Moving between rooms (CPC)

[egotrip]

How do you move from room to room? I have designed some and edited the map. I have tried the code

if key 0
if x <= 16
screenleft
let x = 256
else
(rest of code)

and similar for each other direction, yet it completely refuses to work. Am I doing something wrong, or is there a bug in the CPC version?

[Jonathan Cauldwell]

X is the vertical position, Y is horizontal. 256 is twice the horizontal resolution, so I'm guessing something like
IF Y <= 16
 SCREENLEFT
 LET Y = 106
 EXIT
ELSE
 ...

is more along the lines of what you're after.

[egotrip]

thanks I will try this out. It seems to be working ok now.

Why are x and y swapped around in AGD? x is horizontal in pretty much every other thing I've used.

[Jonathan Cauldwell]

Historical reasons mostly. When calculating the screen address it makes sense to use the first variable to store the number of pixels from the top of the screen and the second one to indicate the number of pixels from the left edge. And I don't like putting Y before X...