Update Monkey-X - FloodFill Pathfinding - code example.monkey

Monkey-X - FloodFill Pathfinding - code example.monkey

@@ -1,5 +1,6 @@
 Import mojo
 
+' This is a class that holds x and y variables.
 Class pathnode
 	Field x:Int,y:Int
 	Method New(x:Int,y:Int)
@@ -9,19 +10,29 @@ Class pathnode
 End Class
 
 Class MyGame Extends App
+	'Our map. it holds the walls(-1) and the distance
+	'from the start to end position.
 	Field cmap:Int[][]
+	' map width and height
 	Field mw:Int=20,mh:Int=20
+	' tile width and height
 	Field tw:Float=22,th:Float=18
+	' our start and end position
 	Field sx:Int,sy:Int,ex:Int,ey:Int
+	' this holds our path
 	Field path:List<pathnode>
     Method OnCreate()
         SetUpdateRate(1)
+        ' create a new map array
         cmap = New Int[mw][]
         For Local i:=0 Until mw
         	cmap[i] = New Int[mh]
         Next
+        ' set the tile width and height.
         tw = DeviceWidth() / Float(mw)
         th = DeviceHeight() / Float(mh)
+        ' get a random seed so every time we run
+        ' this program we get a different result.
         Seed = GetDate[4] + GetDate[5]
     End Method
     Method OnUpdate()
@@ -47,12 +58,15 @@ Class MyGame Extends App
     		Next
     		Next
     	Next
+
     	For Local y:=0 Until mh Step 5
     		For Local x:=0 Until mw
     			cmap[x][y] = 0
     		Next
     	Next
 
+
+
  		'find start and end position
  		Repeat
  			sx = Rnd(0,mw)
@@ -68,58 +82,101 @@ Class MyGame Extends App
 
  		'flood the map with distance from
  		'sx and sy
+ 		' Create a list with a class inside it (the class has
+ 		' the x and y variables)
  		Local ol:List<pathnode> = New List<pathnode>
+ 		' Add the start position on the list
  		ol.AddLast(New pathnode(sx,sy))
+ 		' set the cloes map at the start position to distance 1
  		cmap[sx][sy] = 1
+ 		' some helper arrays. We can determine the top,right,and bottom
+ 		' and left position cells with these numbers.
  		Local dx:Int[] = [0,1,0,-1]
  		Local dy:Int[] = [-1,0,1,0]
+ 		' While there is contents in the list
  		While ol.Count <> 0
+ 			' Get the current location
  			Local x1:Int=ol.First.x
  			Local y1:Int=ol.First.y
+ 			' Remove the current location from the list
  			ol.RemoveFirst
+ 			' Get 4 new positions around the current positions
 			For Local i:=0 Until 4
+				' Set new x and y
 				Local nx:Int=x1+dx[i]
 				Local ny:Int=y1+dy[i]
+				' If the coordinates are inside the map
 				If nx>=0 And ny>=0 And nx<mw And ny<mh
+				' If the closedmap is not written to yet
  				If cmap[nx][ny] = 0 
+ 					' Set the new distance based on the current distance
  					cmap[nx][ny] = cmap[x1][y1] + 1
+ 					' Add new position to the list
  					ol.AddLast(New pathnode(nx,ny))
  				End If
  				End If
 			Next
  		Wend
 
- 		' Make the path
+ 		' Make the path. Here we start at the end position
+ 		' and find the lowest value around our current position
+ 		' and so on until we are at the start position.
+ 		' Get the current position
  		Local x1:Int=ex,y1:Int=ey
+ 		' Reset our path list
  		path = New List<pathnode>
+ 		' Set the first path contents(end x and y)
  		path.AddLast(New pathnode(x1,y1))
+ 		' Little counter for if we enter an infinite loop
  		Local cnt:Int=0
+ 		' While we are not near the map distance of 1
 		While cmap[x1][y1] > 1		
+			' Get tge current poditions distance	
 			Local lowest:Int=cmap[x1][y1]
+			' Create 2 new variables that hold the new location
 			Local nx:Int,ny:Int
+			' If the position left of our current position is on the map
+			' and is not a wall and has a distance smaller that of our
+			' current position.
 			If x1-1>=0 And cmap[x1-1][y1]>-1 And cmap[x1-1][y1] < lowest Then 
+				' set new position
 				nx=x1-1
 				ny=y1
+				' set new lowest variable
 				lowest = cmap[nx][ny]
 			End If
+			' If the position right of our current position is on the map
+			' and is not a wall and has a distance smaller that of our
+			' current position.
 			If x1+1<mw And cmap[x1+1][y1]>-1 And cmap[x1+1][y1] < lowest
 				nx=x1+1
 				ny=y1
 				lowest = cmap[nx][ny]
 			End If
+			' If the position top of our current position is on the map
+			' and is not a wall and has a distance smaller that of our
+			' current position.
 			If y1-1>=0 And cmap[x1][y1-1]>-1 And cmap[x1][y1-1] < lowest
 				nx=x1
 				ny=y1-1
 				lowest = cmap[nx][ny]
 			End If
+			' If the position at the bottom of our current position is on the map
+			' and is not a wall and has a distance smaller that of our
+			' current position.
 			If y1+1 < mh And cmap[x1][y1+1]>-1 And cmap[x1][y1+1] < lowest
 				nx=x1
 				ny=y1+1
 				lowest = cmap[nx][ny]
 			End If
+			' Here we should have a new position so we put it into 
+			' our current position
 			x1 = nx
 			y1 = ny
+			' Add the next position to the bottom of our path list
 			path.AddLast(New pathnode(x1,y1))
+			' If we can not go anywhere then exit this loop if we have done
+			' a thousand loops.
 			cnt+=1
 			If cnt>1000 Then Exit
 		Wend
@@ -133,7 +190,6 @@ Class MyGame Extends App
         	If cmap[x][y] = -1 Then
         		DrawRect x*tw,y*th,tw,th
         	End If
-'        	DrawText cmap[x][y],x*tw,y*th
         Next
         Next
         'draw the path