#include <stddef.h>	/* NULL */

#include "../headers/glut_graphics.h"

/* each request simply sets a flag to be consumed by the main loop, (no need for more than one redraw per cycle) */
int must_redraw = 0;
const int REDRAW_TIMER_INIT = 16;
int redraw_timer = 0;

void (*redraw_callback) (void) = NULL;

void assignRedrawCallback( void ( *callback) ( void)){
	if( NULL != redraw_callback){
		return;
	}

	redraw_callback = callback;
}

void issueRedraw(){
	must_redraw = 1;
}

void consume_redraws(){
	/* ensuring a minimum interval of 1/FPS secs between redraws
		if the timer 
	*/
	redraw_timer--;
	if( redraw_timer < 0){
		redraw_timer = 0;
	}
	else{
		return;
	}

	if( 0 == must_redraw){
		return;
	}

	must_redraw = 0;

	/* what to do if the redraw callback is not set? 
		is not necessarily an error
	*/
	if( NULL == redraw_callback){
		return;
	}

	redraw_timer = REDRAW_TIMER_INIT;
	/* here the drawing implementation */
	
	redraw_callback();
}