package polaris.sdk.ui;
/** Frame-rate-independent damped spring. Values are render state, never layout/hit-test state. */
public final class MotionValue {
 private double value,velocity,last;private boolean initialized;
 public MotionValue(){}public MotionValue(float value){snap(value,0);}
 public void snap(float target,double time){value=target;velocity=0;last=time;initialized=true;}
 public float value(){return (float)value;}public float velocity(){return (float)velocity;}
 public float to(float target,double time,float frequency,float damping,boolean reduced){
  if(!initialized||reduced){snap(target,time);return target;}
  double dt=Math.max(0,Math.min(.10,time-last));last=time;if(dt==0)return (float)value;
  double omega=Math.max(.1,frequency),zeta=Math.max(.05,Math.min(.999,damping));
  double wd=omega*Math.sqrt(1-zeta*zeta),y=value-target,v=velocity;
  double a=y,b=(v+zeta*omega*y)/wd,co=Math.cos(wd*dt),si=Math.sin(wd*dt),decay=Math.exp(-zeta*omega*dt);
  double next=decay*(a*co+b*si);
  velocity=decay*((-a*wd*si+b*wd*co)-zeta*omega*(a*co+b*si));value=target+next;
  if(Math.abs(value-target)<.00002&&Math.abs(velocity)<.0002){value=target;velocity=0;}
  return (float)value;
 }
 /** Critically predictable exponential tracking: no stale spring recoil on release. */
 public float follow(float target,double time,float response,boolean reduced){
  if(!initialized||reduced){snap(target,time);return target;}
  double dt=Math.max(0,Math.min(.10,time-last));last=time;if(dt==0)return (float)value;
  double previous=value;value+=(target-value)*(-Math.expm1(-Math.max(1,response)*dt));
  velocity=(value-previous)/dt;
  if(Math.abs(value-target)<.00002){value=target;velocity=0;}
  return (float)value;
 }
 public static float clamp(float x){return Math.max(0,Math.min(1,x));}
}