code:
//=============================================================================
// TRP_DisplacementFilter.js
//=============================================================================
/*:
 * @plugindesc 水中マップ用のゆらぎフィルター
 * @author Thirop
 * @help
 *
 * 1.img/systemフォルダに指定する画像名の変形用画像ファイルを配置
 * 2.マップのメモ欄に設定を記述
 * <displacement:x方向スピード,y方向スピード,拡大率,画像名>
 * 拡大率を省略時のデフォルト値は20
 * 画像名を省略時のデフォルト値はDisplacementMap
 *
 */
//=============================================================================

(function(){
var parameters = PluginManager.parameters('TRP_DisplacementFilter');

//=============================================================================
// Game_Screen
//=============================================================================
var _Game_Screen_clear = Game_Screen.prototype.clear;
Game_Screen.prototype.clear = function(){
	_Game_Screen_clear.call(this);
	this._displacementSetting = null;
};

Game_Screen.prototype.startDisplacementFilter = function(sx,sy,scale,image){
	this._displacementSetting = {
		sx:sx||0,
		sy:sy||0,
		scale:scale||20,
		image:image||'DisplacementMap'
	};
};
Game_Screen.prototype.clearDisplacementFilter = function(sx,sy,scale,image){
	this._displacementSetting = null;
};

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

	var displacement = $dataMap.meta ? $dataMap.meta.displacement : null;
	if(displacement){
		this.setupDisplacement(displacement);
	}else{
		$gameScreen.clearDisplacementFilter();
	}
};

Game_Map.prototype.setupDisplacement = function(displacement){
	var dispArgs = displacement.split(',');
	var sx = Number(dispArgs[0]);
	var sy = Number(dispArgs[1]);
	var scale = Number(dispArgs[2])||0;
	var image = dispArgs[3];
	$gameScreen.startDisplacementFilter(sx,sy,scale,image);
};

//=============================================================================
// Scene_Map
//=============================================================================
var _Scene_Map_initialize = Scene_Map.prototype.initialize;
Scene_Map.prototype.initialize = function(){
	_Scene_Map_initialize.call(this);
	this.clearDisplacement();
};

Scene_Map.prototype.clearDisplacement = function(){
	this._displacement = {
		image:'',
		scale:0,
		filter:null,
		dx:-1,
		dy:-1
	};
};

var _Scene_Map_update = Scene_Map.prototype.update;
Scene_Map.prototype.update = function(){
	_Scene_Map_update.call(this);

	this.updateDisplacementFilter();
};

Scene_Map.prototype.updateDisplacementFilter = function(){
	var setting = $gameScreen._displacementSetting;
	if(setting){
		if(this._displacement.image !== setting.image){
			this._displacement.image = setting.image;
			this.setupDisplacementFilters(setting);
		}else if(this._displacement.filter){
			this._updateDisplacemenFilters(setting);
		}
	}else if(this._displacement.filter){
		ths.removeDisplacementFilter();
	}
};
Scene_Map.prototype._updateDisplacemenFilters = function(setting){
	var displacement = this._displacement;
	var filter = displacement.filter;
    filter.maskSprite.x += setting.sx;
    filter.maskSprite.y += setting.sy;

    var dx = $gameMap.displayX();
    if(displacement.dx !== dx){
    	filter.maskSprite.x += (displacement.dx - dx)*48;
    	displacement.dx = dx;
    }
    var dy = $gameMap.displayY();
    if(displacement.dy !== dy){
    	filter.maskSprite.y += (displacement.dy - dy)*48;
    	displacement.dy = dy;
    }

    if(this._displacement.scale !== setting.scale){
    	this._displacement.scale = setting.scale;
    	filter.scale = new PIXI.Point(setting.scale,setting.scale);
    }
};

Scene_Map.prototype.setupDisplacementFilters = function(setting){
	if(!this._displacement.filter){
		this.createDisplacementFilter(setting);
	}
	var bitmap = ImageManager.loadSystem(setting.image);
	bitmap.addLoadListener(function(bitmap){
		bitmap.baseTexture.wrapMode = PIXI.WRAP_MODES.REPEAT;
	});

	this._displacement.filter.maskSprite.bitmap = bitmap;

	this._displacement.scale = setting.scale;
	this._displacement.filter.scale = new PIXI.Point(setting.scale,setting.scale);
};

Scene_Map.prototype.createDisplacementFilter = function(setting){
	var sprite = new Sprite();
	var filter = new PIXI.filters.DisplacementFilter(sprite);
	this.addChild(sprite);
	this._displacement.filter = filter;

	var allFilters = this._spriteset.filters || [];
	allFilters.push(filter);
	this._spriteset.filters = allFilters;
};

Scene_Map.prototype.removeDisplacementFilter = function(){
	var allFilters = this.filters;
	var filter = this._displacement.filter;
	var index = allFilters.indexOf(filter);
	if(index>=0){
     	allFilters.splice(index,1);
    }
    this.filters = allFilters;

    if(filter.maskSprite.parent){
    	filter.maskSprite.parent.removeChild(filter.maskSprite);
    }

    this.clearDisplacement();

};

})();