[ scummvm-Bugs-3231867 ] SCI32: KQ7 scrolling bug

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Bugs item #3231867, was opened at 2011-03-21 15:21
Message generated for change (Tracker Item Submitted) made by vakons
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Category: Graphics
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Valentin Solodin (vakons)
Assigned to: Nobody/Anonymous (nobody)
Summary: SCI32: KQ7 scrolling bug

Initial Comment:
I know that the game is not officially supported,
but there is a bug which appeared in v1.2.0svn52804 and can be fixed by making the things as in revision 52802.

In engines\sci\graphics\frameout.cpp, in IF operator:

// We get negative left in kq7 in scrolling rooms
if (it->planeRect.left < 0) {
	it->planeOffsetX = -it->planeRect.left;
	it->planeRect.left = 0;
}

adding the ELSE branch

else {
	it->planeOffsetX = 0;
}

will ensure the initialized value for planeOffsetX and will fix current bug with scrolling bar:
- start the game from chapter 1, press menu gem, and menu will be somewhere off screen (it will be visible), although menu buttons will work);
- start the game from chapter 5, move the scrolling slider to the left, press menu gem, and menu will be shifted;
- start the game from chapter 1, go to the well, walk one screen up between the mountains above the well, move the scrolling slider to it's leftmost position, as far as it possible. Now go back 1 screen down, and all objects' hotspots will be displaced. Don't move the scrolling slider and go to the left screen. It will be corrupted.

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=418820&aid=3231867&group_id=37116