// Cloned by Chen Zhenshuo on 20 Oct 2020 from World "A star" by Chen Zhenshuo
// Please leave this clone trail here.
// Cloned by Chen Zhenshuo on 19 Oct 2020 from World "A star" by "Coding Train" project
// Please leave this clone trail here.
// Port of
// https://github.com/nature-of-code/NOC-S17-2-Intelligence-Learning/tree/master/week1-graphs/05_astar
// Daniel Shiffman
// Nature of Code: Intelligence and Learning
// https://github.com/shiffman/NOC-S17-2-Intelligence-Learning
// Part 1: https://youtu.be/aKYlikFAV4k
// Part 2: https://youtu.be/EaZxUCWAjb0
// Part 3: https://youtu.be/jwRT4PCT6RU
// is diagonal move allowed
const diagonal = false;
const MUD = 1;
const mudCost = 10;
const mudAmount = 0.3;
// canvas size
const cw = 900;
const ch = 600;
// How many columns and rows
// different each time
var rando = AB.randomIntAtoB(1, 5);
var cols = 9 * rando;
var rows = 6 * rando;
// how many walls to make, from 0 to 1
// different each time
const wallAmount = 0.2;
const backcolor = 'white';
const wallcolor = 'black';
const mudcolor = 'orange';
const pathcolor = 'darkred';
// 2D array
var grid = new Array(cols);
// Open and closed set
var openSet = [];
var closedSet = [];
// Start and end
var start;
var end;
var startPos = {x: 0, y: randomInt(0, rows)};
var endPos= {x: cols - 1, y: randomInt(0, rows)};
// Width and height of each cell of grid
var w, h;
// The road taken
var path = [];
//=== heuristic ===========================
// this must be always optimistic - real time will be this or longer
function heuristic(src, dest) {
if (diagonal) {
return dist(src.i, src.j, dest.i, dest.j);
} else {
return Math.abs(src.i - dest.i) + Math.abs(src.j - dest.j);
}
}
function randomInt(min, max) {
return Math.floor(Math.random() * (max - min)) + min;
}
// Function to delete element from the array
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 showPoint(x, y) {
stroke('blue');
strokeWeight(w / 1.5);
point(x * w + w / 2, y * w + w / 2);
}
// Daniel Shiffman
// Nature of Code: Intelligence and Learning
// https://github.com/shiffman/NOC-S17-2-Intelligence-Learning
// Part 1: https://youtu.be/aKYlikFAV4k
// Part 2: https://youtu.be/EaZxUCWAjb0
// Part 3: https://youtu.be/jwRT4PCT6RU
// An object to describe a spot in the grid
function Spot(i, j) {
// Location
this.i = i;
this.j = j;
// f, g, and h values for A*
this.f = 0;
this.g = 0;
this.h = 0;
if (random(1) < mudAmount) this.type = MUD;
else this.type = 0;
// Neighbors
this.neighbors = [];
// Where did I come from?
this.previous = undefined;
// Am I an wall?
if (random(1) < wallAmount) this.wall = true;
else this.wall = false;
// Display me
this.show = function () {
if (this.wall) {
fill(wallcolor);
// wall fills square
rect(this.i * w, this.j * h, w, h);
// wall only partially fills square
// ellipse ( this.i * w + w / 2, this.j * h + h / 2, w * 0.7, h * 0.7 );
} else if (this.type === MUD) {
fill(mudcolor);
rect(this.i * w, this.j * h, w, h);
}
};
// Figure out who my neighbors are
this.addNeighbors = function (grid) {
var i = this.i;
var j = this.j;
if (i < cols - 1) this.neighbors.push(grid[i + 1][j]);
if (i > 0) this.neighbors.push(grid[i - 1][j]);
if (j < rows - 1) this.neighbors.push(grid[i][j + 1]);
if (j > 0) this.neighbors.push(grid[i][j - 1]);
if (diagonal)
// diagonals are also neighbours:
{
if (i > 0 && j > 0) this.neighbors.push(grid[i - 1][j - 1]);
if (i < cols - 1 && j > 0) this.neighbors.push(grid[i + 1][j - 1]);
if (i > 0 && j < rows - 1) this.neighbors.push(grid[i - 1][j + 1]);
if (i < cols - 1 && j < rows - 1) this.neighbors.push(grid[i + 1][j + 1]);
}
}
}
function setup() {
// slower frame rate to see how it is working
// frameRate (2);
createCanvas(cw, ch);
// Grid cell size
w = width / cols;
h = height / rows;
// Making a 2D array
for (var i = 0; i < cols; i++)
grid[i] = new Array(rows);
for (var i = 0; i < cols; i++)
for (var j = 0; j < rows; j++)
grid[i][j] = new Spot(i, j);
// All the neighbors
for (var i = 0; i < cols; i++)
for (var j = 0; j < rows; j++)
grid[i][j].addNeighbors(grid);
// Start and end
start = grid[startPos.x][startPos.y];
end = grid[endPos.x][endPos.y];
start.wall = false;
end.wall = false;
// openSet starts with beginning only
openSet.push(start);
console.log('start search');
}
function draw()
// the search goes on over many timesteps
// each timestep, check one more square and draw current partial solution
{
// --- begin still searching -----------------------------
if (openSet.length > 0) {
// Best next option
var winner = 0;
for (var i = 0; i < openSet.length; i++)
if (openSet[i].f < openSet[winner].f)
winner = i;
var current = openSet[winner];
// Did I finish?
if (current === end) {
noLoop();
console.log("success - found 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 -----------
for (var i = 0; i < neighbors.length; i++) {
var neighbor = neighbors[i];
// Valid next spot?
if (!closedSet.includes(neighbor) && !neighbor.wall) {
var tempG = current.g + heuristic(neighbor, current);
if (neighbor.type === MUD) {
tempG += mudCost;
}
// Is this a better path than before?
var newPath = false;
if (openSet.includes(neighbor)) {
if (tempG < neighbor.g) {
neighbor.g = tempG;
newPath = true;
}
} else {
neighbor.g = tempG;
newPath = true;
openSet.push(neighbor);
}
// Yes, it's a better path
if (newPath) {
neighbor.h = heuristic(neighbor, end);
neighbor.f = neighbor.g + neighbor.h;
neighbor.previous = current;
}
}
}
//--- end of for loop -----------
}
// --- end still searching -----------------------------
else {
console.log('fail - no path exists');
noLoop();
return;
}
// Draw current state of everything
background(backcolor);
stroke('white');
strokeWeight(1);
for (var i = 0; i < cols; i++)
for (var j = 0; j < rows; j++)
grid[i][j].show();
showPoint(startPos.x, startPos.y);
showPoint(endPos.x, endPos.y);
// Find the path by working backwards
path = [];
var temp = current;
path.push(temp);
while (temp.previous) {
path.push(temp.previous);
temp = temp.previous;
}
noFill();
stroke(pathcolor);
strokeWeight(w / 8);
beginShape();
for (var i = 0; i < path.length; i++)
vertex((path[i].i * w) + w / 2, (path[i].j * h) + h / 2);
endShape();
}