Backends: Win32, SDL, GLFW: only honor io.WantSetMousePos when focused + fix GLFW uninstalling handler + tweaks to reduce branch drift with docking. (#787, #2445, #2696, #3751, #4377)

ocornut · ocornut · commit 2ad912bb854c · 2021-08-02T16:19:50.000+02:00
diff --git a/backends/imgui_impl_glfw.cpp b/backends/imgui_impl_glfw.cpp
@@ -55,7 +55,7 @@
 #define GLFW_HAS_WINDOW_ALPHA         (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3300) // 3.3+ glfwSetWindowOpacity
 #define GLFW_HAS_PER_MONITOR_DPI      (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3300) // 3.3+ glfwGetMonitorContentScale
 #define GLFW_HAS_VULKAN               (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3200) // 3.2+ glfwCreateWindowSurface
-#ifdef GLFW_RESIZE_NESW_CURSOR  // let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2019-11-29 (cursors defines) // FIXME: Remove when GLFW 3.4 is released?
+#ifdef GLFW_RESIZE_NESW_CURSOR        // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2019-11-29 (cursors defines) // FIXME: Remove when GLFW 3.4 is released?
 #define GLFW_HAS_NEW_CURSORS          (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3400) // 3.4+ GLFW_RESIZE_ALL_CURSOR, GLFW_RESIZE_NESW_CURSOR, GLFW_RESIZE_NWSE_CURSOR, GLFW_NOT_ALLOWED_CURSOR
 #else
 #define GLFW_HAS_NEW_CURSORS          (0)
@@ -116,7 +116,7 @@ static void ImGui_ImplGlfw_SetClipboardText(void* user_data, const char* text)
 void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int action, int mods)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackMousebutton != NULL)
+    if (bd->PrevUserCallbackMousebutton != NULL && window == bd->Window)
         bd->PrevUserCallbackMousebutton(window, button, action, mods);
 
     if (action == GLFW_PRESS && button >= 0 && button < IM_ARRAYSIZE(bd->MouseJustPressed))
@@ -126,7 +126,7 @@ void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int acti
 void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yoffset)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackScroll != NULL)
+    if (bd->PrevUserCallbackScroll != NULL && window == bd->Window)
         bd->PrevUserCallbackScroll(window, xoffset, yoffset);
 
     ImGuiIO& io = ImGui::GetIO();
@@ -137,7 +137,7 @@ void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yo
 void ImGui_ImplGlfw_KeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackKey != NULL)
+    if (bd->PrevUserCallbackKey != NULL && window == bd->Window)
         bd->PrevUserCallbackKey(window, key, scancode, action, mods);
 
     ImGuiIO& io = ImGui::GetIO();
@@ -174,7 +174,7 @@ void ImGui_ImplGlfw_CursorEnterCallback(GLFWwindow* window, int entered)
 void ImGui_ImplGlfw_CharCallback(GLFWwindow* window, unsigned int c)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackChar != NULL)
+    if (bd->PrevUserCallbackChar != NULL && window == bd->Window)
         bd->PrevUserCallbackChar(window, c);
 
     ImGuiIO& io = ImGui::GetIO();
@@ -298,6 +298,7 @@ void ImGui_ImplGlfw_Shutdown()
 
     if (bd->InstalledCallbacks)
     {
+        glfwSetCursorEnterCallback(bd->Window, bd->PrevUserCallbackCursorEnter);
         glfwSetMouseButtonCallback(bd->Window, bd->PrevUserCallbackMousebutton);
         glfwSetScrollCallback(bd->Window, bd->PrevUserCallbackScroll);
         glfwSetKeyCallback(bd->Window, bd->PrevUserCallbackKey);
@@ -316,32 +317,32 @@ void ImGui_ImplGlfw_Shutdown()
 static void ImGui_ImplGlfw_UpdateMousePosAndButtons()
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-
-    // Update buttons
     ImGuiIO& io = ImGui::GetIO();
+
+    const ImVec2 mouse_pos_prev = io.MousePos;
+    io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
+
+    // Update mouse buttons
+    // (if a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame)
     for (int i = 0; i < IM_ARRAYSIZE(io.MouseDown); i++)
     {
-        // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
         io.MouseDown[i] = bd->MouseJustPressed[i] || glfwGetMouseButton(bd->Window, i) != 0;
         bd->MouseJustPressed[i] = false;
     }
 
 #ifdef __EMSCRIPTEN__
-    const bool focused = true; // Emscripten
+    const bool focused = true;
 #else
     const bool focused = glfwGetWindowAttrib(bd->Window, GLFW_FOCUSED) != 0;
 #endif
     GLFWwindow* mouse_window = (bd->MouseWindow == bd->Window || focused) ? bd->Window : NULL;
 
-    // Update mouse position
-    const ImVec2 mouse_pos_backup = io.MousePos;
-    io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
-    if (io.WantSetMousePos)
-    {
-        if (focused)
-            glfwSetCursorPos(bd->Window, (double)mouse_pos_backup.x, (double)mouse_pos_backup.y);
-    }
-    else if (mouse_window != NULL)
+    // Set OS mouse position from Dear ImGui if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
+    if (io.WantSetMousePos && focused)
+        glfwSetCursorPos(bd->Window, (double)mouse_pos_prev.x, (double)mouse_pos_prev.y);
+
+    // Set Dear ImGui mouse position from OS position
+    if (mouse_window != NULL)
     {
         double mouse_x, mouse_y;
         glfwGetCursorPos(mouse_window, &mouse_x, &mouse_y);
diff --git a/backends/imgui_impl_sdl.cpp b/backends/imgui_impl_sdl.cpp
@@ -59,10 +59,11 @@
 #include "TargetConditionals.h"
 #endif
 
-#define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    SDL_VERSION_ATLEAST(2,0,4)
+#define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    (SDL_VERSION_ATLEAST(2,0,4) && !defined(__EMSCRIPTEN__) && !defined(__ANDROID__) && !(defined(__APPLE__) && TARGET_OS_IOS))
 #define SDL_HAS_MOUSE_FOCUS_CLICKTHROUGH    SDL_VERSION_ATLEAST(2,0,5)
 #define SDL_HAS_VULKAN                      SDL_VERSION_ATLEAST(2,0,6)
 
+// SDL Data
 struct ImGui_ImplSDL2_Data
 {
     SDL_Window* Window;
@@ -156,6 +157,17 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window)
     ImGuiIO& io = ImGui::GetIO();
     IM_ASSERT(io.BackendPlatformUserData == NULL && "Already initialized a platform backend!");
 
+    // Check and store if we are on a SDL backend that supports global mouse position
+    // ("wayland" and "rpi" don't support it, but we chose to use a white-list instead of a black-list)
+    const char* sdl_backend = SDL_GetCurrentVideoDriver();
+    const char* global_mouse_whitelist[] = { "windows", "cocoa", "x11", "DIVE", "VMAN" };
+    bool mouse_can_use_global_state = false;
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+    for (int n = 0; n < IM_ARRAYSIZE(global_mouse_whitelist); n++)
+        if (strncmp(sdl_backend, global_mouse_whitelist[n], strlen(global_mouse_whitelist[n])) == 0)
+            mouse_can_use_global_state = true;
+#endif
+
     // Setup backend capabilities flags
     ImGui_ImplSDL2_Data* bd = IM_NEW(ImGui_ImplSDL2_Data)();
     io.BackendPlatformUserData = (void*)bd;
@@ -164,6 +176,7 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;        // We can honor io.WantSetMousePos requests (optional, rarely used)
 
     bd->Window = window;
+    bd->MouseCanUseGlobalState = mouse_can_use_global_state;
 
     // Keyboard mapping. Dear ImGui will use those indices to peek into the io.KeysDown[] array.
     io.KeyMap[ImGuiKey_Tab] = SDL_SCANCODE_TAB;
@@ -204,20 +217,11 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window)
     bd->MouseCursors[ImGuiMouseCursor_Hand] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_HAND);
     bd->MouseCursors[ImGuiMouseCursor_NotAllowed] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_NO);
 
-    // Check and store if we are on a SDL backend that supports global mouse position
-    // ("wayland" and "rpi" don't support it, but we chose to use a white-list instead of a black-list)
-    const char* sdl_backend = SDL_GetCurrentVideoDriver();
-    const char* global_mouse_whitelist[] = { "windows", "cocoa", "x11", "DIVE", "VMAN" };
-    bd->MouseCanUseGlobalState = false;
-    for (int n = 0; n < IM_ARRAYSIZE(global_mouse_whitelist); n++)
-        if (strncmp(sdl_backend, global_mouse_whitelist[n], strlen(global_mouse_whitelist[n])) == 0)
-            bd->MouseCanUseGlobalState = true;
-
 #ifdef _WIN32
-    SDL_SysWMinfo wmInfo;
-    SDL_VERSION(&wmInfo.version);
-    SDL_GetWindowWMInfo(window, &wmInfo);
-    io.ImeWindowHandle = wmInfo.info.win.window;
+    SDL_SysWMinfo info;
+    SDL_VERSION(&info.version);
+    if (SDL_GetWindowWMInfo(window, &info))
+        io.ImeWindowHandle = info.info.win.window;
 #else
     (void)window;
 #endif
@@ -278,55 +282,59 @@ void ImGui_ImplSDL2_Shutdown()
 
 static void ImGui_ImplSDL2_UpdateMousePosAndButtons()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    ImGuiIO& io = ImGui::GetIO();
 
-    // Set OS mouse position if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
-    if (io.WantSetMousePos)
-        SDL_WarpMouseInWindow(bd->Window, (int)io.MousePos.x, (int)io.MousePos.y);
-    else
-        io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
+    ImVec2 mouse_pos_prev = io.MousePos;
+    io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
 
-    int mx, my;
-    Uint32 mouse_buttons = SDL_GetMouseState(&mx, &my);
+    // Update mouse buttons
+    int mouse_x_local, mouse_y_local;
+    Uint32 mouse_buttons = SDL_GetMouseState(&mouse_x_local, &mouse_y_local);
     io.MouseDown[0] = bd->MousePressed[0] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_LEFT)) != 0;  // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
     io.MouseDown[1] = bd->MousePressed[1] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_RIGHT)) != 0;
     io.MouseDown[2] = bd->MousePressed[2] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_MIDDLE)) != 0;
     bd->MousePressed[0] = bd->MousePressed[1] = bd->MousePressed[2] = false;
 
-#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE && !defined(__EMSCRIPTEN__) && !defined(__ANDROID__) && !(defined(__APPLE__) && TARGET_OS_IOS)
-    SDL_Window* focused_window = SDL_GetKeyboardFocus(); // Mouse position won't be reported unless window is focused.
-#if SDL_HAS_MOUSE_FOCUS_CLICKTHROUGH
-    SDL_Window* hovered_window = SDL_GetMouseFocus();    // This is better but is only reliably useful with SDL 2.0.5+ and SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH enabled.
-    SDL_Window* mouse_window = (bd->Window == focused_window || bd->Window == hovered_window) ? bd->Window : NULL;
+    // Obtain focused and hovered window. We forward mouse input when focused or when hovered (and no other window is capturing)
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+    SDL_Window* focused_window = SDL_GetKeyboardFocus();
+    SDL_Window* hovered_window = SDL_HAS_MOUSE_FOCUS_CLICKTHROUGH ? SDL_GetMouseFocus() : NULL; // This is better but is only reliably useful with SDL 2.0.5+ and SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH.
+    SDL_Window* mouse_window = NULL;
+    if (hovered_window && bd->Window == hovered_window)
+        mouse_window = hovered_window;
+    else if (focused_window && bd->Window == focused_window)
+        mouse_window = focused_window;
+
+    // SDL_CaptureMouse() let the OS know e.g. that our imgui drag outside the SDL window boundaries shouldn't e.g. trigger other operations outside
+    SDL_CaptureMouse(ImGui::IsAnyMouseDown() ? SDL_TRUE : SDL_FALSE);
 #else
-    SDL_Window* mouse_window = (bd->Window == focused_window) ? bd->Window : NULL;
+    // SDL 2.0.3 and non-windowed systems: single-viewport only
+    SDL_Window* mouse_window = (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_INPUT_FOCUS) ? bd->Window : NULL;
 #endif
-    if (mouse_window != NULL)
+
+    if (mouse_window == NULL)
+       return;
+
+    // Set OS mouse position from Dear ImGui if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
+    if (io.WantSetMousePos)
+        SDL_WarpMouseInWindow(bd->Window, (int)mouse_pos_prev.x, (int)mouse_pos_prev.y);
+
+    // Set Dear ImGui mouse position from OS position + get buttons. (this is the common behavior)
+    if (bd->MouseCanUseGlobalState)
     {
-        if (bd->MouseCanUseGlobalState)
-        {
-            // SDL_GetMouseState() gives mouse position seemingly based on the last window entered/focused(?)
-            // The creation of a new windows at runtime and SDL_CaptureMouse both seems to severely mess up with that, so we retrieve that position globally.
-            // Won't use this workaround on SDL backends that have no global mouse position, like Wayland or RPI
-            int wx, wy;
-            SDL_GetWindowPosition(mouse_window, &wx, &wy);
-            SDL_GetGlobalMouseState(&mx, &my);
-            mx -= wx;
-            my -= wy;
-        }
-        io.MousePos = ImVec2((float)mx, (float)my);
+        // Single-viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
+        // Unlike local position obtained earlier this will be valid when straying out of bounds.
+        int mouse_x_global, mouse_y_global;
+        SDL_GetGlobalMouseState(&mouse_x_global, &mouse_y_global);
+        int window_x, window_y;
+        SDL_GetWindowPosition(mouse_window, &window_x, &window_y);
+        io.MousePos = ImVec2((float)(mouse_x_global - window_x), (float)(mouse_y_global - window_y));
+    }
+    else
+    {
+        io.MousePos = ImVec2((float)mouse_x_local, (float)mouse_y_local);
     }
-
-    // SDL_CaptureMouse() let the OS know e.g. that our imgui drag outside the SDL window boundaries shouldn't e.g. trigger the OS window resize cursor.
-    // The function is only supported from SDL 2.0.4 (released Jan 2016)
-    bool any_mouse_button_down = ImGui::IsAnyMouseDown();
-    SDL_CaptureMouse(any_mouse_button_down ? SDL_TRUE : SDL_FALSE);
-#else
-    // SDL 2.0.3 and non-windowed systems
-    if (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_INPUT_FOCUS)
-        io.MousePos = ImVec2((float)mx, (float)my);
-#endif
 }
 
 static void ImGui_ImplSDL2_UpdateMouseCursor()
@@ -393,9 +401,9 @@ static void ImGui_ImplSDL2_UpdateGamepads()
 
 void ImGui_ImplSDL2_NewFrame()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
     IM_ASSERT(bd != NULL && "Did you call ImGui_ImplSDL2_Init()?");
+    ImGuiIO& io = ImGui::GetIO();
 
     // Setup display size (every frame to accommodate for window resizing)
     int w, h;
diff --git a/backends/imgui_impl_win32.cpp b/backends/imgui_impl_win32.cpp
@@ -219,31 +219,36 @@ static bool ImGui_ImplWin32_UpdateMouseCursor()
 
 static void ImGui_ImplWin32_UpdateMousePos()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    ImGuiIO& io = ImGui::GetIO();
     IM_ASSERT(bd->hWnd != 0);
 
-    // Set OS mouse position if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
-    if (io.WantSetMousePos)
-    {
-        POINT pos = { (int)io.MousePos.x, (int)io.MousePos.y };
-        if (::ClientToScreen(bd->hWnd, &pos))
-            ::SetCursorPos(pos.x, pos.y);
-    }
-
-    // Set mouse position
+    const ImVec2 mouse_pos_prev = io.MousePos;
     io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
+
+    // Obtain focused and hovered window. We forward mouse input when focused or when hovered (and no other window is capturing)
     HWND focused_window = ::GetForegroundWindow();
     HWND hovered_window = bd->MouseHwnd;
     HWND mouse_window = NULL;
-    if (hovered_window && (hovered_window == bd->hWnd) || ::IsChild(hovered_window, bd->hWnd))
+    if (hovered_window && (hovered_window == bd->hWnd || ::IsChild(hovered_window, bd->hWnd)))
         mouse_window = hovered_window;
-    else if (focused_window && (focused_window == bd->hWnd) || ::IsChild(focused_window, bd->hWnd))
+    else if (focused_window && (focused_window == bd->hWnd || ::IsChild(focused_window, bd->hWnd)))
         mouse_window = focused_window;
+    if (mouse_window == NULL)
+        return;
+
+    // Set OS mouse position from Dear ImGui if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
+    if (io.WantSetMousePos)
+    {
+        POINT pos = { (int)mouse_pos_prev.x, (int)mouse_pos_prev.y };
+        if (::ClientToScreen(bd->hWnd, &pos))
+            ::SetCursorPos(pos.x, pos.y);
+    }
+
+    // Set Dear ImGui mouse position from OS position
     POINT pos;
-    if (mouse_window)
-        if (::GetCursorPos(&pos) && ::ScreenToClient(mouse_window, &pos))
-            io.MousePos = ImVec2((float)pos.x, (float)pos.y);
+    if (::GetCursorPos(&pos) && ::ScreenToClient(mouse_window, &pos))
+        io.MousePos = ImVec2((float)pos.x, (float)pos.y);
 }
 
 // Gamepad navigation mapping
