' lets play some music while the demo is running - how about "Hotel California"
' substitute something more to your taste here or comment out
play mp3 "hotel"

'set to 640x400 mode with 2 video layers and 12-bit colour. Page 0 is the bottom layer and page 1 is the top
mode 2,12

'clear the first three framebuffers (pages)
for i=0 to 2:page write i:cls:next i

'load a sprite which is the image of the ghost from a png file.
'The fact it is a png is important as png files encode transparency as well as solid colours
sprite loadpng 1,"ghost"

'set that we are going to write to the background layer
page write 0

'load the background image to the background layer - page 0
load png "part02"

'The image I am using is only 320x200 so I'm going to resize it to fit the screen
image resize 0,0,320,200,0,0,640,400

'initialise the display position of the ghost
x=100
y=50

'initialise the transparency of the ghost
' transparencies go from 1 (nearly invisible) to 15 (solid colour)
t=8

'set to write to page 2 which is not being displayed
page write 2

' output the ghost on page 2
sprite show 1,x,y,1


i=0

'start the main process loop
do

'do some silly maths to create a random walk of the ghost in both position and
' transparency while keeping it within the display bounds and the transparency
' within useful limits
 i=i+1
 if i mod 5 = 0 then c=rnd()-0.5
 if i mod 3 = 0 then a=rnd()*8-4
 if i mod 3 = 0 then b=rnd()*6-3
 x=x+a
 if x<0 then x=0
 if x>MM.HRES-sprite(w,1) then x=mm.hres-sprite(w,1)
 y=y+b
 if y<0 then y=0
 if y>MM.VRES-sprite(h,1) then y=mm.vres-sprite(h,1)
 t=t+c
 if t<3 then t=3
 if t>12 then t=12

'display the sprite in the new position and with the new transparency
 sprite transparency 1,t
 sprite show 1,x,y,1

'now copy page 2 to the foreground layer during frame blanking
'this ensures that there are no tearing effects in the image

 page copy 2 to 1,b

'slow things down a bit, the CMM2 is too fast
pause 100
loop