D3dScenePresenter - How to present and manipulate a 3D scene using MDX

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.DirectX;

namespace MdxScene.Cameras
{
    public class D3dPerspectiveOffCenterCamera : D3dPerspectiveCameraBase
    {
        public D3dPerspectiveOffCenterCamera()
        {
            Left = -0.5f;
            Right = 0.5f;
            Bottom = 0.5f;
            Top = -0.5f;
        }

        #region D3dPerspectiveCameraBase implementation
        public override Matrix GetProjectionMatrix()
        {
            return CameraCoordinateSystem.LeftHanded == CoordinateSystem
                       ? Matrix.PerspectiveOffCenterLH(Left, Right, Bottom, Top, ZNearPlane, ZFarPlane)
                       : Matrix.PerspectiveOffCenterRH(Left, Right, Bottom, Top, ZNearPlane, ZFarPlane);
        }

        public override void Zoom(float scalingFactorX, float scalingFactorY)
        {
            float centerX = (Left + Right) / 2;
            float centerY = (Bottom + Top) / 2;

            float halfWidth = ((Right - Left) / 2) * scalingFactorX;
            float halfHeight = ((Top - Bottom) / 2) * scalingFactorY;

            Left = centerX - halfWidth;
            Right = centerX + halfWidth;
            Bottom = centerY - halfHeight;
            Top = centerY + halfHeight;
        }

        public override void GetFov(out float fovX, out float fovY)
        {
            float width = Right - Left;
            float height = Top - Bottom;

            fovX = (float)Math.Atan(width / (2 * ZNearPlane)) * 2;
            fovY = (float)Math.Atan(height / (2 * ZNearPlane)) * 2;
        }
        #endregion

        #region properties

        #region Left
        private float _left;
        public float Left
        {
            get { return _left; }
            set
            {
                lock (this)
                {
                    _left = value;
                    _isProjectionMatrixValid = false;
                }
            }
        }
        #endregion

        #region Right
        private float _right;
        public float Right
        {
            get { return _right; }
            set
            {
                lock (this)
                {
                    _right = value;
                    _isProjectionMatrixValid = false;
                }
            }
        }
        #endregion

        #region Bottom
        private float _bottom;
        public float Bottom
        {
            get { return _bottom; }
            set
            {
                lock (this)
                {
                    _bottom = value;
                    _isProjectionMatrixValid = false;
                }
            }
        }
        #endregion

        #region Top
        private float _top;
        public float Top
        {
            get { return _top; }
            set
            {
                lock (this)
                {
                    _top = value;
                    _isProjectionMatrixValid = false;
                }
            }
        }
        #endregion

        #endregion
    }
}