Why Do I get this Error?

BlitzMax Forums/BlitzMax Beginners Area/Why Do I get this Error?

Graphics 1024,768
Global Rocks:TList = New TList

Type ScreenObject

Field X:Int
Field Y:Int
Field XV:Float
Field YV:Float
Field Rotation:Float
Field RotationSpeed:Float
Field Image:Timage
Method Update() Abstract
End Type

Type Ship Extends ScreenObject
Function Create:Ship(XX,YY)
P:Ship = New Ship
P.Image:Timage=LoadImage("PlayerShip.Bmp")
SetImageHandle (p.Image,36,42)
P.X=Rand(1000)
P.Y=Rand(700)
Return P
End Function
Method Update()
SetRotation Self.Rotation
DrawImage (Self.Image,Self.X,Self.Y)
End Method

End Type

Type Rock Extends ScreenObject

Function Create:Rock(XX,YY)
R:Rock=New Rock
R.X=Rand(1024)
R.Y=Rand(768)
R.Rotation=Rand(360)
R.RotationSpeed=Rnd(5.0)
R.Image:Timage=LoadImage("Asteriod.bmp")
SetImageHandle (R.Image,64,64)
ListAddLast Rocks,R
Return R
End Function

Method Update()
Local Asteroid:Rock
For Asteroid=EachIn Rocks
Asteroid.Rotation:+1
If Asteroid.Rotation>360 Then Asteroid.Rotation=0
SetRotation Asteroid.Rotation
DrawImage (Asteroid.Image,Asteroid.X,Asteroid.Y)
Next
End Method
End Type
Player:Ship=Ship.Create(0,0)
For tt=1 To 50
Rock.Create(10,10)
Next
Repeat

Cls
SetBlend(alphaBlend)

Player.Update()
Rock.Update()

Flip
Until KeyHit(Key_Escape)

Identifier 'Update' Not Found... It happens at Rock.Update()

What am I doing Wrong?

Thanks,
Eric

Sarge

You have to create a new object like - "R:Rock = New Rock"

Graphics 1024,768
Global Rocks:TList = New TList

Type ScreenObject

Field X:Int
Field Y:Int
Field XV:Float
Field YV:Float
Field Rotation:Float
Field RotationSpeed:Float
Field Image:Timage
Method Update() Abstract 
End Type

Type Ship Extends ScreenObject
Function Create:Ship(XX,YY)
P:Ship = New Ship
P.Image:Timage=LoadImage("PlayerShip.Bmp")
SetImageHandle (p.Image,36,42)
P.X=Rand(1000) 
P.Y=Rand(700) 
Return P
End Function
Method Update()
SetRotation Self.Rotation
DrawImage (Self.Image,Self.X,Self.Y)
End Method

End Type

Type Rock Extends ScreenObject

Function Create:Rock(XX,YY)
R:Rock=New Rock
R.X=Rand(1024)
R.Y=Rand(768)
R.Rotation=Rand(360)
R.RotationSpeed=Rnd(5.0)
R.Image:Timage=LoadImage("Asteriod.bmp")
SetImageHandle (R.Image,64,64)
ListAddLast Rocks,R
Return R
End Function

Method Update()
Local Asteroid:Rock
For Asteroid=EachIn Rocks 
Asteroid.Rotation:+1
If Asteroid.Rotation>360 Then Asteroid.Rotation=0
SetRotation Asteroid.Rotation
DrawImage (Asteroid.Image,Asteroid.X,Asteroid.Y)
Next
End Method
End Type 
Player:Ship=Ship.Create(0,0)
For tt=1 To 50 
R:Rock = New Rock
Rock.Create(10,10)
Next 
Repeat

Cls
SetBlend(alphaBlend)

Player.Update()
R.Update()


Flip
Until KeyHit(Key_Escape)

blitzbasic.com forurm tag "code /code" - include the brackets

Eric

I have that line in my Create:Rock Function... I noticed that if I don't have Abstract Update() and change the Update Method in the Rock Type to a Function my code Runs. This OOP is very new to me.

Sarge

But if you put that in a function it will only be called within the function not out of it its similar to Local but your looking for Global.

FlameDuck

change the Update Method in the Rock Type to a Function my code Runs.

That's because you are invoking update() on the Type in general, not a specific instance of said type (thus it's looking for a Function called Update, which you don't have).

Methods belong to objects/instances, and can only be invoked with a suitable object handle.

Functions belong to the entire type/class and is traditionally invoked like in your example.

The "Abstract" keyword means that you would like a particular function or method to be part of a type interface, but that implementation will be different depending on which extended object/class you're dealing with (polymorphism).

Eric

ok thanks...That helps alot... It's going to take me a little getting use to all of this new stuff...Just like "Types" in general when I first started with BlitzBasic (2d). Thanks for all of the input.