Manual Projection/Scene Perspective

[kevin]

 Manual Projection/Scene Perspective

   This is quick mod of the one of the demos from the PB example pack.  The original version zooms the scene in /out,  this version sets up a test scene for scrolling Left/right...  The scene has perspective, so foreground objects appear larger than background objects.
 

PlayBASIC Code: [Select]

Constant ProjectionX = 400
Constant ProjectionY = 300

 Type tBox
    X,y,Z,Width#,Height#,col
 EndType

 Dim Objs(150) As tBox



 XRange=20000
 Width=500
 Height=1000
 gap =400



   BlockRow(Xrange,Width,Height,1000,gap)

   BlockRow(Xrange,Width,Height,750,gap)

   BlockRow(Xrange,Width,Height,500,gap)

   BlockRow(Xrange,Width,Height,250,gap)


 

 CamX=00
 CamY=00
 CamZ=-500
 
 CreateCamera 1
 
Do

   ; redirect all drawing To PB scene buffer 
      CaptureToScene   
   
   ; Clear the scene buffer
       ClsScene
         
      ; Calc the center of the Camera
      CameraCenterX#=(GetCameraWidth(1)/2)
      CameraCenterY#=(GetCameraHeight(1)/2)

   ; Transform And render Boxes (with Z To the screen)
     For lp=0 To GetArrayElements(objs().tbox,1)

        ; Translate the Obejcts Z To the cameras Z
         Z#=Objs(lp).Z-CamZ

       ; Check if the Object is in front of the camera (positive)
         If Z#>0
   
          ; Translate the X# / Y# cooords object To the camera
            X#=Objs(lp).X-CamX
            Y#=Objs(lp).Y-CamY

         ; Calc projected X /Y coords
            PX#=CameraCenterX#+((x#*ProjectionX)/Z#)
            PY#=CameraCenterY#+((y#*ProjectionY)/Z#)
   
         ; Calc perspective sizing
            Width#=(Objs(lp).Width*ProjectionX)/Z#
            Height#=(Objs(lp).Height*ProjectionY)/Z#
         
          ; Set PB To capture the Next drawing operations at this Z# depth in the
          ; scene buffer
            CaptureDepth Z#                  
   
          ; Draw the object To the scene buffer 
            x2#=px#-(width#/2)
            Y2#=pY#-(Height#/2)
            BoxC X2#,y2#,x2#+width#,y2#+height#,1,Objs(lp).Col

         EndIf
         
      Next
      
          

   ; Move the camera   
     Speed=3
   

    If UpKey() Then Camy=Camy+-Speed   
    If DownKey() Then Camy=Camy+Speed

    If LeftKey() Then CamX=CamX+-Speed   
    If RightKey() Then CamX=CamX+speed   



   

    DrawCamera 1
      text 0,0,fps()

   Sync
Loop



Function BlockRow(Xrange,Width,Height,Depth,Gap)

 for lp=-Xrange to Xrange step Width+Gap
   index=getfreecell(Objs())
    objs(index)=new tbox
    
   Objs(index).X = lp
   Objs(index).y = 0
   Objs(index).z = depth

   Objs(index).width = width
   Objs(index).height = height
   Objs(index).Col = RndRGB()    
 
 
 next



EndFunction

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