node-haxball/examples/plugins/CMD_speedHack.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_speedHack", true, { // "CMD_speedHack" 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 can modify the movement speed of individual players using the gravity and speed properties. 
    Available commands: 
    - !speedHack [id] [value]: Activates/deactivates speedhack for the player whose playerId=[id].
    - !speedHackProp [id] [prop] [value]: set the value of a speedhack property for the player whose playerId=[id].`,
    allowFlags: AllowFlags.CreateRoom // We allow this plugin to be activated on CreateRoom only.
  });

  this.defineVariable({
    name: "instaStop",
    description: "Initial value of instant stop for all players",
    type: VariableType.Boolean,
    value: true
  });

  this.defineVariable({
    name: "xCoefficient",
    description: "Initial value of x coefficient for all players",
    type: VariableType.Number,
    value: 1,
    range: {
      min: -20,
      max: 20,
      step: 0.01
    }
  });

  this.defineVariable({
    name: "yCoefficient",
    description: "Initial value of y coefficient for all players",
    type: VariableType.Number,
    value: 1,
    range: {
      min: -20,
      max: 20,
      step: 0.01
    }
  });

  var playerProps, permissionCtx, permissionIds, that = this;

  this.initialize = function(){
    playerProps = {};
    permissionCtx = that.room.librariesMap.permissions?.createContext("speedHack");
    if (permissionCtx)
      permissionIds = {
        speedHack: permissionCtx.addPermission("speedHack"),
        speedHackProps: permissionCtx.addPermission("speedHackProps")
      };
    that.room.librariesMap.commands?.add({
      name: "speedHack",
      parameters: [{
        name: "playerId",
        type: VariableType.Integer,
        range: {
          min: 0
        }
      }, {
        name: "value",
        type: VariableType.Boolean
      }],
      minParameterCount: 2,
      helpText: "Activates/deactivates speedhack for a player.",
      callback: ({playerId, value}, byId) => {
        if (byId!=0 && !permissionCtx?.checkPlayerPermission(byId, permissionIds.speedHack)){
          that.room.librariesMap.commands?.announcePermissionDenied(byId);
          return;
        }
        if (playerProps[playerId])
          playerProps[playerId].enabled = value;
        else
          playerProps[playerId] = {
            enabled: value,
            instaStop: that.instaStop,
            xCoef: that.xCoefficient,
            yCoef: that.yCoefficient
          };
      }
    });
    that.room.librariesMap.commands?.add({
      name: "speedHackProps",
      parameters: [{
        name: "playerId",
        type: VariableType.Integer,
        range: {
          min: 0
        }
      }, {
        name: "prop",
        type: VariableType.Integer,
        range: {
          min: 0,
          max: 2
        }
      }, {
        name: "value",
        type: VariableType.String
      }],
      minParameterCount: 3,
      helpText: "Changes speedhack parameters for a player.",
      callback: ({playerId, prop, value}, byId) => {
        if (byId!=0 && !permissionCtx?.checkPlayerPermission(byId, permissionIds.speedHackProps)){
          that.room.librariesMap.commands?.announcePermissionDenied(byId);
          return;
        }
        var props = playerProps[playerId], f;
        if (!props)
          props = {
            enabled: false,
            instaStop: that.instaStop,
            xCoef: that.xCoefficient,
            yCoef: that.yCoefficient
          };
        switch(prop){
          case 0:
            props.instaStop = (value=="1");
            break;
          case 1:
            f = parseFloat(value);
            if (isNaN(f))
              break;
            props.xCoef = f;
            break;
          case 2:
            f = parseFloat(value);
            if (isNaN(f))
              break;
            props.yCoef = f;
            break;
        }
        playerProps[playerId] = props;
      }
    });
  };

  this.finalize = function(){
    that.room.librariesMap.commands?.remove("speedHack");
    that.room.librariesMap.commands?.remove("speedHackProps");
    that.room.librariesMap.permissions?.removeContext(permissionCtx);
    playerProps = null;
    permissionCtx = null;
    permissionIds = null;
  };

  this.onOperationReceived = function(type, msg, globalFrameNo, clientFrameNo, customData){ // this is host-only
    if (type!=OperationType.SendInput)
      return true;
    var id = msg.byId;
    var props = playerProps[id];
    if (!props?.enabled)
      return true;
    var {dirX, dirY, kick} = Utils.reverseKeyState(msg.input);
    var d = Math.abs(dirX)+Math.abs(dirY);
    if (d>0){
      d = (d==2)?Math.SQRT1_2:1;
			that.room.setPlayerDiscProperties(id, {
        xgravity: props.xCoef*dirX*d, 
        ygravity: props.yCoef*dirY*d
      });
      return true;
    }
    var prop={
      xgravity: 0, 
      ygravity: 0
    };
    if (props.instaStop && kick){
      prop.xspeed = 0;
      prop.yspeed = 0;
    }
    that.room.setPlayerDiscProperties(id, prop);
    msg.input = 0;
    return true;
  };

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