71 Astar - JcerelusDev/CanvasGameJs GitHub Wiki

What is Astar algorithm

A* algorithm is a technique used to find the shortest path in a grid . In game pathfinding astar is the suitable algorithm.

Here's a complete example using a json tiled map editor :

function enemyFollow(){

 for(let enemy of enemies){

let grid =  game.parse2D(data.layers[1]) // used to conver1 1d array into 2d array because the system worjs with 2d array

let endX = Math.floor(player.x / data.tilewidth);
let endY = Math.floor(player.y / data.tileheight);

let startX =Math.floor(enemy.x / 16) 
let startY =Math.floor(enemy.y /16) 


let astar = new Astar()
 astar.setIterations(800)
astar.setGrid(grid)
 astar.setAcceptableTiles([0])
 astar.setDiagonal(true)

astar.findPath(startX,startY,endX,endY,function(path){
// Check if the path is found
  
   if (path ) {
  
     for(let i = 0; i<path.length; i++){
      enemy.path = path

  // Move the enemy if the path is available
    }
    let nextX = enemy.path[1].x  * data.tilewidth;
    let nextY = enemy.path[1].y  * data.tileheight;

    let speed = 1

    // Move the enemy towards the next point
    if (enemy.x < nextX) {


      enemy.vx = speed
         enemy.x +=enemy.vx ; // Move right
    } 
     
     if (enemy.x > nextX) {

       enemy.vx = - speed
         enemy.x +=enemy.vx; // Move left
    }

      if (enemy.y < nextY) {

       enemy.vy = speed
        enemy.y += enemy.vy; // Move down
    } 
    
      if (enemy.y > nextY) {

     enemy.vy = - speed
        enemy.y += enemy.vy; // Move up
    }
    


  }

});
    game.avoidSameOverlapping(enemies) // learn about that method later on .

}


}

Here's a short method :

let astar = game.setAstar(16,data.layers[1],[0],900,true)

// 16 is for tileSize

//data.layers[1] is the grid

//[0] is the acceptable tile

// 800 is iteration timer

// true is the dialogmovement enable

you can jump directly in astar.findPath method