feat: restore restrained drive texture

tests/unit/drive-texture.test.ts

@@ -0,0 +1,55 @@
+import { describe, expect, it } from 'vitest';
+import { createDriveTexture } from '@/audio/drive-texture';
+import { createFakeAudioHarness } from '../helpers/fake-audio-context';
+
+describe('drive texture', () => {
+  it('preallocates one texture and uses exact attack and release ramps', () => {
+    const harness = createFakeAudioHarness();
+    const texture = createDriveTexture(harness.context, harness.destination);
+    const sourceCount = harness.sources.length;
+    const eventCount = () => harness.params.flatMap((record) => record.events).length;
+
+    harness.setCurrentTime(2);
+    const beforeAttack = eventCount();
+    texture.setEnergy({ energy: 1, source: 'physical' });
+    expect(harness.sources).toHaveLength(sourceCount);
+    expect(harness.params.flatMap((record) => record.events).slice(beforeAttack))
+      .toContainEqual(expect.objectContaining({ kind: 'linear', at: 2.22 }));
+
+    harness.setCurrentTime(3);
+    const beforeRelease = eventCount();
+    texture.setEnergy({ energy: 0, source: 'idle' });
+    expect(harness.sources).toHaveLength(sourceCount);
+    expect(harness.params.flatMap((record) => record.events).slice(beforeRelease))
+      .toContainEqual(expect.objectContaining({ kind: 'linear', at: 3.9 }));
+  });
+
+  it('stops and disconnects every scheduled source exactly once', () => {
+    const harness = createFakeAudioHarness();
+    const texture = createDriveTexture(harness.context, harness.destination);
+    texture.dispose();
+    texture.dispose();
+
+    for (const source of harness.sources) {
+      expect(source.stops).toHaveLength(1);
+      expect(source.disconnectCount).toBe(1);
+    }
+  });
+
+  it('creates deterministic decorrelated stereo road noise', () => {
+    const first = createFakeAudioHarness();
+    const second = createFakeAudioHarness();
+    createDriveTexture(first.context, first.destination);
+    createDriveTexture(second.context, second.destination);
+
+    const firstNoise = first.buffers[0];
+    const secondNoise = second.buffers[0];
+    expect(firstNoise).toBeDefined();
+    expect(secondNoise).toBeDefined();
+    if (firstNoise === undefined || secondNoise === undefined) return;
+
+    expect([...firstNoise.getChannelData(0)]).toEqual([...secondNoise.getChannelData(0)]);
+    expect([...firstNoise.getChannelData(1)]).toEqual([...secondNoise.getChannelData(1)]);
+    expect([...firstNoise.getChannelData(0)]).not.toEqual([...firstNoise.getChannelData(1)]);
+  });
+});