Deprecate System.Random leakage

Robust.Shared/Map/ITileDefinitionManager.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using Robust.Shared.Random;
 
@@ -12,10 +13,12 @@ namespace Robust.Shared.Map
     {
         Tile GetVariantTile(string name, IRobustRandom random);
 
+        [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
         Tile GetVariantTile(string name, System.Random random);
 
         Tile GetVariantTile(ITileDefinition tileDef, IRobustRandom random);
 
+        [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
         Tile GetVariantTile(ITileDefinition tileDef, System.Random random);
 
         /// <summary>

Robust.Shared/Random/IRobustRandom.cs

@@ -176,8 +176,10 @@ public interface IRobustRandom
     }
 }
 
+[Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
 public static class RandomHelpers
 {
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static void Shuffle<T>(this System.Random random, IList<T> list)
     {
         var n = list.Count;
@@ -189,24 +191,28 @@ public static class RandomHelpers
         }
     }
 
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static bool Prob(this System.Random random, double chance)
     {
         return random.NextDouble() < chance;
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static byte NextByte(this System.Random random, byte maxValue)
     {
         return NextByte(random, 0, maxValue);
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static byte NextByte(this System.Random random)
     {
         return NextByte(random, byte.MaxValue);
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static byte NextByte(this System.Random random, byte minValue, byte maxValue)
     {
         return (byte)random.Next(minValue, maxValue);

Robust.Shared/Random/RandomExtensions.cs

@@ -19,7 +19,13 @@ public static class RandomExtensions
     /// <param name="σ">The standard deviation of the normal distribution.</param>
     public static double NextGaussian(this IRobustRandom random, double μ = 0, double σ = 1)
     {
-        return random.GetRandom().NextGaussian(μ, σ);
+        // https://stackoverflow.com/a/218600
+        var α = random.NextDouble();
+        var β = random.NextDouble();
+
+        var randStdNormal = Math.Sqrt(-2.0 * Math.Log(α)) * Math.Sin(2.0 * Math.PI * β);
+
+        return μ + σ * randStdNormal;
     }
 
     /// <summary>Picks a random element from a collection.</summary>
@@ -78,6 +84,7 @@ public static class RandomExtensions
     /// Picks a random element from a set and returns it.
     /// This is O(n) as it has to iterate the collection until the target index.
     /// </summary>
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static T Pick<T>(this System.Random random, ICollection<T> collection)
     {
         var index = random.Next(collection.Count);
@@ -97,6 +104,7 @@ public static class RandomExtensions
     /// Picks a random from a collection then removes it and returns it.
     /// This is O(n) as it has to iterate the collection until the target index.
     /// </summary>
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static T PickAndTake<T>(this System.Random random, ICollection<T> set)
     {
         var tile = Pick(random, set);
@@ -110,6 +118,7 @@ public static class RandomExtensions
     /// <param name="random">The random object to generate the number from.</param>
     /// <param name="μ">The average or "center" of the normal distribution.</param>
     /// <param name="σ">The standard deviation of the normal distribution.</param>
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static double NextGaussian(this System.Random random, double μ = 0, double σ = 1)
     {
         // https://stackoverflow.com/a/218600
@@ -121,17 +130,21 @@ public static class RandomExtensions
         return μ + σ * randStdNormal;
     }
 
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static Angle NextAngle(this System.Random random) => NextFloat(random) * MathF.Tau;
 
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static Angle NextAngle(this System.Random random, Angle minAngle, Angle maxAngle)
     {
         DebugTools.Assert(minAngle < maxAngle);
         return minAngle + (maxAngle - minAngle) * random.NextDouble();
     }
 
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static Vector2 NextPolarVector2(this System.Random random, float minMagnitude, float maxMagnitude)
         => random.NextAngle().RotateVec(new Vector2(random.NextFloat(minMagnitude, maxMagnitude), 0));
 
+    [Obsolete("Exists as a method directly on IRobustRandom.")]
     public static float NextFloat(this IRobustRandom random)
     {
         // This is pretty much the CoreFX implementation.
@@ -140,11 +153,13 @@ public static class RandomExtensions
         return random.Next() * 4.6566128752458E-10f;
     }
 
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static float NextFloat(this System.Random random)
     {
         return random.Next() * 4.6566128752458E-10f;
     }
 
+    [Obsolete("Always use RobustRandom/IRobustRandom, System.Random does not provide any extra functionality.")]
     public static float NextFloat(this System.Random random, float minValue, float maxValue)
         => random.NextFloat() * (maxValue - minValue) + minValue;
 

Robust.Shared/Random/RobustRandom.cs

@@ -4,15 +4,23 @@ using Robust.Shared.Utility;
 namespace Robust.Shared.Random;
 
 /// <summary>
-/// Wrapper for <see cref="Random"/>.
+///     Provides random numbers, can be constructed in user code or used as a dependency in the form of
+///     <see cref="IRobustRandom"/>. Methods that take RNG as input should take an IRobustRandom instead.
 /// </summary>
-/// <remarks>
-/// This should not contain any logic, not directly related to calling specific methods of <see cref="Random"/>.
-/// To write additional logic, attached to random roll, please create interface-implemented methods on <see cref="IRobustRandom"/>
-/// or add it to <see cref="RandomExtensions"/>.
-/// </remarks>
+/// <example>
+/// <code>
+///     var myRng = new RobustRandom();
+///     // Optionally, seed your RNG. By default, the RNG is seeded randomly.
+///     myRng.SetSeed(17);
+///     <br/>
+///     var fairDiceRoll = myRng.Next(1, 6); // Will be 4 with this seed.
+/// </code>
+/// </example>
 public sealed class RobustRandom : IRobustRandom
 {
+    // This should not contain any logic, not directly related to calling specific methods of <see cref="Random"/>.
+    // To write additional logic, attached to random roll, please create interface-implemented methods on <see cref="IRobustRandom"/>
+    // or add it to <see cref="RandomExtensions"/>.
     private System.Random _random = new();
 
     public System.Random GetRandom() => _random;
@@ -24,7 +32,10 @@ public sealed class RobustRandom : IRobustRandom
 
     public float NextFloat()
     {
-        return _random.NextFloat();
+        // This is pretty much the CoreFX implementation.
+        // So credits to that.
+        // Except using float instead of double.
+        return Next() * 4.6566128752458E-10f;
     }
 
     public int Next()