they lose height

[RaverDave]

ok a very good friend of mine has been learning me gravity and stuff, he has been using one language and showing me the code, i have been translating it to playbasic, now then the problem is that when i run mine,they seem to lose height after every bounce, but with his they retain the same heighth, could someone look at the code and explain why??

Code Select Expand

; PROJECT : gravity
; AUTHOR  : Raverdave
; CREATED : 16/10/2006
; EDITED  : 16/10/2006
; ---------------------------------------------------------------------
OpenScreen 640,480,32,2
SetFPS 60
ScreenVsync On
Mouse Off
Global numofp=100
Global amg#=0.05
Type tpumpkin
bally#
ballx#
newspeed#
oldspeed#
gravity#
angle#
state
EndType
Dim pumpkin(numofp) As tpumpkin
makegfx()
For n=1 To numofp
pumpkin(n).gravity#=0.05
pumpkin(n).angle#=180
pumpkin(n).ballx#=Rnd(640)
pumpkin(n).bally#=Rnd(260)+10
Next
Do
Cls 0
SetCursor 0,0
Print pumpkin(n).bally#
For n=1 To numofp
DrawImage 1,pumpkin(n).ballx#,pumpkin(n).bally#,1
Select pumpkin(n).angle#
Case 180.0
pumpkin(n).newspeed#=pumpkin(n).oldspeed#+pumpkin(n).gravity#
pumpkin(n).bally#=pumpkin(n).bally#-(Cos(pumpkin(n).angle#)*pumpkin(n).newspeed#)
If pumpkin(n).bally#>=380
pumpkin(n).angle#=0
pumpkin(n).bally#=380
EndIf
pumpkin(n).oldspeed#=pumpkin(n).newspeed#
ContCase
Case 0
pumpkin(n).newspeed#=pumpkin(n).oldspeed#-(pumpkin(n).gravity#+amg#)
pumpkin(n).bally#=pumpkin(n).bally#-(Cos(pumpkin(n).angle#)*pumpkin(n).newspeed#)
If pumpkin(n).newspeed#<=0
pumpkin(n).angle#=180
EndIf
pumpkin(n).oldspeed#=pumpkin(n).newspeed#
EndSelect

Next
Sync
Loop
Function makegfx()
Cls 0
Circle 15,15,15,0
TempImage=GetFreeImage()
GetImage TempImage,0,0,32,32
EndFunction




[RaverDave]

hmmm..changing
Global amg#=0.00005
makes them gain height,but i dont want em to gain or lose!

[RaverDave]

ahaaaa..... this works!

Code Select Expand

; PROJECT : gravity
; AUTHOR  : Raverdave
; CREATED : 16/10/2006
; EDITED  : 16/10/2006
; ---------------------------------------------------------------------
OpenScreen 640,480,32,2
SetFPS 60
ScreenVsync On
Mouse Off
Global numofp=1
Global amg#=0.000002
Type tpumpkin
bally#
ballx#
newspeed#
oldspeed#
gravity#
angle#
state
EndType
Dim pumpkin(numofp) As tpumpkin
makegfx()
For n=1 To numofp
pumpkin(n).gravity#=0.05
pumpkin(n).angle#=180
pumpkin(n).ballx#=Rnd(640)
pumpkin(n).bally#=Rnd(260)+10
ly=pumpkin(n).bally#
Next

Do
Cls 0
SetCursor 0,0
Line 0,ly,640,ly
Print pumpkin(n).newspeed#
For n=1 To numofp
DrawImage 1,pumpkin(n).ballx#,pumpkin(n).bally#,1
Select pumpkin(n).angle#
Case 180
pumpkin(n).newspeed#=pumpkin(n).oldspeed#+pumpkin(n).gravity#
pumpkin(n).bally#=pumpkin(n).bally#-(Cos(pumpkin(n).angle#)*pumpkin(n).newspeed#)
If pumpkin(n).bally#>=380
pumpkin(n).angle#=0
pumpkin(n).bally#=375
EndIf
pumpkin(n).oldspeed#=pumpkin(n).newspeed#
ContCase
Case 0
pumpkin(n).newspeed#=pumpkin(n).oldspeed#-(pumpkin(n).gravity#+amg#)
pumpkin(n).bally#=pumpkin(n).bally#-(Cos(pumpkin(n).angle#)*pumpkin(n).newspeed#)
If pumpkin(n).newspeed#<=0
pumpkin(n).angle#=180
EndIf
pumpkin(n).oldspeed#=pumpkin(n).newspeed#
EndSelect

Next
Sync
Loop
Function makegfx()
Cls 0
Circle 15,15,15,0
TempImage=GetFreeImage()
GetImage TempImage,0,0,32,32
EndFunction





dunno why yet,but hell...maybe someone can explain it! :D:D

[stef]

this is similar

Code Select Expand


; ---------------------------------------------------------------------
OpenScreen 640,480,32,2
;SetFPS 60
;ScreenVsync On
Mouse Off
Global numofp=100
Global amg#=0.0499
Type tpumpkin
bally#
ballx#
newspeed#
oldspeed#
gravity#
angle#
state
EndType
Dim pumpkin(numofp) As tpumpkin
makegfx()
For n=1 To numofp
pumpkin(n).gravity#=0.05
pumpkin(n).angle#=180
pumpkin(n).ballx#=Rnd(640)
pumpkin(n).bally#=Rnd(260)+10
Next
Do
Cls 0
SetCursor 0,0
Print pumpkin(n).bally#
For n=1 To numofp
DrawImage 1,pumpkin(n).ballx#,pumpkin(n).bally#,1
Select pumpkin(n).angle#
Case 180.0
pumpkin(n).newspeed#=pumpkin(n).oldspeed#+pumpkin(n).gravity#
pumpkin(n).bally#=pumpkin(n).bally#-(Cos(pumpkin(n).angle#)*pumpkin(n).newspeed#)
If pumpkin(n).bally#>=380
pumpkin(n).angle#=0
pumpkin(n).bally#=380
EndIf
pumpkin(n).oldspeed#=pumpkin(n).newspeed#
;ContCase
Case 0
pumpkin(n).newspeed#=pumpkin(n).oldspeed#-amg#
pumpkin(n).bally#=pumpkin(n).bally#-(Cos(pumpkin(n).angle#)*pumpkin(n).newspeed#)
If pumpkin(n).newspeed#<=0
pumpkin(n).angle#=180
pumpkin(n).newspeed#=0
EndIf
pumpkin(n).oldspeed#=pumpkin(n).newspeed#
EndSelect

Next
Sync
Loop
Function makegfx()
Cls 0
Circle 15,15,15,0
TempImage=GetFreeImage()
GetImage TempImage,0,0,32,32
EndFunction






[RaverDave]

damnit i should have tested more..some runs its ok..some it aint..this is all rather odd

[stef]

Don' know if you have noticed:
I added the line

   pumpkin(n).newspeed#=0

[RaverDave]

ah right..yeh seems to work..thanks!! well i had to unrem the fps setting..i mean really!!

ok i have added x speed now and they seem to be rebounding nicely all over the place


couldyou explain what was wrong then..i need to learn this fully

[stef]

Nothing was wrong!

It is all an approach to the real physical solution
It is a system of elasticity (the real solution must be quite complicated)

I think it is important to set the speed at the ground to zero (to have always same conditions)
and change experimentally the "elasticity/resistance-factor"  (amg#) to a fitting value with desired result (spooky pumpkins :))

[RaverDave]

well yeh my goal is to do something for halloween1 :D:D just for fun really

They bounce around nicely now... here is the code for anyone whom may find it handy...

Code Select Expand

; PROJECT : gravity
; AUTHOR  : Raverdave
; CREATED : 16/10/2006
; EDITED  : 17/10/2006
; ---------------------------------------------------------------------
OpenScreen 640,480,32,2
SetFPS 60
;ScreenVsync On
Mouse Off
Global numofp=2
Global amg#=0.0499
Type tpumpkin
bally#
ballx#
speedx#
newspeed#
adx#
oldspeed#
gravity#
angle#
state
EndType
Dim pumpkin(numofp) As tpumpkin
makegfx()
For n=1 To numofp
pumpkin(n).adx#=Rnd(2)+1
pumpkin(n).speedx#=pumpkin(n).adx#
pumpkin(n).gravity#=0.05
pumpkin(n).angle#=180
pumpkin(n).ballx#=Rnd(640)
pumpkin(n).bally#=Rnd(260)+10
ly=pumpkin(n).bally
Next
Do
Cls 0
SetCursor 0,0
m=RGB(255,255,255)
Ink m
Line 0,ly,640,ly
c=RGB(200,0,0)
Ink c
Line 0,410,640,410
Print pumpkin(n).bally#
For n=1 To numofp
DrawImage 1,pumpkin(n).ballx#,pumpkin(n).bally#,1
pumpkin(n).ballx#=pumpkin(n).ballx#+pumpkin(n).speedx#

If pumpkin(n).ballx#>=640
pumpkin(n).speedx#=-pumpkin(n).adx#
EndIf
If pumpkin(n).ballx#<=0
pumpkin(n).speedx#=pumpkin(n).adx#
EndIf
Select pumpkin(n).angle#
Case 180.0
pumpkin(n).newspeed#=pumpkin(n).oldspeed#+pumpkin(n).gravity#
pumpkin(n).bally#=pumpkin(n).bally#-(Cos(pumpkin(n).angle#)*pumpkin(n).newspeed#)
If pumpkin(n).bally#>=380
pumpkin(n).angle#=0
pumpkin(n).bally#=380
EndIf
pumpkin(n).oldspeed#=pumpkin(n).newspeed#
;ContCase
Case 0
pumpkin(n).newspeed#=pumpkin(n).oldspeed#-amg#
pumpkin(n).bally#=pumpkin(n).bally#-(Cos(pumpkin(n).angle#)*pumpkin(n).newspeed#)
If pumpkin(n).newspeed#<=0
pumpkin(n).angle#=180
pumpkin(n).newspeed#=0
EndIf
pumpkin(n).oldspeed#=pumpkin(n).newspeed#
EndSelect

Next
Sync
Loop
Function makegfx()
Cls 0
Circle 15,15,15,0
TempImage=GetFreeImage()
GetImage TempImage,0,0,32,32
EndFunction


A couple of lines are drawn simply for some visualnesssss

[stef]

well yeh my goal is to do something for halloween1 :D just for fun really

Great idea!

I must do something too!

That will be a Just-for-fun-competition :)

13 nights to halloween