+ Added an auto-incrementing Id to OSCADObjects

OSCADSharp/OSCADSharp.UnitTests/OSCADObjectTests.cs

@@ -1,6 +1,7 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using OSCADSharp.Solids;
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -79,5 +80,45 @@ namespace OSCADSharp.UnitTests
             Assert.IsFalse(sphere.GetType() == cube.GetType());
             Assert.AreEqual(0, sphere.Children().Count());
         }
+
+        [TestMethod]
+        public void OSCADObject_IdsAreSequentialAndDistinct()
+        {
+            var obj1 = new Sphere();
+            var obj2 = new Cube();
+            var obj3 = new Sphere();
+           
+
+            Assert.IsTrue(obj1.Id < obj2.Id && obj2.Id < obj3.Id);
+
+            Assert.IsTrue(obj1.Id + 1 == obj2.Id);
+            Assert.IsTrue(obj2.Id + 1 == obj3.Id);
+        }
+
+        [TestMethod]
+        public void OSCADObject_ParallelObjectCreationDoesNotYieldDuplicateIds()
+        {
+            ConcurrentBag<OSCADObject> bag = new ConcurrentBag<OSCADObject>();
+
+            Parallel.For(0, 1000, (i) => {
+                bag.Add(new Sphere());
+            });
+
+            var ids = bag.Select(obj => obj.Id).ToList();
+            Assert.AreEqual(ids.Count, ids.Distinct().Count());
+        }
+
+        [TestMethod]
+        public void OSCADObject_EachOscadObjectChildHasDistinctId()
+        {
+            var obj = new Cube(5, 5, 10, true)
+                .Translate(0, 5, 10).Rotate(0, 90, 0)
+                .Translate(0, 0, 10).Scale(1, 1, 2);
+
+            List<uint> ids = obj.Children().Select(child => child.Id).ToList();
+            ids.Add(obj.Id);
+
+            Assert.AreEqual(ids.Count, ids.Distinct().Count());
+        }
     }
 }

OSCADSharp/OSCADSharp/Ids.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace OSCADSharp
+{
+    /// <summary>
+    /// Responsible for creating identifiers for objects
+    /// </summary>
+    internal static class Ids
+    {
+        private static uint globalId = 0;
+        private static object idLockObject = new object();
+
+        /// <summary>
+        /// Gets a unique auto-incrementing integer id
+        /// </summary>
+        /// <returns></returns>
+        internal static uint Get()
+        {
+            lock (idLockObject)
+            {
+                globalId++;
+                return globalId;
+            }
+        }
+    }
+}

OSCADSharp/OSCADSharp/OSCADObject.cs

@@ -14,6 +14,16 @@ namespace OSCADSharp
     /// </summary>
     public abstract class OSCADObject
     {
+        #region Fields
+        private uint id = Ids.Get();
+
+        /// <summary>
+        /// The unique Id of the object
+        /// these values auto-increment
+        /// </summary>
+        public uint Id { get { return this.id; } }
+        #endregion
+
         #region Transforms
         /// <summary>
         /// Applies Color and/or Opacity to this object

OSCADSharp/OSCADSharp/OSCADSharp.csproj

@@ -42,6 +42,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Ids.cs" />
     <Compile Include="Sizes.cs" />
     <Compile Include="Spatial\Matrix.cs" />
     <Compile Include="Transforms\HulledObject.cs" />