XNA Scrolling background - xna

Question

Hi, I'm working on a 2D game and I was working on the scrolling background but whatever I try it doesn't get it scrolled.
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
//The size of the Sprite
public Rectangle Size;
//Used to size the Sprite up or down from the original image
public float Scale = 1.0f;
// Create an instance of Texture2D that will
// contain the background texture.
Texture2D background;
// Create a Rectangle that will definee
// the limits for the main game screen.
Rectangle mainFrame;
private GamePadState gamePadState;
private KeyboardState keyboardState;
public class Camera
{
public Camera(Viewport viewport)
{
Origin = new Vector2(viewport.Width / 2.0f, viewport.Height / 2.0f);
Zoom = 1.0f;
}
public Vector2 Position { get; set; }
public Vector2 Origin { get; set; }
public float Zoom { get; set; }
public float Rotation { get; set; }
public Matrix GetViewMatrix(Vector2 parallax)
{
// To add parallax, simply multiply it by the position
return Matrix.CreateTranslation(new Vector3(-Position * parallax, 0.0f)) *
// The next line has a catch. See note below.
Matrix.CreateTranslation(new Vector3(-Origin, 0.0f)) *
Matrix.CreateRotationZ(Rotation) *
Matrix.CreateScale(Zoom, Zoom, 1) *
Matrix.CreateTranslation(new Vector3(Origin, 0.0f));
}
}
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
IsMouseVisible = true;
graphics.IsFullScreen = true;
}
protected override void Initialize()
{
gamePadState = GamePad.GetState(PlayerIndex.One);
keyboardState = Keyboard.GetState();
base.Initialize();
}
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
// Load the background content.
background = Content.Load<Texture2D>("Images\\muur");
// Set the rectangle parameters.
mainFrame = new Rectangle(0, 0, GraphicsDevice.Viewport.Width, GraphicsDevice.Viewport.Height);
}
protected override void Update(GameTime gameTime)
{
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
base.Update(gameTime);
}
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.Black);
// Draw the background.
// Start building the sprite.
spriteBatch.Begin();
// Draw the background.
spriteBatch.Draw(background, mainFrame, Color.White);
// End building the sprite.
spriteBatch.End();
base.Draw(gameTime);
}
}
How can I achieve this functionality?

Answer 1

I don't see where you use the camera transform...
you should have a parallax vector and update it...
Vector2 parallax_position;
float parallax_speed;
public void Update (Gametime time)
{
parallax_position += parallax_speed * Vector2.UnitX * (float) time.elapsed.totalseconds;
}
and then in Draw method, you should use it in your spritebatch....
public void Draw()
{
spriteBatch.begin(..,...,..,..,.., GetCameraTransform(Parallax));
...
}