REM --- Demo - Amiga BASIC Graphics demo --- 20-July-85
REM --- Modified 08/87 C. Scheppner - added Close gadget/logic to final window
  DEFINT a-z

  wins = 0  'cs
  
  IF FRE(-1)<60000 THEN
    REM --- on 256k machine, this is more limited demo
    WINDOW 1,,,15
    GOSUB InitAnimation
    WHILE (WINDOW(7))
      SLEEP 'Object Collisions will wake us up
    WEND
  ELSE
    WINDOW 1,"Animation",(10,10)-(270,70),15
    WINDOW 2,"Lines",(310,10)-(580,70),30
    WINDOW 3,"Polygons",(10,95)-(270,170),30
    COLOR 1,3
    CLS
    WINDOW 4,"Circles",(310,95)-(580,170),30
    GOSUB InitAnimation
    iDraw = 30
    iErase = 0
    
    wins = 15   'cs  4 bits, 1 for each window
       
    WHILE (wins > 0)

      WINDOW OUTPUT 1
      IF WINDOW(7)=0 THEN wins = wins AND 14
      
      NextLine 2
      NextPoly 3
      NextCircle 4
      
    WEND

  END IF

  END   'cs


SUB NextLine(win) STATIC
  SHARED iDraw, iErase
  WINDOW OUTPUT win
  'See if user closed the window
  IF WINDOW(7)=0 THEN 
     wins = wins AND 13   'cs
     EXIT SUB
  END IF
  DrawLine iDraw,1
  DrawLine iErase,0
  END SUB
  
SUB DrawLine(iStep, fDraw) STATIC
  GetWindowDim winWidth, winHeight
  iStep = (iStep + 1) MOD 60
  hue = fDraw * ((iStep MOD 3) + 1)
  side = INT(iStep / 15)
  i!=(iStep MOD 15)/15
  i1!=1-i!
  ON side+1 GOSUB top,left,bottom,right
  EXIT SUB
top:
  LINE(winWidth*i!,0)-(winWidth,winHeight*i!),hue
  RETURN
left:
  LINE(winWidth,winHeight*i!)-(winWidth*i1!,winHeight),hue
  RETURN
bottom:
  LINE(winWidth*i1!,winHeight)-(0,winHeight*i1!),hue
  RETURN
right:
  LINE(0,winHeight*i1!)-(winWidth*i!,0),hue
  RETURN
END SUB
 
SUB NextPoly(win) STATIC
  WINDOW OUTPUT win
  'See if user closed the window
  IF WINDOW(7)=0 THEN 
     wins = wins AND 11  'cs
     EXIT SUB
  END IF
  GetWindowDim winWidth, winHeight
  i=(i MOD 8) + 1
  IF i=1 THEN CLS
  x = winWidth/2
  y = winHeight/2
  cosI! = (9-i)*0.1*COS(i)
  sinI! = (9-i)*0.1*SIN(i)
  XcosI = x*cosI!
  XsinI = x*sinI!
  YcosI = y*cosI!
  YsinI = y*sinI!
  AREA (x+XcosI,y+YsinI)
  AREA (x+XsinI,y-YcosI)
  AREA (x-XcosI,y-YsinI)
  AREA (x-XsinI,y+YcosI)
  COLOR RND*3
  AREAFILL
  END SUB

SUB NextCircle(win) STATIC
  WINDOW OUTPUT win
  'See if user closed the window
  IF WINDOW(7)=0 THEN
     winds = wins AND 7  'cs
     EXIT SUB
  END IF
  GetWindowDim winWidth, winHeight
  x = RND*winWidth
  y = RND*winHeight
  radius = RND*30+20
  hue = INT(RND*4)
  CIRCLE (x,y),radius,hue
  PAINT (x,y),hue
  END SUB

SUB GetWindowDim(winWidth, winHeight) STATIC
  winWidth = WINDOW(2)
  winHeight = WINDOW(3)
  END SUB

InitAnimation:
  WINDOW 1
  LOCATE 4,4
  COLOR 3,2
  PRINT "Amiga Microsoft BASIC"
  COLOR 1,0
  ON COLLISION GOSUB BounceOff
  COLLISION ON
  OPEN "ball" FOR INPUT AS 1
  OBJECT.SHAPE 1,INPUT$(LOF(1),1)
  CLOSE 1
  OBJECT.X 1,60
  OBJECT.Y 1,50
  OBJECT.VX 1,80
  OBJECT.VY 1,80

  OBJECT.SHAPE 2,1
  OBJECT.X 2,50
  OBJECT.Y 2,10
  OBJECT.VX 2,40
  OBJECT.VY 2,40
  OBJECT.ON
  OBJECT.START
  RETURN

REM - BouncOff is called between BASIC
REM - statements whenever an object
REM - collides with another object or
REM - the border.
BounceOff:
  saveId = WINDOW(1)
  WINDOW OUTPUT 1
  'See if user closed the window
  IF WINDOW(7)=0 THEN RETURN
  'Make object border sensitive to change in wie
  CountDown = CountDown-1
  IF CountDown<0 THEN
    CountDown=10
    OBJECT.CLIP (0,0)-(WINDOW(2),WINDOW(3))
  END IF
BounceLoop:
  i=COLLISION(0)
  IF i=0 THEN BounceExit
  j=COLLISION(i)
  vxi = OBJECT.VX(i)
  vyi = OBJECT.VY(i)
  IF (j=-1 AND vyi < 0) OR (j=-3 AND vyi > 0) THEN
    'object bounced off top or bottom border
    OBJECT.VY i,-vyi
  ELSEIF (j=-2 AND vxi < 0) OR (j=-4 AND vxi > 0) THEN
    'object bounced off left or right border
    OBJECT.VX i,-vxi
  ELSEIF j>0 THEN
    '2 objects bounced off each other
    vyj = OBJECT.VY(j)
    vxj = OBJECT.VX(j)
    IF vyi*vyj < 0 THEN
      OBJECT.VY i,-vyi
      OBJECT.VY j,-vyj
    END IF
    IF vxi*vxj < 0 THEN
      OBJECT.VX i,-vxi
      OBJECT.VX j,-vxj
    END IF
    OBJECT.START j
  END IF
  OBJECT.START i
  GOTO BounceLoop
BounceExit:
  WINDOW OUTPUT saveId
  RETURN