when scrolling a form vertically the "y" coords of a picturebox are reset!

[Scott M]

Hi,

I am writing a small game that is using a form 800 * 600. The form
can be scrolled vertically up to a height of 1200 (basically the form
can be scrolled down one screen vertically).

The user controls a picturebox (my sprite) with the cursor keys

When the sprite hits the y value of 600 the screen scrolls down to
display the bottom part of the screen (by focusing on a hidden
picturebox at (0,1200).

This works fine and the sprite is displayed at the top the scrolled
down form.

However the "y" coordinate of the picturebox is now 1 instead of 601.
It appears as soon as the form is scrolled the x,y cordinates become
relative rather than absolute. So that even though we are at position
y=601 because we are at the top of the (scrolled down) form it thinks
we are at position 1.

Of course this is causing havoc with my collision routine as the
sprite keeps bumping into objects from the top part of the form even
though it is on the bottom part of the form!!!

Does anyone have a solution for this?

p.s. I've tried adding 600 to the "y" value when we first scroll the
form, but this just then moves the sprite to the bottom of the
scrolled down form. I also noticed if you don't scroll the form but
continue to move the sprite down the way then the "y" value keeps it's
absolute value.

Regards,

Scott M.

 

[Robin Tucker]

Yes, its a pain but you need to apply the AutoScrollPosition property to
your coordinates.