ncatalani / fpsloop

C library for managing game loop

FPSLoop

A good & simple gameplay loop for C and SDL2.

Dependencies

• A C compiler
• SDL2

Building

The easiest way is just to run make, which will build the shared lib & the test program. There are other methods in the Makefile as well.

Example

// Return 1 to exit, 0 to keep going
int frame()
{
    // Keep going forever
    return 0;
}

int main()
{
    FPSLoop* fps = FPSLoop_Create(
        // How should the app keep time?
        FPSLOOP_TYPE_SLEEPSMART,
        // How many frames per second?
        60,
        // Pointer to the function that holds your game logic
        frame
    );
    
    // Your application will run inside this function
    // It will stop running when your logic function has decided to close
    FPSLoop_Run(fps);
    
    // Free the FPSLoop* memory
    FPSLoop_Destroy(fps);
    
    return 0;
}

Loop Types

You can change the Loop Type mid-application:

FPSLoop_SetLoopType(fps, FPSLOOP_TYPE_SLEEP); // replace _SLEEP with your desired loop type

The enum FPSLoop_Type contains several values:

BURNCPU

This type should have the closest thing to perfect timing, at the cost of a lot of CPU power.

SLEEP

This type will use the least CPU power, but will also potentially sacrifice accurate timing.

SLEEPSMART

This type combines BURNCPU and SLEEP to use a little more CPU power & get a lot more accuracy.

NOTHING

This type does nothing for timing whatsoever. This might be useful if you explicitly use vsync, but also it really might not.

Other Methods

GetAverageFPS

float FPSLoop_GetAverageFPS(FPSLoop*) will return a float value of the average of the last 120 frames (or a different number, if given a compiler flag for FPSLOOP_FRAME_PERFORMANCE_COUNT).

GetLoopTypeString

char* FPSLoop_GetLoopTypeString(FPSLoop*) will return a string denoting which loop type is being used for the given FPSLoop instance.

GetLoopTypeStringFromType

char* FPSLoop_GetLoopTypeStringFromType(FPSLoop_Type) will return a string corresponding to the given FPSLoop_Type value.