twn_audio: rework interface

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 */
-    bool repeat;
-    /* crossfade between already playing audio on a given channel, if any */
-    /* default: false */
-    bool crossfade;
-    /* range: 0.0f to 1.0f */
-    /* default: 1.0f */
-    float volume;
-    /* range: -1.0 to 1.0f */
-    /* default: 0.0f */
-    float panning;
+    char *path;
+
+    m_option_list(
+        char *, channel,
+        bool,   repeat,
+        float,  volume,
+        float,  panning )
 } PlayAudioArgs;
 
-
-/* plays audio file at specified channel or anywhere if NULL is passed */
-/* path must contain valid file extension to infer which file format it is */
-/* supported formats: .ogg, .xm */
-/* 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);
+TWN_API void audio_play_args(PlayAudioArgs args);
+#define m_audio(...) (audio_play_args((PlayAudioArgs){__VA_ARGS__}))
+
+#endif
 
 #endif