node-haxball/examples/roomConfigs/method1/autoPlay_defensive.js

The most powerful and lightweight API that allows you to develop your original Haxball(www.haxball.com) host, client, and standalone applications both on node.js and browser environments and also includes every possible hack and functionality that you can

const { OperationType, VariableType, ConnectionState, AllowFlags, Direction, CollisionFlags, CameraFollow, BackgroundType, GamePlayState, Callback, Utils, Room, Replay, Query, Library, RoomConfig, Plugin, Renderer, Errors, Language, Impl } = API = require("../../../src/index");

const minCoordAlignDelta = 0.5, minKickDistance = 2, maxDistanceToFollowBallCoeff = 0.2;

function roomCallback(room){ // examples start from here.
  room.onGameTick = () => {

    // ensure extrapolation of the room state before calculating stuff.
    room.extrapolate();

    var { state, gameState, gameStateExt } = room;
    gameState = gameStateExt || gameState;
    
    var cp = state.players.filter((x)=>(x.id==_room.currentPlayerId))[0];
    // get the original data object of the current player
    var playerDisc = cp.disc;
    if (!playerDisc) // check or else error occurs after changing a player's team to spectators, if the player is not actually in the game, or the game is stopped.
      return;
    var teamId = cp.team.id; //, oppositeTeamId = 2 - cpTeamId;
    var goals = state.stadium.goals, ball = gameState.physicsState.discs[0];

    // get the coordinates of the ball
    var {x, y} = ball?.pos || {};

    // if ball is not reachable, do nothing.
    if (x==null || isNaN(x) || !isFinite(x) || y==null || isNaN(y) || !isFinite(y)) // check 
      return;

    var targetX, targetY, sqrDistBetweenBallAndPlayer = (x-playerDisc.pos.x) * (x-playerDisc.pos.x) + (y-playerDisc.pos.y) * (y-playerDisc.pos.y);
    var maxDistanceToFollowBall = maxDistanceToFollowBallCoeff * state.stadium.width;
    var b = false;

    if (sqrDistBetweenBallAndPlayer > ((playerDisc.radius + ball.radius + maxDistanceToFollowBall) * (playerDisc.radius + ball.radius + maxDistanceToFollowBall))){
      var myGoal = goals.filter((g)=>(g.team.id==teamId))[0]; //, opponentGoal = goals[oppositeTeamId - 1];
      if (!myGoal)
        return;
      var MPofMyGoalX = (myGoal.p0.x + myGoal.p1.x) / 2, MPofMyGoalY = (myGoal.p0.y + myGoal.p1.y) / 2;
      targetX = (x + MPofMyGoalX) / 2;
      targetY = (y + MPofMyGoalY) / 2;
    }
    else{
      targetX = x;
      targetY = y;
      b = true;
    }

    // calculate delta difference for both x and y axis.
    var deltaX = targetX - playerDisc.pos.x, deltaY = targetY - playerDisc.pos.y, dirX, dirY, kick;
    if (Math.abs(deltaX) < minCoordAlignDelta) // we can omit small delta.
      dirX = 0;
    else 
      dirX = Math.sign(deltaX); // direction is +1 or -1, depending on the delta difference

    if (Math.abs(deltaY) < minCoordAlignDelta) // we can omit small delta.
      dirY = 0;
    else
      dirY = Math.sign(deltaY); // direction is +1 or -1, depending on the delta difference

    // kick is true if the distance between ball and player is less than minKickDistance
    kick = (deltaX * deltaX + deltaY * deltaY < (playerDisc.radius + ball.radius + minKickDistance) * (playerDisc.radius + ball.radius + minKickDistance));

    // apply current keys
    room.setKeyState(Utils.keyState(dirX, dirY, kick));
  };
};