Added methods to do with random.

Author: DavidF-Dev

Runtime/RandomHelper.cs

@@ -2,9 +2,234 @@
 // Purpose: Various static helper methods to do with randomness
 // Created by: DavidFDev
 
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using UnityEngine;
+
 namespace DavidFDev.Maths
 {
+    /// <summary>
+    ///     Collection of static helper methods to do with randomness.
+    /// </summary>
     public static class RandomHelper
     {
+        #region Static fields and constants
+
+        /// <summary>
+        ///     Random number generator used by the helper methods.
+        /// </summary>
+        public static System.Random RNG { get; private set; } = null;
+
+        /// <summary>
+        ///     Seed used by the random number generator instance.
+        ///     Setting a new seed will initialise a new random number generator.
+        /// </summary>
+        public static int Seed
+        {
+            get
+            {
+                return _seed;
+            }
+            set
+            {
+                _seed = value;
+                RNG = new System.Random(_seed);
+            }
+        }
+
+        private static int _seed = 0;
+
+        private const float PI_2 = Mathf.PI * 2f;
+
+        #endregion
+
+        #region Static constructor
+
+        static RandomHelper()
+        {
+            Seed = Environment.TickCount;
+        }
+
+        #endregion
+
+        #region Static methods
+
+        /// <summary>
+        ///     Retrieve a random bool value.
+        /// </summary>
+        /// <returns></returns>
+        [Pure]
+        public static bool NextBool()
+        {
+            return RNG.Next(1) == 0;
+        }
+
+        /// <summary>
+        ///     Retrieve a random float value between 0 [inclusive] and 1 [exclusive].
+        /// </summary>
+        /// <returns></returns>
+        [Pure]
+        public static float NextFloat()
+        {
+            return (float)RNG.NextDouble();
+        }
+
+        /// <summary>
+        ///     Retrieve a random float between 0 [inclusive] and a max value [exclusive].
+        /// </summary>
+        /// <param name="max"></param>
+        /// <returns></returns>
+        [Pure]
+        public static float NextFloat(float max)
+        {
+            return NextFloat() * max;
+        }
+
+        /// <summary>
+        ///     Retrieve a random int between 0 [inclusive] and a max value [exclusive].
+        /// </summary>
+        /// <param name="max"></param>
+        /// <returns></returns>
+        [Pure]
+        public static int NextInt(int max)
+        {
+            return RNG.Next(max);
+        }
+
+        /// <summary>
+        ///     Retrieve a random angle between 0 and 2 PI (radians).
+        /// </summary>
+        /// <returns></returns>
+        [Pure]
+        public static float NextAngle()
+        {
+            return NextFloat(PI_2);
+        }
+
+        /// <summary>
+        ///     Retrieve a colour with random component values (rgb).
+        /// </summary>
+        /// <returns></returns>
+        [Pure]
+        public static Color NextColour()
+        {
+            return new Color(NextFloat(), NextFloat(), NextFloat());
+        }
+
+        /// <summary>
+        ///     Retrieve a random unit vector.
+        /// </summary>
+        /// <param name="magnitude"></param>
+        /// <returns></returns>
+        [Pure]
+        public static Vector2 NextVector2(float magnitude = 1f)
+        {
+            return MathsHelper.GetDirection(NextAngle() * Mathf.Rad2Deg) * magnitude;
+        }
+
+        /// <summary>
+        ///     Retrive a random unit vector.
+        /// </summary>
+        /// <param name="magnitude"></param>
+        /// <returns></returns>
+        [Pure]
+        public static Vector3 NextVector3(float magnitude = 1f)
+        {
+            return MathsHelper.GetDirection(NextAngle() * Mathf.Rad2Deg) * magnitude;
+        }
+
+        /// <summary>
+        ///     Retrieve a random float between a min value [inclusive] and a max value [exclusive].
+        /// </summary>
+        /// <param name="min"></param>
+        /// <param name="max"></param>
+        /// <returns></returns>
+        [Pure]
+        public static float Range(float min, float max)
+        {
+            return min + NextFloat(max - min);
+        }
+
+        /// <summary>
+        ///     Retrieve a random vector with components between a min value [inclusive] and a max value [exclusive].
+        /// </summary>
+        /// <param name="min"></param>
+        /// <param name="max"></param>
+        /// <returns></returns>
+        [Pure]
+        public static Vector2 Range(Vector2 min, Vector2 max)
+        {
+            return min + new Vector2(NextFloat(max.x - min.x), NextFloat(max.y - min.y));
+        }
+
+        /// <summary>
+        ///     Retrieve a random vector with components between a min value [inclusive] and a max value [exclusive].
+        /// </summary>
+        /// <param name="min"></param>
+        /// <param name="max"></param>
+        /// <returns></returns>
+        [Pure]
+        public static Vector3 Range(Vector3 min, Vector3 max)
+        {
+            return min + new Vector3(NextFloat(max.x - min.x), NextFloat(max.y - min.y), NextFloat(max.z - min.z));
+        }
+
+        /// <summary>
+        ///     Retrieve a random float betwen -1 and 1.
+        /// </summary>
+        /// <returns></returns>
+        [Pure]
+        public static float MinusOneToOne()
+        {
+            return NextFloat(2f) - 1f;
+        }
+
+        /// <summary>
+        ///     Retrieve a random integer, either -1 or 1.
+        /// </summary>
+        /// <returns></returns>
+        [Pure]
+        public static int MinusOneOrOne()
+        {
+            return NextBool() ? -1 : 1;
+        }
+
+        /// <summary>
+        ///     Roll a random chance.
+        /// </summary>
+        /// <param name="percent">0.0 - 1.0.</param>
+        /// <returns></returns>
+        [Pure]
+        public static bool Chance(float percent)
+        {
+            return NextFloat() < percent;
+        }
+
+        /// <summary>
+        ///     Roll a random chance.
+        /// </summary>
+        /// <param name="percent">0 - 100.</param>
+        /// <returns></returns>
+        [Pure]
+        public static bool Chance(int percent)
+        {
+            return NextInt(100) < percent;
+        }
+
+        /// <summary>
+        ///     Retrieve a random element from a collection.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="collection"></param>
+        /// <returns></returns>
+        [Pure]
+        public static T Choose<T>(this IReadOnlyCollection<T> collection)
+        {
+            return collection.ElementAt(NextInt(collection.Count));
+        }
+
+        #endregion
     }
 }