Initial Commit

Library/PackageCache/com.unity.timeline@1.5.4/Runtime/Utilities/Extrapolation.cs

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+using System;
+using UnityEngine;
+
+// Extension methods responsible for managing extrapolation time
+namespace UnityEngine.Timeline
+{
+    static class Extrapolation
+    {
+        /// <summary>
+        /// The minimum amount of extrapolation time to apply
+        /// </summary>
+        internal static readonly double kMinExtrapolationTime = TimeUtility.kTimeEpsilon * 1000;
+
+        // Calculates the extrapolation times
+        internal static void CalculateExtrapolationTimes(this TrackAsset asset)
+        {
+            TimelineClip[] clips = asset.clips;
+            if (clips == null || clips.Length == 0)
+                return;
+
+            // extrapolation not supported
+            if (!clips[0].SupportsExtrapolation())
+                return;
+
+            var orderedClips = SortClipsByStartTime(clips);
+            if (orderedClips.Length > 0)
+            {
+                // post extrapolation is the minimum time to the next clip
+                for (int i = 0; i < orderedClips.Length; i++)
+                {
+                    double minTime = double.PositiveInfinity;
+                    for (int j = 0; j < orderedClips.Length; j++)
+                    {
+                        if (i == j)
+                            continue;
+
+                        double deltaTime = orderedClips[j].start - orderedClips[i].end;
+                        if (deltaTime >= -TimeUtility.kTimeEpsilon && deltaTime < minTime)
+                            minTime = Math.Min(minTime, deltaTime);
+                        // check for overlapped clips
+                        if (orderedClips[j].start <= orderedClips[i].end && orderedClips[j].end > orderedClips[i].end)
+                            minTime = 0;
+                    }
+                    minTime = minTime <= kMinExtrapolationTime ? 0 : minTime;
+                    orderedClips[i].SetPostExtrapolationTime(minTime);
+                }
+
+                // the first clip gets pre-extrapolation, then it's only respected if there is no post extrapolation
+                orderedClips[0].SetPreExtrapolationTime(Math.Max(0, orderedClips[0].start));
+                for (int i = 1; i < orderedClips.Length; i++)
+                {
+                    double preTime = 0;
+                    int prevClip = -1;
+                    for (int j = 0; j < i; j++)
+                    {
+                        // overlap, no pre-time
+                        if (orderedClips[j].end > orderedClips[i].start)
+                        {
+                            prevClip = -1;
+                            preTime = 0;
+                            break;
+                        }
+
+                        double gap = orderedClips[i].start - orderedClips[j].end;
+                        if (prevClip == -1 || gap < preTime)
+                        {
+                            preTime = gap;
+                            prevClip = j;
+                        }
+                    }
+                    // check for a post extrapolation time
+                    if (prevClip >= 0)
+                    {
+                        if (orderedClips[prevClip].postExtrapolationMode != TimelineClip.ClipExtrapolation.None)
+                            preTime = 0;
+                    }
+
+                    preTime = preTime <= kMinExtrapolationTime ? 0 : preTime;
+                    orderedClips[i].SetPreExtrapolationTime(preTime);
+                }
+            }
+        }
+
+        static TimelineClip[] SortClipsByStartTime(TimelineClip[] clips)
+        {
+            var orderedClips = new TimelineClip[clips.Length];
+            Array.Copy(clips, orderedClips, clips.Length);
+            Array.Sort(orderedClips, (clip1, clip2) => clip1.start.CompareTo(clip2.start));
+            return orderedClips;
+        }
+    }
+}