Core/Maps: Fixed map min height calculation

Source/Framework/GameMath/Plane.cs

@@ -207,6 +207,19 @@ namespace Framework.GameMath
         {
             return Vector3.DotProduct(p, this.Normal) - this.Constant;
         }
+
+        public void getEquation(ref Vector3 n, out float d)
+        {
+            double _d;
+            getEquation(ref n, out _d);
+            d = (float)_d;
+        }
+
+        void getEquation(ref Vector3 n, out double d)
+        {
+            n = _normal;
+            d = -_const;
+        }
         #endregion
 
         #region Overrides

Source/Framework/GameMath/Ray.cs

@@ -192,6 +192,24 @@ namespace Framework.GameMath
 
         #endregion
 
+        public Vector3 intersection(Plane plane)
+        {
+            float d;
+            Vector3 normal = plane.Normal;
+            plane.getEquation(ref normal, out d);
+            float rate = Direction.dot(normal);
+
+            if (rate >= 0.0f)
+            {
+                return Vector3.Inf;
+            }
+            else
+            {
+                float t = -(d + Origin.dot(normal)) / rate;
+                return Origin + Direction * t;
+            }
+        }
+
         public float intersectionTime(AxisAlignedBox box)
         {
             Vector3 dummy = Vector3.Zero;

Source/Framework/GameMath/Vector3.cs

@@ -91,6 +91,8 @@ namespace Framework.GameMath
         public static readonly Vector3 Zero = new Vector3(0.0f, 0.0f, 0.0f);
 
         public static readonly Vector3 One = new Vector3(1.0f, 1.0f, 1.0f);
+
+        public static readonly Vector3 Inf = new Vector3(float.PositiveInfinity, float.PositiveInfinity, float.PositiveInfinity);
         /// <summary>
         /// 4-Dimentional single-precision floating point X-Axis vector.
         /// </summary>