fix edits not being sent sometimes due to faulty swap-delete algorithm

static/chunk-allocator.js

@@ -293,7 +293,7 @@ export class AtlasAllocator {
         // Add for ticking
 
         return new Promise((resolve) => {
-            this.#pendingDownloads.push({ pbo, fence, resolve });
+            this.#pendingDownloads.push({ pbo, fence, resolve, done: false });
         });
     }
 
@@ -311,6 +311,8 @@ export class AtlasAllocator {
 
         for (let i = 0; i < this.#pendingDownloads.length; ++i) {
             let pending = this.#pendingDownloads[i];
+            if (pending.done) console.error("pending download already done", i, pending);
+
             let status = gl.getSyncParameter(pending.fence, gl.SYNC_STATUS);
             if (status == gl.SIGNALED) {
                 // Transfer complete, fetch pixels back to an array buffer.
@@ -322,19 +324,18 @@ export class AtlasAllocator {
                 gl.bindBuffer(gl.PIXEL_PACK_BUFFER, null);
                 gl.deleteSync(pending.fence);
 
+                pending.done = true;
+
                 pending.resolve({
                     width: this.chunkSize,
                     height: this.chunkSize,
                     data: arrayBuffer,
                 });
 
-                let last = this.#pendingDownloads.pop();
-                if (this.#pendingDownloads.length > 0) {
-                    this.#pendingDownloads[i] = last;
-                    --i;
-                } else {
-                    break; // now empty
-                }
+                this.#pendingDownloads[i] =
+                    this.#pendingDownloads[this.#pendingDownloads.length - 1];
+                this.#pendingDownloads.pop();
+                --i;
             }
         }
     }