Thread: Help with Asteroids Game! (positioning and repainting graphics)

Hey everybody! I'm new here as ive found some other of my questions answered through google search (such a pro searcher) Anyways I'm writing a Asteroids game in VB as a final project. I need some help with logic or how i can do some stuff.

As of right now, I have a ship that can move directions and can move forward and backwards from those directions. This is done with a single PictureBox that changes the image on keypress(A for west, D for East, W for North, X for South and the others inbetween) and then whenever the "Up" key is pressed, it checked the tag on the imagebox and moves accordingly (same with down and backtrack).

My next task at hand is lasers. I originally had the same idea to have a single picture box that changes images and direction according to the Ship's direction. And upon my thinking, i came to the conclusion that this won't work as each time I press the space bar (what ill use to shoot) it will simply revert the picture box to the ship and resend the laser.

How can I make an old laser stay on screen while i shoot a new one? I had the idea of simply making multiple picture boxes, say 10, and call it "ammunition" but how can i "Roll" through ammuniction with a single keystroke? Like on multiple presses of "spacebar" it goes to the next ammunition, and eventually checkes if I have any left. or reloading ammunition? I have many ideas but i simpley don't know the logic behind the code.

Thanks for your help guys, If you want i can keep this updated to show my progress over the next two weeks ill be working on this

Here is the Code so far
-Disclaimer- I'm new to VB and i'm sure this is very inefficiently done, try to work with me plz =D
*******If someone can tell me how to make a spoiler i will edit*********

Public Class Form1

   Dim AsteroidSize As Integer

   Dim AsteroidX(10) As Integer

   Dim AsteroidY(10) As Integer

   Dim ShipSize As Integer

   Dim ShipX As Integer

   Dim ShipY As Integer

   Dim laserX As Integer

   Dim laserY As Integer

   Dim MyGraphics As Graphics

   Dim MyRandom As New Random

   Dim BlankBrush As Brush





   Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing

      MyGraphics.Dispose()

      BlankBrush.Dispose()

   End Sub





   Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown

      'Erase Ship at old location

      MyGraphics.FillRectangle(BlankBrush, ShipX, ShipY, ShipSize, ShipSize)

      'Check for up key

      If e.KeyCode = Keys.Up Then

         'Checks which direction for momvement

         If picShip.Tag = "North" Then

            ShipY = ShipY - 7

         ElseIf picShip.Tag = "NorthEast" Then

            ShipY = ShipY - 7

            ShipX = ShipX + 7

         ElseIf picShip.Tag = "East" Then

            ShipX = ShipX + 7

         ElseIf picShip.Tag = "SouthEast" Then

            ShipX = ShipX + 7

            ShipY = ShipY + 7

         ElseIf picShip.Tag = "South" Then

            ShipY = ShipY + 7

         ElseIf picShip.Tag = "SouthWest" Then

            ShipY = ShipY + 7

            ShipX = ShipX - 7

         ElseIf picShip.Tag = "West" Then

            ShipX = ShipX - 7

         ElseIf picShip.Tag = "NorthWest" Then

            ShipX = ShipX - 7

            ShipY = ShipY - 7

         End If

         'Check for down key

      ElseIf e.KeyCode = Keys.Down Then

         If picShip.Tag = "North" Then

            ShipY = ShipY + 3

         ElseIf picShip.Tag = "NorthEast" Then

            ShipY = ShipY + 3

            ShipX = ShipX - 3

         ElseIf picShip.Tag = "East" Then

            ShipX = ShipX - 3

         ElseIf picShip.Tag = "SouthEast" Then

            ShipX = ShipX - 3

            ShipY = ShipY - 3

         ElseIf picShip.Tag = "South" Then

            ShipY = ShipY - 3

         ElseIf picShip.Tag = "SouthWest" Then

            ShipY = ShipY - 3

            ShipX = ShipX + 3

         ElseIf picShip.Tag = "West" Then

            ShipX = ShipX + 3

         ElseIf picShip.Tag = "NorthWest" Then

            ShipX = ShipX + 3

            ShipY = ShipY + 3

         End If

         'Changes directions

      ElseIf e.KeyCode = Keys.E Then

         picShip.Image = WindowsApplication1.My.Resources.Resources.ShipNorthEast

         picShip.Tag = "NorthEast"

      ElseIf e.KeyCode = Keys.D Then

         picShip.Image = WindowsApplication1.My.Resources.Resources.ShipEast

         picShip.Tag = "East"

      ElseIf e.KeyCode = Keys.C Then

         picShip.Image = WindowsApplication1.My.Resources.Resources.ShipSouthEast_copy

         picShip.Tag = "SouthEast"

      ElseIf e.KeyCode = Keys.X Then

         picShip.Image = WindowsApplication1.My.Resources.Resources.ShipSouth

         picShip.Tag = "South"

      ElseIf e.KeyCode = Keys.Z Then

         picShip.Image = WindowsApplication1.My.Resources.Resources.ShipSouthWest

         picShip.Tag = "SouthWest"

      ElseIf e.KeyCode = Keys.A Then

         picShip.Image = WindowsApplication1.My.Resources.Resources.ShipWest

         picShip.Tag = "West"

      ElseIf e.KeyCode = Keys.Q Then

         picShip.Image = WindowsApplication1.My.Resources.Resources.ShipNorthWest

         picShip.Tag = "NorthWest"

      ElseIf e.KeyCode = Keys.W Then

         picShip.Image = WindowsApplication1.My.Resources.Resources.ShipNorth

         picShip.Tag = "North"

         'Shoot laser. 1st check direction of ship, then shoot laser

      ElseIf e.KeyCode = Keys.Space Then

         If picShip.Tag = "North" Or picShip.Tag = "South" Then

            picLaser.Image = WindowsApplication1.My.Resources.Resources.laserNorth

         ElseIf picShip.Tag = "NorthEast" Or picShip.Tag = "SouthWest" Then

            picLaser.Image = WindowsApplication1.My.Resources.Resources.laserNorthEast

         ElseIf picShip.Tag = "East" Or picShip.Tag = "West" Then

            picLaser.Image = WindowsApplication1.My.Resources.Resources.laserEast

         ElseIf picShip.Tag = "NorthWest" Or picShip.Tag = "SouthEast" Then

            picLaser.Image = WindowsApplication1.My.Resources.Resources.laserSouthEast

         End If



      End If



      'position ship

      MyGraphics.DrawImage(picShip.Image, ShipX, ShipY, ShipSize, ShipSize)

   End Sub





   Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

      Dim X As Integer

      Dim I As Integer

      Dim Y As Integer

      'Asteroids spread across the panel with 20 pixels borders

      AsteroidSize = Int((pnlAsteroids.Width - 6 * 20) / 5)

      X = 10

      For I = 1 To 10

         AsteroidX(I) = X

         X = X + AsteroidSize + 20

      Next

      Y = 10

      For I = 1 To 10

         AsteroidY(I) = Y

         Y = Y + AsteroidSize + 20

      Next

      ShipSize = Int(AsteroidSize / 2)

      MyGraphics = pnlAsteroids.CreateGraphics

      BlankBrush = New SolidBrush(pnlAsteroids.BackColor)

      'Give form focus 

      Me.Focus()

   End Sub



End Class

*Bump* Could i get some help plz? ive been working a lot on the project and could edit the quote with new code. I have finished a working system of asteroids that fly around the screen from all directions. Still need help with the lasers shooting

I don't mean to sound rude, but there are many things wrong with your code and I would advise starting over. For one, you never want to cache the graphics object for reuse (as you do with the myGraphics variable in the Form1_Load procedure). From the documentation for the Control.CreateGraphics Method (System.Windows.Forms):

The Graphics object that you retrieve through the CreateGraphics method should not normally be retained after the current Windows message has been processed, because anything painted with that object will be erased with the next WM_PAINT message. Therefore you cannot cache the Graphics object for reuse, except to use non-visual methods like Graphics.MeasureString. Instead, you must call CreateGraphics every time that you want to use the Graphics object, and then call Dispose when you are finished using it.

Here is a good tutorial on building a pong game from coding4fun: Upgrade Your Game: Tiny Tennis (Visual Basic) | Coding4Fun Articles | Channel 9


If you want to search for other tutorials, use the search terms: vb.net sprite game tutorial

And please, no Crossposting. I have deleted your other thread.