SDL FrameRate cap implementation

Question

I'm really new to game development and I've already made a few programs using SDL2. Frame rate wasn't much of an issue since I never planned to release those programs and just used the SDL_RENDER_PRESENTVSYNC to cap the frame rate to 60 (the refresh rate of my monitor). Now I want to make an application I can send to friends and I wanted to know if my frame-rate implementation is any good.

unsigned int a = SDL_GetTicks();
unsigned int b = SDL_GetTicks();
double delta = 0;

while (running)
{
    a = SDL_GetTicks();
    delta += a - b;

    if (delta > 1000/60.0)
    {
        std::cout << "fps: " << 1000 / delta << std::endl;

        Update();
        Render();
        delta = 0;
    }

    b = SDL_GetTicks();
}

I have a good feeling that I've messed up my calculations horribly but many of the other implementations I have found online usually seem pretty long winded. If possible I would like to keep the frame cap implementation within the game loop and as simple as possible. Any help appreciated!

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score 0 · Answer 1 · answered Feb 11 '19 at 12:02

You should put the line b = SDL_GetTicks(); inside the if statement and before the Update();. And delta = a - b instead of delta += a - b. And you could also use b=a instead of calling the SDL_GetTicks() function.

while (running)
{
    a = SDL_GetTicks();
    delta = a - b;

    if (delta > 1000/60.0)
    {
        std::cout << "fps: " << 1000 / delta << std::endl;

        b = a;    

        Update();
        Render();
    }
}

SDL FrameRate cap implementation

1 Answers1