change signature of initializeWebGPU

index.js

@@ -1,5 +1,3 @@
-// index.js
-
 import { mat4 } from 'https://webgpufundamentals.org/3rdparty/wgpu-matrix.module.js';
 import { fetchShaderCode, generateGlyphTextureAtlas, createTextureFromSource } from './wgpu-utility.js';
 import { config } from './wgpu-config.js';
@@ -9,23 +7,31 @@ import { createState } from './wgpu-state.js';
 import { generateGlyphVerticesForText } from './wgpu-text.js';
 
 const canvas = document.querySelector('canvas');
-const context = canvas.getContext('webgpu');
-const presentationFormat = navigator.gpu.getPreferredCanvasFormat();
 const state = createState(config);
 
-async function main() {
-    const adapter = await navigator.gpu?.requestAdapter();
-    state.device = await adapter?.requestDevice();
-    if (!state.device) {
+async function initializeWebGPU(navigator, adapter, canvas) {
+    const context = canvas.getContext('webgpu');
+    const device = await adapter?.requestDevice();
+    if (!device) {
         alert('need a browser that supports WebGPU');
-        return;
+        return { device: null, context: null, presentationFormat: null };
     }
 
+    const presentationFormat = navigator.gpu.getPreferredCanvasFormat();
     context.configure({
-        device: state.device,
+        device,
         format: presentationFormat,
     });
 
+    return { device, context, presentationFormat };
+}
+
+async function main() {
+    const adapter = await navigator.gpu?.requestAdapter();
+    const { device, context, presentationFormat } = await initializeWebGPU(navigator, adapter, canvas);
+    if (!device) return;
+
+    state.device = device;
     const shaderCode = await fetchShaderCode('shaders.wgsl');
     const vertexSize = config.floatsPerVertex * 4;