This port allows SDL applications to run on Microsoft's platforms that require use of “Windows Runtime”, aka. “WinRT”, APIs. WinRT apps are currently full-screen only, and run in what Microsoft sometimes refers to as their “Modern” (formerly, “Metro”), environment. For Windows 8.x, Microsoft may also refer to them as “Windows Store” apps, due to them being distributed, primarily, via a Microsoft-run online store (of the same name).
Some of the operating systems that include WinRT, are:
Here is a rough list of what works, and what doens't:
What works:
__WINRT__
, will be set to 1 (by SDL) when compiling for WinRT.What partially works:
SDL\src\main\winrt\
) directly in order for their C-style main() functions to be called.What doesn't work:
SDL 2.0.4 fixes two bugs found in the WinRT version of SDL_GetPrefPath(). The fixes may affect older, SDL 2.0.3-based apps' save data. Please note that these changes only apply to SDL-based WinRT apps, and not to apps for any other platform.
SDL_GetPrefPath() would return an invalid path, one in which the path's directory had not been created. Attempts to create files there (via fopen(), for example), would fail, unless that directory was explicitly created beforehand.
SDL_GetPrefPath(), for non-WinPhone-based apps, would return a path inside a WinRT ‘Roaming’ folder, the contents of which get automatically synchronized across multiple devices. This process can occur while an application runs, and can cause existing save-data to be overwritten at unexpected times, with data from other devices. (Windows Phone apps written with SDL 2.0.3 did not utilize a Roaming folder, due to API restrictions in Windows Phone 8.0).
SDL_GetPrefPath(), starting with SDL 2.0.4, addresses these by:
making sure that SDL_GetPrefPath() returns a directory in which data can be written to immediately, without first needing to create directories.
basing SDL_GetPrefPath() off of a different, non-Roaming folder, the contents of which do not automatically get synchronized across devices (and which require less work to use safely, in terms of data integrity).
Apps that wish to get their Roaming folder's path can do so either by using SDL_WinRTGetFSPathUTF8(), SDL_WinRTGetFSPathUNICODE() (which returns a UCS-2/wide-char string), or directly through the WinRT class, Windows.Storage.ApplicationData.
The steps for setting up a project for an SDL/WinRT app looks like the following, at a high-level:
Create a new project using one of Visual C++‘s templates for a plain, non-XAML, “Direct3D App” (XAML support for SDL/WinRT is not yet ready for use). If you don’t see one of these templates, in Visual C++'s ‘New Project’ dialog, try using the textbox titled, ‘Search Installed Templates’ to look for one.
In the new project, delete any file that has one of the following extensions:
When you are done, you should be left with a few files, each of which will be a necessary part of your app's project. These files will consist of:
SDL/WinRT can be built in multiple variations, spanning across three different CPU architectures (x86, x64, and ARM) and two different configurations (Debug and Release). WinRT and Visual C++ do not currently provide a means for combining multiple variations of one library into a single file. Furthermore, it does not provide an easy means for copying pre-built .dll files into your app's final output (via Post-Build steps, for example). It does, however, provide a system whereby an app can reference the MSVC projects of libraries such that, when the app is built:
To set this up for SDL/WinRT, you'll need to run through the following steps:
VisualC-WinRT/UWP_VS2015/
- for Windows 10 / UWP appsVisualC-WinRT/WinPhone81_VS2013/
- for Windows Phone 8.1 appsVisualC-WinRT/WinRT80_VS2012/
- for Windows 8.0 appsVisualC-WinRT/WinRT81_VS2013/
- for Windows 8.1 appsYour project is now linked to SDL's project, insofar that when the app is built, SDL will be built as well, with its build output getting included with your app.
Some build settings need to be changed in your app's project. This guide will outline the following:
To change these settings:
C/C++-based WinRT apps do contain a main
function that the OS will invoke when the app starts launching. The parameters of WinRT main functions are different than those found on other platforms, Win32 included. SDL/WinRT provides a platform-appropriate main function that will perform these actions, setup key portions of the app, then invoke a classic, C/C++-style main function (that take in “argc” and “argv” parameters). The code for this file is contained inside SDL‘s source distribution, under src/main/winrt/SDL_winrt_main_NonXAML.cpp
.
You’ll need to add this file, or a copy of it, to your app's project, and make sure it gets compiled using a Microsoft-specific set of C++ extensions called C++/CX.
NOTE: C++/CX compilation is currently required in at least one file of your app's project. This is to make sure that Visual C++'s linker builds a ‘Windows Metadata’ file (.winmd) for your app. Not doing so can lead to build errors.
To include SDL_winrt_main_NonXAML.cpp
:
SDL_winrt_main_NonXAML.cpp
, which is found inside SDL's source distribution, under src/main/winrt/
. Make sure that the open-file dialog closes, either by double-clicking on the file, or single-clicking on it and then clicking Add.At this point, you can add in SDL-specific source code. Be sure to include a C-style main function (ie: int main(int argc, char *argv[])
). From there you should be able to create a single SDL_Window
(WinRT apps can only have one window, at present), as well as an SDL_Renderer
. Direct3D will be used to draw content. Events are received via SDL‘s usual event functions (SDL_PollEvent
, etc.) If you have a set of existing source files and assets, you can start adding them to the project now. If not, or if you would like to make sure that you’re setup correctly, some short and simple sample code is provided below.
If you are creating a new app (rather than porting an existing SDL-based app), or if you would just like a simple app to test SDL/WinRT with before trying to get existing code working, some working SDL/WinRT code is provided below. To set this up:
right click on your app's project
select Add, then New Item. An “Add New Item” dialog will show up.
from the left-hand list, choose “Visual C++”
from the middle/main list, choose “C++ File (.cpp)”
near the bottom of the dialog, next to “Name:”, type in a name for your source file, such as, “main.cpp”.
click on the Add button. This will close the dialog, add the new file to your project, and open the file in Visual C++'s text editor.
Copy and paste the following code into the new file, then save it.
#include <SDL.h>
int main(int argc, char **argv) { SDL_DisplayMode mode; SDL_Window * window = NULL; SDL_Renderer * renderer = NULL; SDL_Event evt;
if (SDL_Init(SDL_INIT_VIDEO) != 0) { return 1; } if (SDL_GetCurrentDisplayMode(0, &mode) != 0) { return 1; } if (SDL_CreateWindowAndRenderer(mode.w, mode.h, SDL_WINDOW_FULLSCREEN, &window, &renderer) != 0) { return 1; } while (1) { while (SDL_PollEvent(&evt)) { } SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255); SDL_RenderClear(renderer); SDL_RenderPresent(renderer); }
}
If you have existing code and assets that you'd like to add, you should be able to add them now. The process for adding a set of files is as such.
Do note that WinRT only supports a subset of the APIs that are available to Win32-based apps. Many portions of the Win32 API and the C runtime are not available.
A list of unsupported C APIs can be found at http://msdn.microsoft.com/en-us/library/windows/apps/jj606124.aspx
General information on using the C runtime in WinRT can be found at https://msdn.microsoft.com/en-us/library/hh972425.aspx
A list of supported Win32 APIs for WinRT apps can be found at http://msdn.microsoft.com/en-us/library/windows/apps/br205757.aspx. To note, the list of supported Win32 APIs for Windows Phone 8.0 is different.
That list can be found at http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj662956(v=vs.105).aspx
Your app project should now be setup, and you should be ready to build your app.
To run it on the local machine, open the Debug menu and choose “Start Debugging”. This will build your app, then run your app full-screen. To switch out of your app, press the Windows key. Alternatively, you can choose to run your app in a window. To do this, before building and running your app, find the drop-down menu in Visual C++'s toolbar that says, “Local Machine”. Expand this by clicking on the arrow on the right side of the list, then click on Simulator. Once you do that, any time you build and run the app, the app will launch in window, rather than full-screen.
These instructions do not include Windows Phone, despite Windows Phone typically running on ARM processors. They are specifically for devices that use the “Windows RT” operating system, which was a modified version of Windows 8.x that ran primarily on ARM-based tablet computers.
To build and run the app on ARM-based, “Windows RT” devices, you'll need to:
Microsoft's Remote Debugger can be found at https://msdn.microsoft.com/en-us/library/hh441469.aspx. Please note that separate versions of this debugger exist for different versions of Visual C++, one each for MSVC 2015, 2013, and 2012.
To setup Visual C++ to launch your app on an ARM device:
Try adding the following to your linker flags. In MSVC, this can be done by right-clicking on the app project, navigating to Configuration Properties -> Linker -> Command Line, then adding them to the Additional Options section.
For Release builds / MSVC-Configurations, add:
/nodefaultlib:vccorlib /nodefaultlib:msvcrt vccorlib.lib msvcrt.lib
For Debug builds / MSVC-Configurations, add:
/nodefaultlib:vccorlibd /nodefaultlib:msvcrtd vccorlibd.lib msvcrtd.lib