[doc] faq: Correct misinformed question about mouse warp issue

This change not only exposes and allows use of NtDelayExecution, but
also moves the code to set the system timer resolution.

client/displayservers/Wayland/input.c

@@ -444,7 +444,7 @@ void waylandWarpPointer(int x, int y, bool exiting)
 
   INTERLOCKED_SECTION(wlWm.confineLock,
   {
-    if (!wlWm.lockedPointer)
+    if (wlWm.lockedPointer)
     {
       LG_UNLOCK(wlWm.confineLock);
       return;

doc/build.rst

@@ -59,14 +59,12 @@ Required Dependencies
 -  libgl-dev
 -  libfontconfig1-dev
 -  libgmp-dev
--  libsdl2-dev
--  libsdl2-ttf-dev
 -  libspice-protocol-dev
 -  make
 -  nettle-dev
 -  pkg-config
 
-.. _may_be_disabled:
+.. _client_deps_may_be_disabled:
 
 May be disabled
 <<<<<<<<<<<<<<<
@@ -83,6 +81,7 @@ feature is disabled when running :ref:`cmake <client_building>`.
    -  libx11-dev
    -  libxfixes-dev
    -  libxi-dev
+   -  libxinerama-dev
    -  libxss-dev
 
 -  Disable with ``cmake -DENABLE_WAYLAND=no ..``
@@ -91,11 +90,33 @@ feature is disabled when running :ref:`cmake <client_building>`.
    -  libwayland-dev
    -  wayland-protocols
 
-You can fetch these dependencies on Debian systems with the following command:
+.. _client_deps_deprecated:
+
+Deprecated
+<<<<<<<<<<
+
+These dependencies may be used, but are not required, and will be removed
+in the future.
+
+-  Enable with ``cmake -DENABLE_SDL=yes ..``
+
+   -  libsdl2-dev
+   -  libsdl2-ttf-dev
+
+.. _client_fetching_with_apt:
+
+Fetching with APT
+^^^^^^^^^^^^^^^^^
+
+You can fetch these dependencies with the following command:
 
 ``apt-get install binutils-dev cmake fonts-freefont-ttf libfontconfig1-dev
-libsdl2-dev libsdl2-ttf-dev libspice-protocol-dev libx11-dev nettle-dev
-wayland-protocols``
+libegl-dev libspice-protocol-dev nettle-dev libx11-dev libxi-dev libxinerama-dev
+libxss-dev libwayland-dev wayland-protocols``
+
+You may omit some dependencies, if you disable the feature which requires them
+when running :ref:`cmake <client_building>`.
+(See :ref:`client_deps_may_be_disabled`)
 
 
 .. _client_building:

doc/faq.rst

@@ -88,13 +88,20 @@ The mouse is jumpy, slow, laggy when using SPICE
 Please be sure to install the SPICE guest tools from
 https://www.spice-space.org/download.html#windows-binaries.
 
-.. _the_mouse_doesnt_stay_aligned_with_the_host.:
+.. _mouse_desync_when_entering:
 
-The mouse doesn't stay aligned with the host.
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The mouse position is wrong when entering the window
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-This is intentional. The host's mouse no longer interacts with your operating
-system, and is completely captured by Looking Glass.
+This is due to windows mouse acceleration, it can be disabled by
+following one of these methods:
+
+-  Disabling pointer precision (Control Panel > Mouse > Pointer Options
+   > Uncheck Enhance pointer precision)
+-  By changing the acceleration behavior with the following registry
+   magic:
+   http://donewmouseaccel.blogspot.com.au/2010/03/markc-windows-7-mouse-acceleration-fix.html
+   (Contrary to the title this works just fine on Windows 10)
 
 .. _the_cursor_position_doesnt_update_until_i_click:
 

host/include/interface/capture.h

@@ -91,9 +91,10 @@ typedef void (*CapturePostPointerBuffer)(CapturePointer pointer);
 
 typedef struct CaptureInterface
 {
-  const char     *shortName;
-  const char *  (*getName        )();
-  void          (*initOptions    )();
+  const char * shortName;
+  const bool   asyncCapture;
+  const char * (*getName        )();
+  void         (*initOptions    )();
 
   bool(*create)(
     CaptureGetPointerBuffer  getPointerBufferFn,

host/platform/Linux/capture/XCB/src/xcb.c

@@ -236,6 +236,7 @@ static CaptureResult xcb_getFrame(FrameBuffer * frame, const unsigned int height
 struct CaptureInterface Capture_XCB =
 {
   .shortName       = "XCB",
+  .asyncCapture    = true,
   .getName         = xcb_getName,
   .create          = xcb_create,
   .init            = xcb_init,

host/platform/Windows/CMakeLists.txt

@@ -10,6 +10,7 @@ add_library(platform_Windows STATIC
 	src/service.c
 	src/mousehook.c
 	src/force_compose.c
+	src/delay.c
 )
 
 # allow use of functions for Windows Vista or later

host/platform/Windows/capture/DXGI/src/dxgi.c

@@ -142,7 +142,7 @@ static void dxgi_initOptions(void)
     {
       .module         = "dxgi",
       .name           = "useAcquireLock",
-      .description    = "Enable locking around `AcquireFrame` (EXPERIMENTAL, leave enabled if you're not sure!)",
+      .description    = "Enable locking around `AcquireNextFrame` (EXPERIMENTAL, leave enabled if you're not sure!)",
       .type           = OPTION_TYPE_BOOL,
       .value.x_bool   = true
     },
@@ -230,7 +230,7 @@ static bool dxgi_init(void)
   const char * optAdapter = option_get_string("dxgi", "adapter");
   const char * optOutput  = option_get_string("dxgi", "output" );
 
-  for(int i = 0; IDXGIFactory1_EnumAdapters1(this->factory, i, &this->adapter) != DXGI_ERROR_NOT_FOUND; ++i)
+  for (int i = 0; IDXGIFactory1_EnumAdapters1(this->factory, i, &this->adapter) != DXGI_ERROR_NOT_FOUND; ++i)
   {
     if (optAdapter)
     {
@@ -259,7 +259,7 @@ static bool dxgi_init(void)
       DEBUG_INFO("Adapter matched, trying: %ls", adapterDesc.Description);
     }
 
-    for(int n = 0; IDXGIAdapter1_EnumOutputs(this->adapter, n, &this->output) != DXGI_ERROR_NOT_FOUND; ++n)
+    for (int n = 0; IDXGIAdapter1_EnumOutputs(this->adapter, n, &this->output) != DXGI_ERROR_NOT_FOUND; ++n)
     {
       IDXGIOutput_GetDesc(this->output, &outputDesc);
       if (optOutput)
@@ -302,6 +302,16 @@ static bool dxgi_init(void)
     goto fail;
   }
 
+  DXGI_ADAPTER_DESC1 adapterDesc;
+  IDXGIAdapter1_GetDesc1(this->adapter, &adapterDesc);
+  DEBUG_INFO("Device Name      : %ls"    , outputDesc.DeviceName);
+  DEBUG_INFO("Device Descripion: %ls"    , adapterDesc.Description);
+  DEBUG_INFO("Device Vendor ID : 0x%x"   , adapterDesc.VendorId);
+  DEBUG_INFO("Device Device ID : 0x%x"   , adapterDesc.DeviceId);
+  DEBUG_INFO("Device Video Mem : %u MiB" , (unsigned)(adapterDesc.DedicatedVideoMemory  / 1048576));
+  DEBUG_INFO("Device Sys Mem   : %u MiB" , (unsigned)(adapterDesc.DedicatedSystemMemory / 1048576));
+  DEBUG_INFO("Shared Sys Mem   : %u MiB" , (unsigned)(adapterDesc.SharedSystemMemory    / 1048576));
+
   static const D3D_FEATURE_LEVEL win8[] =
   {
     D3D_FEATURE_LEVEL_11_1,
@@ -368,9 +378,6 @@ static bool dxgi_init(void)
     goto fail;
   }
 
-  DXGI_ADAPTER_DESC1 adapterDesc;
-  IDXGIAdapter1_GetDesc1(this->adapter, &adapterDesc);
-
   switch(outputDesc.Rotation)
   {
     case DXGI_MODE_ROTATION_ROTATE90:
@@ -411,12 +418,6 @@ static bool dxgi_init(void)
   this->dpi = monitor_dpi(outputDesc.Monitor);
   ++this->formatVer;
 
-  DEBUG_INFO("Device Descripion: %ls"    , adapterDesc.Description);
-  DEBUG_INFO("Device Vendor ID : 0x%x"   , adapterDesc.VendorId);
-  DEBUG_INFO("Device Device ID : 0x%x"   , adapterDesc.DeviceId);
-  DEBUG_INFO("Device Video Mem : %u MiB" , (unsigned)(adapterDesc.DedicatedVideoMemory  / 1048576));
-  DEBUG_INFO("Device Sys Mem   : %u MiB" , (unsigned)(adapterDesc.DedicatedSystemMemory / 1048576));
-  DEBUG_INFO("Shared Sys Mem   : %u MiB" , (unsigned)(adapterDesc.SharedSystemMemory    / 1048576));
   DEBUG_INFO("Feature Level    : 0x%x"   , this->featureLevel);
   DEBUG_INFO("Capture Size     : %u x %u", this->width, this->height);
   DEBUG_INFO("AcquireLock      : %s"     , this->useAcquireLock ? "enabled" : "disabled");
@@ -542,7 +543,7 @@ static bool dxgi_init(void)
   texDesc.CPUAccessFlags     = D3D11_CPU_ACCESS_READ;
   texDesc.MiscFlags          = 0;
 
-  for(int i = 0; i < this->maxTextures; ++i)
+  for (int i = 0; i < this->maxTextures; ++i)
   {
     status = ID3D11Device_CreateTexture2D(this->device, &texDesc, NULL, &this->texture[i].tex);
     if (FAILED(status))
@@ -583,7 +584,7 @@ static bool dxgi_deinit(void)
 {
   assert(this);
 
-  for(int i = 0; i < this->maxTextures; ++i)
+  for (int i = 0; i < this->maxTextures; ++i)
   {
     this->texture[i].state = TEXTURE_STATE_UNUSED;
 
@@ -764,7 +765,7 @@ static CaptureResult dxgi_capture(void)
   uint32_t bufferSize;
   if (frameInfo.PointerShapeBufferSize > 0)
   {
-    if(!this->getPointerBufferFn(&pointerShape, &bufferSize))
+    if (!this->getPointerBufferFn(&pointerShape, &bufferSize))
       DEBUG_WARN("Failed to obtain a buffer for the pointer shape");
     else
       copyPointer = true;
@@ -881,13 +882,13 @@ static CaptureResult dxgi_waitFrame(CaptureFrame * frame, const size_t maxFrameS
   assert(this->initialized);
 
   // NOTE: the event may be signaled when there are no frames available
-  if(atomic_load_explicit(&this->texReady, memory_order_acquire) == 0)
+  if (atomic_load_explicit(&this->texReady, memory_order_acquire) == 0)
   {
     if (!lgWaitEvent(this->frameEvent, 1000))
       return CAPTURE_RESULT_TIMEOUT;
 
     // the count will still be zero if we are stopping
-    if(atomic_load_explicit(&this->texReady, memory_order_acquire) == 0)
+    if (atomic_load_explicit(&this->texReady, memory_order_acquire) == 0)
       return CAPTURE_RESULT_TIMEOUT;
   }
 
@@ -996,6 +997,7 @@ static CaptureResult dxgi_releaseFrame(void)
 struct CaptureInterface Capture_DXGI =
 {
   .shortName       = "DXGI",
+  .asyncCapture    = true,
   .getName         = dxgi_getName,
   .initOptions     = dxgi_initOptions,
   .create          = dxgi_create,

host/platform/Windows/capture/NVFBC/src/nvfbc.c

@@ -57,7 +57,6 @@ struct iface
 
   NvFBCFrameGrabInfo grabInfo;
 
-  LGEvent * frameEvent;
   LGEvent * cursorEvent;
 
   int mouseX, mouseY, mouseHotX, mouseHotY;
@@ -134,13 +133,6 @@ static bool nvfbc_create(
     return false;
 
   this = (struct iface *)calloc(sizeof(struct iface), 1);
-  this->frameEvent = lgCreateEvent(true, 17);
-  if (!this->frameEvent)
-  {
-    DEBUG_ERROR("failed to create the frame event");
-    nvfbc_free();
-    return false;
-  }
 
   this->seperateCursor      = option_get_bool("nvfbc", "decoupleCursor");
   this->getPointerBufferFn  = getPointerBufferFn;
@@ -165,7 +157,7 @@ static bool nvfbc_init(void)
     privDataLen = (bufferLen - 1) / 2;
     privData    = (uint8_t *)malloc(privDataLen);
     char hex[3] = {0};
-    for(int i = 0; i < privDataLen; ++i)
+    for (int i = 0; i < privDataLen; ++i)
     {
       memcpy(hex, &buffer[i*2], 2);
       privData[i] = (uint8_t)strtoul(hex, NULL, 16);
@@ -186,7 +178,6 @@ static bool nvfbc_init(void)
   free(privData);
 
   getDesktopSize(&this->width, &this->height, &this->dpi);
-  lgResetEvent(this->frameEvent);
 
   HANDLE event;
   if (!NvFBCToSysSetup(
@@ -239,7 +230,6 @@ static void nvfbc_stop(void)
   this->stop = true;
 
   lgSignalEvent(this->cursorEvent);
-  lgSignalEvent(this->frameEvent);
 
   if (this->pointerThread)
   {
@@ -262,9 +252,6 @@ static bool nvfbc_deinit(void)
 
 static void nvfbc_free(void)
 {
-  if (this->frameEvent)
-    lgFreeEvent(this->frameEvent);
-
   if (this->mouseHookCreated)
     mouseHook_remove();
 
@@ -300,28 +287,25 @@ static CaptureResult nvfbc_capture(void)
   bool changed = false;
   const unsigned int h = (this->height + 127) / 128;
   const unsigned int w = (this->width  + 127) / 128;
-  for(unsigned int y = 0; y < h; ++y)
-    for(unsigned int x = 0; x < w; ++x)
+  for (unsigned int y = 0; y < h; ++y)
+    for (unsigned int x = 0; x < w; ++x)
       if (this->diffMap[(y*w)+x])
       {
         changed = true;
-        break;
+        goto done;
       }
 
+done:
   if (!changed)
     return CAPTURE_RESULT_TIMEOUT;
 
   memcpy(&this->grabInfo, &grabInfo, sizeof(grabInfo));
-  lgSignalEvent(this->frameEvent);
   return CAPTURE_RESULT_OK;
 }
 
 static CaptureResult nvfbc_waitFrame(CaptureFrame * frame,
     const size_t maxFrameSize)
 {
-  if (!lgWaitEvent(this->frameEvent, 1000))
-    return CAPTURE_RESULT_TIMEOUT;
-
   if (this->stop)
     return CAPTURE_RESULT_REINIT;
 
@@ -423,6 +407,7 @@ static int pointerThread(void * unused)
 struct CaptureInterface Capture_NVFBC =
 {
   .shortName       = "NvFBC",
+  .asyncCapture    = false,
   .getName         = nvfbc_getName,
   .initOptions     = nvfbc_initOptions,
 

host/platform/Windows/capture/NVFBC/src/wrapper.cpp

@@ -253,6 +253,11 @@ CaptureResult NvFBCToSysCapture(
       handle->retry = 0;
       break;
 
+    case NVFBC_ERROR_PROTECTED_CONTENT:
+      DEBUG_WARN("Protected content is playing, can't capture");
+      Sleep(100);
+      return CAPTURE_RESULT_TIMEOUT;
+
     case NVFBC_ERROR_INVALID_PARAM:
       if (handle->retry < 2)
       {

host/platform/Windows/include/windows/delay.h

@@ -0,0 +1,34 @@
+/**
+ * Looking Glass
+ * Copyright (C) 2017-2021 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <windows.h>
+
+typedef NTSTATUS (__stdcall *ZwSetTimerResolution_t)(ULONG RequestedResolution,
+    BOOLEAN Set, PULONG ActualResolution);
+extern ZwSetTimerResolution_t ZwSetTimerResolution;
+
+typedef NTSTATUS (__stdcall *NtDelayExecution_t)(BOOL Alertable,
+    PLARGE_INTEGER DelayInterval);
+extern NtDelayExecution_t NtDelayExecution;
+
+void delayInit(void);
+
+// like sleep but more accurate
+void delayExecution(float ms);

host/platform/Windows/src/delay.c

@@ -0,0 +1,49 @@
+/**
+ * Looking Glass
+ * Copyright (C) 2017-2021 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "windows/delay.h"
+#include "common/debug.h"
+
+NtDelayExecution_t NtDelayExecution;
+ZwSetTimerResolution_t ZwSetTimerResolution;
+
+void delayInit(void)
+{
+  HMODULE ntdll = GetModuleHandle("ntdll.dll");
+  NtDelayExecution = (NtDelayExecution_t)
+    GetProcAddress(ntdll, "NtDelayExecution");
+
+  // Increase the timer resolution
+  ZwSetTimerResolution = (ZwSetTimerResolution_t)
+    GetProcAddress(ntdll, "ZwSetTimerResolution");
+
+  if (ZwSetTimerResolution)
+  {
+    ULONG actualResolution;
+    ZwSetTimerResolution(1, true, &actualResolution);
+    DEBUG_INFO("System timer resolution: %lu ns", actualResolution * 100);
+  }
+}
+
+void delayExecution(float ms)
+{
+  LARGE_INTEGER interval = { .QuadPart = -1 * (int)(ms * 10000.0f) };
+  NtDelayExecution(FALSE, &interval);
+}

host/platform/Windows/src/mousehook.c

@@ -19,6 +19,7 @@
  */
 
 #include "windows/mousehook.h"
+#include "windows/delay.h"
 #include "common/windebug.h"
 #include "platform.h"
 
@@ -31,8 +32,8 @@ struct mouseHook
   HHOOK       hook;
   MouseHookFn callback;
   int         x, y;
-  HANDLE      event;
-  HANDLE      thread;
+  HANDLE      event , updateEvent;
+  HANDLE      thread, updateThread;
 };
 
 static struct mouseHook mouseHook = { 0 };
@@ -85,6 +86,31 @@ static VOID WINAPI winEventProc(HWINEVENTHOOK hWinEventHook, DWORD event,
   }
 }
 
+static DWORD WINAPI updateThreadProc(LPVOID lParam)
+{
+  HANDLE events[2] = {
+    mouseHook.event,
+    mouseHook.updateEvent
+  };
+
+  while(true)
+  {
+    switch(WaitForMultipleObjects(2, events, FALSE, INFINITE))
+    {
+      case WAIT_OBJECT_0:
+        DEBUG_INFO("Mouse hook update thread received quit request");
+        return 0;
+
+      case WAIT_OBJECT_0 + 1:
+        mouseHook.callback(mouseHook.x, mouseHook.y);
+
+        // limit this to 1000Hz, who has a mouse that updates faster anyway?
+        delayExecution(1.0f);
+        break;
+    }
+  }
+}
+
 static DWORD WINAPI threadProc(LPVOID lParam) {
   if (mouseHook.installed)
   {
@@ -143,11 +169,28 @@ void mouseHook_install(MouseHookFn callback)
     mouseHook.event = CreateEventA(NULL, FALSE, FALSE, NULL);
     if (!mouseHook.event)
     {
-      DEBUG_WINERROR("Failed to create mouse hook uninstall event", GetLastError());
+      DEBUG_WINERROR("Failed to create mouse hook uninstall event",
+          GetLastError());
       return;
     }
   }
-  mouseHook.thread = CreateThread(NULL, 0, threadProc, callback, 0, NULL);
+
+  if (!mouseHook.updateEvent)
+  {
+    mouseHook.updateEvent = CreateEventA(NULL, FALSE, FALSE, NULL);
+    if (!mouseHook.event)
+    {
+      DEBUG_WINERROR("Failed to create mouse hook update event",
+          GetLastError());
+      return;
+    }
+  }
+
+  mouseHook.thread =
+    CreateThread(NULL, 0, threadProc, callback, 0, NULL);
+
+  mouseHook.updateThread =
+    CreateThread(NULL, 0, updateThreadProc, 0, 0, NULL);
 }
 
 void mouseHook_remove(void)
@@ -156,8 +199,10 @@ void mouseHook_remove(void)
     return;
 
   SetEvent(mouseHook.event);
-  WaitForSingleObject(mouseHook.thread, INFINITE);
+  WaitForSingleObject(mouseHook.thread      , INFINITE);
+  WaitForSingleObject(mouseHook.updateThread, INFINITE);
   CloseHandle(mouseHook.thread);
+  CloseHandle(mouseHook.updateThread);
 }
 
 static LRESULT WINAPI mouseHook_hook(int nCode, WPARAM wParam, LPARAM lParam)
@@ -169,7 +214,7 @@ static LRESULT WINAPI mouseHook_hook(int nCode, WPARAM wParam, LPARAM lParam)
     {
       mouseHook.x = msg->pt.x;
       mouseHook.y = msg->pt.y;
-      mouseHook.callback(msg->pt.x, msg->pt.y);
+      SetEvent(mouseHook.updateEvent);
     }
   }
   return CallNextHookEx(mouseHook.hook, nCode, wParam, lParam);

host/platform/Windows/src/platform.c

@@ -20,6 +20,7 @@
 
 #include "platform.h"
 #include "service.h"
+#include "windows/delay.h"
 #include "windows/mousehook.h"
 
 #include <windows.h>
@@ -61,10 +62,6 @@ struct AppState
 static struct AppState app = {0};
 HWND MessageHWND;
 
-// undocumented API to adjust the system timer resolution (yes, its a nasty hack)
-typedef NTSTATUS (__stdcall *ZwSetTimerResolution_t)(ULONG RequestedResolution, BOOLEAN Set, PULONG ActualResolution);
-static ZwSetTimerResolution_t ZwSetTimerResolution = NULL;
-
 // linux mingw64 is missing this
 #ifndef MSGFLT_RESET
   #define MSGFLT_RESET (0)
@@ -504,7 +501,7 @@ void boostPriority(void)
 
 bool app_init(void)
 {
-  const char * logFile   = option_get_string("os", "logFile"  );
+  const char * logFile = option_get_string("os", "logFile");
 
   // redirect stderr to a file
   if (logFile && strcmp(logFile, "stderr") != 0)
@@ -513,14 +510,7 @@ bool app_init(void)
   // always flush stderr
   setbuf(stderr, NULL);
 
-  // Increase the timer resolution
-  ZwSetTimerResolution = (ZwSetTimerResolution_t)GetProcAddress(GetModuleHandle("ntdll.dll"), "ZwSetTimerResolution");
-  if (ZwSetTimerResolution)
-  {
-    ULONG actualResolution;
-    ZwSetTimerResolution(1, true, &actualResolution);
-    DEBUG_INFO("System timer resolution: %.2f ns", (float)actualResolution / 100.0f);
-  }
+  delayInit();
 
   // get the performance frequency for spinlocks
   QueryPerformanceFrequency(&app.perfFreq);

host/src/app.c

@@ -79,17 +79,21 @@ struct app
   PLGMPHost lgmp;
 
   PLGMPHostQueue pointerQueue;
-  PLGMPMemory    pointerMemory[POINTER_SHAPE_BUFFERS];
+  PLGMPMemory    pointerMemory[LGMP_Q_POINTER_LEN];
+  PLGMPMemory    pointerShapeMemory[POINTER_SHAPE_BUFFERS];
   LG_Lock        pointerLock;
   CapturePointer pointerInfo;
   PLGMPMemory    pointerShape;
   bool           pointerShapeValid;
   unsigned int   pointerIndex;
+  unsigned int   pointerShapeIndex;
 
+  long           pageSize;
   size_t         maxFrameSize;
   PLGMPHostQueue frameQueue;
   PLGMPMemory    frameMemory[LGMP_Q_FRAME_LEN];
   unsigned int   frameIndex;
+  bool           frameValid;
 
   CaptureInterface * iface;
 
@@ -138,118 +142,127 @@ static bool lgmpTimer(void * opaque)
   return true;
 }
 
+static bool sendFrame(void)
+{
+  CaptureFrame frame = { 0 };
+  bool repeatFrame = false;
+
+  //wait until there is room in the queue
+  while(app.state == APP_STATE_RUNNING &&
+      lgmpHostQueuePending(app.frameQueue) == LGMP_Q_FRAME_LEN)
+  {
+    usleep(1);
+    continue;
+  }
+
+  if (app.state != APP_STATE_RUNNING)
+    return false;
+
+  switch(app.iface->waitFrame(&frame, app.maxFrameSize))
+  {
+    case CAPTURE_RESULT_OK:
+      break;
+
+    case CAPTURE_RESULT_REINIT:
+    {
+      app.state = APP_STATE_RESTART;
+      DEBUG_INFO("Frame thread reinit");
+      return false;
+    }
+
+    case CAPTURE_RESULT_ERROR:
+    {
+      DEBUG_ERROR("Failed to get the frame");
+      return false;
+    }
+
+    case CAPTURE_RESULT_TIMEOUT:
+    {
+      if (app.frameValid && lgmpHostQueueNewSubs(app.frameQueue) > 0)
+      {
+        // resend the last frame
+        repeatFrame = true;
+        break;
+      }
+
+      return true;
+    }
+  }
+
+  LGMP_STATUS status;
+
+  // if we are repeating a frame just send the last frame again
+  if (repeatFrame)
+  {
+    if ((status = lgmpHostQueuePost(app.frameQueue, 0, app.frameMemory[app.frameIndex])) != LGMP_OK)
+      DEBUG_ERROR("%s", lgmpStatusString(status));
+    return true;
+  }
+
+  // we increment the index first so that if we need to repeat a frame
+  // the index still points to the latest valid frame
+  if (++app.frameIndex == LGMP_Q_FRAME_LEN)
+    app.frameIndex = 0;
+
+  KVMFRFrame * fi = lgmpHostMemPtr(app.frameMemory[app.frameIndex]);
+  switch(frame.format)
+  {
+    case CAPTURE_FMT_BGRA   : fi->type = FRAME_TYPE_BGRA   ; break;
+    case CAPTURE_FMT_RGBA   : fi->type = FRAME_TYPE_RGBA   ; break;
+    case CAPTURE_FMT_RGBA10 : fi->type = FRAME_TYPE_RGBA10 ; break;
+    case CAPTURE_FMT_RGBA16F: fi->type = FRAME_TYPE_RGBA16F; break;
+    default:
+      DEBUG_ERROR("Unsupported frame format %d, skipping frame", frame.format);
+      return true;
+  }
+
+  switch(frame.rotation)
+  {
+    case CAPTURE_ROT_0  : fi->rotation = FRAME_ROT_0  ; break;
+    case CAPTURE_ROT_90 : fi->rotation = FRAME_ROT_90 ; break;
+    case CAPTURE_ROT_180: fi->rotation = FRAME_ROT_180; break;
+    case CAPTURE_ROT_270: fi->rotation = FRAME_ROT_270; break;
+    default:
+      DEBUG_WARN("Unsupported frame rotation %d", frame.rotation);
+      fi->rotation = FRAME_ROT_0;
+      break;
+  }
+
+  fi->formatVer         = frame.formatVer;
+  fi->width             = frame.width;
+  fi->height            = frame.height;
+  fi->realHeight        = frame.realHeight;
+  fi->stride            = frame.stride;
+  fi->pitch             = frame.pitch;
+  fi->offset            = app.pageSize - FrameBufferStructSize;
+  fi->mouseScalePercent = app.iface->getMouseScale();
+  fi->blockScreensaver  = os_blockScreensaver();
+  app.frameValid        = true;
+
+  // put the framebuffer on the border of the next page
+  // this is to allow for aligned DMA transfers by the receiver
+  FrameBuffer * fb = (FrameBuffer *)(((uint8_t*)fi) + fi->offset);
+  framebuffer_prepare(fb);
+
+  /* we post and then get the frame, this is intentional! */
+  if ((status = lgmpHostQueuePost(app.frameQueue, 0, app.frameMemory[app.frameIndex])) != LGMP_OK)
+  {
+    DEBUG_ERROR("%s", lgmpStatusString(status));
+    return true;
+  }
+
+  app.iface->getFrame(fb, frame.height);
+  return true;
+}
+
 static int frameThread(void * opaque)
 {
   DEBUG_INFO("Frame thread started");
 
-  bool         frameValid     = false;
-  bool         repeatFrame    = false;
-  CaptureFrame frame          = { 0 };
-  const long   pageSize       = sysinfo_getPageSize();
-
   while(app.state == APP_STATE_RUNNING)
   {
-    //wait until there is room in the queue
-    if(lgmpHostQueuePending(app.frameQueue) == LGMP_Q_FRAME_LEN)
-    {
-      usleep(1);
-      continue;
-    }
-
-    switch(app.iface->waitFrame(&frame, app.maxFrameSize))
-    {
-      case CAPTURE_RESULT_OK:
-        repeatFrame = false;
-        break;
-
-      case CAPTURE_RESULT_REINIT:
-      {
-        app.state = APP_STATE_RESTART;
-        DEBUG_INFO("Frame thread reinit");
-        return 0;
-      }
-
-      case CAPTURE_RESULT_ERROR:
-      {
-        DEBUG_ERROR("Failed to get the frame");
-        return 0;
-      }
-
-      case CAPTURE_RESULT_TIMEOUT:
-      {
-        if (frameValid && lgmpHostQueueNewSubs(app.frameQueue) > 0)
-        {
-          // resend the last frame
-          repeatFrame = true;
-          break;
-        }
-
-        continue;
-      }
-    }
-
-    LGMP_STATUS status;
-
-    // if we are repeating a frame just send the last frame again
-    if (repeatFrame)
-    {
-      if ((status = lgmpHostQueuePost(app.frameQueue, 0, app.frameMemory[app.frameIndex])) != LGMP_OK)
-        DEBUG_ERROR("%s", lgmpStatusString(status));
-      continue;
-    }
-
-    // we increment the index first so that if we need to repeat a frame
-    // the index still points to the latest valid frame
-    if (++app.frameIndex == LGMP_Q_FRAME_LEN)
-      app.frameIndex = 0;
-
-    KVMFRFrame * fi = lgmpHostMemPtr(app.frameMemory[app.frameIndex]);
-    switch(frame.format)
-    {
-      case CAPTURE_FMT_BGRA   : fi->type = FRAME_TYPE_BGRA   ; break;
-      case CAPTURE_FMT_RGBA   : fi->type = FRAME_TYPE_RGBA   ; break;
-      case CAPTURE_FMT_RGBA10 : fi->type = FRAME_TYPE_RGBA10 ; break;
-      case CAPTURE_FMT_RGBA16F: fi->type = FRAME_TYPE_RGBA16F; break;
-      default:
-        DEBUG_ERROR("Unsupported frame format %d, skipping frame", frame.format);
-        continue;
-    }
-
-    switch(frame.rotation)
-    {
-      case CAPTURE_ROT_0  : fi->rotation = FRAME_ROT_0  ; break;
-      case CAPTURE_ROT_90 : fi->rotation = FRAME_ROT_90 ; break;
-      case CAPTURE_ROT_180: fi->rotation = FRAME_ROT_180; break;
-      case CAPTURE_ROT_270: fi->rotation = FRAME_ROT_270; break;
-      default:
-        DEBUG_WARN("Unsupported frame rotation %d", frame.rotation);
-        fi->rotation = FRAME_ROT_0;
-        break;
-    }
-
-    fi->formatVer         = frame.formatVer;
-    fi->width             = frame.width;
-    fi->height            = frame.height;
-    fi->realHeight        = frame.realHeight;
-    fi->stride            = frame.stride;
-    fi->pitch             = frame.pitch;
-    fi->offset            = pageSize - FrameBufferStructSize;
-    fi->mouseScalePercent = app.iface->getMouseScale();
-    fi->blockScreensaver  = os_blockScreensaver();
-    frameValid            = true;
-
-    // put the framebuffer on the border of the next page
-    // this is to allow for aligned DMA transfers by the receiver
-    FrameBuffer * fb = (FrameBuffer *)(((uint8_t*)fi) + fi->offset);
-    framebuffer_prepare(fb);
-
-    /* we post and then get the frame, this is intentional! */
-    if ((status = lgmpHostQueuePost(app.frameQueue, 0, app.frameMemory[app.frameIndex])) != LGMP_OK)
-    {
-      DEBUG_ERROR("%s", lgmpStatusString(status));
-      continue;
-    }
-    app.iface->getFrame(fb, frame.height);
+    if (!sendFrame())
+      break;
   }
   DEBUG_INFO("Frame thread stopped");
   return 0;
@@ -258,6 +271,9 @@ static int frameThread(void * opaque)
 bool startThreads(void)
 {
   app.state = APP_STATE_RUNNING;
+  if (!app.iface->asyncCapture)
+    return true;
+
   if (!lgCreateThread("FrameThread", frameThread, NULL, &app.frameThread))
   {
     DEBUG_ERROR("Failed to create the frame thread");
@@ -269,20 +285,25 @@ bool startThreads(void)
 
 bool stopThreads(void)
 {
-  bool ok = true;
-
   app.iface->stop();
   if (app.state != APP_STATE_SHUTDOWN)
     app.state = APP_STATE_IDLE;
 
-  if (app.frameThread && !lgJoinThread(app.frameThread, NULL))
-  {
-    DEBUG_WARN("Failed to join the frame thread");
-    ok = false;
-  }
-  app.frameThread = NULL;
+  if (!app.iface->asyncCapture)
+    return true;
 
-  return ok;
+  if (app.frameThread)
+  {
+    if (!lgJoinThread(app.frameThread, NULL))
+    {
+      DEBUG_WARN("Failed to join the frame thread");
+      app.frameThread = NULL;
+      return false;
+    }
+    app.frameThread = NULL;
+  }
+
+  return true;
 }
 
 static bool captureStart(void)
@@ -315,8 +336,8 @@ static bool captureStop(void)
 
 bool captureGetPointerBuffer(void ** data, uint32_t * size)
 {
-  PLGMPMemory mem = app.pointerMemory[app.pointerIndex];
-  *data = ((uint8_t*)lgmpHostMemPtr(mem)) + sizeof(KVMFRCursor);
+  PLGMPMemory mem = app.pointerShapeMemory[app.pointerShapeIndex];
+  *data = (uint8_t*)lgmpHostMemPtr(mem) + sizeof(KVMFRCursor);
   *size = MAX_POINTER_SIZE - sizeof(KVMFRCursor);
   return true;
 }
@@ -342,8 +363,18 @@ static void sendPointer(bool newClient)
   // new clients need the last known shape and current position
   if (newClient)
   {
+    PLGMPMemory mem;
+    if (app.pointerShapeValid)
+      mem = app.pointerShape;
+    else
+    {
+      mem = app.pointerMemory[app.pointerIndex];
+      if (++app.pointerIndex == LGMP_Q_POINTER_LEN)
+        app.pointerIndex = 0;
+    }
+
     // update the saved details with the current cursor position
-    KVMFRCursor *cursor = lgmpHostMemPtr(app.pointerShape);
+    KVMFRCursor *cursor = lgmpHostMemPtr(mem);
     cursor->x = app.pointerInfo.x;
     cursor->y = app.pointerInfo.y;
 
@@ -351,12 +382,24 @@ static void sendPointer(bool newClient)
       (app.pointerShapeValid   ? CURSOR_FLAG_SHAPE   : 0) |
       (app.pointerInfo.visible ? CURSOR_FLAG_VISIBLE : 0);
 
-    postPointer(flags, app.pointerShape);
+    postPointer(flags, mem);
     return;
   }
 
   uint32_t flags = 0;
-  PLGMPMemory mem = app.pointerMemory[app.pointerIndex];
+  PLGMPMemory mem;
+  if (app.pointerInfo.shapeUpdate)
+  {
+    mem = app.pointerShapeMemory[app.pointerShapeIndex];
+    if (++app.pointerShapeIndex == POINTER_SHAPE_BUFFERS)
+      app.pointerShapeIndex = 0;
+  }
+  else
+  {
+    mem = app.pointerMemory[app.pointerIndex];
+    if (++app.pointerIndex == LGMP_Q_POINTER_LEN)
+      app.pointerIndex = 0;
+  }
   KVMFRCursor *cursor = lgmpHostMemPtr(mem);
 
   if (app.pointerInfo.positionUpdate || newClient)
@@ -390,16 +433,9 @@ static void sendPointer(bool newClient)
     app.pointerShapeValid = true;
     flags |= CURSOR_FLAG_SHAPE;
 
-    // retain this memory for new clients
-    app.pointerMemory[app.pointerIndex] = app.pointerShape;
     app.pointerShape = mem;
   }
 
-  // only advance if the pointer shape was not swapped out of the list
-  if ((flags & CURSOR_FLAG_SHAPE) == 0)
-    if (++app.pointerIndex == POINTER_SHAPE_BUFFERS)
-      app.pointerIndex = 0;
-
   postPointer(flags, mem);
 }
 
@@ -525,34 +561,41 @@ int app_main(int argc, char * argv[])
     goto fail_lgmp;
   }
 
-  for(int i = 0; i < POINTER_SHAPE_BUFFERS; ++i)
+  for(int i = 0; i < LGMP_Q_POINTER_LEN; ++i)
   {
-    if ((status = lgmpHostMemAlloc(app.lgmp, MAX_POINTER_SIZE, &app.pointerMemory[i])) != LGMP_OK)
+    if ((status = lgmpHostMemAlloc(app.lgmp, sizeof(KVMFRCursor), &app.pointerMemory[i])) != LGMP_OK)
     {
       DEBUG_ERROR("lgmpHostMemAlloc Failed (Pointer): %s", lgmpStatusString(status));
       exitcode = LG_HOST_EXIT_FATAL;
       goto fail_lgmp;
     }
-    memset(lgmpHostMemPtr(app.pointerMemory[i]), 0, MAX_POINTER_SIZE);
+    memset(lgmpHostMemPtr(app.pointerMemory[i]), 0, sizeof(KVMFRCursor));
   }
 
-  app.pointerShapeValid = false;
-  if ((status = lgmpHostMemAlloc(app.lgmp, MAX_POINTER_SIZE, &app.pointerShape)) != LGMP_OK)
+  for(int i = 0; i < POINTER_SHAPE_BUFFERS; ++i)
   {
-    DEBUG_ERROR("lgmpHostMemAlloc Failed (Pointer Shape): %s", lgmpStatusString(status));
-    exitcode = LG_HOST_EXIT_FATAL;
-    goto fail_lgmp;
+    if ((status = lgmpHostMemAlloc(app.lgmp, MAX_POINTER_SIZE, &app.pointerShapeMemory[i])) != LGMP_OK)
+    {
+      DEBUG_ERROR("lgmpHostMemAlloc Failed (Pointer Shapes): %s", lgmpStatusString(status));
+      exitcode = LG_HOST_EXIT_FATAL;
+      goto fail_lgmp;
+    }
+    memset(lgmpHostMemPtr(app.pointerShapeMemory[i]), 0, MAX_POINTER_SIZE);
   }
 
-  const long sz = sysinfo_getPageSize();
+  app.pageSize          = sysinfo_getPageSize();
+  app.frameValid        = false;
+  app.pointerShapeValid = false;
+
   app.maxFrameSize = lgmpHostMemAvail(app.lgmp);
-  app.maxFrameSize = (app.maxFrameSize - (sz - 1)) & ~(sz - 1);
+  app.maxFrameSize = (app.maxFrameSize - (app.pageSize - 1)) & ~(app.pageSize - 1);
   app.maxFrameSize /= LGMP_Q_FRAME_LEN;
   DEBUG_INFO("Max Frame Size   : %u MiB", (unsigned int)(app.maxFrameSize / 1048576LL));
 
   for(int i = 0; i < LGMP_Q_FRAME_LEN; ++i)
   {
-    if ((status = lgmpHostMemAllocAligned(app.lgmp, app.maxFrameSize, sz, &app.frameMemory[i])) != LGMP_OK)
+    if ((status = lgmpHostMemAllocAligned(app.lgmp, app.maxFrameSize,
+            app.pageSize, &app.frameMemory[i])) != LGMP_OK)
     {
       DEBUG_ERROR("lgmpHostMemAlloc Failed (Frame): %s", lgmpStatusString(status));
       exitcode = LG_HOST_EXIT_FATAL;
@@ -594,6 +637,8 @@ int app_main(int argc, char * argv[])
   }
 
   DEBUG_INFO("Using            : %s", iface->getName());
+  DEBUG_INFO("Capture Method   : %s", iface->asyncCapture ?
+      "Asynchronous" : "Synchronous");
 
   app.state = APP_STATE_RUNNING;
   app.iface = iface;
@@ -688,6 +733,9 @@ int app_main(int argc, char * argv[])
           exitcode = LG_HOST_EXIT_FAILED;
           goto fail_capture;
       }
+
+      if (!iface->asyncCapture)
+        sendFrame();
     }
 
     if (app.state != APP_STATE_SHUTDOWN)
@@ -728,9 +776,10 @@ fail_timer:
 fail_lgmp:
   for(int i = 0; i < LGMP_Q_FRAME_LEN; ++i)
     lgmpHostMemFree(&app.frameMemory[i]);
-  for(int i = 0; i < POINTER_SHAPE_BUFFERS; ++i)
+  for(int i = 0; i < LGMP_Q_POINTER_LEN; ++i)
     lgmpHostMemFree(&app.pointerMemory[i]);
-  lgmpHostMemFree(&app.pointerShape);
+  for(int i = 0; i < POINTER_SHAPE_BUFFERS; ++i)
+    lgmpHostMemFree(&app.pointerShapeMemory[i]);
   lgmpHostFree(&app.lgmp);
 
 fail_ivshmem:

obs/main.c

@@ -22,6 +22,8 @@
 #include <common/version.h>
 #include <stdio.h>
 
+#include "common/debug.h"
+
 #ifdef _WIN32
 #undef EXPORT
 #define EXPORT __declspec(dllexport)
@@ -38,6 +40,7 @@ extern struct obs_source_info lg_source;
 
 MODULE_EXPORT bool obs_module_load(void)
 {
+  debug_init();
   printf("Looking Glass OBS Client (%s)\n", BUILD_VERSION);
   obs_register_source(&lg_source);
   return true;