XNA Camera

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;

namespace gphysics
{
    class Camera : Particle
    {
        private float mMoveSpeed;
        private float mSprintSpeed;
        private float mCurrentSpeed;
        private float mRotateSpeed;
        private float mMouseSpeed;

        private Vector3 mTarget;

        private Matrix mViewMatrix;
        private Matrix mProjectionMatrix;
        private Matrix mCameraRotation;

        public Matrix GetViewMatrix()
        {
            return mViewMatrix;
        }

        public Matrix GetProjectionMatrix()
        {
            return mProjectionMatrix;
        }

        public Matrix GetRotationMatrix()
        {
            return mCameraRotation;
        }

        public Camera()
        {
            ResetCamera();
        }

        public void ResetCamera()
        {
            mPosition = new Vector3(0.0f, 25.0f, 0.0f);
            mRotation = new Vector3(0.0f, -45.0f, 0.0f);

            mMoveSpeed = 15.0f;
            mSprintSpeed = 150.0f;
            mCurrentSpeed = mMoveSpeed;
            mRotateSpeed = 1.0f;
            mMouseSpeed = 0.001f;

            mTarget = Vector3.Zero;

            mViewMatrix = Matrix.Identity;
            mProjectionMatrix = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(65.0f), Game1.Instance.GetAspectRatio(), 1.0f, 10000000.0f);
            mCameraRotation = Matrix.Identity;
        }

        public void Update(GameTime gameTime)
        {
            DoInput(gameTime);
            UpdateViewMatrix();
        }

        private void UpdateViewMatrix()
        {
            mCameraRotation.Forward.Normalize();
            mCameraRotation.Up.Normalize();
            mCameraRotation.Right.Normalize();

            mCameraRotation *= Matrix.CreateFromAxisAngle(mCameraRotation.Right, mRotation.Y);
            mCameraRotation *= Matrix.CreateFromAxisAngle(Vector3.Up, mRotation.X);
            mCameraRotation *= Matrix.CreateFromAxisAngle(mCameraRotation.Forward, mRotation.Z);

            mRotation = Vector3.Zero;

            mTarget = mPosition + mCameraRotation.Forward;

            mViewMatrix = Matrix.CreateLookAt(mPosition, mTarget, mCameraRotation.Up);
        }

        //This should probably be handled somewhere else but for now I don't really care enough;
        private void DoInput(GameTime gameTime)
        {
            float elapsedTime = gameTime.ElapsedGameTime.Milliseconds / 1000.0f;

            KeyboardState keyboardState = Keyboard.GetState();
            MouseState mouseState = Mouse.GetState();
            Vector2 baseMousePosition = new Vector2((Game1.Instance.graphics.GraphicsDevice.Viewport.Width / 2.0f), (Game1.Instance.graphics.GraphicsDevice.Viewport.Height / 2.0f));
            Vector2 mouseChange = new Vector2(baseMousePosition.X - mouseState.X, baseMousePosition.Y - mouseState.Y);

            //Camera Rotation
            //Mouse Rotation
            mRotation.X += mouseChange.X * mMouseSpeed;
            mRotation.Y += -mouseChange.Y * mMouseSpeed;
            //Set the mouse position after we're done here.
            Mouse.SetPosition((int)(Game1.Instance.graphics.GraphicsDevice.Viewport.Width / 2.0f), (int)(Game1.Instance.graphics.GraphicsDevice.Viewport.Height / 2.0f));

            //Keyboard Rotation Keys
            if (keyboardState.IsKeyDown(Keys.J))
            {
                mRotation.X += mRotateSpeed * elapsedTime;
            }
            if (keyboardState.IsKeyDown(Keys.L))
            {
                mRotation.X += -mRotateSpeed * elapsedTime;
            }
            if (keyboardState.IsKeyDown(Keys.I))
            {
                mRotation.Y += mRotateSpeed * elapsedTime;
            }
            if (keyboardState.IsKeyDown(Keys.K))
            {
                mRotation.Y += -mRotateSpeed * elapsedTime;
            }
            //Disabled roll for the moment because it is normally not there anyway.
            //if (keyboardState.IsKeyDown(Keys.U))
            //{
            //    mRotation.Z += -mRotateSpeed * elapsedTime;
            //}
            //if (keyboardState.IsKeyDown(Keys.O))
            //{
            //    mRotation.Z += mRotateSpeed * elapsedTime;
            //}

            //Fast Movement
            if (keyboardState.IsKeyDown(Keys.LeftShift))
                mCurrentSpeed = mSprintSpeed;
            else
                mCurrentSpeed = mMoveSpeed;

            //Camera Movement
            if (keyboardState.IsKeyDown(Keys.W))
            {
                Move(mCameraRotation.Forward * mCurrentSpeed * elapsedTime);
            }
            if (keyboardState.IsKeyDown(Keys.S))
            {
                Move(-mCameraRotation.Forward * mCurrentSpeed * elapsedTime);
            }
            if (keyboardState.IsKeyDown(Keys.A))
            {
                Move(-mCameraRotation.Right * mCurrentSpeed * elapsedTime);
            }
            if (keyboardState.IsKeyDown(Keys.D))
            {
                Move(mCameraRotation.Right * mCurrentSpeed * elapsedTime);
            }
            //Make up and down absolute so we don't get confused.
            //Actually don't do that.

            if (keyboardState.IsKeyDown(Keys.Q))
            {
                Move(mCameraRotation.Up * mCurrentSpeed * elapsedTime);
            }
            if (keyboardState.IsKeyDown(Keys.E))
            {
                Move(-mCameraRotation.Up * mCurrentSpeed * elapsedTime);
            }

            //Reset camera button
            if (keyboardState.IsKeyDown(Keys.K))
            {
                ResetCamera();
            }

        }
    }
}