Flash MX 2004 Games : Art to ActionScript

Chapter 15: Mazes
sequence to show is based on the values of the paths from that cell. For example if we have a
‘T_Right’ junction when facing north, the value for this cell would be 7, made up of North (1),
South (2) and East (4). If we faced south at the same cell then the image sequence should be
‘T_Left’. Facing east we should show ‘Straight’ and facing west we should show ‘T_Both’. What
we need is a mapping for each direction. When facing south, north maps to south and south
maps to north, while west maps to east and east maps to west; so the value changes as shown in
Table 15.4.
Table 15.4 How mapping from a north to a south
direction affects the value
North South East West Total
Original 1 2 4 0 7
Mapped 1 2 0 8 11
This maps a T_Right to a T_Left as you can see from the values displayed in Table 15.2.
It is important that the program knows when an animation is playing and when to wait
for user input. The movie clip ‘Tunnel’ contains a ‘mode’ variable that can take the values
‘STATIONARY’, ‘EXITING’, ‘EXITED’, ‘ENTERING’ or ‘NOTLOADED’. These constants
are declared on frame 1 of the Tunnel clip. It is customary to define constants using upper-case
letters.
1 function enterCell(){
2 var val, tmp, exitcell, nm, path = new Array(4);
3
4 nm = "lv.val" + row + "_" + col;
5 val = eval(nm) & 0xF;
6 exitcell = eval(nm) & 0x20;
7
8 cell = eval("cell" + row + "_" + col);
9 Location._x = cell._x;
10 Location._y = cell._y;
11
12 switch(dir){
13 case NORTH:
14 //Already correct value
15 Location.gotoAndStop(1);
16 break;
17 case SOUTH:
18 tmp = 0;
19 if (val & SOUTH) tmp += NORTH;
20 if (val & NORTH) tmp += SOUTH;
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