Reveals a Polyline component in Shapes

PolylineRevealer.cs

using System.Collections.Generic;
using Freya;
using Shapes;
using UnityEngine;

[RequireComponent( typeof(Polyline) )]
public class PolylineRevealer : MonoBehaviour {

	// Animate this to reveal the line. 0 = invisible, 1 = fully visible
	[Range( 0, 1 )] public float t;

	List<PolylinePoint> originalPoints;
	List<float> distances;
	Polyline polyline;

	void Awake() {
		polyline = GetComponent<Polyline>();

		// Cache the original points so that we don't lose them when editing the polyline
		originalPoints = new List<PolylinePoint>();
		originalPoints.AddRange( polyline.points );

		// Cache the distances between the points so that we can reveal with a uniform speed
		distances = new List<float> { 0 };
		for( int i = 1; i < originalPoints.Count; i++ ) {
			Vector3 prev = originalPoints[i - 1].point;
			Vector3 next = originalPoints[i].point;
			distances.Add( distances[i - 1] + Vector3.Distance( prev, next ) );
		}
	}

	// Updates the polyline based on the t-value.
	void UpdatePolyline() {
		polyline.points.Clear();
		if( t > 0 ) {
			float dist = t * distances[^1];
			for( int i = 0; i < originalPoints.Count - 1; i++ ) {
				float dPrev = distances[i];
				float dNext = distances[i + 1];
				if( dist > dPrev )
					polyline.points.Add( originalPoints[i] );
				if( dist <= dNext ) {
					float tIntp = Mathfs.InverseLerp( dPrev, dNext, dist );
					PolylinePoint pt = PolylinePoint.Lerp( originalPoints[i], originalPoints[i + 1], tIntp );
					polyline.points.Add( pt );
					break;
				}
			}
		}
		polyline.meshOutOfDate = true;
	}

	// live update when changing t in the inspector, in play mode
	void OnValidate() {
		if( Application.isPlaying )
			UpdatePolyline();
	}

	// ensures it updates when animating
	void OnDidApplyAnimationProperties() => UpdatePolyline();

}

Hi @FreyaHolmer I've been having an issue where the OnValidate() function is called before the originalPoints list gets populated for some reason.

Therefore when I hit Play, the polyline disappears, the polyline points in the inspector are cleared and the reveal doesn't work. I fixed the issue by adding extra check on line 55, but you might know a better way:
if (Application.isPlaying && originalPoints.Count > 0)

There's also a small syntax error on line 43:
Mathf.InverseLerp instead of Mathfs.InverseLerp

The code performs well after I make the above changes.

Thanks for sharing!