AnimationCurve - Provide the value to find the time?

Your curve need to be strictly monotonic to be able to do that. Otherwise, there could be multi times with the same value. But if it is the case and that your curve is juste piecewise line, you can reverse the curve :

 static AnimationCurve ReverseCurve(AnimationCurve c)
 {
     // TODO: check c is strictly monotonic and Piecewise linear, log error otherwise
     var rev = new AnimationCurve();
     for(int i=0;i<c.keys.Length;i++) {
         var kf=c.keys[i];
         var rkf = new Keyframe(kf.value,kf.time);
         if(kf.inTangent < 0) {
             rkf.inTangent = 1/kf.outTangent;
             rkf.outTangent = 1/kf.inTangent;
         } else {
             rkf.inTangent = 1/kf.inTangent;
             rkf.outTangent = 1/kf.outTangent;
         }
         rev.AddKey(rkf);
     }
     return rev;
 }

It will not work with non piecewise linear curve. In that case, I guess you'll have to use something like a simple bisection method or a fancier Newton's method. Here is the code for bisection method :

 static float TimeFromValue(AnimationCurve c, float value, float precision = 1e-6f)
 {
     float minTime = c.keys[0].time;
     float maxTime = c.keys[c.keys.Length-1].time;
     float best = (maxTime + minTime) / 2;
     float bestVal = c.Evaluate(best);
     int it=0;
     const int maxIt = 1000;
     float sign = Mathf.Sign(c.keys[c.keys.Length-1].value -c.keys[0].value);
     while(it < maxIt && Mathf.Abs(minTime - maxTime) > precision) {
         if((bestVal - value) * sign > 0) {
             maxTime = best;
         } else {
             minTime = best;
         }
         best = (maxTime + minTime) / 2;
         bestVal = c.Evaluate(best);
         it++;
     }
     return best;
 }

If you are using an animation curve in your script, you can just access it through the Evaluate() method.

like so:

 public AnimationCurve anim;
 public float curveIndex;
 public float curveValue;
 
 
 void Update()
 {
     curveIndex = Mathf.Clamp(curveIndex, 0, curve.Length);
     curveValue = anim.Evaluate(curveIndex);
 }

the above code will give you a value "curveValue" in the inspector that is the value of the curve at time "curveIndex".

I had faced similar Problem, I was using the curve with 2 key frames

• one starts at the 0th location of Graph

• next at 20 towards y axis(Value) "20". 100,000 towards X axis(Time)

the in build API in animation curve Evaluate only based on time to value and this simple trick will help you to find the data other way around

Just loop the time and use the Evaluate until you find your desired Value.

code Example for my problem

 float time = 0;
 float value = 10.0f; 
 public AnimationCurve levelCurve;
 
 IEnumerator RequiredTime(){
 while(true){
 time +=100;
 var sceond = levelCurve.Evaluate(time);
 if(sceond > value + 1f) { 
  Debug.Log(time+" the Timerequired to next level up");  break;
  }
 }            
 yield return null;
 }
 

 

my value was 10 and i want to find the time taken to reach value 11. so that I can use it in my game as a feed back to player the time or progress required to reach next Stage or so.

this is just the sample code for the logic.

I'm also on this topic as of now I have something that works, but feel that it's not as optimal as I'd like it to be, here is my simple code so far. (btw I have only to keys and only care about the second one so its hard coded like that feel free to change it as you need)

 private int GetLevelByXP(float experience)
 {
     int level = 1;
 
     for (int i = 0; i < xpReqruirmentPerLevel.keys[1].time; i++)
     {
         if (Expirience < xpReqruirmentPerLevel.Evaluate(i))
         {
             level = i;
             break;
         }
 
     }
 
     return level;
 }