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PlayBASIC -   Code Snippet  - Sine Wave Scroller - 18th June  2006

This is classic source code example from way back in 2006.  The demo shows a simple right to left scrolling message with sine wave distortions applied.   First we start with the basic scroller, next we add sine distortion on the X axis, then the Y axis finishing off by combining them..


  VIDEO:




music by: https://BenSound.com


  Code:


[pbcode]
; PROJECT : Sine_Scrollers
; AUTHOR  : Kevin Picone
; CREATED : 18/06/2006
; EDITED  : 18/06/2006
; ---------------------------------------------------------------------

; load the Courier New font
   Loadfont  "Courier New",1,32,0
   MakeBitmapFont 1,$ff0000

; load the Courier New font
   Loadfont  "Courier New",2,64,0
   MakeBitmapFont 2,$8f70a0
   setfont 2

   ; Make a type to hold the various bits of info ab

   SineWaveWidth=32
   ScrollHeight=GetTextHeight("Y")


   ; CReate an array to hold the Scroll text in charater form
   Dim ScrollText(0)
   Read_Text_To_Scroller_Array(ScrollText())
   

   ; Original Scroll buffer
   ScrollBuffer=NewImage(800+(SineWaveWidth*2)+GetFontWidth(2),ScrollHeight)

   ScrollBuffer2=NewImage(800+(SineWaveWidth*2)+GetFontWidth(2),ScrollHeight)
   

setfps 60
   RendertoScreen
   Do
      Cls 0      
      
         ; Update the Scroll Buffer
         setfont 2
         UpdateScroller(ScrollText(),ScrollBuffer)


         ; select What effect render
         Select Effect
            case 0
                  ; draw the scroll messagae
                  Drawimage ScrollBuffer,0,280,true
                  EffectName$="Standard Scroller"

            case 1
                  Draw_XSine_Image(ScrollBuffer,0,280,32)
                  EffectName$="Scroller with sine X distortion"

            case 2
                  Draw_YSine_Image(ScrollBuffer,0,280,270)
                  EffectName$="Scroller with sine Y distortion"

            case 3   
                  rendertoimage Scrollbuffer2
                  Draw_XSine_Image(ScrollBuffer,0,0,24)
                  rendertoscreen
                  Draw_YSine_Image(ScrollBuffer2,0,280,270)
                  EffectName$="Scroller with combined X&Y distortion"
         endselect




         if Spacekey()
            Inc Effect
            If effect>3 then effect=0
            flushkeys
         endif

         Setfont 1
         x=getscreenwidth()/2
         y=GetScreenheight()/2+200
         centertext x,y,EffectName$
         centertext x,y+50,"Press Space"


      Sync   
   loop


; ---------------------------------------------------------------------
; Copy an Image width a X sine wave applied
; ---------------------------------------------------------------------

Function Draw_XSine_Image(ThisImage,Xpos,Ypos,XwaveRAdius)
   Static BaseAngle#

   OutputBuffer=getsurface()

   IW=GetImageWidth(ThisImage)
   IH=GetImageheight(ThisImage)

   For Angle#=BaseAngle# to Baseangle#+IH
      X=SinRadius(Angle#,XwaveRadius)               
      CopyStripH ThisImage,y,0,iw,OutPutBuffer,Xpos-XwaveRAdius+X,ypos
      inc Y      
      inc Ypos
   next
   
   BaseAngle#=wrapangle(BaseAngle#,0.5)
   rendertoscreen
EndFUnction




; ---------------------------------------------------------------------
; Copy an Image with a Y sine wave applied
; ---------------------------------------------------------------------

Function Draw_YSine_Image(ThisImage,Xpos,Ypos,WaveRAdius)
   Static BaseAngle#

   OutputBuffer=getsurface()

   IW=GetImageWidth(ThisImage)
   IH=GetImageheight(ThisImage)

   Angle#=baseangle#
   if iw>GetImageWidth(Outputbuffer) then iw=GetImageWidth(Outputbuffer)
   For x=0 to iw-1
      Y=SinRadius(Angle#,waveRadius)               
      ; to reduce the number of blits
      CopyRect ThisImage,x,0,x+2,ih,OutPutBuffer,Xpos,ypos+Y
      inc xpos
      inc xpos
      Angle#=wrapangle(Angle#,0.5)
   next
   
   BaseAngle#=wrapangle(BaseAngle#,2)
   rendertoscreen
EndFUnction







; ---------------------------------------------------------------------
; Refresh Scroll Text/ Buffer
; ---------------------------------------------------------------------

Function UpdateScroller(ChrBuffer(),ScrollBuffer)
   ; use static variables to keep track of the displacement
   Static PixelShifts,CurrentChr
   CurrentSurface=getSurface()

   ; get the current fonts + width & height
   ThisFont=GetCurrentFOnt()
   FontWidth=GetFontWidth(ThisFont)
   FontHeight=GetFontHeight(ThisFont)
      
   ; Get the Scroll Buffers Width and Height
   IW=GetImagewidth(ScrollBuffer)
   IH=GetImageHeight(ScrollBuffer)


   ; Move the Scroll buffer 1 pixel to the left
    CopyRect  ScrollBuffer,1,0,IW,IH,ScrollBuffer,0,0

    Inc PixelShifts
    if PixelShifts=>GetFontWidth(GetCurrentFont())
       PixelShifts=0
      
       rendertoimage scrollbuffer
      ; clear any left over pixels
         boxc iw-fontwidth,0,iw,ih,true,0
      ; draw a new character on the end of the scroll image buffer
        text iw-FontWidth,0,chr$(ChrBuffer(CurrentChr))

      ; bump the current character index
      inc CurrentChr
      ; check if the current character index is inside the buonds
      ; of the Scroll text array
      if CurrentChr=>GetArrayElements(Chrbuffer(),1)
            CurrentChr=0
      endif
    endif

   ; restore old render surface
   RenderToImage    CurrentSurface
   
EndFunction



Function Read_Text_To_Scroller_Array(Buffer())
   Dim buffer(0)   
   repeat
      Size=GetArrayElements(Buffer(),1)
      t$=readdata$()
      if t$<>""
         redim Buffer(Size+Len(t$))
         For c=1 to len(t$)
               buffer(size+c-1)=mid(t$,c)
         next                        
      endif
   until t$=""   
EndFUnction


data "Hello World... Here's some old skool scroll text"
Data "......................."
data ""  ; end of scroll text


[/pbcode]