twn_audio.c: .wav support and scratch channels

src/twn_audio.c

@@ -7,6 +7,7 @@
 #include <SDL2/SDL.h>
 #include <stb_ds.h>
 #include <physfs.h>
+#include <physfsrwops.h>
 
 #define STB_VORBIS_NO_PUSHDATA_API
 #define STB_VORBIS_HEADER_ONLY
@@ -17,6 +18,7 @@
 
 static const char *audio_exts[AUDIO_FILE_TYPE_COUNT] = {
     ".ogg", /* AUDIO_FILE_TYPE_OGG */
+    ".wav", /* AUDIO_FILE_TYPE_WAV */
     ".xm",  /* AUDIO_FILE_TYPE_XM */
 };
 
@@ -73,6 +75,7 @@ static AudioFileType infer_audio_file_type(const char *path) {
 
 /* TODO: error propagation and clearing of resources on partial success? */
 /*       or should we expect things to simply fail? */
+/* TODO: reuse often used decoded/decompressed data */
 static union AudioContext init_audio_context(const char *path, AudioFileType type) {
     switch (type) {
     case AUDIO_FILE_TYPE_OGG: {
@@ -102,6 +105,25 @@ static union AudioContext init_audio_context(const char *path, AudioFileType typ
         };
     }
 
+    /* TODO: transform to destination format immediately? */
+    case AUDIO_FILE_TYPE_WAV: {
+        SDL_AudioSpec spec;
+        uint8_t *data;
+        uint32_t len;
+        if (!SDL_LoadWAV_RW(PHYSFSRWOPS_openRead(path), 1, &spec, &data, &len)) {
+            CRY_SDL("Cannot load .wav file:");
+            break;
+        }
+
+        return (union AudioContext) {
+            .wav = {
+                .position = 0,
+                .samples = data,
+                .spec = spec
+            }
+        };
+    }
+
     case AUDIO_FILE_TYPE_XM: {
         unsigned char *data;
         int64_t len = get_audio_data(path, &data);
@@ -138,6 +160,18 @@ static union AudioContext init_audio_context(const char *path, AudioFileType typ
 }
 
 
+static void free_audio_channel(AudioChannel channel) {
+    switch (channel.file_type) {
+    case AUDIO_FILE_TYPE_WAV: {
+        SDL_free(channel.context.wav.samples);
+        break;
+    }
+    default:
+        break;
+    }
+}
+
+
 static void repeat_audio(AudioChannel *channel) {
     switch (channel->file_type) {
     case AUDIO_FILE_TYPE_OGG: {
@@ -145,6 +179,11 @@ static void repeat_audio(AudioChannel *channel) {
         break;
     }
 
+    case AUDIO_FILE_TYPE_WAV: {
+        channel->context.wav.position = 0;
+        break;
+    }
+
     case AUDIO_FILE_TYPE_XM: {
         xm_restart(channel->context.xm.handle);
         break;
@@ -165,11 +204,12 @@ void audio_play(const char *path,
                 float volume,
                 float panning)
 {
+    if (channel) {
         AudioChannelItem *pair = shgetp_null(ctx.audio_channels, channel);
 
         /* create a channel if it doesn't exist */
         if (!pair) {
-        AudioFileType file_type = infer_audio_file_type(path);
+            AudioFileType const file_type = infer_audio_file_type(path);
             AudioChannel new_channel = {
                 .file_type = file_type,
                 .context = init_audio_context(path, file_type),
@@ -188,6 +228,24 @@ void audio_play(const char *path,
         /* works for both restarts and new audio */
         if (strcmp(pair->value.path, path) == 0)
             repeat_audio(&pair->value);
+    } else {
+        /* audio without channel plays without repeat and ability to change parameters over its course, nor stop it */
+        AudioFileType const file_type = infer_audio_file_type(path);
+        AudioChannel new_channel = {
+            .file_type = file_type,
+            .context = init_audio_context(path, file_type),
+            .path = path,
+            .name = channel,
+            .repeat = false,
+            .volume = volume,
+            .panning = panning,
+        };
+
+        if (repeat)
+            log_warn("Cannot repeat audio played on unnamed scratch channel (for %s)", path);
+
+        arrpush(ctx.unnamed_audio_channels, new_channel);
+    }
 }
 
 
@@ -243,12 +301,12 @@ static void audio_mixin_streams(const AudioChannel *channel,
 
 
 /* remember: sample is data for all channels where frame is a part of it */
-static void audio_sample_and_mixin_channel(const AudioChannel *channel,
+static void audio_sample_and_mixin_channel(AudioChannel *channel,
                                            uint8_t *stream,
                                            int len)
 {
     static uint8_t buffer[16384];
-    const int float_buffer_frames = sizeof (buffer) / sizeof (float);
+    const int float_buffer_frames = sizeof (buffer) / sizeof (float) / 2;
     const int stream_frames = len / (int)(sizeof (float));
 
     switch (channel->file_type) {
@@ -270,10 +328,12 @@ static void audio_sample_and_mixin_channel(const AudioChannel *channel,
                     /* seek to start and try sampling some more */
                     stb_vorbis_seek_start(channel->context.vorbis.handle);
                     continue;
-                } else
+                } else {
                     /* leave silence */
+                    channel->finished = true;
                     break;
                 }
+            }
 
             /* panning and mixing */
             audio_mixin_streams(channel,
@@ -286,6 +346,66 @@ static void audio_sample_and_mixin_channel(const AudioChannel *channel,
         break;
     }
 
+    case AUDIO_FILE_TYPE_WAV: {
+        /* feed stream for needed conversions */
+        for (int i = 0; i < stream_frames; ) {
+            const int n_frames = (stream_frames - i) > float_buffer_frames ?
+                float_buffer_frames : stream_frames - i;
+
+            int const limit = MIN(n_frames, channel->context.wav.spec.samples);
+
+            switch (channel->context.wav.spec.format) {
+            case AUDIO_U16: {
+                if (channel->context.wav.spec.channels == 1) {
+                    for (int x = 0; x < limit; ++x) {
+                        ((float *)buffer)[x * 2 + 0] = (float)((uint16_t *)channel->context.wav.samples)[x] / (float)UINT16_MAX;
+                        ((float *)buffer)[x * 2 + 1] = (float)((uint16_t *)channel->context.wav.samples)[x] / (float)UINT16_MAX;
+                    }
+                }
+
+                break;
+            }
+            case AUDIO_S16: {
+                if (channel->context.wav.spec.channels == 1) {
+                    for (int x = 0; x < limit; ++x) {
+                        if ((float)((int16_t *)channel->context.wav.samples)[x] < 0) {
+                            ((float *)buffer)[x * 2 + 0] = (float)((int16_t *)channel->context.wav.samples)[x] / (float)INT16_MIN;
+                            ((float *)buffer)[x * 2 + 1] = (float)((int16_t *)channel->context.wav.samples)[x] / (float)INT16_MIN;
+                        } else {
+                            ((float *)buffer)[x * 2 + 0] = (float)((int16_t *)channel->context.wav.samples)[x] / (float)INT16_MAX;
+                            ((float *)buffer)[x * 2 + 1] = (float)((int16_t *)channel->context.wav.samples)[x] / (float)INT16_MAX;
+                        }
+                    }
+                }
+
+                break;
+            }
+            default:
+                log_warn("Unsupported .wav PCM format (%x), producing silence", channel->context.wav.spec.format);
+                return;
+            }
+
+            /* panning and mixing */
+            audio_mixin_streams(channel, &stream[i * sizeof(float)], buffer, limit * 2);
+
+            channel->context.wav.position += limit;
+
+            if (channel->context.wav.position == channel->context.wav.spec.samples) {
+                if (channel->repeat)
+                    channel->context.wav.position = 0;
+                else {
+                    /* leave silence */
+                    channel->finished = true;
+                    break;
+                }
+            }
+
+            i += limit * 2;
+        }
+
+        break;
+    }
+
     case AUDIO_FILE_TYPE_XM: {
         for (int i = 0; i < stream_frames; ) {
             const int n_frames = (stream_frames - i) > float_buffer_frames ?
@@ -301,10 +421,12 @@ static void audio_sample_and_mixin_channel(const AudioChannel *channel,
                     /* seek to start and try sampling some more */
                     xm_restart(channel->context.xm.handle);
                     continue;
-                } else
+                } else {
+                    channel->finished = true;
                     /* leave silence */
                     break;
                 }
+            }
 
             /* panning and mixing */
             audio_mixin_streams(channel,
@@ -346,8 +468,23 @@ void audio_callback(void *userdata, uint8_t *stream, int len) {
         sanity_check_channel(&ctx.audio_channels[i].value);
         audio_sample_and_mixin_channel(&ctx.audio_channels[i].value, stream, len);
     }
+
+    for (int i = 0; i < arrlen(ctx.unnamed_audio_channels); ++i) {
+        sanity_check_channel(&ctx.unnamed_audio_channels[i]);
+        audio_sample_and_mixin_channel(&ctx.unnamed_audio_channels[i], stream, len);
     }
 
+    /* ditch finished unnamed */
+    int i = 0;
+    while (i < arrlen(ctx.unnamed_audio_channels)) {
+        if (ctx.unnamed_audio_channels[i].finished) {
+            free_audio_channel(ctx.unnamed_audio_channels[i]);
+            arrdelswap(ctx.unnamed_audio_channels, i);
+        } else i++;
+    }
+}
+
+
 TWN_API void audio_play_args(PlayAudioArgs args) {
     const char *channel = m_or(args, channel, NULL);
     const bool repeat = m_or(args, repeat, false);

src/twn_audio_c.h

@@ -13,9 +13,12 @@
 
 #define AUDIO_FREQUENCY 48000
 
-
+/* TODO: specify which PCM formats are usable with WAV */
+/* TODO: specify limitations of libxm */
+/* TODO: specify limitations of stb_vorbis */
 typedef enum AudioFileType {
     AUDIO_FILE_TYPE_OGG,
+    AUDIO_FILE_TYPE_WAV,
     AUDIO_FILE_TYPE_XM,
     AUDIO_FILE_TYPE_COUNT,
     AUDIO_FILE_TYPE_UNKNOWN,
@@ -30,6 +33,12 @@ union AudioContext {
         uint8_t channel_count;
     } vorbis;
 
+    struct {
+        void *samples;
+        SDL_AudioSpec spec;
+        size_t position;
+    } wav;
+
     struct {
         xm_context_t *handle;
     } xm;
@@ -44,6 +53,7 @@ typedef struct AudioChannel {
     bool repeat;
     float volume;
     float panning;
+    bool finished;
 } AudioChannel;
 
 

src/twn_engine_context_c.h

@@ -53,6 +53,7 @@ typedef struct EngineContext {
 
     /* audio */
     AudioChannelItem *audio_channels;
+    AudioChannel *unnamed_audio_channels;
     SDL_AudioDeviceID audio_device;
     int audio_stream_frequency;
     SDL_AudioFormat audio_stream_format;