twn_audio: rework interface

apps/scenery/scenes/ingame.c

@@ -106,10 +106,9 @@ Scene *ingame_scene(State *state) {
 
     new_scene->cam = (Camera){ .pos = { 32, 0, 1 }, .up = { 0, 1, 0 }, .fov = (float)M_PI_2 };
 
-    audio_play_ex("music/mod65.xm", "soundtrack", (PlayAudioArgs){
+    m_audio(m_set("music/mod65.xm"),
-        .repeat = true,
+            m_opt(channel, "soundtrack"),
-        .volume = 1.0f
+            m_opt(repeat, true));
-    });
 
     input_set_mouse_captured(&ctx.input, true);
 

common-data/scripts/game.lua

@@ -1,31 +0,0 @@
-ORIGIN = { x = 320, y = 180 }
-RADIUS = 48
-offset = { x = 0, y = 0 }
-angle = 0
-
-function game_tick()
-    rectangle {
-        rect = { x = 0, y = 0, w = 640, h = 360 },
-        color = { r = 127, g = 0, b = 127, a = 255 },
-    }
-
-    sprite {
-        path = "/assets/title.png",
-        rect = {
-            x = 320 - (320 / 2),
-            y = 180 - (128 / 2),
-            w = 320,
-            h = 128,
-        },
-    }
-
-    text {
-        string = "IT KEEPS HAPPENING",
-        position = offset,
-        font = "/fonts/kenney-pixel.ttf",
-    }
-
-    offset.x = ORIGIN.x + (math.cos(angle) * RADIUS)
-    offset.y = ORIGIN.y + (math.sin(angle) * RADIUS)
-    angle = angle + 0.1
-end

include/twn_audio.h

@@ -2,37 +2,45 @@
 #define TWN_AUDIO_H
 
 #include "twn_engine_api.h"
+#include "twn_option.h"
 
 #include <stdbool.h>
 
+/* plays audio file at specified channel or at scratch channel if NULL is passed, without ability to refer to it later */
+/* path path must contain valid file extension to infer which file format it is */
+/* supported formats: .ogg, .xm */
+TWN_API void audio_play(const char *path,
+                        const char *channel,    /* optional */
+                        bool  repeat,           /* default: false */
+                        float volume,           /* default: 1.0f, range: 0.0f to 1.0f */
+                        float panning);         /* default: 0.0f, range: -1.0 to 1.0f */
+
+typedef enum {
+    AUDIO_PARAM_REPEAT,
+    AUDIO_PARAM_VOLUME,
+    AUDIO_PARAM_PANNING,
+} AudioParam;
+
+TWN_API void audio_set(const char *channel, AudioParam param, float value);
+
+/* TODO */
+// TWN_API bool audio_ended(const char *channel);
+
+#ifndef TWN_NOT_C
 
 typedef struct PlayAudioArgs {
-    /* default: false */
+    char *path;
-    bool repeat;
+
-    /* crossfade between already playing audio on a given channel, if any */
+    m_option_list(
-    /* default: false */
+        char *, channel,
-    bool crossfade;
+        bool,   repeat,
-    /* range: 0.0f to 1.0f */
+        float,  volume,
-    /* default: 1.0f */
+        float,  panning )
-    float volume;
-    /* range: -1.0 to 1.0f */
-    /* default: 0.0f */
-    float panning;
 } PlayAudioArgs;
 
-
+TWN_API void audio_play_args(PlayAudioArgs args);
-/* plays audio file at specified channel or anywhere if NULL is passed */
+#define m_audio(...) (audio_play_args((PlayAudioArgs){__VA_ARGS__}))
-/* path must contain valid file extension to infer which file format it is */
+
-/* supported formats: .ogg, .xm */
+#endif
-/* preserves args that are already specified on the channel */
-TWN_API void audio_play(const char *path, const char *channel);
-
-TWN_API void audio_play_ex(const char *path, const char *channel, PlayAudioArgs args);
-
-/* could be used for modifying args */
-/* warn: is only valid if no other calls to audio are made */
-TWN_API PlayAudioArgs *audio_get_args(const char *channel);
-
-TWN_API PlayAudioArgs audio_get_default_args(void);
 
 #endif

src/twn_audio.c

@@ -54,15 +54,6 @@ static int64_t get_audio_data(const char *path, unsigned char **data) {
 }
 
 
-void audio_play(const char *path, const char *channel) {
-    const AudioChannelItem *pair = shgetp_null(ctx.audio_channels, channel);
-    if (!pair)
-        audio_play_ex(path, channel, audio_get_default_args());
-    else
-        audio_play_ex(path, channel, pair->value.args);
-}
-
-
 static AudioFileType infer_audio_file_type(const char *path) {
     size_t path_len = SDL_strlen(path);
 
@@ -163,18 +154,25 @@ static void repeat_audio(AudioChannel *channel) {
 }
 
 
-void audio_play_ex(const char *path, const char *channel, PlayAudioArgs args) {
+void audio_play(const char *path,
+                const char *channel,
+                bool  repeat,
+                float volume,
+                float panning)
+{
     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);
         AudioChannel new_channel = {
-            .args = args,
             .file_type = file_type,
             .context = init_audio_context(path, file_type),
             .path = path,
             .name = channel,
+            .repeat = repeat,
+            .volume = volume,
+            .panning = panning,
         };
         shput(ctx.audio_channels, channel, new_channel);
         pair = shgetp_null(ctx.audio_channels, channel);
@@ -188,22 +186,40 @@ void audio_play_ex(const char *path, const char *channel, PlayAudioArgs args) {
 }
 
 
-PlayAudioArgs *audio_get_args(const char *channel) {
+TWN_API void audio_set(const char *channel, AudioParam param, float value) {
     AudioChannelItem *pair = shgetp_null(ctx.audio_channels, channel);
-    if (!pair)
+    if (!pair) {
-        return NULL;
+        log_warn("No channel by the name of %s to set a parameter for", channel);
-
+        return;
-    return &pair->value.args;
     }
 
-
+    switch (param) {
-PlayAudioArgs audio_get_default_args(void) {
+    case AUDIO_PARAM_REPEAT:
-    return (PlayAudioArgs){
+        pair->value.repeat = (bool)value;
-        .repeat = false,
+        break;
-        .crossfade = false,
+    case AUDIO_PARAM_VOLUME:
-        .volume = 1.0f,
+        if (value > 1.0f) {
-        .panning = 0.0f,
+            log_warn("Out of range volume for channel %s set", channel);
-    };
+            value = 1.0f;
+        }
+        if (value < 0.0f) {
+            log_warn("Out of range volume for channel %s set", channel);
+            value = 0.0f;
+        }
+        pair->value.volume = value;
+        break;
+    case AUDIO_PARAM_PANNING:
+        if (value > 1.0f) {
+            log_warn("Out of range panning for channel %s set", channel);
+            value = 1.0f;
+        }
+        if (value < -1.0f) {
+            log_warn("Out of range panning for channel %s set", channel);
+            value = -1.0f;
+        }
+        pair->value.panning = value;
+        break;
+    }
 }
 
 
@@ -216,15 +232,15 @@ static void audio_mixin_streams(const AudioChannel *channel,
     float *const sa = (float *)a;
     float *const sb = (float *)b;
 
-    const float left_panning = fminf(fabsf(channel->args.panning - 1.0f), 1.0f);
+    const float left_panning = fminf(fabsf(channel->panning - 1.0f), 1.0f);
-    const float right_panning = fminf(fabsf(channel->args.panning + 1.0f), 1.0f);
+    const float right_panning = fminf(fabsf(channel->panning + 1.0f), 1.0f);
 
     for (size_t s = 0; s < frames; s += 2) {
         /* left channel */
-        sa[s] += (float)(sb[s] * channel->args.volume * left_panning);
+        sa[s] += (float)(sb[s] * channel->volume * left_panning);
 
         /* right channel */
-        sa[s + 1] += (float)(sb[s + 1] * channel->args.volume * right_panning);
+        sa[s + 1] += (float)(sb[s + 1] * channel->volume * right_panning);
     }
 }
 
@@ -253,7 +269,7 @@ static void audio_sample_and_mixin_channel(const AudioChannel *channel,
 
             /* handle end of file */
             if (samples_per_channel == 0) {
-                if (channel->args.repeat) {
+                if (channel->repeat) {
                     /* seek to start and try sampling some more */
                     stb_vorbis_seek_start(channel->context.vorbis.handle);
                     continue;
@@ -284,7 +300,7 @@ static void audio_sample_and_mixin_channel(const AudioChannel *channel,
 
             /* handle end of file */
             if (samples_per_channel == 0) {
-                if (channel->args.repeat) {
+                if (channel->repeat) {
                     /* seek to start and try sampling some more */
                     xm_restart(channel->context.xm.handle);
                     continue;
@@ -313,10 +329,10 @@ static void audio_sample_and_mixin_channel(const AudioChannel *channel,
 
 
 static void sanity_check_channel(const AudioChannel *channel) {
-    if (channel->args.volume < 0.0f || channel->args.volume > 1.0f)
+    if (channel->volume < 0.0f || channel->volume > 1.0f)
         log_warn("Volume argument is out of range for channel (%s)", channel->name);
 
-    if (channel->args.panning < -1.0f || channel->args.panning > 1.0f)
+    if (channel->panning < -1.0f || channel->panning > 1.0f)
         log_warn("Panning argument is out of range for channel (%s)", channel->name);
 }
 
@@ -332,3 +348,11 @@ void audio_callback(void *userdata, uint8_t *stream, int len) {
         audio_sample_and_mixin_channel(&ctx.audio_channels[i].value, stream, len);
     }
 }
+
+TWN_API void audio_play_args(PlayAudioArgs args) {
+    const char *channel = m_or(args, channel, NULL);
+    const bool repeat = m_or(args, repeat, false);
+    const float volume = m_or(args, volume, 1.0f);
+    const float panning = m_or(args, panning, 0.0f);
+    audio_play(args.path, channel, repeat, volume, panning);
+}

src/twn_audio_c.h

@@ -36,11 +36,13 @@ union AudioContext {
 
 
 typedef struct AudioChannel {
-    PlayAudioArgs args;
     AudioFileType file_type;
     union AudioContext context; /* interpreted by `file_type` value */
     const char *path;
     const char *name;
+    bool repeat;
+    float volume;
+    float panning;
 } AudioChannel;