Vector rotation helper functions in Vector2 (MonoGame#8117)

* Added vector rotation helper functions

* Moved Vector rotation function to Vector2 & added non static versions

Author: itsBuggingMe

MonoGame.Framework/MathHelper.cs

@@ -78,7 +78,7 @@ public static float Barycentric(float value1, float value2, float value3, float
         public static float CatmullRom(float value1, float value2, float value3, float value4, float amount)
         {
             // Using formula from http://www.mvps.org/directx/articles/catmull/
-            // Internally using doubles not to lose precission
+            // Internally using doubles not to lose precision
             double amountSquared = amount * amount;
             double amountCubed = amountSquared * amount;
             return (float)(0.5 * (2.0 * value2 +
@@ -142,7 +142,7 @@ public static float Distance(float value1, float value2)
         /// <returns>The result of the Hermite spline interpolation.</returns>
         public static float Hermite(float value1, float tangent1, float value2, float tangent2, float amount)
         {
-            // All transformed to double not to lose precission
+            // All transformed to double not to lose precision
             // Otherwise, for high numbers of param:amount the result is NaN instead of Infinity
             double v1 = value1, v2 = value2, t1 = tangent1, t2 = tangent2, s = amount, result;
             double sCubed = s * s * s;
@@ -265,29 +265,29 @@ public static float SmoothStep(float value1, float value2, float amount)
 
             return result;
         }
-        
+
         /// <summary>
         /// Converts radians to degrees.
         /// </summary>
         /// <param name="radians">The angle in radians.</param>
         /// <returns>The angle in degrees.</returns>
         /// <remarks>
-        /// This method uses double precission internally,
+        /// This method uses double precision internally,
         /// though it returns single float
         /// Factor = 180 / pi
         /// </remarks>
         public static float ToDegrees(float radians)
         { 
             return (float)(radians * 57.295779513082320876798154814105);
         }
-        
+
         /// <summary>
         /// Converts degrees to radians.
         /// </summary>
         /// <param name="degrees">The angle in degrees.</param>
         /// <returns>The angle in radians.</returns>
         /// <remarks>
-        /// This method uses double precission internally,
+        /// This method uses double precision internally,
         /// though it returns single float
         /// Factor = pi / 180
         /// </remarks>
@@ -313,14 +313,14 @@ public static float WrapAngle(float angle)
             return angle;
         }
 
- 	/// <summary>
+ 	    /// <summary>
         /// Determines if value is powered by two.
         /// </summary>
         /// <param name="value">A value.</param>
         /// <returns><c>true</c> if <c>value</c> is powered by two; otherwise <c>false</c>.</returns>
-	public static bool IsPowerOfTwo(int value)
-	{
-	     return (value > 0) && ((value & (value - 1)) == 0);
-	}
+	    public static bool IsPowerOfTwo(int value)
+	    {
+	         return (value > 0) && ((value & (value - 1)) == 0);
+	    }
     }
 }

MonoGame.Framework/Vector2.cs

@@ -1187,7 +1187,7 @@ public static void TransformNormal(ref Vector2 normal, ref Matrix matrix, out Ve
             result.X = x;
             result.Y = y;
         }
-
+        
         /// <summary>
         /// Apply transformation on normals within array of <see cref="Vector2"/> by the specified <see cref="Matrix"/> and places the results in an another array.
         /// </summary>
@@ -1254,6 +1254,79 @@ Vector2[] destinationArray
             }
         }
 
+        /// <summary>
+        /// Rotates a vector by the specified number of radians
+        /// </summary>
+        /// <param name="value">The vector to be rotated.</param>
+        /// <param name="radians">The amount to rotate the vector.</param>
+        /// <returns>A rotated copy of value.</returns>
+        /// <remarks>
+        /// A positive angle and negative angle
+        /// would rotate counterclockwise and clockwise,
+        /// respectively
+        /// </remarks>
+        public static Vector2 Rotate(Vector2 value, float radians)
+        {
+            float cos = MathF.Cos(radians);
+            float sin = MathF.Sin(radians);
+
+            return new Vector2(value.X * cos - value.Y * sin, value.X * sin + value.Y * cos);
+        }
+
+        /// <summary>
+        /// Rotates a <see cref="Vector2"/> by the specified number of radians
+        /// </summary>
+        /// <param name="radians">The amount to rotate this <see cref="Vector2"/>.</param>
+        /// <remarks>
+        /// A positive angle and negative angle
+        /// would rotate counterclockwise and clockwise,
+        /// respectively
+        /// </remarks>
+        public void Rotate(float radians)
+        {
+            float cos = MathF.Cos(radians);
+            float sin = MathF.Sin(radians);
+
+            float oldx = X;
+
+            X = X * cos - Y * sin;
+            Y = oldx * sin + Y * cos;
+        }
+
+        /// <summary>
+        /// Rotates a <see cref="Vector2"/> around another <see cref="Vector2"/> representing a location
+        /// </summary>
+        /// <param name="value">The <see cref="Vector2"/> to be rotated</param>
+        /// <param name="origin">The origin location to be rotated around</param>
+        /// <param name="radians">The amount to rotate by in radians</param>
+        /// <returns>The rotated <see cref="Vector2"/></returns>
+        /// <remarks>
+        /// A positive angle and negative angle
+        /// would rotate counterclockwise and clockwise,
+        /// respectively
+        /// </remarks>
+        public static Vector2 RotateAround(Vector2 value, Vector2 origin, float radians)
+        {
+            return Rotate(value - origin, radians) + origin;
+        }
+
+        /// <summary>
+        /// Rotates a <see cref="Vector2"/> around another <see cref="Vector2"/> representing a location
+        /// </summary>
+        /// <param name="origin">The origin location to be rotated around</param>
+        /// <param name="radians">The amount to rotate by in radians</param>
+        /// <remarks>
+        /// A positive angle and negative angle
+        /// would rotate counterclockwise and clockwise,
+        /// respectively
+        /// </remarks>
+        public void RotateAround(Vector2 origin, float radians)
+        {
+            this -= origin;
+            Rotate(radians);
+            this += origin;
+        }
+
         /// <summary>
         /// Deconstruction method for <see cref="Vector2"/>.
         /// </summary>