A quick example of lerp-based animations with StereoKit

LerpAnimations.cs

// This demo can be seen in motion here:
// https://twitter.com/koujaku/status/1407538105070997504

using StereoKit;
using System;

class Program {
	static void Main(string[] args) {
		// Initialize StereoKit
		if (!SK.Initialize(new SKSettings { appName = "LerpAnim" }))
			Environment.Exit(1);

		Pose  window = new Pose(0,0,-0.4f, Quat.LookDir(0,0,1));
		float start=0, length=0;
		float curr =0, duration=0;
		while (SK.Step(() =>
		{
			UI.WindowBegin("Press things here!", ref window);
			if (UI.Button("Start/Length")) {
				start  = Time.Totalf;
				length = 0.5f;
			}
			if (UI.Button("Duration/Curr")) {
				curr     = 0;
				duration = 0.5f;
			}
			UI.WindowEnd();

			curr += Time.Elapsedf;
			float cdPercent = duration == 0 ? 0 : MathF.Min(1, curr / duration);
			Default.MeshSphere.Draw(Default.Material,
				Matrix.TS(V.XYZ(-0.3f, 0, -0.5f), SKMath.Lerp(0.15f, 0.25f, cdPercent)));

			float slPercent = length == 0 ? 0 : MathF.Min(1, (Time.Totalf - start) / length);
			Default.MeshSphere.Draw(Default.Material, 
				Matrix.TS(V.XYZ( 0.3f, 0, -0.5f), SKMath.Lerp(0.15f, 0.25f, slPercent)));

			// Remap them both to bounces, see https://github.com/Michaelangel007/easing
			Func<float, float> OutBack = (p) => { 
				float m = p - 1;
				float k = 1.70158f;
				return 1 + m * m * (m * (k + 1) + k);
			};
			Default.MeshSphere.Draw(Default.Material,
				Matrix.TS(V.XYZ(-0.3f, 0.3f, -0.5f), SKMath.Lerp(0.15f, 0.25f, OutBack(cdPercent))));
			Default.MeshSphere.Draw(Default.Material,
				Matrix.TS(V.XYZ( 0.3f, 0.3f, -0.5f), SKMath.Lerp(0.15f, 0.25f, OutBack(slPercent))));
		})) ;
		SK.Shutdown();
	}
}