added optional grid

assets/config.json

@@ -13,5 +13,8 @@
 		"enabled": true,
 		"deadzone": 0.5,
 		"buffer": true
+	},
+	"appearance": {
+		"grid": "none"
 	}
 }

assets/metaConfig.json

@@ -15,5 +15,12 @@
 			"min": 0,
 			"max": 1
 		}
+	},
+	"appearance": {
+		"grid": [
+			"grid",
+			"checkerboard",
+			"none"
+		]
 	}
 }

src/js/main.js

@@ -102,7 +102,7 @@
 		const rules=levelList[category].rules || {};
 		const level=await levels.get(filename);
 
-		// create the game and attach the callbacks
+		// create the game and attach the callbacks and config
 		const snek=currentGame=new SnekGame(level, canvas, rules);
 		snek.callback=evt => {
 			if(evt=='tick') {
@@ -114,6 +114,7 @@
 				handleDeath(snek);
 			}
 		};
+		snek.config=config;
 
 		// setup the DOM
 		nav.classList.add('hidden');

src/js/snek.js

@@ -104,6 +104,7 @@ class SnekGame {
 
 	draw() {
 		const assets=require('assets');
+		const config=this.config;
 
 		// clear the canvas, because it's easier than having to deal with everything
 		this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
@@ -123,7 +124,31 @@ class SnekGame {
 		this.ctx.fillRect(offsetX+cellSize*this.dimensions[0], 0, offsetX, this.canvas.height);
 		this.ctx.fillRect(0, offsetY+cellSize*this.dimensions[1], this.canvas.width, offsetY);
 
-		// draw our walls
+		// draw a grid/checkerboard if requested
+		if(config.appearance.grid=='grid') {
+			this.ctx.strokeStyle='rgba(0, 0, 0, 50%)';
+			this.ctx.lineCap='square';
+			this.ctx.lineWidth=1;
+			this.ctx.beginPath();
+			for(let x=1; x<this.dimensions[0]; x++) {
+				this.ctx.moveTo(offsetX+x*cellSize, offsetY);
+				this.ctx.lineTo(offsetX+x*cellSize, this.canvas.height-offsetY);
+			}
+			for(let y=1; y<this.dimensions[1]; y++) {
+				this.ctx.moveTo(offsetX, offsetY+y*cellSize);
+				this.ctx.lineTo(this.canvas.width-offsetX, offsetY+y*cellSize);
+			}
+			this.ctx.stroke();
+		} else if(config.appearance.grid=='checkerboard') {
+			this.ctx.fillStyle='rgba(0, 0, 0, 10%)';
+			for(let x=0; x<this.dimensions[0]; x++) {
+				for(let y=(x+1)%2; y<this.dimensions[1]; y+=2) {
+					this.ctx.fillRect(offsetX+x*cellSize, offsetY+y*cellSize, cellSize, cellSize);
+				}
+			}
+		}
+
+		// draw our tiles
 		const wall=assets.get('wall');
 		const hole=assets.get('hole');
 		const fire=assets.get('fire');