GLSL Time loop tricks

TimeLoops.glsl

float loopWithPause(float scale) {
   // sinusoidal, with a short pause at start/end
   float overshoot = 1.5;
   
   // iTime is a variable available in shadertoy.com
   // Replace with your own variable as needed
   float t = iTime * scale; // scale time here
   float a = clamp((mod(t, 2.0) - 1.0) * overshoot, -1.0, 1.0);
   return sin(a * PI);
}