Vector3.Lerp curving along three destinations

Question

Hi, I'm working on a game in which the player can freeze time and place up to three destinations (stored in array) and then dash through them in sequence. I've got dash working but it seems to be curving through the from the starting position to the last destination rather than going from point to point. Any help would be appreciated!

 void SetDestinations()
 {
     if (dashNumber < 3)
     {
         dashMarks[dashNumber].transform.position = dashDestination;
         dashMarks[dashNumber].SetActive(true);
         dashOrigin = dashMarks[dashNumber].transform.position;
         dashNumber++;
     }
 }
 
 void TriggerDashes()
 {
     dashNumber = 0;

     foreach (GameObject gameObject in dashMarks)
     {
         if (dashMarks[dashNumber].transform.position != Vector3.zero)
         {
             StartCoroutine(LerpDash(dashMarks[dashNumber].transform.position, dashSpeed));
             dashMarks[dashNumber].SetActive(false);
             dashMarks[dashNumber].transform.position = Vector3.zero; //reset position to limit next dashes
             dashNumber++;
         }
     }
 }

 IEnumerator LerpDash(Vector3 targetPosition, float duration) //still seems to be smoothing between points?
 {
     float time = 0;

     while (time < duration)
     {
         transform.LookAt(targetPosition);
         transform.position = Vector3.Lerp(transform.position, targetPosition, time / duration);
         time += Time.deltaTime;
         yield return null;
     }
     transform.position = targetPosition; //snapping
 }

Answer 1

Best Answer

Answer by Namey5 · Jun 21, 2021 at 01:18 AM

The problem lies in that you are updating the position of the transform while also using it as the input parameter to the lerp - meaning the translation is no longer linear. To fix this, you just need to keep the inputs constant;

  IEnumerator LerpDash(Vector3 targetPosition, float duration)
  {
      float time = 0;
      Vector3 startPos = transform.position;
      while (time < duration)
      {
          transform.LookAt(targetPosition);
          transform.position = Vector3.Lerp(startPos, targetPosition, time / duration);
          time += Time.deltaTime;
          yield return null;
      }
      transform.position = targetPosition;
  }

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PlasticFrames · Jun 21, 2021 at 09:03 AM 0

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When I add the constraints, the player lerps straight to the final destination and disregards any previously placed destinations altogether.

I've tried setting the startPos outside of the coroutine but it has the same result.

Namey5 PlasticFrames · Jun 21, 2021 at 10:06 AM 0

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That is because you are running all LerpDash instances at the same time (meaning only the last one will have an impact). You would need to either rejig the LerpDash function to include all points or make TriggerDashes a coroutine that yields upon each dash;

  IEnumerator TriggerDashes()
  {
      dashNumber = 0;
      foreach (GameObject gameObject in dashMarks)
      {
          if (dashMarks[dashNumber].transform.position != Vector3.zero)
          {
              yield return LerpDash (dashMarks[dashNumber].transform.position, dashSpeed);
              dashMarks[dashNumber].SetActive(false);
              dashMarks[dashNumber].transform.position = Vector3.zero; //reset position to limit next dashes
              dashNumber++;
          }
      }
  }

PlasticFrames Namey5 · Jun 21, 2021 at 10:43 AM 0

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Thank you so much, it took a little tweaking but it's finally working as intended!

Vector3.Lerp curving along three destinations

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