try to fetch unloaded chunk on every renderChunk triggering ui update

closes #9

src/ui/ChunkLoader2D.js

@@ -1,7 +1,5 @@
 /*
  * Fetching and storing of 2D chunks
- *
- * @flow
  */
 
 import ChunkRGB from './ChunkRGB';
@@ -25,12 +23,12 @@ import {
 
 class ChunkLoader {
   store = null;
-  canvasId: number;
+  canvasId;
-  canvasMaxTiledZoom: number;
+  canvasMaxTiledZoom;
-  historicalMaxTiledZooms: Array;
+  historicalMaxTiledZooms;
   palette;
-  canvasSize: number;
+  canvasSize;
-  chunks: Map<string, ChunkRGB>;
+  chunks;
 
   constructor(store, canvasId, palette, canvasSize, historicalSizes) {
     this.store = store;
@@ -56,10 +54,10 @@ class ChunkLoader {
   }
 
   getPixelUpdate(
-    cx: number,
+    cx,
-    cy: number,
+    cy,
-    offset: number,
+    offset,
-    color: number,
+    color,
   ) {
     const chunk = this.chunks.get(`${this.canvasMaxTiledZoom}:${cx}:${cy}`);
     if (chunk) {
@@ -70,8 +68,8 @@ class ChunkLoader {
   }
 
   getColorIndexOfPixel(
-    x: number,
+    x,
-    y: number,
+    y,
   ) {
     const { canvasSize } = this;
     const [cx, cy] = getChunkOfPixel(canvasSize, x, y);
@@ -92,11 +90,11 @@ class ChunkLoader {
    * @return ColorIndex or null if chunks not loaded or historical view not set
    */
   getHistoricalIndexOfPixel(
-    x: number,
+    x,
-    y: number,
+    y,
-    historicalDate: string,
+    historicalDate,
-    historicalTime: string,
+    historicalTime,
-    historicalCanvasSize: number,
+    historicalCanvasSize,
   ) {
     if (!historicalDate) {
       return null;
@@ -132,9 +130,9 @@ class ChunkLoader {
    * available lower zoomlevel chunks
    */
   preLoadChunk(
-    zoom: number,
+    zoom,
-    cx: number,
+    cx,
-    cy: number,
+    cy,
     chunkRGB,
   ) {
     if (zoom <= 0) return null;
@@ -174,12 +172,12 @@ class ChunkLoader {
 
 
   getChunk(
-    zoom: number,
+    zoom,
-    cx: number,
+    cx,
-    cy: number,
+    cy,
-    fetch: boolean,
+    fetch = true,
-    showLoadingTile: boolean = true,
+    showLoadingTile = true,
-    chunkPreLoading: boolean = true,
+    chunkPreLoading = true,
   ) {
     const chunkKey = `${zoom}:${cx}:${cy}`;
     let chunkRGB = this.chunks.get(chunkKey);
@@ -244,10 +242,10 @@ class ChunkLoader {
   }
 
   async fetchHistoricalChunk(
-    cx: number,
+    cx,
-    cy: number,
+    cy,
-    historicalDate: string,
+    historicalDate,
-    historicalTime: string,
+    historicalTime,
     historicalCanvasMaxTiledZoom,
     chunkRGB,
   ) {
@@ -278,7 +276,7 @@ class ChunkLoader {
     }
   }
 
-  async fetchBaseChunk(zoom, cx: number, cy: number, chunkRGB) {
+  async fetchBaseChunk(zoom, cx, cy, chunkRGB) {
     const center = [zoom, cx, cy];
     this.store.dispatch(requestBigChunk(center));
     chunkRGB.isBasechunk = true;
@@ -303,7 +301,7 @@ class ChunkLoader {
     }
   }
 
-  async fetchTile(zoom, cx: number, cy: number, chunkRGB) {
+  async fetchTile(zoom, cx, cy, chunkRGB) {
     const center = [zoom, cx, cy];
     this.store.dispatch(requestBigChunk(center));
     try {

src/ui/Renderer2D.js

@@ -341,13 +341,12 @@ class Renderer {
     context.save();
     context.fillStyle = '#C4C4C4';
     context.scale(relScale, relScale);
-    // decide if we will fetch missing chunks
+    // decide if we update the timestamps of accessed chunks
-    // and update the timestamps of accessed chunks
     const curTime = Date.now();
-    let fetch = false;
+    let touch = false;
     if (curTime > this.lastFetch + 150) {
       this.lastFetch = curTime;
-      fetch = true;
+      touch = true;
     }
 
     const xOffset = CANVAS_WIDTH / 2 / relScale - TILE_SIZE / 2;
@@ -380,10 +379,10 @@ class Renderer {
           // if out of bounds
           context.fillRect(x, y, TILE_SIZE, TILE_SIZE);
         } else {
-          chunk = this.chunkLoader.getChunk(tiledZoom, cx, cy, fetch);
+          chunk = this.chunkLoader.getChunk(tiledZoom, cx, cy);
           if (chunk) {
             context.drawImage(chunk, x, y);
-            if (fetch) {
+            if (touch) {
               chunk.timestamp = curTime;
             }
           } else {
@@ -580,13 +579,12 @@ class Renderer {
     }
     // scale
     context.scale(scale, scale);
-    // decide if we will fetch missing chunks
+    // decide if we update the timestamps of accessed chunks
-    // and update the timestamps of accessed chunks
     const curTime = Date.now();
-    let fetch = false;
+    let touch = false;
     if (curTime > this.lastFetch + 150) {
       this.lastFetch = curTime;
-      fetch = true;
+      touch = true;
     }
 
     const xOffset = CANVAS_WIDTH / 2 / scale - TILE_SIZE / 2;
@@ -618,10 +616,10 @@ class Renderer {
         } else {
           // full chunks
           chunk = this.chunkLoader
-            .getHistoricalChunk(cx, cy, fetch, historicalDate);
+            .getHistoricalChunk(cx, cy, true, historicalDate);
           if (chunk) {
             context.drawImage(chunk, x, y);
-            if (fetch) {
+            if (touch) {
               chunk.timestamp = curTime;
             }
           } else {
@@ -630,11 +628,11 @@ class Renderer {
           // incremential chunks
           if (historicalTime === '0000') continue;
           chunk = this.chunkLoader
-            .getHistoricalChunk(cx, cy, fetch, historicalDate, historicalTime);
+            .getHistoricalChunk(cx, cy, true, historicalDate, historicalTime);
           if (chunk) {
             if (!chunk.isEmpty) {
               context.drawImage(chunk, x, y);
-              if (fetch) {
+              if (touch) {
                 chunk.timestamp = curTime;
               }
             }
@@ -649,7 +647,7 @@ class Renderer {
               );
             if (chunk && !chunk.isEmpty) {
               context.drawImage(chunk, x, y);
-              if (fetch) {
+              if (touch) {
                 chunk.timestamp = curTime;
               }
             }