Fix volume rendering sample (#506)

The files were changed from `.bin-gz` to `.gz` and then left
to the browser to decompress. But that only happened to work
because the local dev server served `.gz` files with
`content-encoding: gzip` headers. Github didn't do this.

Revert to using `.bin-gz` and manually decompressing with
`DecompressionStream`

Author: greggman

public/assets/img/volume/t1_icbm_normal_1mm_pn0_rf0.py

@@ -56,7 +56,7 @@ def load_byte_array_from_file(file_path):
 with open("t1_icbm_normal_1mm_pn0_rf0_180x216x180_uint8_1x1.bin", "rb") as f:
     bytes_data = f.read()
 
-gzip_filename = "t1_icbm_normal_1mm_pn0_rf0_180x216x180_uint8_1x1.bin.gz"
+gzip_filename = "t1_icbm_normal_1mm_pn0_rf0_180x216x180_uint8_1x1.bin-gz"
 
 with gzip.open(gzip_filename, "wb", compresslevel=9) as f:
     f.write(bytes_data)

public/assets/img/volume/t1_icbm_normal_1mm_pn0_rf0_180x216x180_astc_12x12.bin.gz renamed to public/assets/img/volume/t1_icbm_normal_1mm_pn0_rf0_180x216x180_astc_12x12.bin-gz

@@ -14,22 +14,22 @@ const brainImages = {
     blockLength: 1,
     feature: undefined,
     dataPath:
-      '../../assets/img/volume/t1_icbm_normal_1mm_pn0_rf0_180x216x180_uint8_1x1.bin.gz',
+      '../../assets/img/volume/t1_icbm_normal_1mm_pn0_rf0_180x216x180_uint8_1x1.bin-gz',
   },
   'bc4-r-unorm': {
     bytesPerBlock: 8,
     blockLength: 4,
     feature: 'texture-compression-bc-sliced-3d',
     dataPath:
-      '../../assets/img/volume/t1_icbm_normal_1mm_pn0_rf0_180x216x180_bc4_4x4.bin.gz',
+      '../../assets/img/volume/t1_icbm_normal_1mm_pn0_rf0_180x216x180_bc4_4x4.bin-gz',
     // Generated with texconv from https://github.com/microsoft/DirectXTex/releases
   },
   'astc-12x12-unorm': {
     bytesPerBlock: 16,
     blockLength: 12,
     feature: 'texture-compression-astc-sliced-3d',
     dataPath:
-      '../../assets/img/volume/t1_icbm_normal_1mm_pn0_rf0_180x216x180_astc_12x12.bin.gz',
+      '../../assets/img/volume/t1_icbm_normal_1mm_pn0_rf0_180x216x180_astc_12x12.bin-gz',
     // Generated with astcenc from https://github.com/ARM-software/astc-encoder/releases
   },
 };
@@ -158,11 +158,20 @@ async function createVolumeTexture(format: GPUTextureFormat) {
   });
 
   const response = await fetch(dataPath);
-  const buffer = await response.arrayBuffer();
-
+  const compressedBlob = await response.blob();
+
+  // Decompress the data using DecompressionStream for gzip format
+  const decompressionStream = new DecompressionStream('gzip');
+  const decompressedStream = compressedBlob
+    .stream()
+    .pipeThrough(decompressionStream);
+  const decompressedArrayBuffer = await new Response(
+    decompressedStream
+  ).arrayBuffer();
+  const byteArray = new Uint8Array(decompressedArrayBuffer);
   device.queue.writeTexture(
     { texture: volumeTexture },
-    buffer,
+    byteArray,
     { bytesPerRow: bytesPerRow, rowsPerImage: blocksHigh },
     [width, height, depth]
   );