/* ARC LENGTH
*
*/

#include <math.h>
#include <stdlib.h>
#include <stdio.h>

#define PI 3.141596535

/* #define DEBUG */
float ease(float,float,float);

float ease(float t, float k1, float k2)
{
	float f;
	float s;
	float f1,f2,f3;
  
    f1 = k1*2/PI;
    f2 = (1.0-k2)*2/PI;
	f = f1 + k2 - k1 + (1.0-k2)*2/PI;
	if (t<k1) {
		s = f1*(sin(((t/k1)*PI/2)-PI/2)+1)/f;
	}
	else if (t < k2) {
		s = (f1 + t-k1)/f;
	}
	else {
		s= (f1 + k2-k1 + f2*sin(((t-k2)/(1.0-k2))*PI/2))/f; 
	}
	return s;
}