1 files changed, 49 insertions, 0 deletions
diff --git a/frontend/audio_hotplug.h b/frontend/audio_hotplug.h
new file mode 100644
index 0000000..db4eb59
--- /dev/null
+++ b/frontend/audio_hotplug.h
@@ -0,0 +1,49 @@
+#ifndef CHECK_AUDIO_H
+#define CHECK_AUDIO_H
+
+#include <stdio.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+/* Only check once every 60 calls, so this can be called every frame
+ * without much penalty */
+#define AUDIO_CHECK_THROTTLE 60
+
+bool found_usb_audio = false;
+bool has_usb_audio = false;
+
+/* Every AUDIO_CHECK_THROTTLE calls, check to see if the USB audio
+ * device has been plugged or unplugged. When the status changes,
+ * calls `reinit_callback` with the new status. */
+void audio_hotplug_check(void (*reinit_callback)(bool has_usb_audio)) {
+  static int count;
+
+  if (++count < AUDIO_CHECK_THROTTLE) return;
+
+  count = 0;
+
+  if (access("/dev/dsp1", R_OK | W_OK) == 0) {
+    found_usb_audio = true;
+  } else {
+    found_usb_audio = false;
+  }
+
+  if (!has_usb_audio && found_usb_audio) {
+    has_usb_audio = true;
+    reinit_callback(true);
+  } else if (has_usb_audio && !found_usb_audio) {
+    has_usb_audio = false;
+    reinit_callback(false);
+  }
+}
+
+/* For SDL apps, set audio to the correct device. */
+void audio_hotplug_set_device(bool has_usb_audio) {
+  if (has_usb_audio) {
+    SDL_putenv("AUDIODEV=/dev/dsp1");
+  } else {
+    SDL_putenv("AUDIODEV=/dev/dsp");
+  }
+}
+
+#endif