Accept an IntPtr for VertexBuffer.SetData.

OpenRA.Game/Graphics/IGraphicsDevice.cs

@@ -82,6 +82,7 @@ namespace OpenRA
 		void Bind();
 		void SetData(T[] vertices, int length);
 		void SetData(T[] vertices, int start, int length);
+		void SetData(IntPtr data, int start, int length);
 	}
 
 	public interface IShader

OpenRA.Renderer.Null/NullGraphicsDevice.cs

@@ -105,6 +105,7 @@ namespace OpenRA.Renderer.Null
 		public void Bind() { }
 		public void SetData(T[] vertices, int length) { }
 		public void SetData(T[] vertices, int start, int length) { }
+		public void SetData(IntPtr data, int start, int length) { }
 		public void Dispose() { }
 	}
 }

OpenRA.Renderer.Sdl2/VertexBuffer.cs

@@ -48,6 +48,16 @@ namespace OpenRA.Renderer.Sdl2
 			ErrorHandler.CheckGlError();
 		}
 
+		public void SetData(IntPtr data, int start, int length)
+		{
+			Bind();
+			GL.BufferSubData(BufferTarget.ArrayBuffer,
+				new IntPtr(VertexSize * start),
+				new IntPtr(VertexSize * length),
+				data);
+			ErrorHandler.CheckGlError();
+		}
+
 		public void Bind()
 		{
 			GL.BindBuffer(BufferTarget.ArrayBuffer, buffer);