Display Settings and Game Restart

Games may require restarts for display setting changes due to several technical factors:

Engine Architecture

Some game engines initialize critical systems based on the display settings during startup. These might include:

• Memory allocation for rendering buffers
• Creation of rendering contexts and pipelines
• Loading of shaders and textures at specific resolutions
• Setup of post-processing effects

Changing these settings while the game is running could require complex reconstruction of these systems, which might be risky or impractical.

Resource Management

Games often load and optimize resources based on the initial display settings:

1class ResourceManager {
2  std::vector<SDL_Texture*> TextureCache;
3  SDL_Renderer* Renderer;
4  int CurrentWidth;
5  int CurrentHeight;
6
7public:
8  ResourceManager(
9    SDL_Renderer* R, int W, int H
10  ) : Renderer{R},
11      CurrentWidth{W},
12      CurrentHeight{H}
13  {
14    // Resources loaded and optimized for
15    // this resolution
16    LoadResources();
17  }
18
19private:
20  void LoadResources() {
21    // Load textures at appropriate sizes
22    // for current resolution
23    // ...
24    
25    // Calculate mipmap chains
26    // ...
27    
28    // Set up render targets
29    // ...
30  }
31};

Changing resolution might require reloading these resources, which could be time-consuming and memory-intensive during gameplay.

Safe Implementation

For games that do support instant changes, careful implementation is required:

1#include <SDL.h>
2
3class DynamicRenderer {
4  SDL_Window* Window;
5  SDL_Renderer* Renderer;
6
7  bool RecreateRenderer() {
8    // Destroy old renderer and resources
9    if (Renderer) {
10      SDL_DestroyRenderer(Renderer);
11    }
12
13    // Create new renderer for current settings
14    Renderer = SDL_CreateRenderer(
15      Window, -1,
16      SDL_RENDERER_ACCELERATED
17    );
18
19    return Renderer != nullptr;
20  }
21
22public:
23  bool ChangeDisplayMode(
24    const SDL_DisplayMode& Mode) {
25    // Apply new mode
26    if (SDL_SetWindowDisplayMode(
27      Window, &Mode) < 0) {
28      return false;
29    }
30
31    // Recreate renderer for new settings
32    return RecreateRenderer();
33  }
34};

The choice between instant changes and requiring a restart often comes down to balancing technical complexity against user convenience.