SDL: SDL_windowsevents: add support for multiple mice

From c2e8a791bbd80c4e631984a286fc5b5873ae412a Mon Sep 17 00:00:00 2001
From: scribam <[EMAIL REDACTED]>
Date: Sat, 12 Jun 2021 16:20:47 +0200
Subject: [PATCH] SDL_windowsevents: add support for multiple mice

---
 src/video/windows/SDL_windowsevents.c | 42 ++++++++++++++-------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/src/video/windows/SDL_windowsevents.c b/src/video/windows/SDL_windowsevents.c
index 2d47759f0..06857d724 100644
--- a/src/video/windows/SDL_windowsevents.c
+++ b/src/video/windows/SDL_windowsevents.c
@@ -294,31 +294,31 @@ WIN_CheckWParamMouseButtons(WPARAM wParam, SDL_WindowData *data, SDL_MouseID mou
 }
 
 static void
-WIN_CheckRawMouseButtons(ULONG rawButtons, SDL_WindowData *data)
+WIN_CheckRawMouseButtons(ULONG rawButtons, SDL_WindowData *data, SDL_MouseID mouseID)
 {
     if (rawButtons != data->mouse_button_flags) {
         Uint32 mouseFlags = SDL_GetMouseState(NULL, NULL);
         SDL_bool swapButtons = GetSystemMetrics(SM_SWAPBUTTON) != 0;
         if ((rawButtons & RI_MOUSE_BUTTON_1_DOWN))
-            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_1_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_LEFT, 0);
+            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_1_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_LEFT, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_1_UP))
-            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_1_UP), mouseFlags, swapButtons, data, SDL_BUTTON_LEFT, 0);
+            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_1_UP), mouseFlags, swapButtons, data, SDL_BUTTON_LEFT, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_2_DOWN))
-            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_2_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_RIGHT, 0);
+            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_2_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_RIGHT, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_2_UP))
-            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_2_UP), mouseFlags, swapButtons, data, SDL_BUTTON_RIGHT, 0);
+            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_2_UP), mouseFlags, swapButtons, data, SDL_BUTTON_RIGHT, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_3_DOWN))
-            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_3_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_MIDDLE, 0);
+            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_3_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_MIDDLE, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_3_UP))
-            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_3_UP), mouseFlags, swapButtons, data, SDL_BUTTON_MIDDLE, 0);
+            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_3_UP), mouseFlags, swapButtons, data, SDL_BUTTON_MIDDLE, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_4_DOWN))
-            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_4_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_X1, 0);
+            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_4_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_X1, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_4_UP))
-            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_4_UP), mouseFlags, swapButtons, data, SDL_BUTTON_X1, 0);
+            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_4_UP), mouseFlags, swapButtons, data, SDL_BUTTON_X1, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_5_DOWN))
-            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_5_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_X2, 0);
+            WIN_CheckWParamMouseButton((rawButtons & RI_MOUSE_BUTTON_5_DOWN), mouseFlags, swapButtons, data, SDL_BUTTON_X2, mouseID);
         if ((rawButtons & RI_MOUSE_BUTTON_5_UP))
-            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_5_UP), mouseFlags, swapButtons, data, SDL_BUTTON_X2, 0);
+            WIN_CheckWParamMouseButton(!(rawButtons & RI_MOUSE_BUTTON_5_UP), mouseFlags, swapButtons, data, SDL_BUTTON_X2, mouseID);
         data->mouse_button_flags = rawButtons;
     }
 }
@@ -714,15 +714,17 @@ 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) {
+                SDL_MouseID mouseID;
                 if (SDL_GetNumTouchDevices() > 0 &&
                     (GetMouseMessageSource() == SDL_MOUSE_EVENT_SOURCE_TOUCH || (GetMessageExtraInfo() & 0x82) == 0x82)) {
                     break;
                 }
+                mouseID = (SDL_MouseID)(uintptr_t)inp.header.hDevice;
                 if (isRelative) {
                     RAWMOUSE* rawmouse = &inp.data.mouse;
 
                     if ((rawmouse->usFlags & 0x01) == MOUSE_MOVE_RELATIVE) {
-                        SDL_SendMouseMotion(data->window, 0, 1, (int)rawmouse->lLastX, (int)rawmouse->lLastY);
+                        SDL_SendMouseMotion(data->window, mouseID, 1, (int)rawmouse->lLastX, (int)rawmouse->lLastY);
                     } else if (rawmouse->lLastX || rawmouse->lLastY) {
                         /* synthesize relative moves from the abs position */
                         static SDL_Point lastMousePoint;
@@ -737,12 +739,12 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
                             lastMousePoint.y = y;
                         }
 
-                        SDL_SendMouseMotion(data->window, 0, 1, (int)(x-lastMousePoint.x), (int)(y-lastMousePoint.y));
+                        SDL_SendMouseMotion(data->window, mouseID, 1, (int)(x-lastMousePoint.x), (int)(y-lastMousePoint.y));
 
                         lastMousePoint.x = x;
                         lastMousePoint.y = y;
                     }
-                    WIN_CheckRawMouseButtons(rawmouse->usButtonFlags, data);
+                    WIN_CheckRawMouseButtons(rawmouse->usButtonFlags, data, mouseID);
                 } else if (isCapture) {
                     /* we check for where Windows thinks the system cursor lives in this case, so we don't really lose mouse accel, etc. */
                     POINT pt;
@@ -758,12 +760,12 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
                     if(currentHnd != hwnd || pt.x < 0 || pt.y < 0 || pt.x > hwndRect.right || pt.y > hwndRect.right) {
                         SDL_bool swapButtons = GetSystemMetrics(SM_SWAPBUTTON) != 0;
 
-                        SDL_SendMouseMotion(data->window, 0, 0, (int)pt.x, (int)pt.y);
-                        SDL_SendMouseButton(data->window, 0, GetAsyncKeyState(VK_LBUTTON) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, !swapButtons ? SDL_BUTTON_LEFT : SDL_BUTTON_RIGHT);
-                        SDL_SendMouseButton(data->window, 0, GetAsyncKeyState(VK_RBUTTON) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, !swapButtons ? SDL_BUTTON_RIGHT : SDL_BUTTON_LEFT);
-                        SDL_SendMouseButton(data->window, 0, GetAsyncKeyState(VK_MBUTTON) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, SDL_BUTTON_MIDDLE);
-                        SDL_SendMouseButton(data->window, 0, GetAsyncKeyState(VK_XBUTTON1) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, SDL_BUTTON_X1);
-                        SDL_SendMouseButton(data->window, 0, GetAsyncKeyState(VK_XBUTTON2) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, SDL_BUTTON_X2);
+                        SDL_SendMouseMotion(data->window, mouseID, 0, (int)pt.x, (int)pt.y);
+                        SDL_SendMouseButton(data->window, mouseID, GetAsyncKeyState(VK_LBUTTON) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, !swapButtons ? SDL_BUTTON_LEFT : SDL_BUTTON_RIGHT);
+                        SDL_SendMouseButton(data->window, mouseID, GetAsyncKeyState(VK_RBUTTON) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, !swapButtons ? SDL_BUTTON_RIGHT : SDL_BUTTON_LEFT);
+                        SDL_SendMouseButton(data->window, mouseID, GetAsyncKeyState(VK_MBUTTON) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, SDL_BUTTON_MIDDLE);
+                        SDL_SendMouseButton(data->window, mouseID, GetAsyncKeyState(VK_XBUTTON1) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, SDL_BUTTON_X1);
+                        SDL_SendMouseButton(data->window, mouseID, GetAsyncKeyState(VK_XBUTTON2) & 0x8000 ? SDL_PRESSED : SDL_RELEASED, SDL_BUTTON_X2);
                     }
                 } else {
                     SDL_assert(0 && "Shouldn't happen");