/**
 * Sigmoid interpolation between the components of a vector based on x ∈ [0; 1],
 * cycling through its components then wrapping back to the first one, 
 * and repeating periodically when x ∈ ℝ \ [0; 1].
 */

float smoothCycleMix(vec2 v, float x) {
  float t = mod(x, 1.) * 2.;
  float i = floor(t);

  return dot(mix(v, v.yx, smoothstep(0., 1., fract(t))), vec2(
    1. - step(1., i),
    step(1., i)
  ));
}

float smoothCycleMix(vec3 v, float x) {
  float t = mod(x, 1.) * 3.;
  float i = floor(t);

  return dot(mix(v, v.yzx, smoothstep(0., 1., fract(t))), vec3(
    1. - step(1., i),
    step(1., i) * (1. - step(2., i)),
    step(2., i)
  ));
}

float smoothCycleMix(vec4 v, float x) {
  float t = mod(x, 1.) * 4.;
  float i = floor(t);

  return dot(mix(v, v.yzwx, smoothstep(0., 1., fract(t))), vec4(
    1. - step(1., i),
    step(1., i) * (1. - step(2., i)),
    step(2., i) * (1. - step(3., i)),
    step(3., i)
  ));
}