fix access block scene after destroyed

frontend/src/app/components/block-overview-graph/block-overview-graph.component.ts

@@ -453,7 +453,7 @@ export class BlockOverviewGraphComponent implements AfterViewInit, OnDestroy, On
     }
     this.applyQueuedUpdates();
     // skip re-render if there's no change to the scene
-    if (this.scene && this.gl) {
+    if (this.scene && this.gl && this.vertexArray) {
       /* SET UP SHADER UNIFORMS */
       // screen dimensions
       this.gl.uniform2f(this.gl.getUniformLocation(this.shaderProgram, 'screenSize'), this.displayWidth, this.displayHeight);

frontend/src/app/components/block-overview-graph/fast-vertex-array.ts

@@ -19,6 +19,7 @@ export class FastVertexArray {
   freeSlots: number[];
   lastSlot: number;
   dirty = false;
+  destroyed = false;
 
   constructor(length, stride) {
     this.length = length;
@@ -32,6 +33,9 @@ export class FastVertexArray {
   }
 
   insert(sprite: TxSprite): number {
+    if (this.destroyed) {
+      return;
+    }
     this.count++;
 
     let position;
@@ -45,11 +49,14 @@ export class FastVertexArray {
       }
     }
     this.sprites[position] = sprite;
-    return position;
     this.dirty = true;
+    return position;
   }
 
   remove(index: number): void {
+    if (this.destroyed) {
+      return;
+    }
     this.count--;
     this.clearData(index);
     this.freeSlots.push(index);
@@ -61,20 +68,26 @@ export class FastVertexArray {
   }
 
   setData(index: number, dataChunk: number[]): void {
+    if (this.destroyed) {
+      return;
+    }
     this.data.set(dataChunk, (index * this.stride));
     this.dirty = true;
   }
 
-  clearData(index: number): void {
+  private clearData(index: number): void {
     this.data.fill(0, (index * this.stride), ((index + 1) * this.stride));
     this.dirty = true;
   }
 
   getData(index: number): Float32Array {
+    if (this.destroyed) {
+      return;
+    }
     return this.data.subarray(index, this.stride);
   }
 
-  expand(): void {
+  private expand(): void {
     this.length *= 2;
     const newData = new Float32Array(this.length * this.stride);
     newData.set(this.data);
@@ -82,7 +95,7 @@ export class FastVertexArray {
     this.dirty = true;
   }
 
-  compact(): void {
+  private compact(): void {
     // New array length is the smallest power of 2 larger than the sprite count (but no smaller than 512)
     const newLength = Math.max(512, Math.pow(2, Math.ceil(Math.log2(this.count))));
     if (newLength !== this.length) {
@@ -117,5 +130,6 @@ export class FastVertexArray {
     this.freeSlots = null;
     this.lastSlot = 0;
     this.dirty = false;
+    this.destroyed = true;
   }
 }