UnderwareDESIGN

This examples produces the classic Rot-Zoom effect seen in many games/demos over the years.  


 Updated Code (Dec 2023) for suitable for the PlayBASIC learning edition and retail editions before PlayBASIC V1.64

[pbcode]

   //  Locate some media sorted within the PLayBASIC help files
   Path$=programdir$()+"Help\Commands\Media\"

   // Load it
  loadfximage Path$+"bg22.jpg",1



; get images size, which are used when drawing the textured quad
  iw=getimagewidth(1)-1
  ih=getimageHeight(1)-1

; Create Vertex Type
 Type tVert
     X#
     Y#
     RotatedX#
     RotatedY#
 Endtype

; GridSize is the NUmber vertex in vertex plane  
 GridSize=13
 Dim Verts(GridSize,GridSize) as tVert

; FaceSe is the Size of the Faces (in pixels)
 FaceSize=128  

; ====================================
; Init Vertex (cnenter around a mid point)
; ====================================
  y=0
  x=0
   For ylp=0 to GridSize
      y2=y+FaceSize          
    x=0
    For Xlp=0 to gridsize
   x2=x+FaceSize          
   Verts(xlp,ylp).x#= x-((GridSize*FaceSize)/2)
   Verts(xlp,ylp).y#= y-((GridSize*FaceSize)/2)
     x=x2
    next
    y=y2
 next

      BaseX=getScreenwidth()/2
      BaseY=getscreenheight()/2


; start of DO/loop
   timestart=timer()
   
   do
      
      
      TimePast#=(timer()-timeStart)


 
    ; bump rotation angle on the time past
    ;  and not the frame rate
        Angle# = (TimePast# / 20)  
        angle#=wrapangle(angle#,360)

   ; bump scaler zoom
      scale#=500+CosRadius(Zoomangle#,400)

      ZoomAngle# = (TimePast# / 20) *2
      Zoomangle#=mod(ZoomAngle#,360)


 ; Get the screen Center point

 ; Pre calc the Cos & Sin
 ca#=cos(angle#)
 sa#=sin(angle#)

 ; rotate the points
 For ylp=0 to GridSize
    For Xlp=0 to gridsize
          X#=Verts(xlp,ylp).x
           Y#=Verts(xlp,ylp).y
          newx#=(((ca#*x#)-(sa#*y#))*500)/Scale#
          newy#=(((ca#*y#)+(sa#*x#))*500)/Scale#
          Verts(xlp,ylp).rotatedx#=basex+newx#
          Verts(xlp,ylp).rotatedy#=basey+newy#
      next
 next

  ; Lock Screen Buffer
 lockbuffer
      ; DRaw textured polygons
    For ylp=0 to GridSize-1
         For Xlp=0 to gridsize-1
       ; Get Verts of Quad
          x1=Verts(xlp,ylp).rotatedx
      Y1=Verts(xlp,ylp).rotatedy
      X2=Verts(xlp+1,ylp).rotatedx
      Y2=Verts(xlp+1,ylp).rotatedy
      X3=Verts(xlp+1,ylp+1).rotatedx
      Y3=Verts(xlp+1,ylp+1).rotatedy
      X4=Verts(xlp,ylp+1).rotatedx
      Y4=Verts(xlp,ylp+1).rotatedy
             ; draw textrued quad
      TextureQuad 1,x1,y1,0,0,x2,y2,iw,0,x3,y3,iw,ih,x4,y4,0,ih,0
   next
    next
 unlockbuffer

  ; Show the screen and loop back to the do
  sync  
loop


[/pbcode]









Note: This code required PlayBASIC V1.069 or above to work correctly

[pbcode]

;   loadimage "..\..\gfx\bg22.jpg",1
;   loadimage "..\..\gfx\back20.jpg",1
; Load and image and prepare it as an FX image
  loadimage "..\..\gfx\pblogo1.jpg",1
   preparefximage 1

; get images size, which are used when drawing the textured quad
   iw=getimagewidth(1)-1
   ih=getimageHeight(1)-1

; Create Vertex Type
 Type tVert
     X#
     Y#
     RotatedX#
     RotatedY#
 Endtype

; GridSize is the NUmber vertex in vertex plane  
 GridSize=13
 Dim Verts(GridSize,GridSize) as tVert

; FaceSe is the Size of the Faces (in pixels)
 FaceSize=120  

; ====================================
; Init Vertex (cnenter around a mid point)
; ====================================
  y=0
  x=0
   For ylp=0 to GridSize
      y2=y+FaceSize          
    x=0
    For Xlp=0 to gridsize
   x2=x+FaceSize          
   Verts(xlp,ylp).x#= x-((GridSize*FaceSize)/2)
   Verts(xlp,ylp).y#= y-((GridSize*FaceSize)/2)
     x=x2
    next
    y=y2
 next

; start of DO/loop
do
 
; bump rotation angle
   angle#=mod(angle#+1,360)

; bump scaler zoom
   scale#=500+CosRadius(Zoomangle#,400)
   Zoomangle#=mod(ZoomAngle#+2,360)


 ; Get the screen Center point
   BaseX=getScreenwidth()/2
   BaseY=getscreenheight()/2

 ; Pre calc the Cos & Sin
 ca#=cos(angle#)
 sa#=sin(angle#)

  ; rotate the points
   For ylp=0 to GridSize
    For Xlp=0 to gridsize
     X#=Verts(xlp,ylp).x
     Y#=Verts(xlp,ylp).y
   newx#=(((ca#*x#)-(sa#*y#))*500)/Scale#
   newy#=(((ca#*y#)+(sa#*x#))*500)/Scale#
   Verts(xlp,ylp).rotatedx#=basex+newx#
   Verts(xlp,ylp).rotatedy#=basey+newy#
    next
 next

  ; Lock Screen Buffer
 lockbuffer
      ; DRaw textured polygons
    For ylp=0 to GridSize-1
     For Xlp=0 to gridsize-1
   ; Get Verts of Quad
      x1=Verts(xlp,ylp).rotatedx
      Y1=Verts(xlp,ylp).rotatedy
      X2=Verts(xlp+1,ylp).rotatedx
      Y2=Verts(xlp+1,ylp).rotatedy
      X3=Verts(xlp+1,ylp+1).rotatedx
      Y3=Verts(xlp+1,ylp+1).rotatedy
      X4=Verts(xlp,ylp+1).rotatedx
      Y4=Verts(xlp,ylp+1).rotatedy
             ; draw textrued quad
      TextureQuad 1,x1,y1,0,0,x2,y2,iw,0,x3,y3,iw,ih,x4,y4,0,ih
   next
    next
 unlockbuffer

  ; Show the screen and loop back to the do
   sync   
loop
[/pbcode]

Here's  piccy

Hmmm well no wonder it doesn't work when I tried it, (1.068 here)...
All I get is strange plain strips of the image...