wasapi: Initial WASAPI support, for Windows Vista and later.

This should remain binary compatible with Windows XP, as we dynamically
load anything we need and fall back to DirectSound/WinMM/XAudio2 if not
available.

VisualC/SDL/SDL.vcxproj

@@ -361,6 +361,7 @@
     <ClInclude Include="..\..\src\video\windows\SDL_windowsshape.h" />
     <ClInclude Include="..\..\src\video\windows\SDL_windowsvideo.h" />
     <ClInclude Include="..\..\src\video\windows\SDL_windowswindow.h" />
+    <ClInclude Include="..\..\src\audio\wasapi\SDL_wasapi.h" />
     <ClInclude Include="..\..\src\audio\winmm\SDL_winmm.h" />
     <ClInclude Include="..\..\src\core\windows\SDL_xinput.h" />
     <ClInclude Include="..\..\src\haptic\windows\SDL_xinputhaptic_c.h" />
@@ -491,6 +492,7 @@
     <ClCompile Include="..\..\src\video\windows\SDL_windowsshape.c" />
     <ClCompile Include="..\..\src\video\windows\SDL_windowsvideo.c" />
     <ClCompile Include="..\..\src\video\windows\SDL_windowswindow.c" />
+    <ClCompile Include="..\..\src\audio\wasapi\SDL_wasapi.c" />
     <ClCompile Include="..\..\src\audio\winmm\SDL_winmm.c" />
     <ClCompile Include="..\..\src\audio\xaudio2\SDL_xaudio2.c" />
     <ClCompile Include="..\..\src\core\windows\SDL_xinput.c" />

VisualC/SDL/SDL_VS2008.vcproj

@@ -1437,6 +1437,14 @@
 			RelativePath="..\..\src\video\windows\SDL_windowswindow.h"
 			>
 		</File>
+		<File
+			RelativePath="..\..\src\audio\wasapi\SDL_wasapi.c"
+			>
+		</File>
+		<File
+			RelativePath="..\..\src\audio\wasapi\SDL_wasapi.h"
+			>
+		</File>
 		<File
 			RelativePath="..\..\src\audio\winmm\SDL_winmm.c"
 			>

include/SDL_config_windows.h

@@ -154,6 +154,7 @@ typedef unsigned int uintptr_t;
 #endif
 
 /* Enable various audio drivers */
+#define SDL_AUDIO_DRIVER_WASAPI 1
 #define SDL_AUDIO_DRIVER_DSOUND 1
 #define SDL_AUDIO_DRIVER_XAUDIO2    1
 #define SDL_AUDIO_DRIVER_WINMM  1

src/audio/SDL_audio.c

@@ -68,6 +68,9 @@ static const AudioBootStrap *const bootstrap[] = {
 #if SDL_AUDIO_DRIVER_NAS
     &NAS_bootstrap,
 #endif
+#if SDL_AUDIO_DRIVER_WASAPI
+    &WASAPI_bootstrap,
+#endif
 #if SDL_AUDIO_DRIVER_XAUDIO2
     &XAUDIO2_bootstrap,
 #endif

src/audio/wasapi/SDL_wasapi.h

@@ -0,0 +1,46 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2017 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "../../SDL_internal.h"
+
+#ifndef SDL_wasapi_h_
+#define SDL_wasapi_h_
+
+#include "../SDL_sysaudio.h"
+
+/* Hidden "this" pointer for the audio functions */
+#define _THIS SDL_AudioDevice *this
+
+struct SDL_PrivateAudioData
+{
+    IMMDevice *device;
+    WAVEFORMATEX *waveformat;
+    IAudioClient *client;
+    IAudioRenderClient *render;
+    IAudioCaptureClient *capture;
+    SDL_AudioStream *capturestream;
+    HANDLE task;
+    SDL_bool coinitialized;
+    int framesize;
+};
+
+#endif /* SDL_wasapi_h_ */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/core/windows/SDL_windows.c

@@ -142,6 +142,8 @@ Registry, and a unhelpful "Microphone(Yeti Stereo Microph" in winmm. Sigh.
 
 (Also, DirectSound shouldn't be limited to 32 chars, but its device enum
 has the same problem.)
+
+WASAPI doesn't need this. This is just for DirectSound/WinMM.
 */
 char *
 WIN_LookupAudioDeviceName(const WCHAR *name, const GUID *guid)