Define rectangle how to - actionscript-3

Question

I 'm trying to develop a game.In my project i have a movieclip which is the character for the game.I also have 5 buttons(left right down up and stop) so the user can move.The game is for android.In my library i have a square with dimnesions 50 x 50.I have filled the stage with copies of this square with different instances so the character can move on them.The point of the game is that the user moves the character and with HitTestObject() function he removes the square that he is walking on.I used a timer so if 5 seconds are over and the player hasn't completed a rectangle of missing squares the squares appear again.But if he makes a rectangle(lets say that he makes it by removing 8 squares) the squares that are inside this rectangle must dissapear also.I need to find a way to see when the player completes this rectangle.I also think that my aproach to what i want to do is draft and there is a much better one.
Thanks in advance!
i think i may haven't explained my problem well..sorry for this its my mistake!everytime the character touches on a square it disapears.if in 5 seconds the character hasn't completed a "rectangle" of missing squares they appear again.When i say rectangle i mean rectangle of squares.For example if 4 squares missing(not in a row) its a rectangle,or if 8 squares or 12 etc...
import flash.utils.Timer;
stop();
Multitouch.inputMode = MultitouchInputMode.TOUCH_POINT;
var hunterxspeed:Number=0;
var hunteryspeed:Number=0;
var timerformove:Timer=new Timer(30);
var timerforblocks:Number=0;
var simpletimer:Number=0;
var rectanglearray:Array = new Array();
var sumvertical:int=0;
var sumhorizontal:int=0;
var i:int=0;
moveup.addEventListener(TouchEvent.TOUCH_TAP, fl_TapHandler_2);
function fl_TapHandler_2(event:TouchEvent):void
{
hunteryspeed = -4;
hunterxspeed = 0;
rectanglearray[0] = 0;
rectanglearray[1] = -1;
sumvertical+=rectanglearray[0]+rectanglearray[1];
i++;
}
movedown.addEventListener(TouchEvent.TOUCH_TAP, fl_TapHandler_3);
function fl_TapHandler_3(event:TouchEvent):void
{
hunteryspeed = 4;
hunterxspeed = 0;
rectanglearray[0] = 0;
rectanglearray[1] = 1;
sumvertical+=rectanglearray[0]+rectanglearray[1];
i++;
}
moveright.addEventListener(TouchEvent.TOUCH_TAP, fl_TapHandler_4);
function fl_TapHandler_4(event:TouchEvent):void
{
hunterxspeed = 4;
hunteryspeed = 0;
hunter.scaleX = 2/4;
rectanglearray[2] = 1;
rectanglearray[3] = 0;
sumhorizontal+= rectanglearray[2] +rectanglearray[3];
i++;
}
moveleft.addEventListener(TouchEvent.TOUCH_TAP, fl_TapHandler_5);
function fl_TapHandler_5(event:TouchEvent):void
{
hunterxspeed = -4;
hunteryspeed = 0;
hunter.scaleX = -(2/4);
rectanglearray[2] = -1;
rectanglearray[3] = 0;
sumhorizontal+= rectanglearray[2] + rectanglearray[3];
i++;
}
stopmove.addEventListener(TouchEvent.TOUCH_TAP, fl_TapHandler_6);
function fl_TapHandler_6(event:TouchEvent):void
{
hunterxspeed = 0;
hunteryspeed = 0;
}
timerformove.addEventListener(TimerEvent.TIMER,huntermove);
function huntermove(e:TimerEvent) :void
{
if (hunter.y > stage.stageHeight-160)
{
hunter.y = stage.stageHeight-161;
hunteryspeed = 0;
}
if (hunter.y < 20)
{
hunter.y = 21;
hunteryspeed = 0;
}
if (hunter.x > stage.stageWidth-30)
{
hunter.x = stage.stageWidth-31;
hunterxspeed = 0;
}
if (hunter.x < 30)
{
hunter.x = 31;
hunterxspeed = 0;
}
hunterlegs.y = hunter.y+20;
hunterlegs.x = hunter.x;
hunter.y += hunteryspeed;
hunter.x += hunterxspeed;
if(timerforblocks==5000)
{
simpletimer+=50;
}
if(simpletimer>timerforblocks)
{
simpletimer=0;
timerforblocks=0;
}
if(hunterlegs.hitTestObject(grass))
{
timerforblocks=5000;
grass.x=grass.x-100;
}
if(hunterlegs.hitTestObject(grass1))
{
timerforblocks=5000;
grass1.x=grass1.x-100;
}
if(hunterlegs.hitTestObject(grass2))
{
timerforblocks=5000;
grass2.x=grass2.x-200;
}
if(hunterlegs.hitTestObject(grass12))
{
timerforblocks=5000;
grass12.x=grass12.x-300;
}
if(hunterlegs.hitTestObject(grass22))
{
timerforblocks=5000;
grass22.x=grass22.x-300;
}
if(hunterlegs.hitTestObject(grass21))
{
timerforblocks=5000;
grass21.x=grass21.x-300;
}
if(hunterlegs.hitTestObject(grass20))
{
timerforblocks=5000;
grass20.x=grass20.x-300;
}
if(hunterlegs.hitTestObject(grass10))
{
timerforblocks=5000;
grass10.x=grass10.x-300;
}
if(sumvertical==0 && sumhorizontal==0 && i==4)
{
grass.x=2000;
grass1.x=2000;
grass2.x=2000;
grass12.x=2000;
grass22.x=2000;
grass21.x=2000;
grass20.x=2000;
grass10.x=2000;
}
}
timerformove.start();
All objects are in the first frame.
I named grass the first square and i copied it to 100 more or less with different instances.
Hunter is my character.

Answer 1

A rectangle has 4 corners, and the character ends up at the origin square.
What you could try is to keep an array where you store the movement of the character. For instance, if the character moves upward, store {x: 0, y: -1} and if it moves left, store {x: 1, y: 0}.
Then, when it's time to check for valid rectangles, step through the list of movements and keep track of corners (where the direction changes) and check to see if the following criteria is fulfilled:
The sum of all horizontal movements is 0
The sum of all vertical movements is 0
The sum of corners is 4
This will check to see if the character ended up in the same position it originally started in and if it's movements formed a valid rectangle.
If the criteria isn't met, do the same check of the array, but start on position number 2. Etc.
This way, you will check if a valid rectangle has been formed at any stage during the character's movements (even if a rectangle was only part of the character's total moves). It will also validate for a rectangle of any size.
Here's an illustration that could perhaps clear things up:
In the first case, when the horizontal and vertical counters both sums 0, the corner count is 4. This is a valid rectangle.
In the second case, when the horizontal and vertical counters both sums 0, the corner count is 6. This is not a rectangle.
Edit to respond to follow-up question:
It's a bit tricky since it appears like the character is able to move around freely. The system described above becomes trivial if you have a game where the character moves across the grid one step at a time.
The system still applies though, but you need to look at the order of which the "squares" are being eaten. You can still make the same array of movement by keeping track of the last square to be hit and what place it had in the grid.
For example, if we follow the pattern of the first example the squares are eaten in the following order:
Square 1: [2, 4]
Square 2: [1, 4] -> subtract from last position: [1-2, 4-4] = [-1, 0] <- add this to the movement array
Square 3: [1, 3] -> subtract from last position: [1-1, 3-4] = [0, -1] <- add this to the movement array
Square 4: [1, 2] -> subtract from last position: [1-1, 2-3] = [0, -1] <- add this to the movement array
...
Square 12: [3, 4] -> subtract from last position: [3-4, 4-4] = [-1, 0] <- add this to the movement array
Square 13: [2, 4] -> subtract from last position: [2-3, 4-4] = [-1, 0] <- add this to the movement array
You will now have the same movement array as in the example above.