how can i get these invaders right ?

[RaverDave]

been messing around but they wont move far left before changing direction !

PlayBASIC Code: [Select]

; PROJECT : spaceinvaders
; AUTHOR  : david wheeler
; CREATED : 27/01/2011
; EDITED  : 23/02/2011
; ---------------------------------------------------------------------
OpenScreen 640,480,32,2
SetFPS 60
ScreenVsync On
Mouse Off
global quit=false
global invaderimage1=1
global invaderimage2=4
global shipimage=60
global numofinvaders=0
global shipsprite=60
global movem
global anim
global dropem
global tit
global changedir
   Type tinvader
   image
   oldimage
   Status
   speed
   Xpos,Ypos
   animadd
   count
EndType
type tship
   image
   xpos
   ypos
   speed
   status
   
endtype

Dim invaders(100) As tinvader
dim ship(1) as tship
creategfx()
setupwave()
s$="Number of Invaders = "
s$=s$+str$(numofinvaders)
ship(1).speed=2
repeat
   cls 0
   print s$
   print shipimage
   tick=tick+1
   if tick>40
      tick=0
      tit=1
      movem=1
   endif
   for n=1 to numofinvaders
      if movem=1
         
         invaders(n).xpos=invaders(n).xpos+invaders(n).speed
         tit=1
   
         
      endif
      if tit=1 and invaders(n).count=0
         inc invaders(n).count
         invaders(n).image=invaders(n).animadd
         spriteimage n,invaders(inv).image
         
      endif      
       if tit=1 and invaders(n).count>30
          invaders(n).count=0
          tit=0
         invaders(n).image=invaders(n).image-invaders(n).animadd
         spriteimage n,invaders(inv).image
      endif      
      if invaders(n).xpos>608 or invaders(n).xpos<0 and drop=0
           changedir=1
      endif
      if movem=0
         invaders(n).image=1
      endif
   ;spriteimage n,invaders(n).image   
      positionsprite n,invaders(n).xpos,invaders(n).ypos
      ;spriteimage n,invaders(inv).image
   
      drawsprite n

next
      
   
   if changedir = 1 and drop=0
      changedir=0
      drop=1
      for n=1 to numofinvaders
         
         invaders(n).speed = -invaders(n).speed
      
   next
   ;movem=1   
endif
if drop = 1 and changedir=0

   for n = 1 to numofinvaders
      if invaders(n).speed >0
      invaders(n).xpos=invaders(n).xpos-32
      endif
   
      invaders(n).ypos = invaders(n).ypos+16
      
      ;print "poop"
next
   
endif   
movem=0
drop=0
changedir=0      
   positionsprite shipsprite,ship(1).xpos,ship(1).ypos
   drawsprite shipsprite   
    
   check_keys()
   sync
until quit=true

function check_keys()
   v=ScanCode()
     print v
     if v=203
        ship(1).xpos=ship(1).xpos-ship(1).speed
     endif
         if v=205
        ship(1).xpos=ship(1).xpos+ship(1).speed
     endif
   If v=16
        quit=true
   EndIf   
endfunction

Function creategfx()

   restore gfx
   Invaderimage1=MakeImageFromData(13,10,32,20)
   Invaderimage2=MakeImageFromData(13,10,32,20)
   ;********************** Create Players Ship Sprite *************

   ShipImage=MakeImageFromData(13,10,32,20)

 // This  resource really should created dynamically 
        createsprite shipsprite
        spriteimage shipsprite,shipimage

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[stevmjon]

hey david

i fixed the problem for you.  it was easy, just a mistake easily made.  you had it set so if baddies speed is +x ,then head in -x direction after drop. i marked my change in the code for you.

hope this helps , stevmjon

[Big C.]

Its not so diffcult as you thought...

Here is another solution for you...

Before you change the new xpos of your aliens you should check whether the closest left or right alien reaches your borderlimits. If so then drop the complete alienwave and change the direction.

I use your code and marked the passage I have supplemented/edit. So keep in mind that your code isn't optimized and the way to coding this part of game routine could be made in a different way. But for the moment I hope it will helps you and I will be curious how your way will go on.

PlayBASIC Code: [Select]

; PROJECT : spaceinvaders
; AUTHOR  : david wheeler edit by Big C.
; CREATED : 26.02.2011
; EDITED  : 26.02.2011
; ---------------------------------------------------------------------
OpenScreen 640,480,32,2
SetFPS 60
ScreenVsync On
Mouse Off
Global quit=False
Global invaderimage1=1
Global invaderimage2=4
Global shipimage=60
Global numofinvaders=0
Global shipsprite=60
Global movem
Global anim
Global dropem
Global tit
Global changedir = 1 ; *** edit here and give a start direction; could be 1 or -1
   Type tinvader
   image
   oldimage
   Status
   speed
   Xpos,Ypos
   animadd
   count
EndType
Type tship
   image
   xpos
   ypos
   speed
   status
   
EndType

Dim invaders(100) As tinvader
Dim ship(1) As tship
creategfx()
setupwave()
s$="Number of Invaders = "
s$=s$+Str$(numofinvaders)
ship(1).speed=2
Repeat
   Cls 0
   Print s$
   Print shipimage
   tick=tick+1
   If tick>40
      tick=0
      tit=1
      movem=1
   EndIf
   ;*** this is to check wether to change dir and drop or not
   For n=1 To numofinvaders
      If invaders(n).xpos+invaders(n).speed > 608
         drop = 1
         changedir = -1
         ExitFor
      ElseIf invaders(n).xpos+invaders(n).speed < 0
         drop = 1
         changedir = 1
         ExitFor
      Else
         drop = 0   
      EndIf
   Next
   ;*** end edit part
   For n=1 To numofinvaders
      If movem=1
         
         invaders(n).xpos=invaders(n).xpos+(invaders(n).speed*changedir) ; <-- here: calculate xpos with the changdir
         
         ;*** if drop = 1 the we calculate the new ypos
         If drop = 1
            invaders(n).ypos = invaders(n).ypos+16
         EndIf
         ;*** end edit part
         tit=1
   
         
      EndIf
      If tit=1 And invaders(n).count=0
         Inc invaders(n).count
         invaders(n).image=invaders(n).animadd
         SpriteImage n,invaders(inv).image
         
      EndIf      
       If tit=1 And invaders(n).count>30
          invaders(n).count=0
          tit=0
         invaders(n).image=invaders(n).image-invaders(n).animadd
         SpriteImage n,invaders(inv).image
      EndIf      
      Remstart *** we dont need this 
      If invaders(n).xpos>608 Or invaders(n).xpos<0 And drop=0
           changedir=1
      EndIf
      Remend 
      If movem=0
         invaders(n).image=1
      EndIf
   ;spriteimage n,invaders(n).image   
      
      
      PositionSprite n,invaders(n).xpos,invaders(n).ypos
      ;spriteimage n,invaders(inv).image
   
      DrawSprite n

   Next
      
   RemStart *** we dont need this
   If changedir = 1 And drop=0
      changedir=0
      drop=1
      For n=1 To numofinvaders
         
         invaders(n).speed = -invaders(n).speed
      
      Next
   ;movem=1   
   EndIf
   
   
If drop = 1 And changedir=0

   For n = 1 To numofinvaders
      
      If invaders(n).speed >0
         invaders(n).xpos=invaders(n).xpos-32
      EndIf
      
      invaders(n).ypos = invaders(n).ypos+16
      
      ;print "poop"
   Next
   
EndIf
RemEnd

movem=0
drop=0
;changedir=0      
   PositionSprite shipsprite,ship(1).xpos,ship(1).ypos
   DrawSprite shipsprite   
    

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[RaverDave]

Ah! thanks guys, I never knew about the exitfor command! Silly me, part ignorance and part hatred of reading online docs! And why I didnt think of using 3 values for changedir god knows! But thanks again, hopefully I can plod on with the other stuff now and dump all the code into the Resources forum on here! Yeh I will try and clean the code up also ...

[RaverDave]

Already made improvements.. hopefully this is better :

(login required)

I've moved stuff in their own function and used the DrawAllSprites command instead of drawing em all separately .

[Big C.]

Some hint from me  ;)

Invaderimage1=MakeImageFromData(13,10,32,20)
Invaderimage2=MakeImageFromData(13,10,32,20)

At this point you create your two invaderimage and the function give the imagenumber in use back to the vars invaderimage1 and invaderimage2. How often do you use the vars invaderimage1 and invaderimage2 in your code (hint: use crtl+f and search  ;) )? What will happened if you use image creation commands before you create the image for your invader aliens (take a look to your function setupwave to the point where you will assign the alien sprites to the the alien type vars ;))?