#ifndef _COMMON_GLSL
#define _COMMON_GLSL

#ifndef TWOPI
#define TWOPI 6.28318530718
#endif

#ifndef PI
#define PI 3.14159265359
#endif

/* Window value t that resides in range [0, sz] */
#define window(t, sz) (0.53836 - (0.46164 * cos(TWOPI * t / sz)))
#define window_frame(t, sz) (0.6 - (0.4 * cos(TWOPI * t / sz)))
#define window_shallow(t, sz) (0.7 - (0.3 * cos(TWOPI * t / sz)))
/* Do nothing (used as an option for configuration) */
#define linear(x) (x)
/* Take value x that scales linearly between [0, 1) and return its sinusoidal curve */
#define sinusoidal(x) ((0.5 * sin((PI * (x)) - (PI / 2))) + 0.5)
/* Take value x that scales linearly between [0, 1) and return its circlar curve */
#define circular(x) sqrt(1 - (((x) - 1) * ((x) - 1)))

#endif