Implementing a Basic Game Loop with SDL2

1#include <SDL.h>
2
3const int FPS = 60;
4const int DELAY_TIME = 1000.0f / FPS;
5
6int main(int argc, char** argv) {
7  SDL_Init(SDL_INIT_VIDEO);
8
9  SDL_Window* window{SDL_CreateWindow(
10    "Game Loop Example",
11    SDL_WINDOWPOS_CENTERED,
12    SDL_WINDOWPOS_CENTERED,
13    800, 600, SDL_WINDOW_SHOWN
14  )};
15
16  SDL_Renderer* renderer{SDL_CreateRenderer(
17    window, -1, 0)};
18
19  Uint32 frameStart, frameTime;
20
21  bool quit{false};
22  while (!quit) {
23    frameStart = SDL_GetTicks();  
24
25    // 1. Handle events
26    SDL_Event e;
27    while (SDL_PollEvent(&e)) {
28      if (e.type == SDL_QUIT) {
29        quit = true;
30      }
31    }
32
33    // 2. Update game state
34    // ...
35
36    // 3. Render
37    SDL_SetRenderDrawColor(
38      renderer, 0, 0, 0, 255);
39    SDL_RenderClear(renderer);
40
41    // Render game objects
42    // ...
43
44    SDL_RenderPresent(renderer);
45
46    frameTime = SDL_GetTicks() - frameStart;  
47
48    if (frameTime < DELAY_TIME) {
49      SDL_Delay((int)(DELAY_TIME - frameTime));  
50    }
51  }
52
53  SDL_DestroyRenderer(renderer);
54  SDL_DestroyWindow(window);
55  SDL_Quit();
56
57  return 0;
58}