switch root namespace name to NITLOAD

src/Nitload.Mathematics/Geometries/PlainGeometry/Define/PlainGeometry.cs

@@ -0,0 +1,51 @@
+// -----------------------------------------------------------------------------
+// file="PlainGeometry"
+// Project: StgSharp
+// Copyright (c) Nitload.
+// SPDX-License-Identifier: MIT
+// -----------------------------------------------------------------------------
+
+using Nitload;
+using Nitload.Mathematics;
+using Nitload.Mathematics.Numeric.Graphics;
+
+using System;
+using System.ComponentModel;
+
+namespace Nitload.Geometries
+{
+    /// <summary>
+    ///   Plain geometry only contains straight sides.
+    /// </summary>
+    public abstract class PlainGeometry : IGeometry
+    {
+
+        protected Vec4[] vertexMat;
+        internal CoordinationBase coordinate;
+
+        internal PlainGeometry(
+                 CoordinationBase coordination
+        )
+        {
+            coordinate = coordination;
+        }
+
+        public Point this[
+                     int index
+        ]
+        {
+            get => new Point(vertexMat[index]);
+            set => vertexMat[index].vec = value.coordVec;
+        }
+
+        public int VertexCount => this.vertexMat.Length;
+
+        public abstract ReadOnlySpan<int> VertexIndices { get; }
+
+        #pragma warning disable CA1819 
+        public Vec4[] VertexStream => vertexMat;
+
+        public CoordinationBase Coordination => this.coordinate;
+#pragma warning restore CA1819
+    }
+}