Code viewer for World: Plant vs Zombie using A_st...

/**
// MCM Foundations of AI
// Student Name: Md Shamsul Abedin Malik
// Student ID: 19215008 
// Assignment: A* algorithm to a 3D visual world
// Description: 
// This is an implementation of the a-star algorithm using realistic three-dimensional pathfinding
// There are three functions that we keep track of for nodes that we look at:

// g(x): The total cost of getting to that node from start. If we reach a node for the first time or reach a node in less time than it currently took, then update the g(x) to the cost to reach this node.
// h(x): The estimated time to reach the finish from the current node. This is also called a heuristic. The distance to the end will not change even if the path to arrive at a node changes. Note: There are many different ways to // guess how far the node is from the end, I have used Euclidean distance in this implementation.
// f(x): Simply g(x) + h(x). The lower the f(x), the better. Think about it like this: the best node is one that takes the least total amount of time to arrive at and to get to the end. So, a node that took only 1 step to arrive // at and 5 to get to the end is more ideal than one that took 10 to arrive and and only 1 to get to the end.

// The code has been developed considering that the enemy (plant) will always start from top left corner and the agent (Zombie) usually placed on the bottom right corner which is a diagonal movement.
// grid size and box density has been defined following the instruction

// Standalone grid are using by the A* function which is made up of objects containg the A data elements and includes the hueristic,
// openset and closedset are managing the sets which are flag in the A* array. 
**/


// ==== Starter World ===============================================================================================
// (c) Ancient Brain Ltd. All rights reserved.
// This code is only for use on the Ancient Brain site.
// This code may be freely copied and edited by anyone on the Ancient Brain site.
// This code may not be copied, re-published or used on any other website.
// To include a run of this code on another website, see the "Embed code" links provided on the Ancient Brain site.
// ==================================================================================================================

// =============================================================================================
// More complex starter World 
// 3d-effect Maze World (really a 2-D problem)
// Movement is on a semi-visible grid of squares 
//
// This more complex World shows:
// - Skybox
// - Internal maze (randomly drawn each time)
// - Enemy actively chases agent
// - Music/audio
// - 2D world (clone this and set show3d = false)
// - User keyboard control (clone this and comment out Mind actions to see)
// =============================================================================================


// =============================================================================================
// Scoring:
// Bad steps = steps where enemy is within one step of agent.
// Good steps = steps where enemy is further away. 
// Score = good steps as percentage of all steps.
//
// There are situations where agent is trapped and cannot move.
// If this happens, you score zero.
// =============================================================================================


// ===================================================================================================================
// === Start of tweaker's box ======================================================================================== 
// ===================================================================================================================

// The easiest things to modify are in this box.
// You should be able to change things in this box without being a JavaScript programmer.
// Go ahead and change some of these. What's the worst that could happen?


AB.clockTick = 100;

// Speed of run: Step every n milliseconds. Default 100.

AB.maxSteps = 1000;

// Length of run: Maximum length of run in steps. Default 1000.

AB.screenshotStep = 50;

// Take screenshot on this step. (All resources should have finished loading.) Default 50.



//---- global constants: -------------------------------------------------------


const show3d = true;						// Switch between 3d and 2d view (both using Three.js) 

const TEXTURE_WALL 	= '/uploads/starter/door.jpg' ;
const TEXTURE_MAZE 	= '/uploads/starter/latin.jpg' ;
const TEXTURE_AGENT 	= '/uploads/shamsul/Zombie.JPG' ;
const TEXTURE_ENEMY 	= '/uploads/shamsul/plant-1.JPG' ;


// credits:
// http://commons.wikimedia.org/wiki/File:Old_door_handles.jpg
// https://commons.wikimedia.org/wiki/Category:Pac-Man_icons
// https://commons.wikimedia.org/wiki/Category:Skull_and_crossbone_icons
// http://en.wikipedia.org/wiki/File:Inscription_displaying_apices_(from_the_shrine_of_the_Augustales_at_Herculaneum).jpg


 
const MUSIC_BACK  = '/uploads/starter/Defense.Line.mp3' ;
const SOUND_ALARM = '/uploads/starter/air.horn.mp3' ;

// credits:
// http://www.dl-sounds.com/royalty-free/defense-line/
// http://soundbible.com/1542-Air-Horn.html 

																									  


const gridsize = 50;                                            // number of squares along side of world           

const NOBOXES = Math.trunc((gridsize * gridsize) / 3);
// density of maze - number of internal boxes
// (bug) use trunc or can get a non-integer 

const squaresize = 100;                                 // size of square in pixels

const MAXPOS = gridsize * squaresize;           // length of one side in pixels 

const SKYCOLOR = 0xddffdd;                             // a number, not a string 


const startRadiusConst = MAXPOS * 0.8;                // distance from centre to start the camera at
const maxRadiusConst = MAXPOS * 10;                // maximum distance from camera we will render things  



//--- change ABWorld defaults: -------------------------------

ABHandler.MAXCAMERAPOS = maxRadiusConst;

ABHandler.GROUNDZERO = true;                                         // "ground" exists at altitude zero



//--- skybox: -------------------------------
// skybox is a collection of 6 files 
// x,y,z positive and negative faces have to be in certain order in the array 
// https://threejs.org/docs/#api/en/loaders/CubeTextureLoader 

// mountain skybox, credit:
// http://stemkoski.github.io/Three.js/Skybox.html

 const SKYBOX_ARRAY = [										 
                "/uploads/starter/dawnmountain-xpos.png",
                "/uploads/starter/dawnmountain-xneg.png",
                "/uploads/starter/dawnmountain-ypos.png",
                "/uploads/starter/dawnmountain-yneg.png",
                "/uploads/starter/dawnmountain-zpos.png",
                "/uploads/starter/dawnmountain-zneg.png"
                ];


// space skybox, credit:
// http://en.spaceengine.org/forum/21-514-1
// x,y,z labelled differently

/*
 const SKYBOX_ARRAY = [										 
                "/uploads/starter/sky_pos_z.jpg",
                "/uploads/starter/sky_neg_z.jpg",
                "/uploads/starter/sky_pos_y.jpg",
                "/uploads/starter/sky_neg_y.jpg",
                "/uploads/starter/sky_pos_x.jpg",
                "/uploads/starter/sky_neg_x.jpg"
                ];
*/				


// urban photographic skyboxes, credit:
// http://opengameart.org/content/urban-skyboxes

/*
 const SKYBOX_ARRAY = [										 
                "/uploads/starter/posx.jpg",
                "/uploads/starter/negx.jpg",
                "/uploads/starter/posy.jpg",
                "/uploads/starter/negy.jpg",
                "/uploads/starter/posz.jpg",
                "/uploads/starter/negz.jpg"
                ];
*/



// ===================================================================================================================
// === End of tweaker's box ==========================================================================================
// ===================================================================================================================


// You will need to be some sort of JavaScript programmer to change things below the tweaker's box.

//--- Mind can pick one of these actions -----------------

const ACTION_LEFT = 0;
const ACTION_RIGHT = 1;
const ACTION_UP = 2;
const ACTION_DOWN = 3;
const ACTION_STAYSTILL = 4;

// in initial view, (smaller-larger) on i axis is aligned with (left-right)
// in initial view, (smaller-larger) on j axis is aligned with (away from you - towards you)


// contents of a grid square

const GRID_BLANK = 0;
const GRID_WALL = 1;
const GRID_MAZE = 2;

var BOXHEIGHT;          // 3d or 2d box height 

var GRID = new Array(gridsize);                  // can query GRID about whether squares are occupied, will in fact be initialised as a 2D array   

//----------------A* Algorithm dataset -------------------------

var SpotGrid = new Array(gridsize);
var openSet = [];
var closedSet = [];
var enemy;
var agent;
var path = [];
var diagonal = true;
var autoTrap = true;				
var keepAllPathsDone = true;

function dist(x1,y1,x2,y2){
var distX = Math.abs(x1 - x2);
var distY = Math.abs(y1 - y2);
return Math.sqrt( distX*distX + distY*distY );
}

function heuristic(a, b) {
//if (diagonal) // 2D distance - dist is a P5 function 
return (dist(a.i, a.j, b.i, b.j));
}

function removeFromArray(arr, elt) {
// Could use indexOf here instead to be more efficient
for (var i = arr.length - 1; i >= 0; i--)
	if (arr[i] == elt)
		arr.splice(i, 1);
}

var theagent, theenemy;

var wall_texture, agent_texture, enemy_texture, maze_texture;


// enemy and agent position on squares
var ei, ej, ai, aj;

var badsteps;
var goodsteps;



function loadResources()                // asynchronous file loads - call initScene() when all finished 
{
var loader1 = new THREE.TextureLoader();
var loader2 = new THREE.TextureLoader();
var loader3 = new THREE.TextureLoader();
var loader4 = new THREE.TextureLoader();

loader1.load(TEXTURE_WALL, function (thetexture) {
	thetexture.minFilter = THREE.LinearFilter;
	wall_texture = thetexture;
	if (asynchFinished()) initScene();            // if all file loads have returned 
});

loader2.load(TEXTURE_AGENT, function (thetexture) {
	thetexture.minFilter = THREE.LinearFilter;
	agent_texture = thetexture;
	if (asynchFinished()) initScene();
});

loader3.load(TEXTURE_ENEMY, function (thetexture) {
	thetexture.minFilter = THREE.LinearFilter;
	enemy_texture = thetexture;
	if (asynchFinished()) initScene();
});

loader4.load(TEXTURE_MAZE, function (thetexture) {
	thetexture.minFilter = THREE.LinearFilter;
	maze_texture = thetexture;
	if (asynchFinished()) initScene();
});

}


function asynchFinished()                // all file loads returned 
{
if (wall_texture && agent_texture && enemy_texture && maze_texture) return true;
else return false;
}

//--- grid system -------------------------------------------------------------------------------
// my numbering is 0 to gridsize-1


function occupied(i, j)              // is this square occupied
{
if ((ei == i) && (ej == j)) return true;         // variable objects 
if ((ai == i) && (aj == j)) return true;

if (GRID[i][j] == GRID_WALL) return true;            // fixed objects         
if (GRID[i][j] == GRID_MAZE) return true;

return false;
}


// translate my (i,j) grid coordinates to three.js (x,y,z) coordinates
// logically, coordinates are: y=0, x and z all positive (no negative)    
// logically my dimensions are all positive 0 to MAXPOS
// to centre everything on origin, subtract (MAXPOS/2) from all dimensions 

function translate(i, j) {

var v = new THREE.Vector3();

v.y = 0;
v.x = (i * squaresize) - (MAXPOS / 2);
v.z = (j * squaresize) - (MAXPOS / 2);

return v;
}


// An object to describe a spot in the grid
function Spot(i, j) {
// Location

this.i = i;
this.j = j;

this.wall = false;
this.neighbors = [];

// f, g, and h values for A*
this.f = 0;
this.g = 0;
this.h = 0;
// Where did I come from?
this.previous = undefined;

// Figure out who my neighbors are
this.addNeighbors = function () {
	var i = this.i;
	var j = this.j;

    //East
    
	if (SpotGrid[i+1] && SpotGrid[i+1][j])
		this.neighbors.push(SpotGrid[i+1][j]);

    //West
    
	if (SpotGrid[i-1] && SpotGrid[i-1][j])
		this.neighbors.push(SpotGrid[i-1][j]);

    //North

	if (SpotGrid[i] && SpotGrid[i][j+1])
		this.neighbors.push(SpotGrid[i][j+1]);

    //South

	if (SpotGrid[i] && SpotGrid[i][j-1])
		this.neighbors.push(SpotGrid[i][j-1]);


	if (diagonal)	//diagonal are also neighbours:
	{

        //Southwest
            
		if (SpotGrid[i-1] && SpotGrid[i-1][j-1])
			this.neighbors.push(SpotGrid[i-1][j-1]);
			
        //Southeast			
			
		if (SpotGrid[i+1] && SpotGrid[i+1][j-1])
			this.neighbors.push(SpotGrid[i+1][j-1]);
			
        //Northwest
			
		if (SpotGrid[i-1] && SpotGrid[i-1][j+1])
			this.neighbors.push(SpotGrid[i-1][j+1]);
			
        //Northeast
			
		if (SpotGrid[i+1] && SpotGrid[i+1][j+1])
			this.neighbors.push(SpotGrid[i+1][j+1]);
   
	}
}
}





function initScene()            // all file loads have returned 
{
var i, j, shape, thecube;

// set up GRID as 2D array


SpotGrid = new Array(gridsize);
for (i = 0; i < gridsize; i++) {
	GRID[i] = new Array(gridsize);
	SpotGrid[i] = new Array(gridsize);
}


// set up walls

for (i = 0; i < gridsize; i++)
	for (j = 0; j < gridsize; j++) {

		SpotGrid[i][j] = new Spot(i, j);
		if ((i == 0) || (i == gridsize - 1) || (j == 0) || (j == gridsize - 1)) {
			GRID[i][j] = GRID_WALL;
			SpotGrid[i][j].wall = true;
			shape = new THREE.BoxGeometry(squaresize, BOXHEIGHT, squaresize);
			thecube = new THREE.Mesh(shape);
			thecube.material = new THREE.MeshBasicMaterial({ map: wall_texture });
			thecube.position.copy(translate(i, j));                       // translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 
			ABWorld.scene.add(thecube);
		}
		else {
			GRID[i][j] = GRID_BLANK;
			SpotGrid[i][j].wall = false;
		}
	}
// set up maze 

for (var c = 1; c <= NOBOXES; c++) {

	i = AB.randomIntAtoB(1, gridsize - 2);             // inner squares are 1 to gridsize-2
	j = AB.randomIntAtoB(1, gridsize - 2);

	GRID[i][j] = GRID_MAZE;
	SpotGrid[i][j].wall = true;

	shape = new THREE.BoxGeometry(squaresize, BOXHEIGHT, squaresize);
	thecube = new THREE.Mesh(shape);
	thecube.material = new THREE.MeshBasicMaterial({ map: maze_texture });

	thecube.position.copy(translate(i, j));                       // translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 
	ABWorld.scene.add(thecube);
}


// All the neighbors
for (var i = 0; i < gridsize; i++)
	for (var j = 0; j < gridsize; j++)
		SpotGrid[i][j].addNeighbors();

console.log('start app');
console.log(SpotGrid);

// set up enemy 
// start in random location
do {


	i = AB.randomIntAtoB(1, gridsize - 2);
	j = AB.randomIntAtoB(1, gridsize - 2);
}
while (occupied(i, j));         // search for empty square 

//ei = i;
//ej = j;
ei = 1;
ej = 1;

shape = new THREE.BoxGeometry(squaresize, BOXHEIGHT, squaresize);
theenemy = new THREE.Mesh(shape);
theenemy.material = new THREE.MeshBasicMaterial({ map: enemy_texture });
ABWorld.scene.add(theenemy);
drawEnemy();



// set up agent 
// start in random location

do {

	i = AB.randomIntAtoB(1, gridsize - 2);
	j = AB.randomIntAtoB(1, gridsize - 2);
}
while (occupied(i, j));         // search for empty square 

//ai = i;
//aj = j;
ai = gridsize - 2;
aj = gridsize - 2;

SetupAStar();

shape = new THREE.BoxGeometry(squaresize, BOXHEIGHT, squaresize);
theagent = new THREE.Mesh(shape);
theagent.material = new THREE.MeshBasicMaterial({ map: agent_texture });
ABWorld.scene.add(theagent);
drawAgent();


// finally skybox 
// setting up skybox is simple 
// just pass it array of 6 URLs and it does the asych load 

ABWorld.scene.background = new THREE.CubeTextureLoader().load(SKYBOX_ARRAY, function () {

	ABWorld.render();

	AB.removeLoading();

	AB.runReady = true;             // start the run loop
});

}

function SetupAStar(){
for (var i = 0; i < gridsize; i++)
	for (var j = 0; j < gridsize; j++){
		SpotGrid[i][j].f = 0;
		SpotGrid[i][j].g = 0;
		SpotGrid[i][j].h = 0;
		SpotGrid[i][j].previous = undefined;
	}

// closedSet starts empty
closedSet = [];
// openSet starts with beginning only
openSet = [];
}

// --- draw moving objects -----------------------------------


function drawEnemy()            // given ei, ej, draw it 
{
theenemy.position.copy(translate(ei, ej));                    // translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 

ABWorld.lookat.copy(theenemy.position);                      // if camera moving, look back at where the enemy is  
}


function drawAgent()            // given ai, aj, draw it 
{
theagent.position.copy(translate(ai, aj));                    // translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 

ABWorld.follow.copy(theagent.position);                      // follow vector = agent position (for camera following agent)
}



// --- take actions -----------------------------------
					 
function isTraped(i, j) {
	//Parameters are agent position. Returns if the bug is on a trap. He is on a trap if he is between 3 walls. 
	//In the image the bug is the yellow, and the red notes are the spots of interest.
	var numberOfWalls = 0;
	if (SpotGrid[i][j - 1].wall)
		numberOfWalls++;

	if (SpotGrid[i - 1][j].wall)
		numberOfWalls++;

	if (SpotGrid[i + 1][j].wall)
		numberOfWalls++;

	if (SpotGrid[i][j + 1].wall)
		numberOfWalls++;

	if (numberOfWalls == 3)
		return true;
	else
		return false;
}

function trapDoorLocation(i, j) {
	//Given the bug I,J position – returns the trap door. On the above figure, the position when there is no wall. 
	//Must be used when it is trapped, otherwise can return any position.
	 

	if (!SpotGrid[i][j - 1].wall)
		return SpotGrid[i][j - 1];

	if (!SpotGrid[i - 1][j].wall)
		return SpotGrid[i - 1][j];
	if (!SpotGrid[i + 1][j].wall)
		return SpotGrid[i + 1][j];
	if (!SpotGrid[i][j + 1].wall)
		return SpotGrid[i][j + 1];

}

function moveLogicalEnemy() {
// // move towards agent 
// // put some randomness in so it won't get stuck with barriers 
					  

 var i, j;
 if (ei < ai) i = AB.randomIntAtoB(ei, ei + 1);
 if (ei == ai) i = ei;
 if (ei > ai) i = AB.randomIntAtoB(ei - 1, ei);
 if (ej < aj) j = AB.randomIntAtoB(ej, ej + 1);
 if (ej == aj) j = ej;
 if (ej > aj) j = AB.randomIntAtoB(ej - 1, ej);

 if (!occupied(i, j))         // if no obstacle then move, else just miss a turn
 {
 	ei = i;
 	ej = j;
 }
 
}
 
 
function moveLogicalAgent(a)                  // this is called by the infrastructure that gets action a from the Mind 
{
var i = ai;
var j = aj;


    // depending on the agent move, spin the sphere
    switch (a) {
        case ACTION_LEFT:
            i--;
            theagent.rotation.y = 0;
            break;
        case ACTION_RIGHT:
            i++;
            theagent.rotation.y = -1;
            break;
        case ACTION_UP:
            j++;
            theagent.rotation.y = -2;
            break;
        case ACTION_DOWN:
            j--;
            theagent.rotation.y = 2;
            break;
        default:
            break;
    }

if (!occupied(i, j)) {
  

	ai = i;
	aj = j;
}

SpotGrid[ai][aj].wall = false;
}

// --- key handling --------------------------------------------------------------------------------------
// This is hard to see while the Mind is also moving the agent:
// AB.mind.getAction() and AB.world.takeAction() are constantly running in a loop at the same time 
// have to turn off Mind actions to really see user key control 

// we will handle these keys: 

var OURKEYS = [37, 38, 39, 40];

function ourKeys(event) { return (OURKEYS.includes(event.keyCode)); }


function keyHandler(event) {

if (!AB.runReady) return true;               // not ready yet 

// if not one of our special keys, send it to default key handling:
if (!ourKeys(event)) return true;

// else handle key and prevent default handling:

if (event.keyCode == 37) moveLogicalAgent(ACTION_LEFT);
if (event.keyCode == 38) moveLogicalAgent(ACTION_DOWN);
if (event.keyCode == 39) moveLogicalAgent(ACTION_RIGHT);
if (event.keyCode == 40) moveLogicalAgent(ACTION_UP);

// when the World is embedded in an iframe in a page, we want arrow key events handled by World and not passed up to parent 

event.stopPropagation(); event.preventDefault(); return false;
}


// --- score: -----------------------------------


function badstep()                      // is the enemy within one square of the agent
{
if ((Math.abs(ei - ai) < 2) && (Math.abs(ej - aj) < 2)) return true;
else return false;
}


function agentBlocked()                 // agent is blocked on all sides, run over
{
return (occupied(ai - 1, aj) &&
	occupied(ai + 1, aj) &&
	occupied(ai, aj + 1) &&
	occupied(ai, aj - 1));
}


function updateStatusBefore(a)
// this is called before anyone has moved on this step, agent has just proposed an action
// update status to show old state and proposed move 
{
var x = AB.world.getState();
AB.msg(" Step: " + AB.step + "   x = (" + x.toString() + ")   a = (" + a + ") ");
}


function updateStatusAfter()          // agent and enemy have moved, can calculate score
{
// new state after both have moved

var y = AB.world.getState();
var score = (goodsteps / AB.step) * 100;

AB.msg("   y = (" + y.toString() + ") <br>" +
	" Bad steps: " + badsteps +
	"   Good steps: " + goodsteps +
	"   Score: " + score.toFixed(2) + "% ", 2);
}





AB.world.newRun = function () {
					

AB.loadingScreen();

AB.runReady = false;
			   

badsteps = 0;
goodsteps = 0;

if (show3d) {

	BOXHEIGHT = squaresize;
	ABWorld.init3d(startRadiusConst, maxRadiusConst, SKYCOLOR);
}
else {

	BOXHEIGHT = 1;
	ABWorld.init2d(startRadiusConst, maxRadiusConst, SKYCOLOR);
}

loadResources();                // aynch file loads             
// calls initScene() when it returns 

document.onkeydown = keyHandler;

};


AB.world.getState = function () {

var x = [ai, aj, ei, ej];
return (x);
};

function getAStarPath(begin, end) {
openSet.push(begin);

// each timestep, check one more square and draw current partial solution 
// while has nodes to investigate

while (openSet.length > 0) {
	var indexBetterF = 0;
	//neighbor with lowest f (previous one can not be in the openset)
	for (var i = 0; i < openSet.length; i++)
		if (openSet[i].f < openSet[indexBetterF].f)
			indexBetterF = i;

	// Best option moves from openSet to closedSet
	var current = openSet[indexBetterF];

	removeFromArray(openSet, current);
	closedSet.push(current);

	// End
	if (current === end) {
		console.log("success - found path");
		printPath(current);
		return getPath(current);
	}

	// Check all the neighbors
	var neighbors = current.neighbors;

	for (var i = 0; i < neighbors.length; i++) {
		var neighbor = neighbors[i];

		// Valid neighbor?
		if (!closedSet.includes(neighbor) && !neighbor.wall) {

			//tempG = current.G + distance to other node 
			//But our heuristic measure the distance 
			var tempG = current.g + heuristic(neighbor, current);

			//We could set G directly, but for the nodes in the openSet, they may have an better G than this one.
			//Maybe due a previous attempt that was better than that.

			// Is this a better path than before?
			var isBetterPath = false;

									 
			var isFirstVist = false;

			//It is not in the openSet, so the only option we have is tempG
			if (!openSet.includes(neighbor)) {
				neighbor.g = tempG;
				isFirstVist = true;
			} else {
				//It is in the open set. We just update neibhbor.g value with tempG if it is better. 
				//In other words, we want the min(neighbor.g, tempG)
				if (tempG < neighbor.g) {
					neighbor.g = tempG;
					isBetterPath = true;
				}
			}

			// Update values if it is a better path (or first visit)
			if (isBetterPath || isFirstVist) {
				neighbor.h = heuristic(neighbor, agent);
				neighbor.f = neighbor.g + neighbor.h;
				neighbor.previous = current;
			}

			//if is the first visit to this neighbor...
			if (!openSet.includes(neighbor))
				openSet.push(neighbor);
		}
	}
} 
}


function printPath(current) {
// Find the path by working backwards
path = [];
var temp = current;
path.push(temp);
while (temp.previous) {
	path.push(temp.previous);
	temp = temp.previous;
}

var pathStr = "";
for (i = path.length-1; i >= 0; i--) {
	pathStr = pathStr + "(" + path[i].i + "," + path[i].j + ")";
}

console.log(pathStr);
}

function getPath(current) {
// Find the path by working backwards
path = [];
var temp = current;
path.push(temp);
while (temp.previous) {
	path.push(temp.previous);
	temp = temp.previous;
}

var pathInOrder = [];
for (i = path.length-1; i >= 0; i--) {
	pathInOrder.push(path[i]);
}

return pathInOrder;
console.log(pathStr);
}



AB.world.takeAction = function (a) {

enemy = SpotGrid[ei][ej];
agent =  SpotGrid[ai][aj];

SetupAStar();
var aStarPath = getAStarPath(enemy,agent);
if (aStarPath.length == 0){
	console.log("are they in same cell?");
}else if (aStarPath.length == 1){
	console.log("they are one cell away");
}else if (aStarPath.length == 2){
	//Put trapping movement here
	console.log("what happens here?");
}else {
	var nextStep = aStarPath[1];
	ei = nextStep.i;
	ej = nextStep.j;
}


updateStatusBefore(a);                        // show status line before moves 
moveLogicalAgent(a);
					   
//if ((AB.step % 2) == 0)           // slow the enemy down to every nth step
moveLogicalEnemy();


if (badstep()) badsteps++;
else goodsteps++;

drawAgent();
drawEnemy();
updateStatusAfter();                 // show status line after moves  


if (agentBlocked())                 // if agent blocked in, run over 
{
	AB.abortRun = true;
	goodsteps = 0;                  // you score zero as far as database is concerned                        
	musicPause();
	//soundAlarm();
}

};



AB.world.endRun = function () {

musicPause();
if (AB.abortRun) AB.msg(" <br> <font color=red> <B> Agent trapped. Final score zero. </B> </font>   ", 3);
else AB.msg(" <br> <font color=green> <B> Run over. </B> </font>   ", 3);
};


AB.world.getScore = function () {

// only called at end - do not use AB.step because it may have just incremented past AB.maxSteps

var s = (goodsteps / AB.maxSteps) * 100;   // float like 93.4372778 
var x = Math.round(s * 100);                // 9344
return (x / 100);                          // 93.44
};







// --- music and sound effects ----------------------------------------

var backmusic = AB.backgroundMusic(MUSIC_BACK);

function musicPlay() { backmusic.play(); }
function musicPause() { backmusic.pause(); }


function soundAlarm() {

//var alarm = new Audio(SOUND_ALARM);
//alarm.play();  
}