1 files changed, 44 insertions, 0 deletions
diff --git a/src/audio/audio_backend.h b/src/audio/audio_backend.h
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+++ b/src/audio/audio_backend.h
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+// This file is part of the 64k demo project.
+// It defines the interface for audio backend implementations.
+// Enables testing without hardware by abstracting audio output.
+
+#pragma once
+
+// AudioBackend interface for audio output abstraction
+// Production uses MiniaudioBackend, tests use MockAudioBackend
+class AudioBackend {
+ public:
+  virtual ~AudioBackend() {}
+
+  // Initialize backend resources
+  virtual void init() = 0;
+
+  // Start audio playback/recording
+  virtual void start() = 0;
+
+  // Clean up backend resources
+  virtual void shutdown() = 0;
+
+#if !defined(STRIP_ALL)
+  // Hook called when a voice is triggered (test-only)
+  // timestamp: Time in seconds when voice was triggered
+  // spectrogram_id: ID of the spectrogram being played
+  // volume: Voice volume (0.0 - 1.0)
+  // pan: Pan position (-1.0 left, 0.0 center, 1.0 right)
+  virtual void on_voice_triggered(float timestamp, int spectrogram_id,
+                                   float volume, float pan) {
+    // Default implementation does nothing (production path)
+    (void)timestamp;
+    (void)spectrogram_id;
+    (void)volume;
+    (void)pan;
+  }
+
+  // Hook called after rendering audio frames (test-only)
+  // num_frames: Number of frames rendered
+  virtual void on_frames_rendered(int num_frames) {
+    // Default implementation does nothing (production path)
+    (void)num_frames;
+  }
+#endif /* !defined(STRIP_ALL) */
+};