Split audio into stream/ and mixer/ subdirs, fix resulting build breaks

Reorganizes src/dusk/audio/: individual stream implementations
(audiostream, audiostreampcm, audiostreammp3, audiostreammp3decodersw)
move into audio/stream/, and a new audio/mixer/ holds a channel-based
playback queue (audiomixer.c/.h) for future use - not yet wired into
the engine.

Fixes needed to keep the tree buildable after the move:
 - A stray duplicate of audiostreammp3decodersw.c/.h was left at the old
   flat path; removed in favor of the canonical copy in stream/.
 - Updated every #include "audio/audiostream*.h" and the two platform
   CMakeLists.txt (dusklinux, duskdolphin) that still pointed at the old
   flat location.
 - audiomixer.c/.h didn't compile: audiomixerqueue_t was referenced but
   never defined (audiomixerchanneldata_t has the matching fields), a
   trailing comma in audioMixerPlayLooped's parameter list is illegal in
   C, and `file` was declared as an array of pointers instead of a char
   buffer.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

src/dusk/audio/CMakeLists.txt

@@ -7,7 +7,8 @@
 target_sources(${DUSK_LIBRARY_TARGET_NAME}
   PUBLIC
     audio.c
-    audiostream.c
-    audiostreampcm.c
-    audiostreammp3.c
-)
+)
+
+# Subdirs
+add_subdirectory(mixer)
+add_subdirectory(stream)

src/dusk/audio/audio.h

@@ -7,7 +7,7 @@
 
 #pragma once
 #include "dusk.h"
-#include "audio/audiostream.h"
+#include "audio/stream/audiostream.h"
 #include "audio/audioplatform.h"
 
 #ifndef audioPlatformInit

src/dusk/audio/mixer/CMakeLists.txt

@@ -0,0 +1,10 @@
+# Copyright (c) 2026 Dominic Masters
+# 
+# This software is released under the MIT License.
+# https://opensource.org/licenses/MIT
+
+# Sources
+target_sources(${DUSK_LIBRARY_TARGET_NAME}
+  PUBLIC
+    audiomixer.c
+)

src/dusk/audio/mixer/audiomixer.c

@@ -0,0 +1,94 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "audiomixer.h"
+#include "util/memory.h"
+#include "util/string.h"
+#include "assert/assert.h"
+
+audiomixer_t AUDIO_MIXER;
+
+errorret_t audioMixerInit() {
+  memoryZero(&AUDIO_MIXER, sizeof(audiomixer_t));
+
+  errorOk();
+}
+
+errorret_t audioMixerUpdate() {
+  // For each channel.
+  audiomixerchannel_t channel = 0;
+  do {
+    audiomixerchanneldata_t *queue = &AUDIO_MIXER.queue[channel];
+    
+    // File queued?
+    if(queue->file[0] == '\0') {
+      channel++;
+      continue;
+    }
+
+    // Stop this channel
+    audioMixerStop(channel);
+
+    // Get the file
+    // TODO: Loading?
+    // assetentry_t *entry = assetLock(queue->file, ASSET_LOADER_TYPE_WAV, NULL);
+
+    printf("Playing %s on channel %d\n", queue->file, channel);
+  } while(channel < AUDIO_MIXER_CHANNEL_COUNT);
+
+  errorOk();
+}
+
+void audioMixerPlay(
+  const char_t *file,
+  const audiomixerchannel_t channel,
+  const uint8_t volume,
+  const int8_t pan
+) {
+  audioMixerPlayLooped(file, channel, volume, pan, 0, 0.0f, 0.0f);
+}
+
+void audioMixerPlayLooped(
+  const char_t *file,
+  const audiomixerchannel_t channel,
+  const uint8_t volume,
+  const int8_t pan,
+  const uint8_t loopCount,
+  const float_t loopStart,
+  const float_t loopTo
+) {
+  assertStrLenMin(file, 1, "File is required, to stop use audioMixerStop");
+  assertTrue(channel < AUDIO_MIXER_CHANNEL_COUNT, "Channel is out of range");
+  assertTrue(volume <= 0xFF, "Volume is out of range");
+  assertTrue(volume > 0, "Volume must be greater than 0");
+  assertTrue(loopStart >= 0.0f, "Loop start incorrect");
+  assertTrue(loopTo >= 0.0f, "Loop to incorrect");
+
+  audiomixerchanneldata_t *queue = &AUDIO_MIXER.queue[channel];
+  
+  stringCopy(queue->file, file, AUDIO_PATH_MAX);
+  queue->volume = volume;
+  queue->pan = pan;
+  queue->loopCount = loopCount;
+  queue->loopStart = loopStart;
+  queue->loopTo = loopTo;
+}
+
+void audioMixerStop(const audiomixerchannel_t channel) {
+  assertTrue(channel < AUDIO_MIXER_CHANNEL_COUNT, "Channel is out of range");
+  printf("Stopping channel %d\n", channel);
+}
+
+errorret_t audioMixerDispose() {
+  audiomixerchannel_t channel = 0;
+  do {
+    audioMixerStop(channel);
+    channel++;
+  } while(channel < AUDIO_MIXER_CHANNEL_COUNT);
+
+  errorOk();
+}

src/dusk/audio/mixer/audiomixer.h

@@ -0,0 +1,109 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#pragma once
+#include "asset/asset.h"
+
+typedef enum {
+  AUDIO_MIXER_CHANNEL_BGM_0,
+  AUDIO_MIXER_CHANNEL_VOICE_0,
+  AUDIO_MIXER_CHANNEL_VOICE_1,
+  AUDIO_MIXER_CHANNEL_SFX_0,
+  AUDIO_MIXER_CHANNEL_SFX_1,
+  AUDIO_MIXER_CHANNEL_SFX_2,
+  AUDIO_MIXER_CHANNEL_SFX_3,
+  AUDIO_MIXER_CHANNEL_COUNT
+} audiomixerchannel_t;
+
+#define AUDIO_PATH_MAX 256
+
+typedef struct {
+  assetentry_t *asset;
+
+  char_t file[AUDIO_PATH_MAX];
+  uint8_t volume;
+  int8_t pan;
+  uint8_t loopCount;
+  float_t loopStart;
+  float_t loopTo;
+} audiomixerchanneldata_t;
+
+typedef struct {
+  audiomixerchanneldata_t queue[AUDIO_MIXER_CHANNEL_COUNT];
+  uint8_t fade[AUDIO_MIXER_CHANNEL_COUNT];
+} audiomixer_t;
+
+extern audiomixer_t AUDIO_MIXER;
+
+/**
+ * Initializes the audio mixer.
+ */
+errorret_t audioMixerInit();
+
+/**
+ * Updates the audio mixer.
+ */
+errorret_t audioMixerUpdate();
+
+/**
+ * Same as audioMixerPlayLooped() but with no looping.
+ * 
+ * @param file File to be played.
+ * @param channel Channel you want to play this sound on.
+ * @param volume Volume of the sound, from 0 (silent) to 0xFF (loudest).
+ * @param pan Stereo panning of the sound, from AUDIO_STREAM_LEFT to
+ *            AUDIO_STREAM_RIGHT.
+ */
+void audioMixerPlay(
+  const char_t *file,
+  const audiomixerchannel_t channel,
+  const uint8_t volume,
+  const int8_t pan
+);
+
+/**
+ * Queues a sound to be played on the next audio mixer update, which occurs at
+ * the end of each frame.
+ * 
+ * Mixer channels can only hold one voice (audio stream) at a time. If you try
+ * to queue multiple sounds on the same channel only the last one will be played
+ * and will stop any actively playing on that channel currently.
+ * 
+ * Volume is also mixed based on the channel, so supplying volume 0xFF is then
+ * multiplied by the channel's volume, e.g. 0xDD*0xFF = 0xDD.
+ * 
+ * @param file File to be played.
+ * @param channel Channel you want to play this sound on.
+ * @param volume Volume of the sound, from 0 (silent) to 0xFF (loudest).
+ * @param pan Stereo panning of the sound, from AUDIO_STREAM_LEFT to
+ *            AUDIO_STREAM_RIGHT.
+ * @param loopCount How many times to loop the sound, 0 for infinite looping.
+ * @param loopStart Where the loop segment ends, in seconds, or -1 to loop
+ *                   the whole stream (the default).
+ * @param loopTo Where the loop segment starts, in seconds.
+ */
+void audioMixerPlayLooped(
+  const char_t *file,
+  const audiomixerchannel_t channel,
+  const uint8_t volume,
+  const int8_t pan,
+  const uint8_t loopCount,
+  const float_t loopStart,
+  const float_t loopTo
+);
+
+/**
+ * Stops playing sound on the given channel.
+ * 
+ * @param channel Channel to stop.
+ */
+void audioMixerStop(const audiomixerchannel_t channel);
+
+/**
+ * Disposes the audio mixer.
+ */
+errorret_t audioMixerDispose();

src/dusk/audio/stream/CMakeLists.txt

@@ -0,0 +1,12 @@
+# Copyright (c) 2026 Dominic Masters
+# 
+# This software is released under the MIT License.
+# https://opensource.org/licenses/MIT
+
+# Sources
+target_sources(${DUSK_LIBRARY_TARGET_NAME}
+  PUBLIC
+    audiostream.c
+    audiostreampcm.c
+    audiostreammp3.c
+)

src/dusk/audio/stream/audiostream.h

@@ -6,8 +6,8 @@
  */
 
 #pragma once
-#include "audio/audiostreampcm.h"
-#include "audio/audiostreammp3.h"
+#include "audio/stream/audiostreampcm.h"
+#include "audio/stream/audiostreammp3.h"
 #include "audio/audiostreamplatform.h"
 #include "asset/loader/assetentry.h"
 

src/dusk/audio/stream/audiostreammp3decodersw.c

@@ -7,7 +7,7 @@
 
 #define MINIMP3_IMPLEMENTATION
 #include "audiostreammp3decodersw.h"
-#include "audio/audiostream.h"
+#include "audiostream.h"
 #include "assert/assert.h"
 #include "util/memory.h"
 

src/duskdolphin/audio/CMakeLists.txt

@@ -25,5 +25,5 @@ endif()
 target_link_libraries(${DUSK_LIBRARY_TARGET_NAME} PRIVATE minimp3)
 target_sources(${DUSK_LIBRARY_TARGET_NAME}
   PUBLIC
-    "${DUSK_SOURCES_DIR}/dusk/audio/audiostreammp3decodersw.c"
+    "${DUSK_SOURCES_DIR}/dusk/audio/stream/audiostreammp3decodersw.c"
 )

src/duskdolphin/audio/audiostreamdolphin.c

@@ -6,7 +6,7 @@
  */
 
 #include "audiostreamdolphin.h"
-#include "audio/audiostream.h"
+#include "audio/stream/audiostream.h"
 #include "assert/assert.h"
 #include "util/memory.h"
 #include "util/math.h"

src/duskdolphin/audio/audiostreammp3decoder.h

@@ -13,4 +13,4 @@
 // audiostreamdolphin.c already owns - not a fit here), so Dolphin uses the
 // same shared minimp3-based software backend as Linux - see that header's
 // own documentation for the actual struct/interface.
-#include "audio/audiostreammp3decodersw.h"
+#include "audio/stream/audiostreammp3decodersw.h"

src/dusklinux/audio/CMakeLists.txt

@@ -20,5 +20,5 @@ endif()
 target_link_libraries(${DUSK_LIBRARY_TARGET_NAME} PUBLIC minimp3)
 target_sources(${DUSK_LIBRARY_TARGET_NAME}
   PUBLIC
-    "${DUSK_SOURCES_DIR}/dusk/audio/audiostreammp3decodersw.c"
+    "${DUSK_SOURCES_DIR}/dusk/audio/stream/audiostreammp3decodersw.c"
 )

src/dusklinux/audio/audiostreamlinux.c

@@ -6,7 +6,7 @@
  */
 
 #include "audiostreamlinux.h"
-#include "audio/audiostream.h"
+#include "audio/stream/audiostream.h"
 #include "assert/assert.h"
 #include "util/memory.h"
 #include "util/math.h"

src/dusklinux/audio/audiostreammp3decoder.h

@@ -10,4 +10,4 @@
 // Linux has no hardware MP3 decoder to prefer, so it uses the shared
 // minimp3-based software backend (also used by Dolphin) - see that
 // header's own documentation for the actual struct/interface.
-#include "audio/audiostreammp3decodersw.h"
+#include "audio/stream/audiostreammp3decodersw.h"

src/duskpsp/audio/audiostreammp3decoder.c

@@ -6,7 +6,7 @@
  */
 
 #include "audiostreammp3decoder.h"
-#include "audio/audiostream.h"
+#include "audio/stream/audiostream.h"
 #include "assert/assert.h"
 #include "util/memory.h"
 #include <pspmp3.h>

src/duskpsp/audio/audiostreampsp.c

@@ -6,7 +6,7 @@
  */
 
 #include "audiostreampsp.h"
-#include "audio/audiostream.h"
+#include "audio/stream/audiostream.h"
 #include "assert/assert.h"
 #include "util/memory.h"
 #include "util/math.h"