Walkable mask painting

js/tile.js

@@ -1,8 +1,12 @@
 export class Tile {
-    constructor(width, height) {
+    constructor(width, height, masks) {
+        this.masks = masks;
         this.elem = document.createElement('div');
         this.elem.style.gridColumnEnd = `span ${width}`;
         this.elem.style.gridRowEnd = `span ${height}`;
+        // Hack to avoid floating point stitching gaps
+        this.elem.style.width = 'calc(100% + 1px)';
+        this.elem.style.height = 'calc(100% + 1px)';
     }
     remove() {
         this.elem.remove();