to turn VSync
101  off on Windows Phone result either in Direct3D not drawing anything, or it
102  forcing VSync back on. As such, SDL_RENDERER_PRESENTVSYNC will always get
103  turned-on on Windows Phone. This limitation is not present in non-Phone
104  WinRT (such as Windows 8.x), where turning off VSync appears to work.
105  * probably anything else that's not listed as supported
106 
107 
108 
109 Upgrade Notes
110 -------------
111 
112 #### SDL_GetPrefPath() usage when upgrading WinRT apps from SDL 2.0.3
113 
114 SDL 2.0.4 fixes two bugs found in the WinRT version of SDL_GetPrefPath().
115 The fixes may affect older, SDL 2.0.3-based apps' save data. Please note
116 that these changes only apply to SDL-based WinRT apps, and not to apps for
117 any other platform.
118 
119 1. SDL_GetPrefPath() would return an invalid path, one in which the path's
120  directory had not been created. Attempts to create files there
121  (via fopen(), for example), would fail, unless that directory was
122  explicitly created beforehand.
123 
124 2. SDL_GetPrefPath(), for non-WinPhone-based apps, would return a path inside
125  a WinRT 'Roaming' folder, the contents of which get automatically
126  synchronized across multiple devices. This process can occur while an
127  application runs, and can cause existing save-data to be overwritten
128  at unexpected times, with data from other devices. (Windows Phone apps
129  written with SDL 2.0.3 did not utilize a Roaming folder, due to API
130  restrictions in Windows Phone 8.0).
131 
132 
133 SDL_GetPrefPath(), starting with SDL 2.0.4, addresses these by:
134 
135 1. making sure that SDL_GetPrefPath() returns a directory in which data
136  can be written to immediately, without first needing to create directories.
137 
138 2. basing SDL_GetPrefPath() off of a different, non-Roaming folder, the
139  contents of which do not automatically get synchronized across devices
140  (and which require less work to use safely, in terms of data integrity).
141 
142 Apps that wish to get their Roaming folder's path can do so either by using
143 SDL_WinRTGetFSPathUTF8(), SDL_WinRTGetFSPathUNICODE() (which returns a
144 UCS-2/wide-char string), or directly through the WinRT class,
145 Windows.Storage.ApplicationData.
146 
147 
148 
149 Setup, High-Level Steps
150 -----------------------
151 
152 The steps for setting up a project for an SDL/WinRT app looks like the
153 following, at a high-level:
154 
155 1. create a new Visual C++ project using Microsoft's template for a,
156  "Direct3D App".
157 2. remove most of the files from the project.
158 3. make your app's project directly reference SDL/WinRT's own Visual C++
159  project file, via use of Visual C++'s "References" dialog. This will setup
160  the linker, and will copy SDL's .dll files to your app's final output.
161 4. adjust your app's build settings, at minimum, telling it where to find SDL's
162  header files.
163 5. add a file that contains a WinRT-appropriate main function.
164 6. add SDL-specific app code.
165 7. build and run your app.
166 
167 
168 Setup, Detailed Steps
169 ---------------------
170 
171 ### 1. Create a new project ###
172 
173 Create a new project using one of Visual C++'s templates for a plain, non-XAML,
174 "Direct3D App" (XAML support for SDL/WinRT is not yet ready for use). If you
175 don't see one of these templates, in Visual C++'s 'New Project' dialog, try
176 using the textbox titled, 'Search Installed Templates' to look for one.
177 
178 
179 ### 2. Remove unneeded files from the project ###
180 
181 In the new project, delete any file that has one of the following extensions:
182 
183 - .cpp
184 - .h
185 - .hlsl
186 
187 When you are done, you should be left with a few files, each of which will be a
188 necessary part of your app's project. These files will consist of:
189 
190 - an .appxmanifest file, which contains metadata on your WinRT app. This is
191  similar to an Info.plist file on iOS, or an AndroidManifest.xml on Android.
192 - a few .png files, one of which is a splash screen (displayed when your app
193  launches), others are app icons.
194 - a .pfx file, used for code signing purposes.
195 
196 
197 ### 3. Add references to SDL's project files ###
198 
199 SDL/WinRT can be built in multiple variations, spanning across three different
200 CPU architectures (x86, x64, and ARM) and two different configurations
201 (Debug and Release). WinRT and Visual C++ do not currently provide a means
202 for combining multiple variations of one library into a single file.
203 Furthermore, it does not provide an easy means for copying pre-built .dll files
204 into your app's final output (via Post-Build steps, for example). It does,
205 however, provide a system whereby an app can reference the MSVC projects of
206 libraries such that, when the app is built:
207 
208 1. each library gets built for the appropriate CPU architecture(s) and WinRT
209  platform(s).
210 2. each library's output, such as .dll files, get copied to the app's build
211  output.
212 
213 To set this up for SDL/WinRT, you'll need to run through the following steps:
214 
215 1. open up the Solution Explorer inside Visual C++ (under the "View" menu, then
216  "Solution Explorer")
217 2. right click on your app's solution.
218 3. navigate to "Add", then to "Existing Project..."
219 4. find SDL/WinRT's Visual C++ project file and open it. Different project
220  files exist for different WinRT platforms. All of them are in SDL's
221  source distribution, in the following directories:
222  * `VisualC-WinRT/UWP_VS2015/` - for Windows 10 / UWP apps
223  * `VisualC-WinRT/WinPhone81_VS2013/` - for Windows Phone 8.1 apps
224  * `VisualC-WinRT/WinRT80_VS2012/` - for Windows 8.0 apps
225  * `VisualC-WinRT/WinRT81_VS2013/` - for Windows 8.1 apps
226 5. once the project has been added, right-click on your app's project and
227  select, "References..."
228 6. click on the button titled, "Add New Reference..."
229 7. check the box next to SDL
230 8. click OK to close the dialog
231 9. SDL will now show up in the list of references. Click OK to close that
232  dialog.
233 
234 Your project is now linked to SDL's project, insofar that when the app is
235 built, SDL will be built as well, with its build output getting included with
236 your app.
237 
238 
239 ### 4. Adjust Your App's Build Settings ###
240 
241 Some build settings need to be changed in your app's project. This guide will
242 outline the following:
243 
244 - making sure that the compiler knows where to find SDL's header files
245 - **Optional for C++, but NECESSARY for compiling C code:** telling the
246  compiler not to use Microsoft's C++ extensions for WinRT development.
247 - **Optional:** telling the compiler not generate errors due to missing
248  precompiled header files.
249 
250 To change these settings:
251 
252 1. right-click on the project
253 2. choose "Properties"
254 3. in the drop-down box next to "Configuration", choose, "All Configurations"
255 4. in the drop-down box next to "Platform", choose, "All Platforms"
256 5. in the left-hand list, expand the "C/C++" section
257 6. select "General"
258 7. edit the "Additional Include Directories" setting, and add a path to SDL's
259  "include" directory
260 8. **Optional: to enable compilation of C code:** change the setting for
261  "Consume Windows Runtime Extension" from "Yes (/ZW)" to "No". If you're
262  working with a completely C++ based project, this step can usually be
263  omitted.
264 9. **Optional: to disable precompiled headers (which can produce
265  'stdafx.h'-related build errors, if setup incorrectly:** in the left-hand
266  list, select "Precompiled Headers", then change the setting for "Precompiled
267  Header" from "Use (/Yu)" to "Not Using Precompiled Headers".
268 10. close the dialog, saving settings, by clicking the "OK" button
269 
270 
271 ### 5. Add a WinRT-appropriate main function to the app. ###
272 
273 C/C++-based WinRT apps do contain a `main` function that the OS will invoke when
274 the app starts launching. The parameters of WinRT main functions are different
275 than those found on other platforms, Win32 included. SDL/WinRT provides a
276 platform-appropriate main function that will perform these actions, setup key
277 portions of the app, then invoke a classic, C/C++-style main function (that take
278 in "argc" and "argv" parameters). The code for this file is contained inside
279 SDL's source distribution, under `src/main/winrt/SDL_winrt_main_NonXAML.cpp`.
280 You'll need to add this file, or a copy of it, to your app's project, and make
281 sure it gets compiled using a Microsoft-specific set of C++ extensions called
282 C++/CX.
283 
284 **NOTE: C++/CX compilation is currently required in at least one file of your
285 app's project. This is to make sure that Visual C++'s linker builds a 'Windows
286 Metadata' file (.winmd) for your app. Not doing so can lead to build errors.**
287 
288 To include `SDL_winrt_main_NonXAML.cpp`:
289 
290 1. right-click on your project (again, in Visual C++'s Solution Explorer),
291  navigate to "Add", then choose "Existing Item...".
292 2. open `SDL_winrt_main_NonXAML.cpp`, which is found inside SDL's source
293  distribution, under `src/main/winrt/`. Make sure that the open-file dialog
294  closes, either by double-clicking on the file, or single-clicking on it and
295  then clicking Add.
296 3. right-click on the file (as listed in your project), then click on
297  "Properties...".
298 4. in the drop-down box next to "Configuration", choose, "All Configurations"
299 5. in the drop-down box next to "Platform", choose, "All Platforms"
300 6. in the left-hand list, click on "C/C++"
301 7. change the setting for "Consume Windows Runtime Extension" to "Yes (/ZW)".
302 8. click the OK button. This will close the dialog.
303 
304 
305 ### 6. Add app code and assets ###
306 
307 At this point, you can add in SDL-specific source code. Be sure to include a
308 C-style main function (ie: `int main(int argc, char *argv[])`). From there you
309 should be able to create a single `SDL_Window` (WinRT apps can only have one
310 window, at present), as well as an `SDL_Renderer`. Direct3D will be used to
311 draw content. Events are received via SDL's usual event functions
312 (`SDL_PollEvent`, etc.) If you have a set of existing source files and assets,
313 you can start adding them to the project now. If not, or if you would like to
314 make sure that you're setup correctly, some short and simple sample code is
315 provided below.
316 
317 
318 #### 6.A. ... when creating a new app ####
319 
320 If you are creating a new app (rather than porting an existing SDL-based app),
321 or if you would just like a simple app to test SDL/WinRT with before trying to
322 get existing code working, some working SDL/WinRT code is provided below. To
323 set this up:
324 
325 1. right click on your app's project
326 2. select Add, then New Item. An "Add New Item" dialog will show up.
327 3. from the left-hand list, choose "Visual C++"
328 4. from the middle/main list, choose "C++ File (.cpp)"
329 5. near the bottom of the dialog, next to "Name:", type in a name for your
330 source file, such as, "main.cpp".
331 6. click on the Add button. This will close the dialog, add the new file to
332 your project, and open the file in Visual C++'s text editor.
333 7. Copy and paste the following code into the new file, then save it.
334 
335 
336  #include <SDL.h>
337 
338  int main(int argc, char **argv)
339  {
340  SDL_DisplayMode mode;
341  SDL_Window * window = NULL;
342  SDL_Renderer * renderer = NULL;
343  SDL_Event evt;
344 
345  if (SDL_Init(SDL_INIT_VIDEO) != 0) {
346  return 1;
347  }
348 
349  if (SDL_GetCurrentDisplayMode(0, &mode) != 0) {
350  return 1;
351  }
352 
353  if (SDL_CreateWindowAndRenderer(mode.w, mode.h, SDL_WINDOW_FULLSCREEN, &window, &renderer) != 0) {
354  return 1;
355  }
356 
357  while (1) {
358  while (SDL_PollEvent(&evt)) {
359  }
360 
361  SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
362  SDL_RenderClear(renderer);
363  SDL_RenderPresent(renderer);
364  }
365  }
366 
367 
368 #### 6.B. Adding code and assets ####
369 
370 If you have existing code and assets that you'd like to add, you should be able
371 to add them now. The process for adding a set of files is as such.
372 
373 1. right click on the app's project
374 2. select Add, then click on "New Item..."
375 3. open any source, header, or asset files as appropriate. Support for C and
376 C++ is available.
377 
378 Do note that WinRT only supports a subset of the APIs that are available to
379 Win32-based apps. Many portions of the Win32 API and the C runtime are not
380 available.
381 
382 A list of unsupported C APIs can be found at
383 <http://msdn.microsoft.com/en-us/library/windows/apps/jj606124.aspx>
384 
385 General information on using the C runtime in WinRT can be found at
386 <https://msdn.microsoft.com/en-us/library/hh972425.aspx>
387 
388 A list of supported Win32 APIs for WinRT apps can be found at
389 <http://msdn.microsoft.com/en-us/library/windows/apps/br205757.aspx>. To note,
390 the list of supported Win32 APIs for Windows Phone 8.0 is different.
391 That list can be found at
392 <http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj662956(v=vs.105).aspx>
393 
394 
395 ### 7. Build and run your app ###
396 
397 Your app project should now be setup, and you should be ready to build your app.
398 To run it on the local machine, open the Debug menu and choose "Start
399 Debugging". This will build your app, then run your app full-screen. To switch
400 out of your app, press the Windows key. Alternatively, you can choose to run
401 your app in a window. To do this, before building and running your app, find
402 the drop-down menu in Visual C++'s toolbar that says, "Local Machine". Expand
403 this by clicking on the arrow on the right side of the list, then click on
404 Simulator. Once you do that, any time you build and run the app, the app will
405 launch in window, rather than full-screen.
406 
407 
408 #### 7.A. Running apps on older, ARM-based, "Windows RT" devices ####
409 
410 **These instructions do not include Windows Phone, despite Windows Phone
411 typically running on ARM processors.** They are specifically for devices
412 that use the "Windows RT" operating system, which was a modified version of
413 Windows 8.x that ran primarily on ARM-based tablet computers.
414 
415 To build and run the app on ARM-based, "Windows RT" devices, you'll need to:
416 
417 - install Microsoft's "Remote Debugger" on the device. Visual C++ installs and
418  debugs ARM-based apps via IP networks.
419 - change a few options on the development machine, both to make sure it builds
420  for ARM (rather than x86 or x64), and to make sure it knows how to find the
421  Windows RT device (on the network).
422 
423 Microsoft's Remote Debugger can be found at
424 <https://msdn.microsoft.com/en-us/library/hh441469.aspx>. Please note
425 that separate versions of this debugger exist for different versions of Visual
426 C++, one each for MSVC 2015, 2013, and 2012.
427 
428 To setup Visual C++ to launch your app on an ARM device:
429 
430 1. make sure the Remote Debugger is running on your ARM device, and that it's on
431  the same IP network as your development machine.
432 2. from Visual C++'s toolbar, find a drop-down menu that says, "Win32". Click
433  it, then change the value to "ARM".
434 3. make sure Visual C++ knows the hostname or IP address of the ARM device. To
435  do this:
436  1. open the app project's properties
437  2. select "Debugging"
438  3. next to "Machine Name", enter the hostname or IP address of the ARM
439  device
440  4. if, and only if, you've turned off authentication in the Remote Debugger,
441  then change the setting for "Require Authentication" to No
442  5. click "OK"
443 4. build and run the app (from Visual C++). The first time you do this, a
444  prompt will show up on the ARM device, asking for a Microsoft Account. You
445  do, unfortunately, need to log in here, and will need to follow the
446  subsequent registration steps in order to launch the app. After you do so,
447  if the app didn't already launch, try relaunching it again from within Visual
448  C++.
449 
450 
451 Troubleshooting
452 ---------------
453 
454 #### Build fails with message, "error LNK2038: mismatch detected for 'vccorlib_lib_should_be_specified_before_msvcrt_lib_to_linker'"
455 
456 Try adding the following to your linker flags. In MSVC, this can be done by
457 right-clicking on the app project, navigating to Configuration Properties ->
458 Linker -> Command Line, then adding them to the Additional Options
459 section.
460 
461 * For Release builds / MSVC-Configurations, add:
462 
463  /nodefaultlib:vccorlib /nodefaultlib:msvcrt vccorlib.lib msvcrt.lib
464 
465 * For Debug builds / MSVC-Configurations, add:
466 
467  /nodefaultlib:vccorlibd /nodefaultlib:msvcrtd vccorlibd.lib msvcrtd.lib
468