object does not exist error

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Josaih6/10

(Posted 2009) [#1]

What does the "object does not exist" error mean when called on "RectsOverlap"? This error is only appearing when the function returns "True".

_PJ_	(Posted 2009) [#2]

Unless you've made some reference to an image or something by it's handle in the RectsOverlap line, (i.e. RectsOverlap x,y,ImageWidth(Image)... etc.)
Then I am unsure of why such an error would occur there.

Any chance you could post a relevant section ofyour code that might give a clue?

Yasha

(Posted 2009) [#3]

"Object does not exist" normally means you're trying to do something with a custom type variable that's currently Null. Using one?

Josaih6/10

(Posted 2009) [#4]

I'm fairly new to blitz so this code may not be very efficient. It is also not complete.

Graphics 600,600,8,2
SeedRnd MilliSecs()
Global scrx = GraphicsWidth()
Global scry = GraphicsHeight()

SetBuffer FrontBuffer()

Type ent
	Field xv#,yv#
	Field x#,y#
	Field typ$,colr,colg,colb,dia#
End Type 

For n = 1 To 15
CreateRS(Rnd(scrx),Rnd(scry),Rnd(-.5,.5),Rnd(-.5,.5))
Next 

While Not KeyHit(1)

Cls 
UpdateEnts
DrawBord
Flip 

Wend  
End


;Functions-----------------------------------------------

Function DrawBord()

For e.ent = Each ent
Color e\colr,e\colg,e\colb
Oval e\x#-(e\dia#/2),e\y#-(e\dia#/2),e\dia#,e\dia#,True 
Color 255,255,255
Next  

End Function 




Function UpdateEnts()

For e.ent = Each ent 
e\x# = e\x# + e\xv#
e\y# = e\y# + e\yv#
If e\x# <= 0 Or e\x# >= scrx Then e\xv# = -e\xv#
If e\y# <= 0 Or e\y# >= scry Then e\yv# = -e\yv#
Next 
For e.ent = Each ent
For c.ent = Each ent
If e = c Then Goto Skip
If RectsOverlap(e\x#,e\y#,e\dia#,e\dia#,c\x#,c\y#,c\dia#,c\dia#)
	If e\typ$ = "rs" And c\typ$ = "rs" Or c\typ$ = "rs" And e\typ$ = "rs"
		CreateRB(e\x#,e\y#)
		Delete e
		Delete c  
	End If 
End If  
.Skip
Next 
Next 

End Function 






;Create Functions------------------------------------
Function CreateRS(x#,y#,xv#,yv#)

e.ent = New ent
e\x# = x#
e\y# = y#
e\xv# = xv#
e\yv# = yv#
e\colr = 255
e\colg = 0
e\colb = 0
e\dia# = 5
e\typ$ = "rs"

End Function 



Function CreateBS(x#,y#,xv#,yv#)

e.ent = New ent
e\x# = x#
e\y# = y#
e\xv# = xv#
e\yv# = yv#
e\colr = 0
e\colg = 0
e\colb = 255
e\dia# = 5
e\typ$ = "bs"

End Function



Function CreateRB(x#,y#)

e.ent = New ent
e\x# = x#
e\y# = y#
e\colr = 255
e\colg = 0
e\colb = 0
e\dia# = 10
e\typ$ = "rb"

End Function 



Function CreateBB(x#,y#)

e.ent = New ent
e\x# = x#
e\y# = y#
e\colr = 0
e\colg = 0
e\colb = 255
e\dia# = 10
e\typ$ = "bb"

End Function

Gabriel

(Posted 2009) [#5]

I haven't gone over all of your code, so there may be more things to improve, but I've fixed the bug and tidied the surrounding code.

Graphics 600,600,8,2
SeedRnd MilliSecs()
Global scrx = GraphicsWidth()
Global scry = GraphicsHeight()

SetBuffer FrontBuffer()

Type ent
	Field xv#,yv#
	Field x#,y#
	Field typ$,colr,colg,colb,dia#
End Type 

For n = 1 To 15
CreateRS(Rnd(scrx),Rnd(scry),Rnd(-.5,.5),Rnd(-.5,.5))
Next 

While Not KeyHit(1)

Cls 
UpdateEnts
DrawBord
Flip 

Wend  
End


;Functions-----------------------------------------------

Function DrawBord()

For e.ent = Each ent
Color e\colr,e\colg,e\colb
Oval e\x#-(e\dia#/2),e\y#-(e\dia#/2),e\dia#,e\dia#,True 
Color 255,255,255
Next  

End Function 




Function UpdateEnts()

For e.ent = Each ent 
e\x# = e\x# + e\xv#
e\y# = e\y# + e\yv#
If e\x# <= 0 Or e\x# >= scrx Then e\xv# = -e\xv#
If e\y# <= 0 Or e\y# >= scry Then e\yv# = -e\yv#
Next 
For e.ent = Each ent
	For c.ent = Each ent
		If e <> c 
			If e<>Null
				If RectsOverlap(e\x#,e\y#,e\dia#,e\dia#,c\x#,c\y#,c\dia#,c\dia#)
					If e\typ$ = "rs" And c\typ$ = "rs" Or c\typ$ = "rs" And e\typ$ = "rs"
						CreateRB(e\x#,e\y#)
						Delete e
						Delete c  
					End If 
				End If  
			End If
		End If
	Next 
Next 

End Function 






;Create Functions------------------------------------
Function CreateRS(x#,y#,xv#,yv#)

e.ent = New ent
e\x# = x#
e\y# = y#
e\xv# = xv#
e\yv# = yv#
e\colr = 255
e\colg = 0
e\colb = 0
e\dia# = 5
e\typ$ = "rs"

End Function 



Function CreateBS(x#,y#,xv#,yv#)

e.ent = New ent
e\x# = x#
e\y# = y#
e\xv# = xv#
e\yv# = yv#
e\colr = 0
e\colg = 0
e\colb = 255
e\dia# = 5
e\typ$ = "bs"

End Function

Quick explanation of what was wrong. You have nested loops going through the same list. For e= and For c= through the same list of objects, ok? So each loop deals with the object, but you may already have deleted it, in which case it won't be valid any more. SO I check that e is not equal to null. I don't think you need to check c, but I only looked quickly. If you get a similar error with c, you may need to check that is <> null before you attempt to use it. It's always a good practice really.

I changed your if e=c goto skip because it's harder to read. I've reversed it and said if e <> c then execute the block of code.

I also indented a couple for..next loops, again to make things more readable.

Josaih6/10

(Posted 2009) [#6]

Thank you very much.