Lerp angle

Author: ElasticSea

Scripts/Util/Utils.cs

@@ -1304,6 +1304,25 @@ public static T[] Grow<T>(this T[] array, int length)
 
             return array;
         }
+
+        public static float AngleDifference(float angle1, float angle2)
+        {
+            float diff = (angle2 - angle1 + 180) % 360 - 180;
+            return diff < -180 ? diff + 360 : diff;
+        }
+
+        public static Vector3 InverseLerpEulerAngles(Vector3 min, Vector3 max, Vector3 value)
+        {
+            var x = InverseLerpAngle(min.x, max.x, value.x);
+            var y = InverseLerpAngle(min.y, max.y, value.y);
+            var z = InverseLerpAngle(min.z, max.z, value.z);
+            return new Vector3(x, y, z);
+        }
+
+        public static float InverseLerpAngle(float min, float max, float t)
+        {
+            return Mathf.Abs(AngleDifference(t, min) / AngleDifference(max, min));
+        }
     }
 
     public struct PageElement<T>

Tests/Editor/Utils/UtilsTests.cs

@@ -191,5 +191,88 @@ public void NearestNeighbour24BitScaleDown_MT()
 
             CollectionAssert.AreEqual(expected, actual.bytes);
         }
+
+        [Test]
+        public void InverseLerpEulerAngles_1()
+        {
+            var min = 0;
+            var max = 360;
+
+            var value = 360;
+
+            var actual = Utils.InverseLerpAngle(min, max, value);
+            var expected = float.NaN;
+
+            Assert.AreEqual(expected, actual);
+        }
+
+        [Test]
+        public void InverseLerpEulerAngles_10()
+        {
+            var min = 360;
+            var max = 0;
+
+            var value = 360;
+
+            var actual = Utils.InverseLerpAngle(min, max, value);
+            var expected = float.NaN;
+
+            Assert.AreEqual(expected, actual);
+        }
+
+        [Test]
+        public void InverseLerpEulerAngles_2()
+        {
+            var min = 315;
+            var max = 45;
+
+            var value = 0f;
+
+            var actual = Utils.InverseLerpAngle(min, max, value);
+            var expected = 0.5f;
+
+            Assert.AreEqual(expected, actual);
+        }
+
+        [Test]
+        public void InverseLerpEulerAngles_3()
+        {
+            var min = 270;
+            var max = 360;
+
+            var value = 0;
+
+            var actual = Utils.InverseLerpAngle(min, max, value);
+            var expected = 1;
+
+            Assert.AreEqual(expected, actual);
+        }
+
+        [Test]
+        public void InverseLerpEulerAngles_4()
+        {
+            var min = 270;
+            var max = 360;
+
+            var value = 90;
+
+            var actual = Utils.InverseLerpAngle(min, max, value);
+            var expected = 2;
+
+            Assert.AreEqual(expected, actual);
+        }
+
+        [Test]
+        public void InverseLerpEulerAngles_5()
+        {
+            var min = 350;
+            var max = 320;
+            var value = 330;
+
+            var actual = Utils.InverseLerpAngle(min, max, value);
+            var expected = 2 / 3f;
+
+            Assert.AreEqual(expected, actual);
+        }
     }
 }