help needed

Hi all,

I'd be incredibly grateeful if someone could spare a couple of minutes to look over this code. It's the first time I've done any programming for many years, and the first time I have used 'types' - so it's likely i'm missing something really obvious.

After running for a few seconds - all my particles disappear - why????

(Lower mound number if it runs slow)

Hope you can help

markyb
[p4 2.8 / 512mb / 128mb geforce ti4600]
--------------------------------------------------

;bugged particles

Graphics 800,600,32,2

SeedRnd (MilliSecs())


;make a bug type
Type bug
Field size
Field x#
Field y#
Field direction
Field xspeed#
Field yspeed#
End Type



;make mound of bugs
mound = 2000

For i = 1 To mound
nest.bug = New bug
nest\x# = 400
nest\y# = 300
nest\direction# = Rnd(360) - 180
nest\size = Rand(4)
nest\xspeed# = Rnd(nest\size) + Rnd(4)
nest\yspeed# = Rnd(nest\size) + Rnd(4)
Next



; main loop
While Not KeyHit(1)
For nest.bug =Each bug
SetBuffer BackBuffer()
Cls
draw_bug(nest.bug)
Flip
move_bug(nest.bug)
Next
Wend


; move the bugs
Function move_bug(nest.bug)
For nest.bug = Each bug
;check for edge collisions
If nest\x#-nest\size<=100 Or nest\x#+nest\size>=700 Then nest\xspeed# = -nest\xspeed#
If nest\y#-nest\size<=100 Or nest\y#+nest\size>=500 Then nest\yspeed# = -nest\yspeed#
;update bugs position
nest\x# = nest\x# + Sin(nest\direction#)*nest\xspeed#
nest\y# = nest\y# + Cos(nest\direction#)*nest\yspeed#
Next
End Function


; draw the bugs
Function draw_bug(nest.bug)
For nest.bug = Each bug
Color 255-(nest\size*10),255-(nest\size*20),255-(nest\size*15)
Oval nest\x#, nest\y#,nest\size,nest\size
Next
End Function

;--------------------------------------------

Works ok here - might be a pseudo-doublebuffering problem (double-buffering is faked when running in a window). Try running it full-screen and see if it still messes up.

I tidied the main loop up a bit - give this a go:

Graphics 800,600,32,2 
SetBuffer BackBuffer()

SeedRnd (MilliSecs()) 


;make a bug type 
Type bug 
Field size 
Field x# 
Field y# 
Field direction 
Field xspeed# 
Field yspeed# 
End Type 



;make mound of bugs 
mound = 2000 

For i = 1 To mound 
nest.bug = New bug 
nest\x# = 400 
nest\y# = 300 
nest\direction# = Rnd(360) - 180 
nest\size = Rand(4) 
nest\xspeed# = Rnd(nest\size) + Rnd(4) 
nest\yspeed# = Rnd(nest\size) + Rnd(4) 
Next 



; main loop 
While Not KeyHit(1) 
Cls 
move_bug() 
draw_bug() 
Flip 
Wend 


; move the bugs 
Function move_bug() 
For nest.bug = Each bug 
;check for edge collisions 
If nest\x#-nest\size<=100 Or nest\x#+nest\size>=700 Then nest\xspeed# = -nest\xspeed# 
If nest\y#-nest\size<=100 Or nest\y#+nest\size>=500 Then nest\yspeed# = -nest\yspeed# 
;update bugs position 
nest\x# = nest\x# + Sin(nest\direction#)*nest\xspeed# 
nest\y# = nest\y# + Cos(nest\direction#)*nest\yspeed# 
Next 
End Function 


; draw the bugs 
Function draw_bug() 
For nest.bug = Each bug 
Color 255-(nest\size*10),255-(nest\size*20),255-(nest\size*15) 
Oval nest\x#, nest\y#,nest\size,nest\size 
Next 
End Function 

Also note that you can access type collections from inside functions - you don't need to pass any parameters to draw_bug()/move_bug().

Yep - looks like it was the setbuffer inside the main loop - your version works fine - even in a window.

Thanks very much for your speedy response - and the types tip.

Cheers,

markyb