koobas.hobune.stream
Quaternion lerp back and forth
I want to lerp along the Z axis forth and back the same amount to avoid spinning (as my sprite is not a circular one). To do this I planned to random a forward angle, store it, lerp to it then lerp back with the same amount. However, this gives some weird popping as when the backwards rotations starts the starting angle wouldn't be the same, but it is. When I call it, I give it the same time to interpolate between. Some code:
IEnumerator LerpQuat(QuatLerpInput rotThis, float time, float leftBoundary, float rightBoundary)
{
/*
* we want to rotate forward, then backward the same amount
* to avoid spinning. we store the given value to both of these.
*/
Transform stuffToRot = rotThis.godRayGO.transform;
float lastTime = Time.realtimeSinceStartup;
float timer = 0.0f;
switch (rotThis.rotState)
{
case (QuatLerpInput.RotationStates.rotAway):
rotThis.deltaRot = Random.Range(leftBoundary, rightBoundary);
while (timer < time)
{
stuffToRot.rotation = Quaternion.Euler(stuffToRot.rotation.x, stuffToRot.rotation.y,
Mathf.LerpAngle(rotThis.idleRot, rotThis.idleRot + rotThis.deltaRot, timer / time));
timer += (Time.realtimeSinceStartup - lastTime);
lastTime = Time.realtimeSinceStartup;
yield return null;
}
rotThis.rotState = QuatLerpInput.RotationStates.setBack;
break;
case (QuatLerpInput.RotationStates.setBack):
while (timer < time)
{
stuffToRot.rotation = Quaternion.Euler(stuffToRot.rotation.x, stuffToRot.rotation.y,
Mathf.LerpAngle(rotThis.idleRot + rotThis.deltaRot, rotThis.idleRot, timer / time));
timer += (Time.realtimeSinceStartup - lastTime);
lastTime = Time.realtimeSinceStartup;
yield return null;
}
rotThis.rotState = QuatLerpInput.RotationStates.rotAway;
break;
}
}
public class QuatLerpInput
{
public GameObject godRayGO;
public float deltaRot;
public float idleRot;
public enum RotationStates
{
rotAway, setBack
}
public RotationStates rotState = RotationStates.rotAway;
public QuatLerpInput(GameObject godRayGO)
{
this.godRayGO = godRayGO;
deltaRot = godRayGO.transform.rotation.z;
idleRot = godRayGO.transform.rotation.z;
}
}
