kc3-lang/SDL

diff --git a/VisualC/SDL/SDL.vcxproj b/VisualC/SDL/SDL.vcxproj
index 1615d6c..7f1da62 100644
--- a/VisualC/SDL/SDL.vcxproj
+++ b/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" />
diff --git a/VisualC/SDL/SDL_VS2008.vcproj b/VisualC/SDL/SDL_VS2008.vcproj
index 2675dbc..ad52597 100644
--- a/VisualC/SDL/SDL_VS2008.vcproj
+++ b/VisualC/SDL/SDL_VS2008.vcproj
@@ -1438,6 +1438,14 @@
 			>
 		</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"
 			>
 		</File>
diff --git a/include/SDL_config_windows.h b/include/SDL_config_windows.h
index 5791afa..2c25791 100644
--- a/include/SDL_config_windows.h
+++ b/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
diff --git a/src/audio/SDL_audio.c b/src/audio/SDL_audio.c
index 2893c49..1dfa767 100644
--- a/src/audio/SDL_audio.c
+++ b/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
diff --git a/src/audio/wasapi/SDL_wasapi.c b/src/audio/wasapi/SDL_wasapi.c
new file mode 100644
index 0000000..40db3f0
--- /dev/null
+++ b/src/audio/wasapi/SDL_wasapi.c
@@ -0,0 +1,798 @@
+/*
+  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"
+
+#if SDL_AUDIO_DRIVER_WASAPI
+
+#include "../../core/windows/SDL_windows.h"
+#include "SDL_audio.h"
+#include "SDL_timer.h"
+#include "../SDL_audio_c.h"
+#include "../SDL_sysaudio.h"
+#include "SDL_assert.h"
+#include "SDL_log.h"
+
+#define COBJMACROS
+#include <mmdeviceapi.h>
+#include <audioclient.h>
+
+#include "SDL_wasapi.h"
+
+static const ERole SDL_WASAPI_role = eConsole;  /* !!! FIXME: should this be eMultimedia? Should be a hint? */
+
+/* This is global to the WASAPI target, to handle hotplug and default device lookup. */
+static IMMDeviceEnumerator *enumerator = NULL;
+
+/* This is a list of device id strings we have inflight, so we have consistent pointers to the same device. */
+typedef struct DevIdList
+{
+	WCHAR *str;
+	struct DevIdList *next;
+} DevIdList;
+
+static DevIdList *deviceid_list = NULL;
+
+/* handle to Avrt.dll--Vista and later!--for flagging the callback thread as "Pro Audio" (low latency). */
+#ifndef __WINRT__
+static HMODULE libavrt = NULL;
+#endif
+typedef HANDLE (WINAPI *pfnAvSetMmThreadCharacteristicsW)(LPWSTR,LPDWORD);
+typedef BOOL (WINAPI *pfnAvRevertMmThreadCharacteristics)(HANDLE);
+static pfnAvSetMmThreadCharacteristicsW pAvSetMmThreadCharacteristicsW = NULL;
+static pfnAvRevertMmThreadCharacteristics pAvRevertMmThreadCharacteristics = NULL;
+
+/* Some GUIDs we need to know without linking to libraries that aren't available before Vista. */
+static const CLSID SDL_CLSID_MMDeviceEnumerator = { 0xbcde0395, 0xe52f, 0x467c, { 0x8e, 0x3d, 0xc4, 0x57, 0x92, 0x91, 0x69, 0x2e } };
+static const IID SDL_IID_IMMDeviceEnumerator = { 0xa95664d2, 0x9614, 0x4f35, { 0xa7, 0x46, 0xde, 0x8d, 0xb6, 0x36, 0x17, 0xe6 } };
+static const IID SDL_IID_IMMNotificationClient = { 0x7991eec9, 0x7e89, 0x4d85, { 0x83, 0x90, 0x6c, 0x70, 0x3c, 0xec, 0x60, 0xc0 } };
+static const IID SDL_IID_IMMEndpoint = { 0x1be09788, 0x6894, 0x4089, { 0x85, 0x86, 0x9a, 0x2a, 0x6c, 0x26, 0x5a, 0xc5 } };
+static const IID SDL_IID_IAudioClient = { 0x1cb9ad4c, 0xdbfa, 0x4c32, { 0xb1, 0x78, 0xc2, 0xf5, 0x68, 0xa7, 0x03, 0xb2 } };
+static const IID SDL_IID_IAudioRenderClient = { 0xf294acfc, 0x3146, 0x4483, { 0xa7, 0xbf, 0xad, 0xdc, 0xa7, 0xc2, 0x60, 0xe2 } };
+static const IID SDL_IID_IAudioCaptureClient = { 0xc8adbd64, 0xe71e, 0x48a0, { 0xa4, 0xde, 0x18, 0x5c, 0x39, 0x5c, 0xd3, 0x17 } };
+static const GUID SDL_KSDATAFORMAT_SUBTYPE_PCM = { 0x00000001, 0x0000, 0x0010, { 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71 } };
+static const GUID SDL_KSDATAFORMAT_SUBTYPE_IEEE_FLOAT = { 0x00000003, 0x0000, 0x0010, { 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71 } };
+static const PROPERTYKEY SDL_PKEY_Device_FriendlyName = { { 0xa45c254e, 0xdf1c, 0x4efd, { 0x80, 0x20, 0x67, 0xd1, 0x46, 0xa8, 0x50, 0xe0, } }, 14 };
+
+/* PropVariantInit() is an inline function/macro in PropIdl.h that calls the C runtime's memset() directly. Use ours instead, to avoid dependency. */ 
+#ifdef PropVariantInit
+#undef PropVariantInit
+#endif
+#define PropVariantInit(p) SDL_zerop(p)
+
+static void AddWASAPIDevice(const SDL_bool iscapture, IMMDevice *device, LPCWSTR devid);
+static void RemoveWASAPIDevice(const SDL_bool iscapture, LPCWSTR devid);
+
+/* We need a COM subclass of IMMNotificationClient for hotplug support, which is
+   easy in C++, but we have to tapdance more to make work in C.
+   Thanks to this page for coaching on how to make this work:
+     https://www.codeproject.com/Articles/13601/COM-in-plain-C */
+
+typedef struct SDLMMNotificationClient
+{
+    const IMMNotificationClientVtbl *lpVtbl;
+    SDL_atomic_t refcount;
+} SDLMMNotificationClient;
+
+static HRESULT STDMETHODCALLTYPE
+SDLMMNotificationClient_QueryInterface(IMMNotificationClient *this, REFIID iid, void **ppv)
+{
+    if ((WIN_IsEqualIID(iid, &IID_IUnknown)) || (WIN_IsEqualIID(iid, &SDL_IID_IMMNotificationClient)))
+    {
+        *ppv = this;
+        this->lpVtbl->AddRef(this);
+        return S_OK;
+    }
+
+    *ppv = NULL;
+    return E_NOINTERFACE;
+}
+
+static ULONG STDMETHODCALLTYPE
+SDLMMNotificationClient_AddRef(IMMNotificationClient *ithis)
+{
+	SDLMMNotificationClient *this = (SDLMMNotificationClient *) ithis;
+    return (ULONG) (SDL_AtomicIncRef(&this->refcount) + 1);
+}
+
+static ULONG STDMETHODCALLTYPE
+SDLMMNotificationClient_Release(IMMNotificationClient *ithis)
+{
+    /* this is a static object; we don't ever free it. */
+	SDLMMNotificationClient *this = (SDLMMNotificationClient *) ithis;
+    const ULONG retval = SDL_AtomicDecRef(&this->refcount);
+    if (retval == 0) {
+        SDL_AtomicSet(&this->refcount, 0);  /* uhh... */
+        return 0;
+    }
+    return retval - 1;
+}
+
+/* These are the entry points called when WASAPI device endpoints change. */
+static HRESULT STDMETHODCALLTYPE
+SDLMMNotificationClient_OnDefaultDeviceChanged(IMMNotificationClient *ithis, EDataFlow flow, ERole role, LPCWSTR pwstrDeviceId)
+{
+#if 0
+	const char *flowstr = "?";
+	char *utf8;
+	SDLMMNotificationClient *this = (SDLMMNotificationClient *) ithis;
+	if (role != SDL_WASAPI_role) {
+		return S_OK;  /* ignore it. */
+	}
+
+	// !!! FIXME: should probably switch endpoints if we have a default device opened; it's not clear how trivial this is, though.
+	// !!! FIXME:  also not clear yet how painful it is to switch when someone opens a tablet's speaker and then plugs in headphones.
+	utf8 = pwstrDeviceId ? WIN_StringToUTF8(pwstrDeviceId) : NULL;
+	switch (flow) {
+	case eRender: flowstr = "RENDER"; break;
+	case eCapture: flowstr = "CAPTURE"; break;
+	case eAll: flowstr = "ALL"; break;
+	}
+	SDL_Log("WASAPI: OnDefaultDeviceChanged! '%s' [%s]", utf8, flowstr);
+	SDL_free(utf8);
+#endif
+
+	return S_OK;
+}
+
+static HRESULT STDMETHODCALLTYPE
+SDLMMNotificationClient_OnDeviceAdded(IMMNotificationClient *ithis, LPCWSTR pwstrDeviceId)
+{
+	/* we ignore this; devices added here then progress to ACTIVE, if appropriate, in 
+	   OnDeviceStateChange, making that a better place to deal with device adds. More 
+	   importantly: the first time you plug in a USB audio device, this callback will 
+	   fire, but when you unplug it, it isn't removed (it's state changes to NOTPRESENT).
+	   Plugging it back in won't fire this callback again. */
+	return S_OK;
+}
+
+static HRESULT STDMETHODCALLTYPE
+SDLMMNotificationClient_OnDeviceRemoved(IMMNotificationClient *ithis, LPCWSTR pwstrDeviceId)
+{
+	/* See notes in OnDeviceAdded handler about why we ignore this. */
+	return S_OK;
+}
+
+static HRESULT STDMETHODCALLTYPE
+SDLMMNotificationClient_OnDeviceStateChanged(IMMNotificationClient *ithis, LPCWSTR pwstrDeviceId, DWORD dwNewState)
+{
+	SDLMMNotificationClient *this = (SDLMMNotificationClient *) ithis;
+	IMMDevice *device = NULL;
+
+	if (SUCCEEDED(IMMDeviceEnumerator_GetDevice(enumerator, pwstrDeviceId, &device))) {
+		IMMEndpoint *endpoint = NULL;
+		if (SUCCEEDED(IMMDevice_QueryInterface(device, &SDL_IID_IMMEndpoint, (void **) &endpoint))) {
+			EDataFlow flow;
+			if (SUCCEEDED(IMMEndpoint_GetDataFlow(endpoint, &flow))) {
+				const SDL_bool iscapture = (flow == eCapture);
+				if (dwNewState == DEVICE_STATE_ACTIVE) {
+					AddWASAPIDevice(iscapture, device, pwstrDeviceId);
+				} else {
+					RemoveWASAPIDevice(iscapture, pwstrDeviceId);
+				}
+			}
+			IMMEndpoint_Release(endpoint);
+		}
+		IMMDevice_Release(device);
+	}
+
+	return S_OK;
+}
+
+static HRESULT STDMETHODCALLTYPE
+SDLMMNotificationClient_OnPropertyValueChanged(IMMNotificationClient *this, LPCWSTR pwstrDeviceId, const PROPERTYKEY key)
+{
+    return S_OK;  /* we don't care about these. */
+}
+
+static const IMMNotificationClientVtbl notification_client_vtbl = {
+    SDLMMNotificationClient_QueryInterface,
+    SDLMMNotificationClient_AddRef,
+    SDLMMNotificationClient_Release,
+    SDLMMNotificationClient_OnDeviceStateChanged,
+    SDLMMNotificationClient_OnDeviceAdded,
+    SDLMMNotificationClient_OnDeviceRemoved,
+    SDLMMNotificationClient_OnDefaultDeviceChanged,
+    SDLMMNotificationClient_OnPropertyValueChanged
+};
+
+static SDLMMNotificationClient notification_client = { &notification_client_vtbl, 1 };
+
+static SDL_bool
+WStrEqual(const WCHAR *a, const WCHAR *b)
+{
+	while (*a) {
+		if (*a != *b) {
+			return SDL_FALSE;
+		}
+		a++;
+		b++;
+	}
+	return *b == 0;
+}
+
+static WCHAR *
+WStrDupe(const WCHAR *wstr)
+{
+	const int len = (lstrlenW(wstr) + 1) * sizeof (WCHAR);
+	WCHAR *retval = (WCHAR *) SDL_malloc(len);
+	if (retval) {
+		SDL_memcpy(retval, wstr, len);
+	}
+	return retval;
+}
+
+static void 
+RemoveWASAPIDevice(const SDL_bool iscapture, LPCWSTR devid)
+{
+	DevIdList *i;
+	DevIdList *next;
+	DevIdList *prev = NULL;
+	for (i = deviceid_list; i; i = next) {
+		next = i->next;
+		if (WStrEqual(i->str, devid)) {
+			if (prev) {
+				prev->next = next;
+			} else {
+				deviceid_list = next;
+			}
+			SDL_RemoveAudioDevice(iscapture, i->str);
+			SDL_free(i->str);
+			SDL_free(i);
+		}
+		prev = i;
+	}
+}
+
+static void
+AddWASAPIDevice(const SDL_bool iscapture, IMMDevice *device, LPCWSTR devid)
+{
+	IPropertyStore *props = NULL;
+    char *utf8dev = NULL;
+	DevIdList *devidlist;
+    PROPVARIANT var;
+
+	/* You can have multiple endpoints on a device that are mutually exclusive ("Speakers" vs "Line Out" or whatever).
+       In a perfect world, things that are unplugged won't be in this collection. The only gotcha is probably for
+       phones and tablets, where you might have an internal speaker and a headphone jack and expect both to be
+       available and switch automatically. (!!! FIXME...?) */
+
+    /* PKEY_Device_FriendlyName gives you "Speakers (SoundBlaster Pro)" which drives me nuts. I'd rather it be
+       "SoundBlaster Pro (Speakers)" but I guess that's developers vs users. Windows uses the FriendlyName in
+       its own UIs, like Volume Control, etc. */
+
+	/* see if we already have this one. */
+	for (devidlist = deviceid_list; devidlist; devidlist = devidlist->next) {
+		if (WStrEqual(devidlist->str, devid)) {
+			return;  /* we already have this. */
+		}
+	}
+
+	devidlist = (DevIdList *) SDL_malloc(sizeof (*devidlist));
+	if (!devidlist) {
+		return;  /* oh well. */
+	}
+
+	devid = WStrDupe(devid);
+	if (!devid) {
+		SDL_free(devidlist);
+		return;  /* oh well. */
+	}
+
+	devidlist->str = (WCHAR *) devid;
+	devidlist->next = deviceid_list;
+	deviceid_list = devidlist;
+
+    if (SUCCEEDED(IMMDevice_OpenPropertyStore(device, STGM_READ, &props))) {
+	    PropVariantInit(&var);
+	    if (SUCCEEDED(IPropertyStore_GetValue(props, &SDL_PKEY_Device_FriendlyName, &var))) {
+			utf8dev = WIN_StringToUTF8(var.pwszVal);
+			if (utf8dev) {
+				SDL_AddAudioDevice(iscapture, utf8dev, (void *) devid);
+		        SDL_free(utf8dev);
+			}
+		}
+	    PropVariantClear(&var);
+	    IPropertyStore_Release(props);
+	}
+}
+
+static void
+EnumerateEndpoints(const SDL_bool iscapture)
+{
+    IMMDeviceCollection *collection = NULL;
+    UINT i, total;
+
+    /* Note that WASAPI separates "adapter devices" from "audio endpoint devices"
+       ...one adapter device ("SoundBlaster Pro") might have multiple endpoint devices ("Speakers", "Line-Out"). */
+
+    if (FAILED(IMMDeviceEnumerator_EnumAudioEndpoints(enumerator, iscapture ? eCapture : eRender, DEVICE_STATE_ACTIVE, &collection))) {
+        return;
+    }
+
+    if (FAILED(IMMDeviceCollection_GetCount(collection, &total))) {
+        IMMDeviceCollection_Release(collection);
+        return;
+    }
+
+    for (i = 0; i < total; i++) {
+        IMMDevice *device = NULL;
+        if (SUCCEEDED(IMMDeviceCollection_Item(collection, i, &device))) {
+			LPWSTR devid = NULL;
+			if (SUCCEEDED(IMMDevice_GetId(device, &devid))) {
+				AddWASAPIDevice(iscapture, device, devid);
+				CoTaskMemFree(devid);
+			}
+	        IMMDevice_Release(device);
+		}
+	}
+
+    IMMDeviceCollection_Release(collection);
+}
+
+static void
+WASAPI_DetectDevices(void)
+{
+    EnumerateEndpoints(SDL_FALSE);  /* playback */
+    EnumerateEndpoints(SDL_TRUE);   /* capture */
+
+    /* if this fails, we just won't get hotplug events. Carry on anyhow. */
+    IMMDeviceEnumerator_RegisterEndpointNotificationCallback(enumerator, (IMMNotificationClient *) &notification_client);
+}
+
+static int
+WASAPI_GetPendingBytes(_THIS)
+{
+    UINT32 frames = 0;
+    if (FAILED(IAudioClient_GetCurrentPadding(this->hidden->client, &frames))) {
+        return 0;  /* oh well. */
+    }
+
+    return ((int) frames) * this->hidden->framesize;
+}
+
+static Uint8 *
+WASAPI_GetDeviceBuf(_THIS)
+{
+    /* get an endpoint buffer from WASAPI. */
+    BYTE *buffer = NULL;
+	if (FAILED(IAudioRenderClient_GetBuffer(this->hidden->render, this->spec.samples, &buffer))) {
+		IAudioClient_Stop(this->hidden->client);
+        SDL_OpenedAudioDeviceDisconnected(this);  /* uhoh. */
+        SDL_assert(buffer == NULL);
+    }
+    return (Uint8 *) buffer;
+}
+
+static void
+WASAPI_PlayDevice(_THIS)
+{
+    if (SDL_AtomicGet(&this->enabled)) {  /* not shutting down? */
+        if (FAILED(IAudioRenderClient_ReleaseBuffer(this->hidden->render, this->spec.samples, 0))) {
+            IAudioClient_Stop(this->hidden->client);
+            SDL_OpenedAudioDeviceDisconnected(this);  /* uhoh. */
+        }
+    }
+}
+
+static void
+WASAPI_WaitDevice(_THIS)
+{
+	const UINT32 maxpadding = this->spec.samples;
+    while (SDL_AtomicGet(&this->enabled)) {
+		UINT32 padding = 0;
+		if (FAILED(IAudioClient_GetCurrentPadding(this->hidden->client, &padding))) {
+		    IAudioClient_Stop(this->hidden->client);
+			SDL_OpenedAudioDeviceDisconnected(this);
+        }
+
+        if (padding <= maxpadding) {
+			break;
+		}
+
+		/* Sleep long enough for half the buffer to be free. */
+		SDL_Delay(((padding - maxpadding) * 1000) / this->spec.freq);
+	}
+}
+
+static int
+WASAPI_CaptureFromDevice(_THIS, void *buffer, int buflen)
+{
+    SDL_AudioStream *stream = this->hidden->capturestream;
+    const int avail = SDL_AudioStreamAvailable(stream);
+    if (avail > 0) {
+        const int cpy = SDL_min(buflen, avail);
+        SDL_AudioStreamGet(stream, buffer, cpy);
+        return cpy;
+    }
+
+    while (SDL_AtomicGet(&this->enabled)) {
+        HRESULT ret;
+        BYTE *ptr = NULL;
+        UINT32 frames = 0;
+        DWORD flags = 0;
+
+        ret = IAudioCaptureClient_GetBuffer(this->hidden->capture, &ptr, &frames, &flags, NULL, NULL);
+        if ((ret == AUDCLNT_S_BUFFER_EMPTY) || !frames) {
+            WASAPI_WaitDevice(this);
+        } else if (ret == S_OK) {
+            const int total = ((int) frames) * this->hidden->framesize;
+            const int cpy = SDL_min(buflen, total);
+            const int leftover = total - cpy;
+            const SDL_bool silent = (flags & AUDCLNT_BUFFERFLAGS_SILENT) ? SDL_TRUE : SDL_FALSE;
+
+            if (silent) {
+                SDL_memset(buffer, this->spec.silence, cpy);
+            } else {
+                SDL_memcpy(buffer, ptr, cpy);
+            }
+            
+            if (leftover > 0) {
+                ptr += cpy;
+                if (silent) {
+                    SDL_memset(ptr, this->spec.silence, leftover);  /* I guess this is safe? */
+                }
+
+                if (SDL_AudioStreamPut(stream, ptr, leftover) == -1) {
+                    return -1;  /* uhoh, out of memory, etc. Kill device.  :( */
+                }
+            }
+
+            IAudioCaptureClient_ReleaseBuffer(this->hidden->capture, frames);
+            return cpy;
+        } else {
+            break;  /* something totally failed. */
+        }
+    }
+
+    return -1;  /* unrecoverable error. */
+}
+
+static void
+WASAPI_FlushCapture(_THIS)
+{
+    if (SDL_AtomicGet(&this->enabled)) {
+        BYTE *ptr = NULL;
+        UINT32 frames = 0;
+        DWORD flags = 0;
+        HRESULT ret;
+        /* just read until we stop getting packets, throwing them away. */
+        while ((ret = IAudioCaptureClient_GetBuffer(this->hidden->capture, &ptr, &frames, &flags, NULL, NULL)) == S_OK) {
+            IAudioCaptureClient_ReleaseBuffer(this->hidden->capture, frames);
+        }
+        SDL_AudioStreamClear(this->hidden->capturestream);
+    }
+}
+
+static void
+WASAPI_CloseDevice(_THIS)
+{
+    /* don't touch this->hidden->task in here; it has to be reverted from
+      our callback thread. We do that in WASAPI_ThreadDeinit().
+      (likewise for this->hidden->coinitialized). */
+
+	if (this->hidden->client) {
+        IAudioClient_Stop(this->hidden->client);
+	}
+
+    if (this->hidden->render) {
+        IAudioRenderClient_Release(this->hidden->render);
+    }
+
+    if (this->hidden->client) {
+        IAudioClient_Release(this->hidden->client);
+    }
+
+    if (this->hidden->waveformat) {
+        CoTaskMemFree(this->hidden->waveformat);
+    }
+
+    if (this->hidden->device) {
+        IMMDevice_Release(this->hidden->device);
+    }
+
+    if (this->hidden->capturestream) {
+        SDL_FreeAudioStream(this->hidden->capturestream);
+    }
+
+    SDL_free(this->hidden);
+}
+
+static int
+WASAPI_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
+{
+    /* !!! FIXME: we could request an exclusive mode stream, which is lower latency;
+       !!!  it will write into the kernel's audio buffer directly instead of
+       !!!  shared memory that a user-mode mixer then writes to the kernel with
+       !!!  everything else. Doing this means any other sound using this device will
+       !!!  stop playing, including the user's MP3 player and system notification
+       !!!  sounds. You'd probably need to release the device when the app isn't in
+       !!!  the foreground, to be a good citizen of the system. It's doable, but it's
+       !!!  more work and causes some annoyances, and I don't know what the latency
+       !!!  wins actually look like. Maybe add a hint to force exclusive mode at
+       !!!  some point. To be sure, defaulting to shared mode is the right thing to
+       !!!  do in any case. */
+    const AUDCLNT_SHAREMODE sharemode = AUDCLNT_SHAREMODE_SHARED;
+    const EDataFlow dataflow = iscapture ? eCapture : eRender;
+    UINT32 bufsize = 0;  /* this is in sample frames, not samples, not bytes. */
+    REFERENCE_TIME duration = 0;
+    IMMDevice *device = NULL;
+    IAudioClient *client = NULL;
+    IAudioRenderClient *render = NULL;
+    IAudioCaptureClient *capture = NULL;
+    WAVEFORMATEX *waveformat = NULL;
+    SDL_AudioFormat test_format = SDL_FirstAudioFormat(this->spec.format);
+    SDL_AudioFormat wasapi_format = 0;
+    SDL_bool valid_format = SDL_FALSE;
+    HRESULT ret = S_OK;
+
+    /* Initialize all variables that we clean on shutdown */
+    this->hidden = (struct SDL_PrivateAudioData *)
+        SDL_malloc((sizeof *this->hidden));
+    if (this->hidden == NULL) {
+        return SDL_OutOfMemory();
+    }
+    SDL_zerop(this->hidden);
+
+    if (handle == NULL) {
+        ret = IMMDeviceEnumerator_GetDefaultAudioEndpoint(enumerator, dataflow, SDL_WASAPI_role, &device);
+	} else {
+        ret = IMMDeviceEnumerator_GetDevice(enumerator, (LPCWSTR) handle, &device);
+    }
+
+    if (FAILED(ret)) {
+        return WIN_SetErrorFromHRESULT("WASAPI can't find requested audio endpoint", ret);
+    }
+
+    SDL_assert(device != NULL);
+    this->hidden->device = device;
+
+    ret = IMMDevice_Activate(device, &SDL_IID_IAudioClient, CLSCTX_ALL, NULL, (void **) &client);
+    if (FAILED(ret)) {
+        return WIN_SetErrorFromHRESULT("WASAPI can't activate audio endpoint", ret);
+    }
+
+    SDL_assert(client != NULL);
+    this->hidden->client = client;
+
+    ret = IAudioClient_GetMixFormat(client, &waveformat);
+    if (FAILED(ret)) {
+        return WIN_SetErrorFromHRESULT("WASAPI can't determine mix format", ret);
+    }
+
+    SDL_assert(waveformat != NULL);
+    this->hidden->waveformat = waveformat;
+
+    /* WASAPI will not do any conversion on our behalf. Force channels and sample rate. */
+    this->spec.channels = (Uint8) waveformat->nChannels;
+    this->spec.freq = waveformat->nSamplesPerSec;
+
+    /* Make sure we have a valid format that we can convert to whatever WASAPI wants. */
+    if ((waveformat->wFormatTag == WAVE_FORMAT_IEEE_FLOAT) && (waveformat->wBitsPerSample == 32)) {
+        wasapi_format = AUDIO_F32SYS;
+    } else if ((waveformat->wFormatTag == WAVE_FORMAT_PCM) && (waveformat->wBitsPerSample == 16)) {
+        wasapi_format = AUDIO_S16SYS;
+    } else if ((waveformat->wFormatTag == WAVE_FORMAT_PCM) && (waveformat->wBitsPerSample == 32)) {
+        wasapi_format = AUDIO_S32SYS;
+    } else if (waveformat->wFormatTag == WAVE_FORMAT_EXTENSIBLE) {
+        const WAVEFORMATEXTENSIBLE *ext = (const WAVEFORMATEXTENSIBLE *) waveformat;
+        if ((SDL_memcmp(&ext->SubFormat, &SDL_KSDATAFORMAT_SUBTYPE_IEEE_FLOAT, sizeof (GUID)) == 0) && (waveformat->wBitsPerSample == 32)) {
+            wasapi_format = AUDIO_F32SYS;
+        } else if ((SDL_memcmp(&ext->SubFormat, &SDL_KSDATAFORMAT_SUBTYPE_PCM, sizeof (GUID)) == 0) && (waveformat->wBitsPerSample == 16)) {
+            wasapi_format = AUDIO_S16SYS;
+        } else if ((SDL_memcmp(&ext->SubFormat, &SDL_KSDATAFORMAT_SUBTYPE_PCM, sizeof (GUID)) == 0) && (waveformat->wBitsPerSample == 32)) {
+            wasapi_format = AUDIO_S32SYS;
+        }
+    }
+
+    while ((!valid_format) && (test_format)) {
+        if (test_format == wasapi_format) {
+            this->spec.format = test_format;
+            valid_format = SDL_TRUE;
+            break;
+        }
+        test_format = SDL_NextAudioFormat();
+    }
+
+    if (!valid_format) {
+        return SDL_SetError("WASAPI: Unsupported audio format");
+    }
+
+    ret = IAudioClient_GetDevicePeriod(client, NULL, &duration);
+    if (FAILED(ret)) {
+        return WIN_SetErrorFromHRESULT("WASAPI can't determine minimum device period", ret);
+    }
+
+    ret = IAudioClient_Initialize(client, sharemode, 0, duration, sharemode == AUDCLNT_SHAREMODE_SHARED ? 0 : duration, waveformat, NULL);
+    if (FAILED(ret)) {
+        return WIN_SetErrorFromHRESULT("WASAPI can't initialize audio client", ret);
+    }
+
+	ret = IAudioClient_GetBufferSize(client, &bufsize);
+    if (FAILED(ret)) {
+        return WIN_SetErrorFromHRESULT("WASAPI can't determine buffer size", ret);
+    }
+
+    this->spec.samples = (Uint16) bufsize;
+	if (!iscapture) {
+		this->spec.samples /= 2;  /* fill half of the DMA buffer on each run. */
+	}
+
+    /* Update the fragment size as size in bytes */
+    SDL_CalculateAudioSpec(&this->spec);
+
+    this->hidden->framesize = (SDL_AUDIO_BITSIZE(this->spec.format) / 8) * this->spec.channels;
+
+    if (iscapture) {
+        this->hidden->capturestream = SDL_NewAudioStream(this->spec.format, this->spec.channels, this->spec.freq, this->spec.format, this->spec.channels, this->spec.freq);
+        if (!this->hidden->capturestream) {
+            return -1;  /* already set SDL_Error */
+        }
+
+        ret = IAudioClient_GetService(client, &SDL_IID_IAudioCaptureClient, (void**) &capture);
+        if (FAILED(ret)) {
+            return WIN_SetErrorFromHRESULT("WASAPI can't get capture client service", ret);
+        }
+
+        SDL_assert(capture != NULL);
+        this->hidden->capture = capture;
+        ret = IAudioClient_Start(client);
+        if (FAILED(ret)) {
+            return WIN_SetErrorFromHRESULT("WASAPI can't start capture", ret);
+        }
+
+        WASAPI_FlushCapture(this);  /* MSDN says you should flush capture endpoint right after startup. */
+    } else {
+        ret = IAudioClient_GetService(client, &SDL_IID_IAudioRenderClient, (void**) &render);
+        if (FAILED(ret)) {
+            return WIN_SetErrorFromHRESULT("WASAPI can't get render client service", ret);
+        }
+
+        SDL_assert(render != NULL);
+        this->hidden->render = render;
+        ret = IAudioClient_Start(client);
+        if (FAILED(ret)) {
+            return WIN_SetErrorFromHRESULT("WASAPI can't start playback", ret);
+        }
+    }
+
+    return 0;  /* good to go. */
+}
+
+static void
+WASAPI_ThreadInit(_THIS)
+{
+    /* this thread uses COM. */
+    if (SUCCEEDED(WIN_CoInitialize())) {    /* can't report errors, hope it worked! */
+        this->hidden->coinitialized = SDL_TRUE;
+    }
+
+    /* Set this thread to very high "Pro Audio" priority. */
+    if (pAvSetMmThreadCharacteristicsW) {
+        DWORD idx = 0;
+        this->hidden->task = pAvSetMmThreadCharacteristicsW(TEXT("Pro Audio"), &idx);
+    }
+}
+
+static void
+WASAPI_ThreadDeinit(_THIS)
+{
+    /* Set this thread to very high "Pro Audio" priority. */
+    if (this->hidden->task && pAvRevertMmThreadCharacteristics) {
+        pAvRevertMmThreadCharacteristics(this->hidden->task);
+        this->hidden->task = NULL;
+    }
+
+    if (this->hidden->coinitialized) {
+        WIN_CoUninitialize();
+    }
+}
+
+static void
+WASAPI_Deinitialize(void)
+{
+	DevIdList *devidlist;
+	DevIdList *next;
+
+    if (enumerator) {
+        IMMDeviceEnumerator_UnregisterEndpointNotificationCallback(enumerator, (IMMNotificationClient *) &notification_client);
+        IMMDeviceEnumerator_Release(enumerator);
+        enumerator = NULL;
+    }
+
+    #ifndef __WINRT__
+    if (libavrt) {
+        FreeLibrary(libavrt);
+        libavrt = NULL;
+    }
+    #endif
+
+    pAvSetMmThreadCharacteristicsW = NULL;
+    pAvRevertMmThreadCharacteristics = NULL;
+
+	for (devidlist = deviceid_list; devidlist; devidlist = next) {
+		next = devidlist->next;
+		SDL_free(devidlist->str);
+		SDL_free(devidlist);
+	}
+	deviceid_list = NULL;
+
+    WIN_CoUninitialize();
+}
+
+static int
+WASAPI_Init(SDL_AudioDriverImpl * impl)
+{
+	HRESULT ret;
+
+	/* just skip the discussion with COM here. */
+	if (!WIN_IsWindowsVistaOrGreater()) {
+		return SDL_SetError("WASAPI support requires Windows Vista or later");
+	}
+
+	if (FAILED(WIN_CoInitialize())) {
+        SDL_SetError("WASAPI: CoInitialize() failed");
+        return 0;
+    }
+
+	ret = CoCreateInstance(&SDL_CLSID_MMDeviceEnumerator, NULL, CLSCTX_INPROC_SERVER, &SDL_IID_IMMDeviceEnumerator, (LPVOID) &enumerator);
+    if (FAILED(ret)) {
+        WIN_CoUninitialize();
+        WIN_SetErrorFromHRESULT("WASAPI CoCreateInstance(MMDeviceEnumerator)", ret);
+        return 0;  /* oh well. */
+    }
+
+    #ifdef __WINRT__
+    pAvSetMmThreadCharacteristicsW = AvSetMmThreadCharacteristicsW;
+    pAvRevertMmThreadCharacteristics = AvRevertMmThreadCharacteristics;
+    #else
+    libavrt = LoadLibraryW(L"avrt.dll");  /* this library is available in Vista and later. No WinXP, so have to LoadLibrary to use it for now! */
+    if (libavrt) {
+        pAvSetMmThreadCharacteristicsW = (pfnAvSetMmThreadCharacteristicsW) GetProcAddress(libavrt, "AvSetMmThreadCharacteristicsW");
+        pAvRevertMmThreadCharacteristics = (pfnAvRevertMmThreadCharacteristics) GetProcAddress(libavrt, "AvRevertMmThreadCharacteristics");
+    }
+    #endif
+
+    /* Set the function pointers */
+    impl->DetectDevices = WASAPI_DetectDevices;
+    impl->ThreadInit = WASAPI_ThreadInit;
+    impl->ThreadDeinit = WASAPI_ThreadDeinit;
+    impl->OpenDevice = WASAPI_OpenDevice;
+    impl->PlayDevice = WASAPI_PlayDevice;
+    impl->WaitDevice = WASAPI_WaitDevice;
+    impl->GetPendingBytes = WASAPI_GetPendingBytes;
+    impl->GetDeviceBuf = WASAPI_GetDeviceBuf;
+    impl->CaptureFromDevice = WASAPI_CaptureFromDevice;
+    impl->FlushCapture = WASAPI_FlushCapture;
+    impl->CloseDevice = WASAPI_CloseDevice;
+    impl->Deinitialize = WASAPI_Deinitialize;
+    impl->HasCaptureSupport = 1;
+
+    return 1;   /* this audio target is available. */
+}
+
+AudioBootStrap WASAPI_bootstrap = {
+    "wasapi", "WASAPI", WASAPI_Init, 0
+};
+
+#endif  /* SDL_AUDIO_DRIVER_WASAPI */
+
+/* vi: set ts=4 sw=4 expandtab: */
diff --git a/src/audio/wasapi/SDL_wasapi.h b/src/audio/wasapi/SDL_wasapi.h
new file mode 100644
index 0000000..30fb573
--- /dev/null
+++ b/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: */
diff --git a/src/core/windows/SDL_windows.c b/src/core/windows/SDL_windows.c
index 32c4d11..117fb15 100644
--- a/src/core/windows/SDL_windows.c
+++ b/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)