node-haxball/examples/plugins/CMD_setPlayerBall.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

module.exports = function(API){
  const { OperationType, VariableType, ConnectionState, AllowFlags, Direction, CollisionFlags, CameraFollow, BackgroundType, GamePlayState, BanEntryType, Callback, Utils, Room, Replay, Query, Library, RoomConfig, Plugin, Renderer, Errors, Language, EventFactory, Impl } = API;

  Object.setPrototypeOf(this, Plugin.prototype);
  Plugin.call(this, "CMD_setPlayerBall", true, { // "CMD_setPlayerBall" is plugin's name, "true" means "activated just after initialization". Every plugin should have a unique name.
    version: "0.1",
    author: "abc",
    description: `This plugin allows us to use players as balls.`,
    allowFlags: AllowFlags.CreateRoom // We allow this plugin to be activated on CreateRoom only.
  });
  
  this.defineVariable({
    name: "changeAvatar",
    description: "Whether to change the avatar of the ball players.",
    type: VariableType.Boolean,
    value: true
  });

  var ballPlayers, permissionCtx, permissionIds, that = this;

  function updatePlayerDisc(player){
    var disc = player?.disc;
    if (!disc)
      return;
    var ballCGroup = (1<<CollisionFlags.kick)|(1<<CollisionFlags.score)|(1<<CollisionFlags.ball);
    if (ballPlayers.has(player.id)){
      if ((disc.cGroup&ballCGroup)!=ballCGroup){
        var { bCoef, cGroup, damping, gravity, invMass, radius } = that.room.stadium.discs[0];
        that.room.setPlayerDiscProperties(player.id, {
          cGroup: disc.cGroup|ballCGroup,
          bCoef,
          damping,
          xgravity: gravity.x,
          ygravity: gravity.y,
          invMass,
          radius
        });
        if (that.changeAvatar)
          that.room.setPlayerAvatar(player.id, "⚽", true);
      }
    }
    else{
      if ((disc.cGroup&ballCGroup)==ballCGroup){
        var { bCoef, cGroup, damping, gravity, invMass, radius } = that.room.stadium.playerPhysics;
        that.room.setPlayerDiscProperties(player.id, {
          cGroup: disc.cGroup&(~ballCGroup),
          bCoef,
          damping,
          xgravity: gravity.x,
          ygravity: gravity.y,
          invMass,
          radius
        });
        if (that.changeAvatar)
          that.room.setPlayerAvatar(player.id, null, true);
      }
    }
  }

  this.initialize = function(){
    ballPlayers = new Set();
    permissionCtx = that.room.librariesMap.permissions?.createContext("setPlayerBall");
    if (permissionCtx)
      permissionIds = {
        setPlayerBall: permissionCtx.addPermission("setPlayerBall")
      };
    that.room.librariesMap.commands?.add({
      name: "setPlayerBall",
      parameters: [{
        name: "playerId",
        type: VariableType.Integer,
        range: {
          min: 0
        }
      }, {
        name: "value",
        type: VariableType.Integer,
        range: {
          min: 0,
          max: 1
        }
      }],
      minParameterCount: 2,
      helpText: "Changes the ballness status of a player.",
      callback: ({playerId, value}, byId) => {
        if (byId!=0 && !permissionCtx?.checkPlayerPermission(byId, permissionIds.setPlayerBall)){
          that.room.librariesMap.commands?.announcePermissionDenied(byId);
          return;
        }
        var p = that.room.players.find((p)=>p.id==playerId);
        if (!p)
          return;
        var inc = ballPlayers.has(playerId);
        if ((inc && value) || (!inc && !value))
          return;
        if (value)
          ballPlayers.add(playerId);
        else
          ballPlayers.delete(playerId);
        updatePlayerDisc(p);
        that.room.librariesMap.commands?.announceAction("Player " + playerId + " is now a " + (value?"ball":"player") + ".", byId);
      }
    });
  };

  this.finalize = function(){
    that.room.librariesMap.commands?.remove("setPlayerBall");
    that.room.librariesMap.permissions?.removeContext(permissionCtx);
    ballPlayers.clear();
    that.room.players.forEach((p)=>{
      updatePlayerDisc(p);
    });
    ballPlayers = null;
    permissionCtx = null;
    permissionIds = null;
  };

  this.onPositionsReset = function(customData){
    Utils.runAfterGameTick(()=>{
      that.room.players.forEach((p)=>{
        updatePlayerDisc(p);
      });
    });
  };

  this.onPlayerDiscCreated = function(playerObj, customData){
    Utils.runAfterGameTick(()=>{
      updatePlayerDisc(playerObj);
    });
  };

  this.onOperationReceived = function(type, msg, globalFrameNo, clientFrameNo, customData){
    if (type!=OperationType.SendInput)
      return true;
    return !ballPlayers.has(msg.byId);
  };

  this.onPlayerLeave = function(playerObj, reason, isBanned, byId, customData){
    ballPlayers.delete(playerObj.id);
  };
};