/// <summary> Construct, on an item list, a buffer with this size </summary>
 public GLMatrixBufferWithGenerations(GLItemsList items, int maximumsize)
 {
     MatrixBuffer = new GLBuffer();
     items.Add(MatrixBuffer);
     Max = maximumsize;
     MatrixBuffer.AllocateBytes(Max * GLLayoutStandards.Mat4size);
     MatrixBuffer.AddPosition(0);        // CreateMatrix4 needs to have a position
 }