Code viewer for World: Complex World (clone by Da...

// Cloned by Daugirdas Stirbys on 30 Oct 2023 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       = 200; // 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 = false;						// Switch between 3d and 2d view (both using Three.js) 


 const TEXTURE_WALL 	= '/uploads/dastis/Wall.jpg' ;
 const TEXTURE_MAZE 	= '/uploads/dastis/Crate.png' ;
 const TEXTURE_AGENT 	= '/uploads/dastis/Brain.jpg' ;
 const TEXTURE_ENEMY 	= '/uploads/dastis/JS.png' ;

// credits:
// https://vectorportal.com/vector/wall-stone-vector-clip-art/27203
// https://opengameart.org/content/2d-wooden-box
// https://www.freepik.com/free-vector/brain-human-anatomy-biology-organ-body-system-health-care-medical-hand-drawn-cartoon-art-illustration_19613551.htm#query=brain&position=0&from_view=keyword&track=sph
// https://upload.wikimedia.org/wikipedia/commons/thumb/9/99/Unofficial_JavaScript_logo_2.svg/800px-Unofficial_JavaScript_logo_2.svg.png

 
const MUSIC_BACK  = '/uploads/dastis/Right_Behind_You.mp3' ;
const SOUND_ALARM = '/uploads/starter/air.horn.mp3' ;

// credits:
// https://www.fesliyanstudios.com/download-link.php?src=i&id=2864
// http://soundbible.com/1542-Air-Horn.html 

	
	
const gridsize = 40; // 25;						// number of squares along side of world	   

const NOBOXES =  Math.trunc ( (gridsize * gridsize) / 3 );
// const NOBOXES =  Math.trunc ( (gridsize * gridsize) / 5 );
//const NOBOXES =  Math.trunc ( (gridsize * gridsize) / 10 );
//const NOBOXES =  Math.trunc ( (gridsize * gridsize) / 500 );
		// 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 

// skybox, credit:
// https://opengameart.org/content/night-sky-stars-and-galaxies

 const SKYBOX_ARRAY = [										 
                "/uploads/dastis/Sky.png",
                "/uploads/dastis/Sky.png",
                "/uploads/dastis/Sky.png",
                "/uploads/dastis/Sky.png",
                "/uploads/dastis/Sky.png",
                "/uploads/dastis/Sky.png"
                ];



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


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

// DAUG edit - types of heuristics
const ZERO_H		  = 0;		   
const EUCLID_DISTANCE = 1;
const BAD_HEURISTIC   = 2;

// DAUG edit - node class for storage of node information and some associated methods
class Node 
{
    // Every node on creation must have coordinate assigned,
    // and other values initialised
    constructor(column, row) 
    {
    
        this.parent_node = null; // will store parent node
                                 // only start node should have null value
    
        this.column = column; // (column, row) coordinate of the node on the grid
        this.row = row;
    
        this.f = 0; // total cost to end node (f = g + h)
    
        this.g = 0; // distance between start node and this node
                // this assumes distance between adjecent nodes = 1,
                // that is one step value is equal 1
                // we know what this value is for nodes that were searched
                
        this.h = 0; // estimated distance between this node end end node
                // as we dont know exact value this is where we will use heuristic
                // to estimate
    }
  
    // Some getter methods to get node data 
    get_row() { return this.row; }
    get_column() {return this.column; }
    get_f() { return this.f; }
    get_g() { return this.g; }
    get_parent_node() { return this.parent_node; }
  
    // Setter of the patent node (only start node won't have parent)
    set_parent_node(parent_node) { this.parent_node = parent_node; }
    
    // Calculates the f = g + h value
    calculate_f(target_node, h_n_func)
    {
        // Calculate cost so far (from start node to this node)
        // we track cost for each previous node, so we dont need to calculate
        // from scratch, just add to parrent node 
        this.g = this.parent_node.get_g() + 1;
        
        if (h_n_func == EUCLID_DISTANCE)
        {
            // Calculate heuristic (distance between 2 points: this node and end node)
            var delta_r = this.row - target_node.get_row();
            var delta_c = this.column - target_node.get_column();
            this.h = Math.sqrt(delta_r*delta_r + delta_c*delta_c);
        }
        
        if (h_n_func == ZERO_H)
        {
            this.h = 0;
        }
        
        if (h_n_func ==  BAD_HEURISTIC)
        {
            var delta_r = this.row - target_node.get_row();
            var delta_c = this.column - target_node.get_column();
            this.h = delta_r*delta_c;
        }
       
        
        // Calculate total cost
        this.f = this.g + this.h;
        
        // To allow to confirm that method works as expected
        // console.log("This node: " + this.toString())
        // console.log("Target node: " + target_node.toString())
        // console.log(`delta_r: ${delta_r}, delta_c: ${delta_c}), Cost: ${this.f}`);
    }
    
    // Checks if this node coordinate is the same as the node that was passed in
    is_equal(node)
    {
        return (this.column == node.get_column() && this.row == node.get_row())
    }
    
    // Simplified node representation as a string for debugging purposes
    toString()
    {
        return `Coordinate: (${this.column}, ${this.row}), Cost: ${this.f}`;
    }
  
}


//--- 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   

// DAUG edit - colour definitions for the marker boxes
var RED_COLOUR = 0xff0000;
var GREEN_COLOUR = 0x00ff00;
var ORANGE_COLOUR = 0xffa500

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;
}

// DAUG edit - removed agent from check
function occupied_by_objects_or_enemy ( i, j )		// is this square occupied
{
 if ( ( ei == i ) && ( ej == j ) ) return true;		// variable objects

 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;
}

// DAUG edit
function get_node_index_with_lowest_f(node_list)
{
    // lowest f node index
    var best_f_index = 0;
    
    // loop node index
    var current_index = 0;
    
    for (const node of node_list) 
    {
        // check if new node f smaller than previous best
        if (node_list[best_f_index].get_f() > node.get_f())
        {
            // if so then this is our new best
            best_f_index = current_index;
        }
        
        current_index += 1;
    }
    
    return best_f_index;
    
}

// Checks if node is in the array
function is_in_array(test_node, node_list)
{
    for (const node of node_list) 
    {
        if (test_node.is_equal(node))
        {
            return true;
        }
    }
    
    return false;
}

// DAUG edit - marker dot functionality

// DAUG edit - Initialises storage array
dot_markers = []; // storage array


// DAUG edit - Creates and puts the dot marker on this coordinate
// (Indexing starts at top-left corner)
// i - integer column number
// j - integer row number
// colour - rgb colour in hex
function create_dot ( i, j , colour)
{
	shape    = new THREE.BoxGeometry ( squaresize/3, BOXHEIGHT/10, squaresize/3);
	material = new THREE.MeshBasicMaterial({ color: colour, wireframe: false });
	thedot  = new THREE.Mesh(shape, material);
	thedot.position.copy ( translate(i,j) );
	dot_markers.push(thedot);
	ABWorld.scene.add(thedot);	
}

// DAUG edit - Deletes all marker dots from storage array and world
function delete_dots ()
{
    for (const dot of dot_markers) // for each loop
    {
        ABWorld.scene.remove(dot);
    }
    
    dot_markers = [];
}

// DAUG edit - Add new paths markers (red)
function add_path_dots(nodes_list)
{
    for (const node of nodes_list) 
    {
        create_dot(node.get_column(), node.get_row(), RED_COLOUR);
    }
}

// DAUG edit - Add closed nodes markers (green)
function add_closed_dots(nodes_list, excluded_nodes)
{
    for (const node of nodes_list)
    {
        // We dont want to paint the actual path nodes
        if (! is_in_array(node, excluded_nodes))
        {
            // only do this if node is not in excluded list
            create_dot(node.get_column(), node.get_row(), GREEN_COLOUR);
        }
    }
}

function add_open_dots(nodes_list, excluded_nodes)
{
    for (const node of nodes_list)
    {
        // We dont want to paint the actual path nodes
        if (! is_in_array(node, excluded_nodes))
        {
            // only do this if node is not in excluded list
            create_dot(node.get_column(), node.get_row(), ORANGE_COLOUR);
        }
    }
}

// DAUG edit - Prints nodes in the list
function print_list(node_list)
{
    for (const node of node_list) 
    {
        console.log("---" + node.toString());
    }
}

//DAUG edit - This function backtraces the path from provided node to the start node
function get_path_from_start_node(end_node)
{
    var path = [];
    var node = end_node; // we start from end node and backtrace...
    
    while (node.get_parent_node() !== null)  // only start node has a parent == null
    {
        path.push(node);
        node = node.get_parent_node();
    }
    
    // path here will be end node to start node
    // We need to reverse it to get start node to end node
    return path.reverse(); 
}

// DAUG edit - A* function
function a_star(h_n_func)
{
    
    //Create empty list to store the path (that we will hopefully find)
    var path = [];
    
    // Create two empty arrays that will store our nodes
    var open_list = []; // nodes that we are still considering
    var closed_list = []; // nodes that are already searched
    
    // Initialise start and end nodes
    var start_node = new Node(ei, ej); // current location of enemy
    var end_node = new Node(ai, aj);   // current location of agent
    console.log("start_node: " + start_node.toString());
    console.log("end_node: " + end_node.toString());
    
    // Add start node to the open list - that is where we start our search!
    open_list.push(start_node);
    
    // Now start searching...
    while (Array.isArray(open_list) && open_list.length)
    {
        // Find the node with lowest f in the open_list,
        // that node will be our next step
        var current_node_index = get_node_index_with_lowest_f(open_list);
        var current_node = open_list[current_node_index];
        
        // move the node we found from open_list to closed_list
        open_list.splice(current_node_index, 1);
        closed_list.push(current_node);
        
        // Check if we have reached the end node and if we did - get the path
        if (current_node.is_equal(end_node))
        {
            console.log("Reached the end node!!!");
            path = get_path_from_start_node(current_node);
            
            // as we already reached the end node we can terminate loop...
            break;
        }
        
        // Otherwise, we need to check if any new nodes are available for search.
        // New nodes will be children of the current node and if there are any,
        // we will add them to the open list. Note: we ignore diagonals, so only
        // UP, DOWN, LEFT, RIGHT are considered as potential children
        for(const dir of [[0, -1], [0, 1], [-1, 0], [1, 0]])
        {
            //console.log("Generating children...");
            
            var i = current_node.get_column() + dir[0];
            var j = current_node.get_row() + dir[1];
            
            // Create child node...
            var child_node = new Node(i, j);
            
            // ... but need to check if thats not a wall or edge
            if (occupied_by_objects_or_enemy(child_node.get_column(), child_node.get_row()))
            {
                //console.log("Actually can't use this as the node is occupied");
                continue;
            }
            
            // ... also check if it is not already in open list...
            if (is_in_array(child_node, open_list))
            {
                //console.log("Actually can't use this as the node is already in open_list.");
                continue;
            }
            
            // ... or closed list
            if (is_in_array(child_node, closed_list))
            {
                //console.log("Actually can't use this as the node is already in closed_list.");
                continue;
            }
            
            // All good, we can populate child node values
            child_node.set_parent_node(current_node);
            child_node.calculate_f(end_node, h_n_func);
            
            // and add to open list
            open_list.push(child_node);
        }
    }
    
    return [path, open_list, closed_list];
    
}

// DAUG edit - prints number of items in each list
function calculate_stats(start_node, end_node, open_list, closed_list)
{
    var delta_r = start_node.get_row() - end_node.get_row();
    var delta_c = start_node.get_column() - end_node.get_column();
    var distance = Math.sqrt(delta_r*delta_r + delta_c*delta_c);
    
    var total = open_list.length + closed_list.length;
    
    console.log(`Distance between nodes: ${distance}, Open nodes: ${open_list.length}, closed nodes: ${closed_list.length}, total: ${total}`);
}

	
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);		 


	// 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;		 
			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;

		
   // 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 ;
		
		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);		
	}
   
	// 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;
	 
	 // Daug edit - fixed position of the enemy
    // 	 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;

     // Daug edit - fixed position of the agent
    // 	 ai = 20;
    // 	 aj = 20;
 
	 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
	 });
 		
}
 
 
 


// --- 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 moveLogicalEnemy()
{

    var start_node = new Node(ei, ej); // current location of enemy
    var end_node = new Node(ai, aj);   // current location of agent


    // var [path, open_list, closed_list] = a_star(ZERO_H);
    // calculate_stats(start_node, end_node, open_list, closed_list);
    
    var [path, open_list, closed_list] = a_star(EUCLID_DISTANCE);
    calculate_stats(start_node, end_node, open_list, closed_list);
    
    // var [path, open_list, closed_list] = a_star(BAD_HEURISTIC);
    // calculate_stats(start_node, end_node, open_list, closed_list);
    
    
    console.log("Path:");
    print_list(path);
    
    // Clean previous path markers and add fresh red and green ones
    delete_dots ();
    add_path_dots(path);
    add_closed_dots(closed_list, path);
    add_open_dots(open_list, path);

    //There might not be a solution, check if path is empty
    if (Array.isArray(path) && path.length)
    {
        // If no obstacle then move, else just miss a turn
        if ( ! occupied(path[0].get_column(), path[0].get_row()) )  	
        {
            ei = path[0].get_column();
            ej = path[0].get_row();
            
            console.log("Step to: " + path[0].toString());
        }
    }
    
}


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

      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;
 }
}




// --- 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 + " &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();
 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 ];
  return ( x );  
};



AB.world.takeAction = function ( a )
{
  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();							// play once, no loop 
}