Mouse Focus in Fullscreen Mode

1#include <SDL.h>
2#include <iostream>
3#include "Window.h"
4
5void HandleWindowEvent(SDL_WindowEvent& E,
6                       SDL_Window* Window) {
7  bool IsFullscreen = SDL_GetWindowFlags(Window)
8    & SDL_WINDOW_FULLSCREEN;
9
10  if (E.event == SDL_WINDOWEVENT_ENTER) {
11    if (!IsFullscreen) {
12      std::cout << "Window gained mouse focus\n";
13    }
14  } else if (E.event == SDL_WINDOWEVENT_LEAVE) {
15    if (!IsFullscreen) {
16      std::cout << "Window lost mouse focus\n";
17    }
18  }
19}
20
21int main(int argc, char** argv) {
22  SDL_Init(SDL_INIT_VIDEO);
23  Window GameWindow;
24
25  // Toggle fullscreen with F key
26  SDL_Event E;
27  while (true) {
28    while (SDL_PollEvent(&E)) {
29      if (E.type == SDL_KEYDOWN
30        && E.key.keysym.sym == SDLK_f) {
31        bool IsFullscreen = SDL_GetWindowFlags(
32            GameWindow.SDLWindow) &
33          SDL_WINDOW_FULLSCREEN;
34        SDL_SetWindowFullscreen(
35          GameWindow.SDLWindow,
36          IsFullscreen
37            ? 0
38            : SDL_WINDOW_FULLSCREEN);
39      } else if (E.type == SDL_WINDOWEVENT) {
40        HandleWindowEvent(E.window,
41                          GameWindow.SDLWindow);
42      }
43    }
44    GameWindow.Update();
45  }
46
47  SDL_Quit();
48  return 0;
49}

1#include <SDL.h>
2#include <iostream>
3#include "Window.h"
4
5void MonitorMousePosition(SDL_Window* Window) {
6  int MouseX, MouseY;
7  SDL_GetGlobalMouseState(&MouseX, &MouseY);
8
9  int DisplayIndex{
10    SDL_GetWindowDisplayIndex(Window)};
11  SDL_Rect DisplayBounds;
12  SDL_GetDisplayBounds(DisplayIndex,
13                       &DisplayBounds);
14
15  bool MouseOnSameDisplay{
16    MouseX >= DisplayBounds.x &&
17    MouseX < DisplayBounds.x + DisplayBounds.w &&
18    MouseY >= DisplayBounds.y &&
19    MouseY < DisplayBounds.y + DisplayBounds.h
20  };
21
22  std::cout << "\nMouse on game display: "
23    << (MouseOnSameDisplay ? "yes" : "no");
24}
25
26int main(int argc, char** argv) {
27  SDL_Init(SDL_INIT_VIDEO);
28  Window GameWindow;
29  SDL_Event E;
30
31  while (true) {
32    while (SDL_PollEvent(&E)) {
33      if (E.type == SDL_MOUSEMOTION) {
34        MonitorMousePosition(
35          GameWindow.SDLWindow);
36      }
37    }
38    GameWindow.Update();
39  }
40
41  SDL_Quit();
42  return 0;
43}