Fog (MV)

//=============================================================================
// Fog
// by Shaz
// Last Updated: 2015.10.31
//=============================================================================

/*:
 * @plugindesc Adds a fog overlay to maps
 * @author Shaz
 *
 * @help
 *
 * Plugin Command:
 *   ChangeFog filename scroll-x scroll-y opacity
 *
 *   filename = name of file (no extension) in img/fogs folder
 *   scroll-x, scroll-y = amount to scroll each frame (-ve is up/left)
 *                        could be a number or a formula
 *   opacity = fog opacity (0-255)
 *
 */

(function() {
  var _Game_Interpreter_pluginCommand = Game_Interpreter.prototype.pluginCommand;
  Game_Interpreter.prototype.pluginCommand = function(command, args) {
    _Game_Interpreter_pluginCommand.call(this, command, args);

    if (command.toUpperCase() === 'CHANGEFOG') {
      $gameMap.changeFog(args);
    };
  };

  ImageManager.loadFog = function(filename, hue) {
    return this.loadBitmap('img/fogs/', filename, hue, true);
  };

  var _Game_Map_initialize = Game_Map.prototype.initialize;
  Game_Map.prototype.initialize = function() {
    _Game_Map_initialize.call(this);
    this._fogName = '';
    this._fogSx = 0;
    this._fogSy = 0;
    this._fogOpacity = 0;
    this._fogX = 0;
    this._fogY = 0;
  };

  var _Game_Map_setup = Game_Map.prototype.setup;
  Game_Map.prototype.setup = function(mapId) {
    _Game_Map_setup.call(this, mapId);
    this.setupFog();
  };

  Game_Map.prototype.setupFog = function() {
    this._fogName = $dataMap.meta.fogName || '';
    this._fogSx = Number($dataMap.meta.fogSx || 0);
    this._fogSy = Number($dataMap.meta.fogSy || 0);
    this._fogOpacity = Number($dataMap.meta.fogOpacity || 0);
    this._fogX = 0;
    this._fogY = 0;
  };

  Game_Map.prototype.changeFog = function(args) {
    this._fogName = args[0];
    this._fogSx = eval(args[1]);
    this._fogSy = eval(args[2]);
    this._fogOpacity = eval(args[3]);
  };

  var _Game_Map_setDisplayPos = Game_Map.prototype.setDisplayPos;
  Game_Map.prototype.setDisplayPos = function(x, y) {
    _Game_Map_setDisplayPos.call(this, x, y);
    if (this.isLoopHorizontal()) {
      this._fogX = x;
    } else {
      this._fogX = this._displayX;
    }

    if (this.isLoopVertical()) {
      this._fogY = y;
    } else {
      this._fogY = this._displayY;
    }
  };

  Game_Map.prototype.fogOx = function() {
    return this._fogX * this.tileWidth() / 2;
  };

  Game_Map.prototype.fogOy = function() {
    return this._fogY * this.tileHeight() / 2;
  };

  Game_Map.prototype.fogName = function() {
    return this._fogName;
  };

  Game_Map.prototype.fogOpacity = function() {
    return this._fogOpacity;
  };

  var _Game_Map_update = Game_Map.prototype.update;
  Game_Map.prototype.update = function(sceneActive) {
    _Game_Map_update.call(this, sceneActive);
    this.updateFog();
  };

  Game_Map.prototype.updateFog = function() {
    this._fogX += this._fogSx / this.tileWidth() / 2;
    this._fogY += this._fogSy / this.tileHeight() / 2;
  };

  var _Spriteset_Map_createLowerLayer = Spriteset_Map.prototype.createLowerLayer;
  Spriteset_Map.prototype.createLowerLayer = function() {
    _Spriteset_Map_createLowerLayer.call(this);
    this.createFog();
  };

  var _Spriteset_Map_update = Spriteset_Map.prototype.update;
  Spriteset_Map.prototype.update = function() {
    _Spriteset_Map_update.call(this);
    this.updateFog();
  };

  Spriteset_Map.prototype.createFog = function() {
    this._fog = new TilingSprite();
    this._fog.move(0, 0, Graphics.width, Graphics.height);
    this._baseSprite.addChild(this._fog);
  };

  Spriteset_Map.prototype.updateFog = function() {
    if (this._fogName !== $gameMap.fogName()) {
      this._fogName = $gameMap.fogName();
      this._fog.bitmap = ImageManager.loadFog(this._fogName);
    }
    if (this._fog.bitmap) {
      this._fog.origin.x = $gameMap.fogOx();
      this._fog.origin.y = $gameMap.fogOy();
      this._fog.opacity = $gameMap.fogOpacity();
    }
  };

})();