#include "astar.h"
#include "being.h"
const int numberPeople = 1;
int onClosedList = 10;
const int notfinished = 0;// path-related constants
//Create needed arrays
//char get_path_walk [MAP_WIDTH][MAP_HEIGHT];
int openList[MAP_WIDTH*MAP_HEIGHT+2]; //1 dimensional array holding ID# of open list items
int whichList[MAP_WIDTH+1][MAP_HEIGHT+1]; //2 dimensional array used to record
// whether a cell is on the open list or on the closed list.
int openX[MAP_WIDTH*MAP_HEIGHT+2]; //1d array stores the x location of an item on the open list
int openY[MAP_WIDTH*MAP_HEIGHT+2]; //1d array stores the y location of an item on the open list
int parentX[MAP_WIDTH+1][MAP_HEIGHT+1]; //2d array to store parent of each cell (x)
int parentY[MAP_WIDTH+1][MAP_HEIGHT+1]; //2d array to store parent of each cell (y)
int F_cost[MAP_WIDTH*MAP_HEIGHT+2]; //1d array to store F cost of a cell on the open list
int G_cost[MAP_WIDTH+1][MAP_HEIGHT+1]; //2d array to store G_cost cost for each cell.
int H_cost[MAP_WIDTH*MAP_HEIGHT+2]; //1d array to store H cost of a cell on the open list
int pathLength; //stores length of the FOUND path for critter
int pathLocation; //stores current position along the chosen path for critter
int* path_bank ;
//Path reading variables
int pathStatus;
int xPath;
int yPath;
/** Initialize pathfinder */
void pathfinder_init() {
path_bank = (int*)malloc(4);
}
/** Exit pathfinder */
void pathfinder_exit() {
free(path_bank);
}
/** Find path */
PATH_NODE *find_path(int pathfinderID, int s_x, int s_y, int e_x, int e_y) {
int onOpenList=0, parentXval=0, parentYval=0,
a=0, b=0, m=0, u=0, v=0, temp=0, corner=0, numberOfOpenListItems=0,
addedGCost=0, tempG = 0, path = 0, x=0, y=0,
tempx, pathX, pathY, cellPosition,
newOpenListItemID=0;
// If starting location and target are in the same location...
if (s_x==e_x && s_y==e_y && pathLocation>0)return NULL;
else if (s_x==e_x && s_y==e_y && pathLocation==0)return NULL;
// If dest tile is NOT_WALKABLE, return that it's a NOT_FOUND path.
if(get_path_walk(e_x, e_y)==NOT_WALKABLE) {
xPath = s_x;
yPath = s_y;
return NULL;
}
// Reset some variables that need to be cleared
for(x=0;x<MAP_WIDTH;x++) {
for(y=0;y<MAP_HEIGHT;y++)
whichList [x][y] = 0;
}
onClosedList = 2; //changing the values of onOpenList and onClosed list is faster than redimming whichList() array
onOpenList = 1;
pathLength = NOT_STARTED;
pathLocation = NOT_STARTED;
G_cost[s_x][s_y] = 0; //reset starting square's G_cost value to 0
// Add the starting location to the open list of tiles to be checked.
numberOfOpenListItems = 1;
openList[1] = 1;//assign it as the top (and currently only) item in the open list, which is maintained as a binary heap (explained below)
openX[1] = s_x ; openY[1] = s_y;
// Do the following until a path is FOUND or deemed NOT_FOUND.
do {
// If the open list is not empty, take the first cell off of the list.
// This is the lowest F cost cell on the open list.
if (numberOfOpenListItems != 0) {
// Pop the first item off the open list.
parentXval = openX[openList[1]];
parentYval = openY[openList[1]]; //record cell coordinates of the item
whichList[parentXval][parentYval] = onClosedList;//add the item to the closed list
// Open List = Binary Heap: Delete this item from the open list, which
numberOfOpenListItems = numberOfOpenListItems - 1;//reduce number of open list items by 1
// Delete the top item in binary heap and reorder the heap, with the lowest F cost item rising to the top.
openList[1] = openList[numberOfOpenListItems+1];//move the last item in the heap up to slot #1
v = 1;
// Repeat the following until the new item in slot #1 sinks to its proper spot in the heap.
do {
u = v;
if (2*u+1 <= numberOfOpenListItems) { //if both children exist
//Check if the F cost of the parent is greater than each child.
//Select the lowest of the two children.
if(F_cost[openList[u]] >= F_cost[openList[2*u]])v = 2*u;
if(F_cost[openList[v]] >= F_cost[openList[2*u+1]])v = 2*u+1;
} else {
if (2*u <= numberOfOpenListItems) { //if only child #1 exists
//Check if the F cost of the parent is greater than child #1
if (F_cost[openList[u]] >= F_cost[openList[2*u]])v = 2*u;
}
}
if (u!=v) { // if parent's F is > one of its children, swap them
temp = openList[u];
openList[u] = openList[v];
openList[v] = temp;
} else break; //otherwise, exit loop
} while (u!=v); //reorder the binary heap
// Check the adjacent squares. (Its "children" -- these path children
// are similar, conceptually, to the binary heap children mentioned
// above, but don't confuse them. They are different. Path children
// are portrayed in Demo 1 with grey pointers pointing toward
// their parents.) Add these adjacent child squares to the open list
// for later consideration if appropriate (see various if statements
// below).
for(b=parentYval-1;b<=parentYval+1;b++) {
for(a=parentXval-1;a<=parentXval+1;a++) {
// If not off the map (do this first to avoid array out-of-bounds errors)
if(a!=-1 && b!=-1 && a!=MAP_WIDTH && b!=MAP_HEIGHT) {
// If not already on the closed list (items on the closed list have
// already been considered and can now be ignored).
if(whichList[a][b]!=onClosedList) {
// If not a wall/obstacle square.
if (get_path_walk(a, b)!=NOT_WALKABLE) {
// Don't cut across corners
corner = WALKABLE;
if(a==parentXval-1) {
if(b==parentYval-1) {
if(get_path_walk(parentXval-1, parentYval)==NOT_WALKABLE || get_path_walk(parentXval, parentYval-1)==NOT_WALKABLE) // cera slash
corner = NOT_WALKABLE;
} else if (b==parentYval+1) {
if(get_path_walk(parentXval, parentYval+1)==NOT_WALKABLE || get_path_walk(parentXval-1, parentYval)==NOT_WALKABLE)
corner = NOT_WALKABLE;
}
} else if(a==parentXval+1) {
if(b==parentYval-1) {
if(get_path_walk(parentXval, parentYval-1)==NOT_WALKABLE || get_path_walk(parentXval+1, parentYval)==NOT_WALKABLE)
corner = NOT_WALKABLE;
} else if(b==parentYval+1) {
if(get_path_walk(parentXval+1, parentYval)==NOT_WALKABLE || get_path_walk(parentXval, parentYval+1)==NOT_WALKABLE)
corner = NOT_WALKABLE;
}
}
if(corner==WALKABLE) {
// If not already on the open list, add it to the open list.
if (whichList[a][b]!=onOpenList) {
// Create a new open list item in the binary heap.
newOpenListItemID = newOpenListItemID + 1; //each new item has a unique ID #
m = numberOfOpenListItems+1;
openList[m] = newOpenListItemID;//place the new open list item (actually, its ID#) at the bottom of the heap
openX[newOpenListItemID] = a;
openY[newOpenListItemID] = b;//record the x and y coordinates of the new item
//Figure out its G_cost cost
if (abs(a-parentXval) == 1 && abs(b-parentYval) == 1)addedGCost = 14;//cost of going to diagonal squares
else addedGCost = 10;//cost of going to non-diagonal squares
G_cost[a][b] = G_cost[parentXval][parentYval] + addedGCost;
//Figure out its H and F costs and parent
H_cost[openList[m]] = 10*(abs(a - e_x) + abs(b - e_y));
F_cost[openList[m]] = G_cost[a][b] + H_cost[openList[m]];
parentX[a][b] = parentXval ; parentY[a][b] = parentYval;
//Move the new open list item to the proper place in the binary heap.
//Starting at the bottom, successively compare to parent items,
//swapping as needed until the item finds its place in the heap
//or bubbles all the way to the top (if it has the lowest F cost).
while(m!=1) { // While item hasn't bubbled to the top (m=1)
//Check if child's F cost is < parent's F cost. If so, swap them.
if(F_cost[openList[m]]<=F_cost[openList[m/2]]) {
temp = openList[m/2];
openList[m/2] = openList[m];
openList[m] = temp;
m = m/2;
} else break;
}
numberOfOpenListItems = numberOfOpenListItems+1;//add one to the number of items in the heap
//Change whichList to show that the new item is on the open list.
whichList[a][b] = onOpenList;
} else { // If whichList(a,b) = onOpenList
// If adjacent cell is already on the open list, check to see if this
// path to that cell from the starting location is a better one.
// If so, change the parent of the cell and its G_cost and F costs.
//Figure out the G_cost cost of this possible new path
if(abs(a-parentXval)==1 && abs(b-parentYval)==1)addedGCost = 14;//cost of going to diagonal tiles
else addedGCost = 10;//cost of going to non-diagonal tiles
tempG = G_cost[parentXval][parentYval] + addedGCost;
// If this path is shorter (G_cost cost is lower) then change
// the parent cell, G_cost cost and F cost.
if(tempG<G_cost[a][b]) { //if G_cost cost is less,
parentX[a][b] = parentXval; //change the square's parent
parentY[a][b] = parentYval;
G_cost[a][b] = tempG;//change the G_cost cost
// Because changing the G_cost cost also changes the F cost, if
// the item is on the open list we need to change the item's
// recorded F cost and its position on the open list to make
// sure that we maintain a properly ordered open list.
for(int x=1;x<=numberOfOpenListItems;x++) { //look for the item in the heap
if(openX[openList[x]]==a && openY[openList[x]]==b) { //item FOUND
F_cost[openList[x]] = G_cost[a][b] + H_cost[openList[x]];//change the F cost
//See if changing the F score bubbles the item up from it's current location in the heap
m = x;
while(m!=1) { //While item hasn't bubbled to the top (m=1)
//Check if child is < parent. If so, swap them.
if(F_cost[openList[m]]<F_cost[openList[m/2]]) {
temp = openList[m/2];
openList[m/2] = openList[m];
openList[m] = temp;
m = m/2;
} else break;
}
break; //exit for x = loop
} // If openX(openList(x)) = a
} // For x = 1 To numberOfOpenListItems
} // If tempG < G_cost(a,b)
} // else If whichList(a,b) = onOpenList
} // If not cutting a corner
} // If not a wall/obstacle square.
} // If not already on the closed list
} // If not off the map
} // for (a = parentXval-1; a <= parentXval+1; a++){
} // for (b = parentYval-1; b <= parentYval+1; b++){
} else {// if (numberOfOpenListItems != 0)
// If open list is empty then there is no path.
path = NOT_FOUND;
break;
}
//If target is added to open list then path has been FOUND.
if (whichList[e_x][e_y]==onOpenList) {
path = FOUND;
break;
}
} while (path!=FOUND && path!=NOT_FOUND);//Do until path is FOUND or deemed NOT_FOUND
// Save the path if it exists.
if (path == FOUND) {
// Working backwards from the target to the starting location by checking
// each cell's parent, figure out the length of the path.
pathX = e_x; pathY = e_y;
do {
//Look up the parent of the current cell.
tempx = parentX[pathX][pathY];
pathY = parentY[pathX][pathY];
pathX = tempx;
//Figure out the path length
pathLength = pathLength + 1;
} while (pathX != s_x || pathY != s_y);
// Resize the data bank to the right size in bytes
path_bank = (int*) realloc (path_bank, pathLength*8);
// Now copy the path information over to the databank. Since we are
// working backwards from the target to the start location, we copy
// the information to the data bank in reverse order. The result is
// a properly ordered set of path data, from the first step to the last.
pathX = e_x ; pathY = e_y;
cellPosition = pathLength*2;//start at the end
do {
cellPosition = cellPosition - 2;//work backwards 2 integers
path_bank [cellPosition] = pathX;
path_bank [cellPosition+1] = pathY;
// Look up the parent of the current cell.
tempx = parentX[pathX][pathY];
pathY = parentY[pathX][pathY];
pathX = tempx;
// If we have reached the starting square, exit the loop.
} while(pathX!=s_x || pathY!=s_y);
char stringa[80];
sprintf(stringa,"%i %i",s_x,s_y);
PATH_NODE *ret = NULL, *temp = NULL;
pathLocation = 1;
ret = new PATH_NODE(s_x, s_y);
temp = ret;
//alert(stringa,"","","","",0,0);
while(pathLocation<pathLength) {
sprintf(stringa,"%i %i",path_bank[pathLocation*2-2], path_bank[pathLocation*2-1]);
//alert(stringa,"","","","",0,0);
temp->next = new PATH_NODE(
path_bank[pathLocation * 2 - 2],
path_bank[pathLocation * 2 - 1]);
if(temp->next==NULL)ok("Error", "Unable to create path node");
temp = temp->next;
pathLocation++;
}
if(temp!=NULL)temp->next = new PATH_NODE(e_x, e_y);
else ok("Error", "Null reference");
return ret;
}
return NULL; // Path not found
}
/** Read the path data */
void ReadPath(int pathfinderID) {
//If a path exists, read the path data
// from the pathbank.
pathLocation = 1; //set pathLocation to 1st step
while (pathLocation<pathLength) {
int a = path_bank [pathLocation*2-2];
int b = path_bank [pathLocation*2-1];
pathLocation = pathLocation + 1;
whichList[a][b] = 3;//draw dotted path
}
}
