a lil improvement

src/index.js

@@ -138,6 +138,11 @@ class Chunk {
 class ChunkWorld {
   constructor () {
     this.chunks = []
+    this.dirty = true
+  }
+
+  mkdirty () {
+    this.dirty = true
   }
 
   static generateTerrain (c) {
@@ -181,13 +186,15 @@ class ChunkWorld {
   }
 
   update (pos, scale) {
+    if (!this.dirty) return
     let positions = ChunkWorld.getPositionsInViewport(pos, scale)
+    let generated = false
     for (let p in positions) {
       let cpos = positions[p]
       let found = false
       for (let i in this.chunks) {
         let chunk = this.chunks[i]
-        if (chunk.x == cpos.x && chunk.y == cpos.y) {
+        if (chunk.x === cpos.x && chunk.y === cpos.y) {
           found = true
           break
         }
@@ -195,25 +202,33 @@ class ChunkWorld {
 
       if (!found) {
         let chunk = new Chunk(cpos.x, cpos.y)
+        generated = true
         ChunkWorld.generateTerrain(chunk)
         this.chunks.push(chunk)
         break
       }
     }
+
+    // We generated nothing this time around, mark it as not dirty
+    if (!generated) {
+      this.dirty = false
+    }
   }
 
   render (r, o, s) {
-    for (let i in this.chunks) {
-      let chunk = this.chunks[i]
     let scaledSize = TotalSize / s
+
     // Convert to chunk-space coordinates
     let localX = Math.floor(cursor.x / scaledSize) * -1
     let localY = Math.floor(cursor.y / scaledSize) * -1
-      let aw = Math.ceil(canvas.width / scaledSize) + 1
-      let ah = Math.ceil(canvas.height / scaledSize)
+    let localW = Math.ceil(canvas.width / scaledSize) + 1
+    let localH = Math.ceil(canvas.height / scaledSize)
 
-      if (chunk.x <= localX + aw && chunk.x + 1 >= localX &&
-        chunk.y <= localY + ah && chunk.y + 1 >= localY) {
+    for (let i in this.chunks) {
+      let chunk = this.chunks[i]
+
+      if (chunk.x <= localX + localW && chunk.x + 1 >= localX &&
+        chunk.y <= localY + localH && chunk.y + 1 >= localY) {
         Chunk.render(r, chunk, o, s)
       }
     }
@@ -243,14 +258,18 @@ function render () {
 function update (dt) {
   if (input.isDown('w')) {
     cursor.y += 6
+    world.mkdirty()
   } else if (input.isDown('s')) {
     cursor.y -= 6
+    world.mkdirty()
   }
 
   if (input.isDown('a')) {
     cursor.x += 6
+    world.mkdirty()
   } else if (input.isDown('d')) {
     cursor.x -= 6
+    world.mkdirty()
   }
 
   world.update(cursor, zoom)