What's wrong here? Type-creation causing crash

BlitzMax Forums/BlitzMax Beginners Area/What's wrong here? Type-creation causing crash

kronholm

(Posted 2007) [#1]

Strict
Graphics 800,600,0,60


Global gui:tgui = New tgui
'SetColor 255,255,255

'mainloop
Repeat
	gui.update()
	gui.draw()
	Flip;Cls
Until KeyHit(key_escape)


'draws the mouse + a rectangle
Type tgui
	Field x=0,y=0
	Field mouse:tmouse = tmouse.create()
	Method draw()
		DrawRect x,y,300,200
		'mouse.draw()
	EndMethod
	Method update()
		'mouse.update()
	EndMethod
EndType



Type tmouse Extends tgui
	Field x,y
	Method draw()
		DrawOval x,y,10,10	
	EndMethod	
	Method update()
		x = MouseX()
		y = MouseY()
	EndMethod
	Function create:tmouse()
		Local mouse:tmouse = New tmouse
		Return mouse:tmouse
	EndFunction
EndType

It's probably something very basic I haven't learned. But it's bugging me quite a bit. Can someone help?

I really want to have the mouse type inside the gui type so I can do gui.mouse.update() and whatnot. I also wish to have mouse extend gui, such that I can "see" the mouse from other tgui extends, for collisions and whatnot. For instance, tgui:twindow which is extended from gui, would want to see if mouse's lmb is pressed (gui.mouse.lmb) by doing 'if mouse.lmb', naturally refering to gui.mouse.lmb, but since the window is also a child of gui, it could see it.. Does that make any sense?

Maybe I'm supposed to have the mouse stuff built into the tgui type for my purposes, or as a global?

Brucey

(Posted 2007) [#2]

I would guess that your main problem is this line :

Type tmouse Extends tgui

The tgui type has a field "mouse", which calls tmouse.create()... which creates a new instance of tmouse (which is a tgui)... which has a field "mouse", which calls tmouse.create()... which creates a new instance of tmouse (which is a tgui)... which has a field "mouse", which calls tmouse.create()... which creates a new instance of tmouse... etc...
...until it crashes.

:-)

Brucey

(Posted 2007) [#3]

I'm not sure how having mouse extend tgui is going to benefit collision checking etc.
Surely the mouse is "global", and isn't a gui object as such (like a window or a button).

For collision detection, couldn't you just do some kind of bounds checking against you gui objects... starting with the biggest parents (like a window), and then working your way down to a specific child (like a button)... following the parent/child relationships - which means you are only testing against a subset of all the gui objects.

just a thought :-)

kronholm

(Posted 2007) [#4]

Thanks Brucey, see your point :)

Now ignore for a moment the stuff doesn't compile, but is there a way to e.g. inside gui.mouse.update() to refer to the root, i.e. the parent? If I specifically want the x of the gui, but it's from inside the update function in mouse? I tried "print super.x" but that doesn't work :p Is it called something else?

kronholm

(Posted 2007) [#5]

Here's an example..

Strict

Graphics 800,600,0,60

Global gui:tgui = New tgui
gui.windowlist.addlast(twindow.create())


Repeat
	gui.draw()

	Flip;Cls
Until KeyHit(key_escape)



Type tgui
	Field x,y
	Field mouse:tmouse = New tmouse
	Field windowlist:TList = CreateList()
	Method draw()
		mouse.update()
		mouse.draw()
		For Local window:twindow = EachIn windowlist
			window.draw()
			window.checkcollide()
		Next
	EndMethod
EndType

Type tmouse
	Field x,y
	Method update()
		x = MouseX()
		y = MouseY()
	EndMethod
	Method draw()
		DrawOval x,y,60,60
	EndMethod
EndType

Type twindow Extends tgui
	Field x,y,w,h
	Method checkcollide()		'here's the problem, how can I make it so twindow can see gui.mouse?
		If mouse.x > 0 And mouse.y > 0
			If mouse.x > x And mouse.x < x+w And mouse.y > y And mouse.y < y+h
				w = 200
			Else
				w = 100
			EndIf
		EndIf
	EndMethod
	Method draw()
		DrawRect x,y,w,h
	EndMethod
	Function create:twindow(x=200,y=300,w=100,h=100)
		Local window:twindow = New twindow
		window.x = x ; window.y = y 
		window.w = w ; window.h = h
		Return window:twindow
	EndFunction
EndType

I need to have the mouse coordinates callable from e.g, the windows, in the gui's window lists. How is that done? I thought it was supposed to work when I did it this way. The mouse is just a child, it's not extended from gui, so why can't I do mouse.x etc. inside a method of a gui-extend?

Brucey

(Posted 2007) [#6]

The problem is

Field mouse:tmouse = New tmouse

in your tgui.

It means each instance of a gui object has its own (non-updating other than the top gui object) mouse object.

what if you change it to :

Global mouse:tmouse = New tmouse

Then all gui instances "share" the same mouse...

?

kronholm

(Posted 2007) [#7]

So just a global inside the type instead of a field? It's really that simple? Wow :p Thanks!