This time lets scree how to make a scrolling in VB.Net and XNA.
Rather simple : the idea is to load a texture and to draw it into 2 rectangles, next to each other, and to update the rectangles position.
The project files : XNA_DEMO_8
Imports Microsoft.Xna.Framework
Imports Microsoft.Xna.Framework.Graphics
Imports Microsoft.Xna.Framework.Audio
Imports Microsoft.Xna.Framework.Content
Imports Microsoft.Xna.Framework.Media
Imports Microsoft.Xna.Framework.Input
Public Class Game
Inherits Microsoft.Xna.Framework.Game
'Fields in our game graphic manager etc'
Dim graphics As GraphicsDeviceManager
' // 1. Load a Texture2D and SpriteBatch as normal.
Dim texture1 As Texture2D
Dim spriteBatch As SpriteBatch
' // 2. Create two rectangles for the texture.
Dim rectangle1 As Rectangle
Dim rectangle2 As Rectangle
'// 3. step for the scrolling
Dim istep As Integer = 5
'// some text we will display on screen
Dim font1 As SpriteFont
Dim msg As String
Public Sub New()
graphics = New GraphicsDeviceManager(Me)
Window.Title = "lets Scroll!"
graphics.PreferredBackBufferWidth = 800
graphics.PreferredBackBufferHeight = 410
End Sub
Protected Overrides Sub Initialize()
'// 3a. rectangle1 and 2 should be equal to the
'// dimension of the texture.
rectangle1 = New Rectangle(0, 0, 2048, 410)
'// 3b. Position rectangle2 to the immediate right of rectangle1.
rectangle2 = New Rectangle(2048, 0, 2048, 410)
MyBase.Initialize()
End Sub
Protected Overrides Sub LoadContent()
MyBase.LoadContent()
spriteBatch = New SpriteBatch(GraphicsDevice)
texture1 = Content.Load(Of Texture2D)("back1")
'lets create a font
font1 = Content.Load(Of SpriteFont)("myfont")
End Sub
Protected Overrides Sub UnloadContent()
MyBase.UnloadContent()
End Sub
Protected Overrides Sub Update(ByVal gameTime As Microsoft.Xna.Framework.GameTime)
'// 5a. This is where the quote unquote "magic" happens.
'// This is a simple bounds check. If the right edge of
'// rectangle1 is offscreen to the left, you move it to
'// the right side of rectangle2.
If (rectangle1.X + texture1.Width <= 0) Then rectangle1.X = rectangle2.X + texture1.Width
' // You repeat this check for rectangle2.
If (rectangle2.X + texture1.Width <= 0) Then rectangle2.X = rectangle1.X + texture1.Width
'// 6. Otherwise we incrementally move it to the left.
'// You can swap out X for Y if you instead want incremental
'// vertical scrolling.
Dim key As KeyboardState
key = Keyboard.GetState
If key.IsKeyDown(Keys.Add) Then istep = istep + 1
If key.IsKeyDown(Keys.Subtract) Then istep = istep - 1
rectangle1.X -= istep
rectangle2.X -= istep
msg = "step= " & istep.ToString
'
MyBase.Update(gameTime)
End Sub
Protected Overrides Sub Draw(ByVal gameTime As Microsoft.Xna.Framework.GameTime)
'// 4. Load the SpriteBatch as normal.
'// load the same texture into two different rectangles.
spriteBatch.Begin()
spriteBatch.Draw(texture1, rectangle1, Color.White)
spriteBatch.Draw(texture1, rectangle2, Color.White)
spriteBatch.DrawString(font1, msg, New Vector2(20.0F, 20.0F), Color.White)
spriteBatch.End()
MyBase.Draw(gameTime)
End Sub
End Class
