public SkeletonRenderer(GraphicsDevice device)
        {
            this.device = device;

            batcher = new MeshBatcher();

            var basicEffect = new BasicEffect(device);

            basicEffect.World              = Matrix.Identity;
            basicEffect.View               = Matrix.CreateLookAt(new Vector3(0.0f, 0.0f, 1.0f), Vector3.Zero, Vector3.Up);
            basicEffect.TextureEnabled     = true;
            basicEffect.VertexColorEnabled = true;
            effect = basicEffect;

            rasterizerState          = new RasterizerState();
            rasterizerState.CullMode = CullMode.None;

            Bone.yDown = true;
        }