[Entities] Adjust Transform to check whether it was changed;

Author: LittleCodingFox

Engine/Core/Entities/Transform.cs

@@ -124,11 +124,13 @@ public Vector3 Position
 
         set
         {
-            Changed = true;
-
             var parentPosition = parent?.Position ?? Vector3.Zero;
 
-            position = value - parentPosition;
+            var target = value - parentPosition;
+
+            Changed |= target != position;
+
+            position = target;
         }
     }
 
@@ -141,7 +143,7 @@ public Vector3 LocalPosition
 
         set
         {
-            Changed = true;
+            Changed |= value != position;
 
             position = value;
         }
@@ -161,11 +163,13 @@ public Vector3 Scale
 
         set
         {
-            Changed = true;
-
             var parentScale = parent?.Scale ?? Vector3.One;
 
-            scale = value / parentScale;
+            var target = value / parentScale;
+
+            Changed |= target != scale;
+
+            scale = target;
         }
     }
 
@@ -178,7 +182,7 @@ public Vector3 LocalScale
 
         set
         {
-            Changed = true;
+            Changed |= value != scale;
 
             scale = value;
         }
@@ -198,11 +202,13 @@ public Quaternion Rotation
 
         set
         {
-            Changed = true;
-
             var parentRotation = parent?.Rotation ?? Quaternion.Identity;
 
-            rotation = Quaternion.Inverse(parentRotation) * value;
+            var target = Quaternion.Inverse(parentRotation) * value;
+
+            Changed |= target != rotation;
+
+            rotation = target;
         }
     }
 
@@ -215,7 +221,7 @@ public Quaternion LocalRotation
 
         set
         {
-            Changed = true;
+            Changed |= value != rotation;
 
             rotation = value;
         }

Engine/StapleCoreTests/TransformTests.cs

@@ -5,6 +5,74 @@ namespace CoreTests
 {
     internal class TransformTests
     {
+        [Test]
+        public void TestChanged()
+        {
+            var transform = new Transform();
+
+            Assert.IsFalse(transform.Changed);
+
+            transform.LocalPosition = transform.LocalPosition;
+
+            Assert.IsFalse(transform.Changed);
+
+            transform.LocalRotation = transform.LocalRotation;
+
+            Assert.IsFalse(transform.Changed);
+
+            transform.LocalScale = transform.LocalScale;
+
+            Assert.IsFalse(transform.Changed);
+
+            transform.Position = transform.Position;
+
+            Assert.IsFalse(transform.Changed);
+
+            transform.Rotation = transform.Rotation;
+
+            Assert.IsFalse(transform.Changed);
+
+            transform.Scale = transform.Scale;
+
+            Assert.IsFalse(transform.Changed);
+
+            transform.LocalPosition = Vector3.One;
+
+            Assert.IsTrue(transform.Changed);
+
+            transform.Changed = false;
+
+            transform.LocalRotation = Quaternion.CreateFromYawPitchRoll(1, 2, 3);
+
+            Assert.IsTrue(transform.Changed);
+
+            transform.Changed = false;
+
+            transform.LocalScale = Vector3.Zero;
+
+            Assert.IsTrue(transform.Changed);
+
+            transform.Changed = false;
+
+            transform.Position = Vector3.Zero;
+
+            Assert.IsTrue(transform.Changed);
+
+            transform.Changed = false;
+
+            transform.Rotation = Quaternion.Identity;
+
+            Assert.IsTrue(transform.Changed);
+
+            transform.Changed = false;
+
+            transform.Scale = Vector3.One;
+
+            Assert.IsTrue(transform.Changed);
+
+            transform.Changed = false;
+        }
+
         [Test]
         public void TestLocalPosition()
         {