use game.playfield instead of module-global constants

game/js/lib/game-player.js

@@ -7,9 +7,6 @@
 import { NiceVector2d } from 'dtp-nice-game';
 import NiceSprite from 'dtp-nice-game/lib/nice-sprite.js';
 
-const CANVAS_WIDTH = 960;
-const CANVAS_HEIGHT = 540;
-
 const CELL_WIDTH = 82;
 const CELL_HEIGHT = 128;
 
@@ -20,7 +17,7 @@ const CELL_HEIGHT = 128;
 export default class GamePlayer extends NiceSprite {
 
   constructor (game) {
-    super(game, new NiceVector2d(CANVAS_WIDTH / 2, CANVAS_HEIGHT - 20));
+    super(game, new NiceVector2d(game.playfield.width / 2, game.playfield.height - 20));
     this.game = game;
     this.moveSpeed = 12;
     this.registration = new NiceVector2d(CELL_WIDTH / 2, CELL_HEIGHT);