int removeRoofVisibleWindow(unsigned int group_no)

group_no - The tile group number you wish to remove

returns - 0 on error, else 1

"Hides" all roof layer tiles belonging to group number "group_no",
but ONLY in the currently visible region of the screen.

int removeRoofBoundedWindow(unsigned int group_no, unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2)

group_no - The tile group number you wish to remove x1 - coordinate in TILE units of upper left X region y1 - coordinates in TILE units of upper left Y region x2 - coordinates in TILE units of lower right X region y2 - coordinates in TILE units of lower right Y region

returns - 0 on error, else 1

Removes all tiles belonging to group number group_no from a given
boundary (i.e. can encompass more than just the visible screen).  X1, Y1 are the coordinates of
the upper left hand region, and X2, Y2 are the coordinates of the lower right hand region within
which all tiles in group_no will be removed.  NOTE: COORDINATES ARE IN TILE UNITS, NOT PIXELS!!
So basically, think of your world as starting at tile location (0, 0).  The bottom most corner
is (x2, y2) of your world.  You could have a variable that keeps track of the current tile x,y
that the user is on, in addition to what you probably already have, that being the x,y of the user
in pixels.

int removeRoofEntireMap(unsigned int group_no)

group_no - The tile group number you wish to remove

returns - 0 on error, else 1

Removes tiles in the group "group_no" from the ENTIRE
map world, regardless of whether or not it's visible.

int replaceRoofVisibleWindow(unsigned int group_no)

group_no - The tile group number you wish to remove

returns - 0 on error, else 1

This is the opposite of removeRoofVisibleWindow: it puts back the roof layer
tiles belonging to group "group_no" ONLY in the visible region of the
screen.

int replaceRoofBoundedWindow(unsigned int group_no, unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2)

group_no - The tile group number you wish to remove x1 - coordinate in TILE units of upper left X region y1 - coordinates in TILE units of upper left Y region x2 - coordinates in TILE units of lower right X region y2 - coordinates in TILE units of lower right Y region

returns - 0 on error, else 1

This is the opposite of removeRoofBoundedWindow: it puts back the roof layer
tiles belonging to group "group_no" in a given region (specified by x1, y1, x2, y2).  This is
also in TILE UNITS, NOT PIXELS.

int replaceRoofEntireMap(unsigned int group_no)

group_no - The tile group number you wish to remove

returns - 0 on error, else 1

This is the opposite of removeRoofEntireMap: it puts back the roof
layer to tiles in group "group_no" for the ENTIRE MAP WORLD.