Smooth Fullscreen Transitions
How can I smoothly transition between windowed and fullscreen modes without the screen going black?
Creating smooth transitions between window modes requires careful coordination of several SDL operations. Here's a comprehensive approach.
Basic Implementation
Here's a basic framework that allows us to attach additional steps to the process of toggling the fullscreen mode of a window:
#include <SDL.h>
bool SmoothToggleFullscreen(
SDL_Window* Window
) {
// Store current window position and size
int PrevX{}, PrevY{}, PrevW{}, PrevH{};
SDL_GetWindowPosition(Window, &PrevX, &PrevY);
SDL_GetWindowSize(Window, &PrevW, &PrevH);
// Get current fullscreen state
Uint32 Flags{SDL_GetWindowFlags(Window)};
bool IsFullscreen{(
Flags & SDL_WINDOW_FULLSCREEN_DESKTOP
) != 0};
// Disable fullscreen before changing
// window properties
if (IsFullscreen) {
SDL_SetWindowFullscreen(Window, 0);
}
// Update window properties while it's in
// windowed mode
SDL_SetWindowBordered(Window,
IsFullscreen ? SDL_TRUE : SDL_FALSE);
SDL_SetWindowResizable(Window,
IsFullscreen ? SDL_TRUE : SDL_FALSE);
// Enable fullscreen after window properties
// are set
if (!IsFullscreen) {
SDL_SetWindowFullscreen(
Window, SDL_WINDOW_FULLSCREEN_DESKTOP);
} else {
// Restore previous window position and size
SDL_SetWindowSize(Window, PrevW, PrevH);
SDL_SetWindowPosition(Window, PrevX, PrevY);
}
return true;
}Handling Rendering During Transition
To prevent visual artifacts during the transition, you should handle the rendering appropriately:
#include <SDL.h>
void RenderDuringTransition(
SDL_Window* Window, SDL_Renderer* Renderer
) {
// Clear with a solid color to prevent flickering
SDL_SetRenderDrawColor(Renderer, 0, 0, 0, 255);
SDL_RenderClear(Renderer);
// Render your game content here
// ...
// Present immediately to minimize black frames
SDL_RenderPresent(Renderer);
// Small delay to let the window manager catch up
SDL_Delay(50);
}The key to smooth transitions is managing the window properties in the correct order and maintaining continuous rendering throughout the process. Using desktop fullscreen mode (SDL_WINDOW_FULLSCREEN_DESKTOP) generally provides smoother transitions than exclusive fullscreen.
Fullscreen Windows
Learn how to create and manage fullscreen windows in SDL, including desktop and exclusive fullscreen modes.