node-haxball/examples/plugins/explosion.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, "explosion", true, { // "explosion" 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 the room owner to create explosions by clicking on the map using a mouse.`,
    allowFlags: AllowFlags.CreateRoom // We allow this plugin to be activated on CreateRoom only.
  });

  this.defineVariable({
    name: "maxRadius",
    description: "Explosion will only affect objects that have a lower distance than this value",
    type: VariableType.Number,
    value: 100,
    range: {
      min: 1,
      max: 10000,
      step: 1
    }
  });

  this.defineVariable({
    name: "maxSpeedBoost",
    description: "Maximum effective speed boost of the explosion",
    type: VariableType.Number,
    value: 2,
    range: {
      min: -10,
      max: 10,
      step: 0.01
    }
  });

  var that = this;

  this.onMouseDown = function(e){
    var { room, maxSpeedBoost, maxRadius } = that;
    var f = room?.renderer?.transformPixelCoordToMapCoord;
    if (!f || !room.stateExt){
      selectionActive = false;
      return;
    }
    maxSpeedBoost = parseFloat(maxSpeedBoost);
    maxRadius = parseFloat(maxRadius);
    var { x, y } = f(e.offsetX, e.offsetY);
    room.stateExt.gameState?.physicsState?.discs.forEach((disc, idx)=>{
      var { pos, radius } = disc;
      var deltaX = pos.x-x, deltaY = pos.y-y, r = radius+maxRadius;
      if ((deltaX*deltaX+deltaY*deltaY)>r*r)
        return;
      var d = Math.sqrt(deltaX*deltaX+deltaY*deltaY);
      var v = maxSpeedBoost*Math.exp(-d/r);
      Utils.runAfterGameTick(()=>{
        room.setDiscProperties(idx, {
          xspeed: disc.speed.x+v*deltaX/d,
          yspeed: disc.speed.y+v*deltaY/d
        });
      });
    });
  }
};