; --------------------------------------------------------------
;
; OldSkool DemoEffect:  Floor Casting
;
; Converted by: Thorsten Will aka Mr.Vain/Secretly!
; Thanks a lot to "rain storm" for his original source! *thumbs up*
;
; --------------------------------------------------------------

resX = 640
resY = 480
xres = 320
yres = 240

InitSprite()
InitKeyboard()
OpenScreen( resX, resY, 32, "Floor Casting DemoEffect" )

Repeat
   ExamineKeyboard()
   StartDrawing(ScreenOutput())
 
   camY.f = camY  + 2                          ; change for speed
   camX.f = xres * Sin( camY * 3.14159 / 180 )
   b.f = 0
   For y = 0 To resY -1
       w.f = -yres / y
       v.f = (  resX * w - camY )
       u.f = ( -xres * w + camX )
       For x = 0 To resX -1
           t =  ((Int(u) ! Int(v) ) & 255 )
           c = Int((t / resY) * y)
           Plot( x, y, RGB( c, c, c ))
           u = u + w
       Next
       b = b + resX
   Next

   StopDrawing()
   FlipBuffers()
Until KeyboardPushed( #PB_Key_Escape )
End