Code viewer [Ancient Brain]

Code viewer for World: Cat and Mouse (clone by Ja...

// Cloned by Jack O'Brien on 22 Nov 2020 from World "Cat and Mouse" by Jack O'Brien 
// Please leave this clone trail here.
 


// Cloned by Jack O'Brien on 7 Nov 2020 from World "Complex World" by Starter user 
// Please leave this clone trail here.
 



// ==== Starter World =================================================================================================
// This code is designed for use on the Ancient Brain site.
// This code may be freely copied and edited by anyone on the Ancient Brain site.
// To include a working run of this program on another site, see the "Embed code" links provided on Ancient Brain.
// ====================================================================================================================



// =============================================================================================
// 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/jobrien14/alleyway.jpg' ;
 const TEXTURE_MAZE 	= '/uploads/jobrien14/trashcan2.png' ;
 const TEXTURE_AGENT 	= '/uploads/jobrien14/mouse.png' ;
 const TEXTURE_ENEMY 	= '/uploads/jobrien14/angry_cat.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 = 2000;					// 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.

// My code

var myGrid = new Array(gridsize);

// Open and closed set
var openSet = [];
var closedSet = [];

var Path = [];
var Best =[]


function spot(x, y){
    
    // location
    this.i = x;
    this.j = y;
    
    // Wall or Mazw
    this.wall = false;
    this.maze = false;
    
    // f, g, and h values for A*
    this.f = 0;
    this.g = 0;
    this.h = 0;
    
    // Neighbors
    
    
    // Where did I come from?
    this.previous = undefined;
    
    // Figure out who my neighbors are
  this.addNeighbors = function(gridsize){
    this.neighbors = [];
    var i = this.i;
    var j = this.j;
    
    if (i < gridsize - 1)
        this.neighbors.push(myGrid[i + 1][j]);

    if (i > 1)    
        this.neighbors.push(myGrid[i - 1][j]);

    if (j < gridsize - 1)
        this.neighbors.push(myGrid[i][j + 1]);

    if (j > 1) 
        this.neighbors.push(myGrid[i][j - 1]);


    if (i > 1 && j > 1) 
        this.neighbors.push(myGrid[i - 1][j - 1]);
            
    if (i < gridsize - 1 && j > 1)          
        this.neighbors.push(myGrid[i + 1][j - 1]);
        
    if (i > 1 && j < gridsize - 1)          
        this.neighbors.push(myGrid[i - 1][j + 1]);
        
    if (i < gridsize - 1 && j < gridsize - 1)   
        this.neighbors.push(myGrid[i + 1][j + 1]);
    
  }
  
  this.addBlockingNeighbors = function(gridsize){
        this.blockingNeighbors = [];
        var i = this.i;
        var j = this.j;
        
        if (i < gridsize - 1)
            this.blockingNeighbors.push(myGrid[i + 1][j]);
    
        if (i > 1)    
            this.blockingNeighbors.push(myGrid[i - 1][j]);
    
        if (j < gridsize - 1)
            this.blockingNeighbors.push(myGrid[i][j + 1]);
    
        if (j > 1) 
        this.blockingNeighbors.push(myGrid[i][j - 1]);
  }
  
  this.addDiagonalNeighbors = function(gridsize){
        this.diagonalNeighbors = [];
        var i = this.i;
        var j = this.j;
        
        if (i > 1 && j > 1) 
        this.diagonalNeighbors.push(myGrid[i - 1][j - 1]);
            
        if (i < gridsize - 1 && j > 1)          
            this.diagonalNeighbors.push(myGrid[i + 1][j - 1]);
            
        if (i > 1 && j < gridsize - 1)          
            this.diagonalNeighbors.push(myGrid[i - 1][j + 1]);
            
        if (i < gridsize - 1 && j < gridsize - 1)   
            this.diagonalNeighbors.push(myGrid[i + 1][j + 1]);
  }
  
}


//Drawing and Console output related functions
function listNeighbors(spot){
    console.log(spot.neighbors.length + " Neighbors:");
    for(let i=0; i<= spot.neighbors.length -1; i++){
        console.log("X: " + spot.neighbors[i].i + "; Y: "+ spot.neighbors[i].j);
    }
}

function listPath(path){
    console.log("Path: ");
    for(let i=0; i<= path.length -1; i++){
        console.log("X: " + path[i].i + "; Y: "+ path[i].j);
    }
}

function drawPath(Path, colorLine){
    // console.log("In drawPath");
    var geometry = new THREE.Geometry();
    var material = new THREE.LineBasicMaterial( { color: colorLine } );
    if(Path!== null){
        if(Path.length >1){
        // console.log("Path length > 1");
        for(let i = 0; i < Path.length-1; i++){
            geometry.vertices.push(translate(Path[i].i,Path[i].j));
            geometry.vertices.push(translate(Path[i+1].i,Path[i+1].j));
        }
        
        var line = new THREE.LineSegments( geometry, material );
        ABWorld.scene.add(line);
        setTimeout( () => {
		
			geometry.dispose();
			material.dispose();
			ABWorld.scene.remove( line );
		
		}, AB.clockTick);
        }
    }
    
}


function distance(spot1, spot2){
    return Math.sqrt(Math.pow(spot2.i -spot1.i, 2) + Math.pow(spot2.j -spot1.j, 2));
}

//--- 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   

var theagent, theenemy;
  
var wall_texture, agent_texture, enemy_texture, maze_texture; 


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



	
function initScene()		// all file loads have returned 
{
	 var i,j, shape, thecube;
	 
	// set up GRID as 2D array
	 
	 for ( i = 0; i < gridsize ; i++ ) {
		GRID[i] = new Array(gridsize);	
		myGrid[i] = new Array(gridsize);	
	 }

	// set up walls
	 
	 for ( i = 0; i < gridsize ; i++ ) 
	  for ( j = 0; j < gridsize ; j++ ) 
		if ( ( i===0 ) || ( i==gridsize-1 ) || ( j===0 ) || ( j==gridsize-1 ) )
		{
			GRID[i][j] = GRID_WALL;		
			myGrid[i][j] = new spot(i, j);
			myGrid[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;
   			myGrid[i][j] = new spot(i, j);
		}
		
   // 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 ;
		myGrid[i][j].maze = 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-2; i++) 
        for (var j = 0; j <= gridsize-2; j++){ 
          myGrid[i][j].addNeighbors(gridsize); 
          myGrid[i][j].addBlockingNeighbors(gridsize);
        }
   
	// 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;
	 enemyLocation = new spot(ei, ej);
	 enemyLocation.addNeighbors(gridsize);
	 console.log('Enemy location (using spot): x = ' + enemyLocation.i + '; y = ' + enemyLocation.j);
// 	 listNeighbors(enemyLocation);
	 
	 // openSet starts with beginning only
    //  openSet.push(enemyLocation);
  
// 	 console.log(enemyLocation.neighbors.toString());
	 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;
	 agentLocation = new spot(ai, aj);
	 agentLocation.addNeighbors(gridsize);
	 agentLocation.addBlockingNeighbors(gridsize);
// 	 agentLocation.addDiagonalNeighbors(gridsize);
 
	 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; 
// 		console.log("Test: " + myGrid[0][0].x.toString());// start the run loop
	 });
 		
}
 
 
 
function resetValues(Values){
    
    for(let i =0; i<Values.length; i++){
        Values[i].f = 0;
        Values[i].g = 0;
        Values[i].h = 0;
    }
    
}

// --- 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)
}



 //Bresenham's algorithm
 
 function lowLine(p1, p2){
     
     let diffX = p2.i - p1.i;
     let diffY = p2.j - p1.j;
     let yi = 1;
     
     if(diffY < 0){
         yi = -1;
         diffY = -diffY;
     }
     
     let D = (2 * diffY) - diffX;
     let y = p1.j;
      let result = []
     for(var x = p1.i; x<= p2.i; x++){
         result.push(new spot(x, y));
         if(D > 0){
             y = y + yi;
             D = D + (2*(diffY - diffX));
         }
         else {
             D = D + (2*diffY);
         }
     }
     
     return result;
 }
 
 function highLine(p1, p2){
     
     let diffX = p2.i - p1.i;
     let diffY = p2.j - p1.j;
     let xi = 1;
     
     if(diffX < 0){
         xi = -1;
         diffX = -diffX;
     }
     
     let D = (2 * diffX) - diffY;
     let x = p1.i;
     let result = []
     
     for(var y = p1.j; y<= p2.j; y++){
         result.push(new spot(x, y));
         if(D > 0){
             x = x + xi;
             D = D + (2*(diffX - diffY));
         }
         else {
             D = D + (2*diffX);
         }
     }
     
     return result;
 }
 
 
 function bresenhams(p1, p2){
      var output = [];
     if(Math.abs(p2.j - p1.j) < Math.abs(p2.i - p1.i)){
         if(p1.i > p2.i)
            output = lowLine(p2, p1);
         else 
            output = lowLine(p1, p2);
     }
     else{
         if(p1.j > p2.j)
            output = highLine(p2, p1);
         else
            output = highLine(p1, p2);
     }
     
     return output;
 }
 
  //End Bresenham's algorithm
 
// A* search

function aStar(a, b){
    var testPath = bresenhams(a, b);
    var numBlocks = countBlocks(testPath);
    
    var distance = Math.sqrt(Math.pow(a.i -b.i, 2) + Math.pow(a.j -b.j, 2));
    return distance + (numBlocks*0.75);
    // return  distance(a, b);
}

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);
}


function path(){
    
    openSet=[];
    closedSet=[];
    // enemyLocation.f = aStar(enemyLocation, agentLocation);
    enemyLocation = new spot(ei, ej);
	enemyLocation.addNeighbors(gridsize);
    openSet.push(enemyLocation);
     
     while (openSet.length > 0){
         
        var winner = 0;
        
        for (var i = 0; i < openSet.length; i++) 
          if (openSet[i].f < openSet[winner].f){ 
            winner = i;
            // console.log("TEST");
          }
            
        var current = openSet[winner];
        
        // var distCToAgent = aStar(current, agentLocation);
        // Did I finish?
        if (agentLocation.blockingNeighbors.includes(current)) 
        {
        //   noLoop();
        //   console.log("success - found path");
          resetValues(closedSet);
          Path = [];
          var temp = current;
          Path.push(temp);
          while (temp.previous) 
          {
            // console.log("X: " + temp.previous.i + " Y: " + temp.previous.j + " added to path");
            Path.push(temp.previous);
            temp = temp.previous;
          }
        //   console.log("Path length: " +Path.length);
        //   listPath(Path);
          return Path;
        }
        // else if (agentLocation.neighbors.includes(current)) 
        // {
        // //   noLoop();
        // //   console.log("success - found path");
        //   resetValues(closedSet);
        //   Path = [];
        //   var temp = current;
        //   Path.push(temp);
        //   while (temp.previous) 
        //   {
        //     // console.log("X: " + temp.previous.i + " Y: " + temp.previous.j + " added to path");
        //     Path.push(temp.previous);
        //     temp = temp.previous;
        //   }
        // //   console.log("Path length: " +Path.length);
        // //   listPath(Path);
        //   return Path;
        // }
    
        // Best option moves from openSet to closedSet
        removeFromArray(openSet, current);
        closedSet.push(current);
    
        // Check all the neighbors
        var neighbors = current.neighbors;
        
        //--- start of for loop -----------
        // console.log("Current neighbors: ");
        // listNeighbors(current);
        if(neighbors){
        for (var i = 0; i < neighbors.length; i++) 
        {
          var neighbor = neighbors[i];
          var distNToAgent = aStar(neighbor, agentLocation);
          
          // Valid next spot?!closedSet.includes(neighbor) && && distNToAgent < distCToAgent
          if ( !occupied(neighbor.i, neighbor.j) && !closedSet.includes(neighbor)) 
          {
            // console.log("Spot " + i + " is not occupied");
            var tempG = current.g + aStar(neighbor, current);
            
            // Is this a better path than before?
            var newPath = false;
            if (openSet.includes(neighbor)) 
            {
            //   console.log("Current node is present in openSet");
              if (tempG < neighbor.g) 
              {
                // console.log("tempG: " + tempG + " , neighbor G: " + neighbor.g);
                // console.log("Comparing G of current node to neighbor " + i + " , current G is less than neighbors G");
                neighbor.g = tempG;
                newPath = true;
              }
            //   console.log("tempG: " + tempG + " , neighbor G: " + neighbor.g);
            //   console.log("Comparing G of current node to neighbor " + i + " , current G is greater than neighbors G");
            //   removeFromArray(openSet, neighbor);
            //   closedSet.push(neighbor);
            }
            else //if(distCToAgent > distNToAgent)
            {
              neighbor.g = tempG;
              newPath = true;
              openSet.push(neighbor);
            //   console.log("Current node is not present in openSet and is closer to agent, neighbor G is set to tempG. openSet now contains " + openSet.length + " points.");
              
            }
    
            // Yes, it's a better path
            if (newPath) 
            {
            //   console.log("New Path set to true, neighbors h and f values are set using heuristic");
              neighbor.h = aStar(neighbor, agentLocation);
              neighbor.f = neighbor.g + neighbor.h;
              neighbor.previous = current;
            }
          }
        }
        }
    //--- end of for loop -----------
//       else 
//   {
//     console.log('fail - no path exists');
//     // noLoop();
//     return null;
//   }
  
  Path = [];
  var temp = current;
  Path.push(temp);
  while (temp.previous) 
  {
    // console.log("X: " + temp.previous.i + " Y: " + temp.previous.j + " added to path");
    Path.push(temp.previous);
    temp = temp.previous;
  }
//   console.log("Path length: " +Path.length);
//   listPath(Path);
  drawPath(Path, 0xff0000);
     }
}


function countBlocks(path){
    var count =0;
    // console.log("TEST: " + path.length);
    for(let i =0; i<path.length; i++){
        if(myGrid[path[i].i][path[i].j].maze === true)
            count++;
    }
    return count;
}

// --- take actions -----------------------------------

function moveLogicalEnemy(Path)
{ 
// move towards agent 
// put some randomness in so it won't get stuck with barriers 
    var move = path();
    drawPath(move, 0x00ff00);
    var temp = []
    temp.push(move[0]);
    temp.push(move[move.length-1]);
    drawPath(temp, 0x0000FF);
    
    var testPath = bresenhams(move[0], move[move.length-1]);
    drawPath(testPath, 0xFFD700);
    // listPath(testPath);
    // console.log(countBlocks(testPath));
    for(let x=0; x<move.length-1; x++){
        drawPath(move, 0x00ff00);
        ei = move[x].i;
        ej = move[x].j;
    }
    
}


function moveLogicalAgent( a )			// this is called by the infrastructure that gets action a from the Mind 
{ 
 var i = ai;
 var j = aj;		 

// console.log("Distance: " + a);
      if ( a == ACTION_LEFT ) 	i--;
 else if ( a == ACTION_RIGHT ) 	i++;
 else if ( a == ACTION_UP ) 		j++;
 else if ( a == ACTION_DOWN ) 	j--;

 if ( ! occupied(i,j) ) 
 {
  ai = i;
  aj = j;
  
  agentLocation = new spot(ai, aj);
  agentLocation.addNeighbors(gridsize);
  agentLocation.addBlockingNeighbors(gridsize);
 }
}




// --- 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
{
    var score =0;
    if(occupied (ai-1,aj))
        score ++;
    
    if(occupied (ai+1,aj))
        score ++;
        
    if(occupied (  ai,aj+1))
        score++;
        
    if(occupied (  ai,aj-1))
        score++;
    
    // if(occupied (ai-1,aj-1))
    //     score ++;
        
    // if(occupied (  ai+1,aj-1))
    //     score++;
        
    // if(occupied (  ai-1,aj+1))
    //     score++;
        
    // if(occupied (ai+1,aj+1))
    //     score ++;
    return score;
    
//  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();
 removeFromArray(x, x[x.length-1]);
//  removeFromArray(x, x[-1]);
//  removeFromArray(a, a[-1]);
 AB.msg ( " Step: " + AB.step + " &nbsp; x = (" + x.toString() + ") &nbsp; a = (" + a + ") " ); 
}


function   updateStatusAfter()		// agent and enemy have moved, can calculate score
{
 // new state after both have moved
 
 var y 		= AB.world.getState();
 removeFromArray(y, y[y.length-1]);

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

 AB.msg ( " &nbsp; y = (" + y.toString() + ") <br>" +
		" Bad steps: " + badsteps + 
		" &nbsp; Good steps: " + goodsteps + 
		" &nbsp; 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, myGrid];
  return ( x );  
};



AB.world.takeAction = function ( a )
{
  updateStatusBefore(a);			// show status line before moves 

  moveLogicalAgent(a);
//   console.log('Agent location: x = ' + ai + '; y = ' + aj);
  
  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() >= 4 )			// 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();							// play once, no loop 
}