From 6f066779b5e70b468e51c81f1f896925e72eb917 Mon Sep 17 00:00:00 2001
From: JannisX11 <jannis4236@gmail.com>
Date: Sat, 6 Apr 2024 00:40:35 +0200
Subject: [PATCH] Wrap around catmull rom keyframes in loop, closes #1965
 Improve animation looping preview smoothness

---
 js/animations/timeline.js           | 33 ++++++++++++++++-------------
 js/animations/timeline_animators.js |  4 ++++
 2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/js/animations/timeline.js b/js/animations/timeline.js
index 3baf63aee..215739c0e 100644
--- a/js/animations/timeline.js
+++ b/js/animations/timeline.js
@@ -549,23 +549,24 @@ const Timeline = {
 		Timeline.loop()
 	},
 	loop() {
-		Animator.preview(true);
-		if (Animation.selected && Timeline.time < (Animation.selected.length||1e3)) {
+		if (!Animation.selected) return;
 
-			var new_time;
-			if (Animation.selected && Animation.selected.anim_time_update) {
-				var new_time = Animator.MolangParser.parse(Animation.selected.anim_time_update);
-			}
-			if (new_time == undefined || new_time <= Timeline.time) {
-				var new_time = Animator.MolangParser.parse('query.anim_time + query.delta_time')
-			}
-			let time = Timeline.time + (new_time - Timeline.time) * (Timeline.playback_speed/100)
-			if (Animation.selected.loop == 'hold') {
-				time = Math.clamp(time, 0, Animation.selected.length);
-			}
-			Timeline.last_frame_timecode = Date.now();
-			Timeline.setTime(time);
+		let max_length = Animation.selected.length || 1e3;
+		let new_time;
+		if (Animation.selected && Animation.selected.anim_time_update) {
+			new_time = Animator.MolangParser.parse(Animation.selected.anim_time_update);
+		}
+		if (new_time == undefined || new_time <= Timeline.time) {
+			new_time = Animator.MolangParser.parse('query.anim_time + query.delta_time')
+		}
+		let time = Timeline.time + (new_time - Timeline.time) * (Timeline.playback_speed/100)
+		if (Animation.selected.loop == 'hold') {
+			time = Math.clamp(time, 0, Animation.selected.length);
+		}
+		Timeline.last_frame_timecode = Date.now();
 
+		if (time < max_length) {
+			Timeline.setTime(time);
 		} else {
 			if (Animation.selected.loop == 'loop' || BarItems.looped_animation_playback.value) {
 				Timeline.setTime(0)
@@ -574,9 +575,11 @@ const Timeline = {
 				Animator.preview()
 				Timeline.pause()
 			} else if (Animation.selected.loop == 'hold') {
+				Timeline.setTime(max_length);
 				Timeline.pause()
 			}
 		}
+		Animator.preview(true);
 	},
 	pause() {
 		Animator.preview();
diff --git a/js/animations/timeline_animators.js b/js/animations/timeline_animators.js
index 95a14de73..6ef0c26fa 100644
--- a/js/animations/timeline_animators.js
+++ b/js/animations/timeline_animators.js
@@ -435,6 +435,10 @@ class BoneAnimator extends GeneralAnimator {
 				let before_index = sorted.indexOf(before);
 				let before_plus = sorted[before_index-1];
 				let after_plus = sorted[before_index+2];
+				if (this.animation.loop == 'loop' && sorted.length >= 3) {
+					if (!before_plus) before_plus = sorted.at(-2);
+					if (!after_plus) after_plus = sorted[1];
+				}
 
 				return mapAxes(axis => before.getCatmullromLerp(before_plus, before, after, after_plus, axis, alpha));