[csharp] Port of commit 8d058fb: Improved AnimationState behavior whe…

…n paused. See #2705.

spine-csharp/src/AnimationState.cs

@@ -204,16 +204,18 @@ private bool UpdateMixingFrom (TrackEntry to, float delta) {
 			from.animationLast = from.nextAnimationLast;
 			from.trackLast = from.nextTrackLast;
 
-			// Require mixTime > 0 to ensure the mixing from entry was applied at least once.
-			if (to.mixTime > 0 && to.mixTime >= to.mixDuration) {
-				// Require totalAlpha == 0 to ensure mixing is complete, unless mixDuration == 0 (the transition is a single frame).
-				if (from.totalAlpha == 0 || to.mixDuration == 0) {
-					to.mixingFrom = from.mixingFrom;
-					if (from.mixingFrom != null) from.mixingFrom.mixingTo = to;
-					to.interruptAlpha = from.interruptAlpha;
-					queue.End(from);
+			if (to.nextTrackLast != -1) { // The from entry was applied at least once.
+				bool discard = to.mixTime == 0 && from.mixTime == 0; // Discard the from entry when neither have advanced yet.
+				if (to.mixTime >= to.mixDuration || discard) {
+					// Require totalAlpha == 0 to ensure mixing is complete or the transition is a single frame or discarded.
+					if (from.totalAlpha == 0 || to.mixDuration == 0 || discard) {
+						to.mixingFrom = from.mixingFrom;
+						if (from.mixingFrom != null) from.mixingFrom.mixingTo = to;
+						to.interruptAlpha = from.interruptAlpha;
+						queue.End(from);
+					}
+					return finished;
 				}
-				return finished;
 			}
 
 			from.trackTime += delta * from.timeScale;

spine-csharp/src/package.json

@@ -2,7 +2,7 @@
 	"name": "com.esotericsoftware.spine.spine-csharp",
 	"displayName": "spine-csharp Runtime",
 	"description": "This plugin provides the spine-csharp core runtime.",
-	"version": "4.2.32",
+	"version": "4.2.33",
 	"unity": "2018.3",
 	"author": {
 		"name": "Esoteric Software",