Timer Support

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Procedure:

(sdl-delay ms) → void

Parameters:

ms : A number. The number of milliseconds to delay.

C Function Name:

SDL_Delay

Other Docs:

SDL Wiki

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Procedure:

(sdl-get-ticks) → number

Returns:

Number of milliseconds since the SDL library initialized.

C Function Name:

SDL_GetTicks

Other Docs:

SDL Wiki

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Procedure:

(sdl-get-performance-counter) → number

Returns:

The current counter value.

C Function Name:

SDL_GetPerformanceCounter

Other Docs:

SDL Wiki

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Procedure:

(sdl-get-performance-frequency) → number

Returns:

A platform-specific count per second.

C Function Name:

SDL_GetPerformanceFrequency

Other Docs:

SDL Wiki

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Procedure:

(sdl-add-timer! interval procedure) → sdl-timer-id

Parameters:

interval : A number. Delay in milliseconds.

procedure : A procedure of 1 argument. Must return a number which is the new delay interval.

Returns:

A number representing the timer id. If id is 0 an error occured.

C Function Name:

SDL_AddTimer

Other Docs:

SDL Wiki

Examples:

(define my-timer
  (sdl-add-timer! 500
    (lambda (interval)
      (printf "~d~n" interval)
      interval)))

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Procedure:

(sdl-remove-timer! timer-id) → number

Parameters:

timer-id : A number created by calling sdl-add-timer!.

Returns:

SDL-TRUE or SDL-FALSE.

C Function Name:

SDL_RemoveTimer

Other Docs:

SDL Wiki