set display mode 1024, 768, 32
sync on
sync rate 100


`make bitmap 1
create bitmap 1,1024, 768
set current bitmap 1
ink rgb(255,255,255), 0
box 0,0,1024,768, RGB(255,0,0),RGB(0,255,0),RGB(0,0,255),RGB(255,255,0)
for a=1 to 15
  x=rnd(1024)
  y=rnd(768)
  text x,y, "press any key"
next a

for x=1 to 1024 step 50
  line x,1,x,768
  line 1,x,1024, x
next x


`make bitmap 2
create bitmap 2,1024, 768
set current bitmap 2
ink rgb(255,255,255), 0
box 0,0,1024,768, RGB(255,0,255),RGB(0,255,255),RGB(255,0,0),RGB(0,0,255)
for a=1 to 15
  x=rnd(1024)
  y=rnd(768)
  text x,y, "Bitmap 2"
next a


set current bitmap 0
copy bitmap 1,0
sync:sync

`main loop
do
  wait key
  curtain(1,2,1.0)
  wait key
  slide(2,1,2.0)
loop


function curtain(b1, b2, speed as float)
copy bitmap b1,0

n as float
going=1
dim ypos(1024) as float
for x=1 to 1024
  ypos(x)=0
next x
  while going=1

    copy bitmap b2,0
    going=0
    for x=1 to 1024
      n=.08*(sin(x*2.0)+20.0)

      ypos(x)=ypos(x)+(n*speed)
      if ypos(x)<768 then going=1
      `COPY BITMAP From,Left,Top,Right,Bottom,       To, Left,Top,     Right,Bottom
  `    copy bitmap  1,x,0,x+1,768-ypos(x),0,x,ypos(x),x+1,768
      copy bitmap  b1,x,ypos(x),x+1,768,0,x,0,x+1,768-ypos(x)
    next x
    text 10,10, str$(screen fps())
    sync
  endwhile
endfunction


function slide(b1, b2, speed as float)
copy bitmap b1,0

going=1
dim ypos(1024) as float
for x=1 to 1024
  ypos(x)=0
next x
  while going=1

    copy bitmap b2,0
    going=0
    for x=1 to 1024
      ypos(x)=ypos(x)+rnd(speed*4)
      if ypos(x)<768 then going=1
      copy bitmap  b1,x,0,x+1,768-ypos(x),0,x,ypos(x),x+1,768
    next x
    text 10,10, str$(screen fps())
    sync
  endwhile
endfunction