From 0721931f5b92c96ff19bf936186bc4cf3dac38a1 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Mon, 6 Apr 2020 19:21:56 -0700
Subject: [PATCH] Avoid sending regular mouse messages for touch input

---
 src/video/windows/SDL_windowsevents.c | 18 +++++++++++++++---
 src/video/windows/SDL_windowswindow.c |  1 +
 src/video/windows/SDL_windowswindow.h |  1 +
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/video/windows/SDL_windowsevents.c b/src/video/windows/SDL_windowsevents.c
index d79d42c22..516ecdd23 100644
--- a/src/video/windows/SDL_windowsevents.c
+++ b/src/video/windows/SDL_windowsevents.c
@@ -75,6 +75,9 @@
 #ifndef WM_MOUSEHWHEEL
 #define WM_MOUSEHWHEEL 0x020E
 #endif
+#ifndef WM_POINTERUPDATE
+#define WM_POINTERUPDATE 0x0245
+#endif
 #ifndef WM_UNICHAR
 #define WM_UNICHAR 0x0109
 #endif
@@ -523,12 +526,19 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
         returnCode = 0;
         break;
 
+    case WM_POINTERUPDATE:
+        {
+            data->last_pointer_update = lParam;
+            break;
+        }
+
     case WM_MOUSEMOVE:
         {
             SDL_Mouse *mouse = SDL_GetMouse();
             if (!mouse->relative_mode || mouse->relative_mode_warp) {
                 /* Only generate mouse events for real mouse */
-                if (GetMouseMessageSource() != SDL_MOUSE_EVENT_SOURCE_TOUCH) {
+                if (GetMouseMessageSource() != SDL_MOUSE_EVENT_SOURCE_TOUCH &&
+                    lParam != data->last_pointer_update) {
                     SDL_SendMouseMotion(data->window, 0, 0, GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
                     if (isWin10FCUorNewer && mouse->relative_mode_warp) {
                         /* To work around #3931, Win10 bug introduced in Fall Creators Update, where
@@ -563,7 +573,8 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
         {
             SDL_Mouse *mouse = SDL_GetMouse();
             if (!mouse->relative_mode || mouse->relative_mode_warp) {
-                if (GetMouseMessageSource() != SDL_MOUSE_EVENT_SOURCE_TOUCH) {
+                if (GetMouseMessageSource() != SDL_MOUSE_EVENT_SOURCE_TOUCH &&
+                    lParam != data->last_pointer_update) {
                     WIN_CheckWParamMouseButtons(wParam, data, 0);
                 }
             }
@@ -589,7 +600,8 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 
             /* Mouse data (ignoring synthetic mouse events generated for touchscreens) */
             if (inp.header.dwType == RIM_TYPEMOUSE) {
-                if (GetMouseMessageSource() == SDL_MOUSE_EVENT_SOURCE_TOUCH) {
+                if (GetMouseMessageSource() == SDL_MOUSE_EVENT_SOURCE_TOUCH ||
+                    (GetMessageExtraInfo() & 0x82) == 0x82) {
                     break;
                 }
                 if (isRelative) {
diff --git a/src/video/windows/SDL_windowswindow.c b/src/video/windows/SDL_windowswindow.c
index c1162937d..ef73142ac 100644
--- a/src/video/windows/SDL_windowswindow.c
+++ b/src/video/windows/SDL_windowswindow.c
@@ -188,6 +188,7 @@ SetupWindowData(_THIS, SDL_Window * window, HWND hwnd, HWND parent, SDL_bool cre
     data->hinstance = (HINSTANCE) GetWindowLongPtr(hwnd, GWLP_HINSTANCE);
     data->created = created;
     data->mouse_button_flags = 0;
+    data->last_pointer_update = (LPARAM)-1;
     data->videodata = videodata;
     data->initializing = SDL_TRUE;
 
diff --git a/src/video/windows/SDL_windowswindow.h b/src/video/windows/SDL_windowswindow.h
index 71914122c..574a45248 100644
--- a/src/video/windows/SDL_windowswindow.h
+++ b/src/video/windows/SDL_windowswindow.h
@@ -39,6 +39,7 @@ typedef struct
     WNDPROC wndproc;
     SDL_bool created;
     WPARAM mouse_button_flags;
+    LPARAM last_pointer_update;
     SDL_bool initializing;
     SDL_bool expected_resize;
     SDL_bool in_border_change;