Create bare godot project

FixPoint/IntRandom.cs

@@ -0,0 +1,119 @@
+using System;
+
+namespace MagmaEngine.Math;
+
+/// <summary>
+///     Implements a XorShift* PRNG, with 64 bits of internal state.
+///     See http://en.wikipedia.org/wiki/Xorshift
+/// </summary>
+public struct SIntRandom
+{
+    public SIntRandom(ulong seed)
+    {
+        if (seed == 0)
+            throw new InvalidOperationException("Seed needs to be bigger than zero.");
+
+        m_Seed = seed;
+    }
+
+    public ulong Next()
+    {
+        m_Seed ^= m_Seed >> 12;
+        m_Seed ^= m_Seed << 25;
+        m_Seed ^= m_Seed >> 27;
+        return m_Seed * 2685821657736338717UL; // multiplier taken from wikipedia article on XorShift PRNGs
+    }
+
+    public ulong Next(ulong upperLimit)
+    {
+        if (upperLimit == 0)
+        {
+            return 0;
+        }
+
+        return Next() % upperLimit;
+    }
+
+    public FixPoint16 NextFixPoint16()
+    {
+        return new() { m_Value = (int)(Next() & 0xffffUL) };
+    }
+
+    public int RandomizedRound(FixPoint16 value)
+    {
+        int ret = value.ToIntFloor();
+        if (NextFixPoint16() < FixPoint16.Fract(value))
+            ret++;
+
+        return ret;
+    }
+
+    public uint Next(uint upperLimit)
+    {
+        if (upperLimit == 0)
+        {
+            return 0;
+        }
+
+        return (uint)(Next() % upperLimit);
+    }
+
+    public uint Next(uint lowerLimit, uint upperLimit)
+    {
+        if (upperLimit == 0)
+        {
+            return 0;
+        }
+
+        if (lowerLimit == upperLimit)
+        {
+            return lowerLimit;
+        }
+
+        return lowerLimit + (uint)(Next() % (upperLimit - lowerLimit));
+    }
+
+    public int Next(int upperLimit)
+    {
+        if (upperLimit == 0)
+        {
+            return 0;
+        }
+
+        return (int)(Next() % (uint)(upperLimit & 0x7fffffff));
+    }
+
+    public int Next(int lowerLimit, int upperLimit)
+    {
+        if (upperLimit == 0)
+        {
+            return 0;
+        }
+
+        if (lowerLimit == upperLimit)
+        {
+            return lowerLimit;
+        }
+
+        return lowerLimit + (int)(Next() % (uint)((upperLimit - lowerLimit) & 0x7fffffff));
+    }
+
+    public double NextDouble()
+    {
+        return Next(int.MaxValue) * (1.0 / int.MaxValue);
+    }
+
+    public float NextSingle()
+    {
+        return (float)NextDouble();
+    }
+
+    public override readonly string ToString()
+    {
+        return $"0x{m_Seed:X}";
+    }
+
+    public readonly ulong Seed => m_Seed;
+
+    private ulong m_Seed;
+}