Z rotate / Zoom Example

[kevin]

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

PlayBASIC Code: [Select]

   //  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

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

PlayBASIC Code: [Select]

;   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

[kevin]

Here's  piccy

[Draco9898]

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...