From adadde0aa97c014d448e9af03924f0c64d071fa1 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Wed, 1 Sep 2021 14:42:59 +0200
Subject: [PATCH] Add epsilon clamping for keyframes adding in timeline

---
 Source/Editor/GUI/CurveEditor.cs                 | 16 ++++++++++++++--
 .../Editor/GUI/Timeline/GUI/KeyframesEditor.cs   |  8 +++++++-
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/Source/Editor/GUI/CurveEditor.cs b/Source/Editor/GUI/CurveEditor.cs
index b4f1d9333..e60b0554b 100644
--- a/Source/Editor/GUI/CurveEditor.cs
+++ b/Source/Editor/GUI/CurveEditor.cs
@@ -1026,15 +1026,21 @@ namespace FlaxEditor.GUI
         /// <returns>The index of the keyframe.</returns>
         public int AddKeyframe(LinearCurve<T>.Keyframe k)
         {
+            var eps = Mathf.Epsilon;
             if (FPS.HasValue)
             {
                 float fps = FPS.Value;
                 k.Time = Mathf.Floor(k.Time * fps) / fps;
+                eps = 1.0f / fps;
             }
+
             int pos = 0;
             while (pos < _keyframes.Count && _keyframes[pos].Time < k.Time)
                 pos++;
-            _keyframes.Insert(pos, k);
+            if (_keyframes.Count > pos && Mathf.Abs(_keyframes[pos].Time - k.Time) < eps)
+                _keyframes[pos] = k;
+            else
+                _keyframes.Insert(pos, k);
 
             OnKeyframesChanged();
             OnEdited();
@@ -1513,15 +1519,21 @@ namespace FlaxEditor.GUI
         /// <returns>The index of the keyframe.</returns>
         public int AddKeyframe(BezierCurve<T>.Keyframe k)
         {
+            var eps = Mathf.Epsilon;
             if (FPS.HasValue)
             {
                 float fps = FPS.Value;
                 k.Time = Mathf.Floor(k.Time * fps) / fps;
+                eps = 1.0f / fps;
             }
+
             int pos = 0;
             while (pos < _keyframes.Count && _keyframes[pos].Time < k.Time)
                 pos++;
-            _keyframes.Insert(pos, k);
+            if (_keyframes.Count > pos && Mathf.Abs(_keyframes[pos].Time - k.Time) < eps)
+                _keyframes[pos] = k;
+            else
+                _keyframes.Insert(pos, k);
 
             OnKeyframesChanged();
             OnEdited();
diff --git a/Source/Editor/GUI/Timeline/GUI/KeyframesEditor.cs b/Source/Editor/GUI/Timeline/GUI/KeyframesEditor.cs
index aa34657ee..a92998255 100644
--- a/Source/Editor/GUI/Timeline/GUI/KeyframesEditor.cs
+++ b/Source/Editor/GUI/Timeline/GUI/KeyframesEditor.cs
@@ -837,15 +837,21 @@ namespace FlaxEditor.GUI
         /// <param name="k">The keyframe to add.</param>
         public void AddKeyframe(Keyframe k)
         {
+            var eps = Mathf.Epsilon;
             if (FPS.HasValue)
             {
                 float fps = FPS.Value;
                 k.Time = Mathf.Floor(k.Time * fps) / fps;
+                eps = 1.0f / fps;
             }
+
             int pos = 0;
             while (pos < _keyframes.Count && _keyframes[pos].Time < k.Time)
                 pos++;
-            _keyframes.Insert(pos, k);
+            if (_keyframes.Count > pos && Mathf.Abs(_keyframes[pos].Time - k.Time) < eps)
+                _keyframes[pos] = k;
+            else
+                _keyframes.Insert(pos, k);
 
             OnKeyframesChanged();
             OnEdited();