//This acts as if you are using a parent transform as your new pivot and transforming that parent instead of the child.
//So instead of creating a gameobject and parenting "target" to it and translating only the parent gameobject, we can use this method.
public static void SetScaleFrom(this Transform target, Vector3 worldPivot, Vector3 newScale)
{
Vector3 localOffset = target.InverseTransformPoint(worldPivot);
Vector3 localScale = target.localScale;
Vector3 scaleRatio = new Vector3(MathfExtensions.SafeDivide(newScale.x, localScale.x), MathfExtensions.SafeDivide(newScale.y, localScale.y), MathfExtensions.SafeDivide(newScale.z, localScale.z));
Vector3 scaledLocalOffset = Vector3.Scale(localOffset, scaleRatio);
Vector3 newPosition = target.TransformPoint(localOffset - scaledLocalOffset);
target.localScale = newScale;
target.position = newPosition;
}
//This acts as if you are scaling based on a point that is offset from the actual pivot.
//It gives results similar to when you scale an object in the unity editor when in Center mode instead of Pivot mode.
//The Center was an offset from the actual Pivot.
public static void SetScaleFromOffset(this Transform target, Vector3 worldPivot, Vector3 newScale)
{
//Seemed to work, except when under a parent that has a non uniform scale and rotation it was a bit off.
//This might be due to transform.lossyScale not being accurate under those conditions, or possibly something else is wrong...
//Maybe things can work if we can find a way to convert the "newPosition = ..." line to use Matrix4x4 for possibly more scale accuracy.
//However, I have tried and tried and have no idea how to do that kind of math =/
//Seems like unity editor also has some inaccuracies with skewed scales, such as scaling little by little compared to scaling one large scale.
//
//Will mess up or give undesired results if the target.localScale or target.lossyScale has any set to 0.
//Unity editor doesnt even allow you to scale an axis when it is set to 0.
Vector3 localOffset = target.InverseTransformPoint(worldPivot);
Vector3 localScale = target.localScale;
Vector3 scaleRatio = new Vector3(MathfExtensions.SafeDivide(newScale.x, localScale.x), MathfExtensions.SafeDivide(newScale.y, localScale.y), MathfExtensions.SafeDivide(newScale.z, localScale.z));
Vector3 scaledLocalOffset = Vector3.Scale(localOffset, scaleRatio);
Vector3 newPosition = target.rotation * Vector3.Scale(localOffset - scaledLocalOffset, target.lossyScale) + target.position;
target.localScale = newScale;
target.position = newPosition;
}