Added GTWeen

GTweensGodot/GTweens/Source/Interpolators/SystemQuaternionInterpolator.cs

@@ -0,0 +1,37 @@
+using System.Numerics;
+using GTweens.Easings;
+
+namespace GTweens.Interpolators
+{
+    public sealed class SystemQuaternionInterpolator : IInterpolator<Quaternion>
+    {
+        public static readonly SystemQuaternionInterpolator Instance = new();
+
+        SystemQuaternionInterpolator()
+        {
+
+        }
+
+        public Quaternion Evaluate(
+            Quaternion initialValue,
+            Quaternion finalValue,
+            float time,
+            EasingDelegate easingDelegate
+            )
+        {
+            float curveTime = easingDelegate(0f, 1f, time);
+
+            return Quaternion.Slerp(initialValue, finalValue, curveTime);
+        }
+
+        public Quaternion Subtract(Quaternion initialValue, Quaternion finalValue)
+        {
+            return Quaternion.Inverse(initialValue) * finalValue;
+        }
+
+        public Quaternion Add(Quaternion initialValue, Quaternion finalValue)
+        {
+            return initialValue * finalValue;
+        }
+    }
+}