audio_set() -> audio_set_parameter(), with string based convention

docs/interop.txt

@@ -4,7 +4,7 @@ for that certain steps are taken:
 * number of public api calls is kept at the minimum
 * procedure signatures can only use basic types, no aggregates, with exception of Vec/Matrix types and alike,
   with no expectation on new additions (see /include/twn_types.h)
-* optionals can be expressed via pointer passage of value primitives, with NULL expressive default
+* optionals can be expressed via pointer passage of value primitives, with NULL expressive default, but they should be immutable
 * /include/twn_game_api.json file is hand-kept with a schema to aid automatic generation and other tooling
 
 one of main inspirations for that is opengl model

include/twn_audio.h

@@ -15,13 +15,8 @@ TWN_API void audio_play(const char *path,
                         float volume,           /* default: 1.0f, range: 0.0f to 1.0f */
                         float panning);         /* default: 0.0f, range: -1.0 to 1.0f */
 
-typedef enum {
+/* possible parameter options: "volume", "panning", "repeat" */
-    AUDIO_PARAM_REPEAT,
+TWN_API void audio_set_parameter(const char *channel, const char *parameter, float value);
-    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);

include/twn_draw.h

@@ -37,7 +37,7 @@ TWN_API int draw_text_width(char const *string,
                             int         height_px,  /* TODO: make optional */
                             char const *font);
 
-TWN_API void draw_9slice(char const *texture_path,
+TWN_API void draw_nine_slice(char const *texture_path,
                              int         texture_w,
                              int         texture_h,
                              int         border_thickness,

include/twn_engine_api.h

@@ -1,7 +1,9 @@
 #ifndef TWN_ENGINE_API_H
 #define TWN_ENGINE_API_H
 
-#if defined(__WIN32)
+#if defined(TWN_NOT_C)
+	#define TWN_API
+#elif defined(__WIN32)
 	#define TWN_API __declspec(dllexport)
 #else
 	#define TWN_API __attribute__((visibility("default")))

src/rendering/twn_draw.c

@@ -35,7 +35,7 @@ void render_queue_clear(void) {
 }
 
 
-void draw_9slice(const char *texture_path, int texture_w, int texture_h, int border_thickness, Rect rect, Color color) {
+void draw_nine_slice(const char *texture_path, int texture_w, int texture_h, int border_thickness, Rect rect, Color color) {
     const float bt = (float)border_thickness; /* i know! */
     const float bt2 = bt * 2; /* combined size of the two borders in an axis */
 

src/twn_audio.c

@@ -191,42 +191,32 @@ void audio_play(const char *path,
 }
 
 
-TWN_API void audio_set(const char *channel, AudioParam param, float value) {
+TWN_API void audio_set_parameter(const char *channel, const char *param, float value) {
     AudioChannelItem *pair = shgetp_null(ctx.audio_channels, channel);
     if (!pair) {
         log_warn("No channel by the name of %s to set a parameter for", channel);
         return;
     }
 
-    switch (param) {
+    if (SDL_strcmp(param, "repeat") == 0) {
-    case AUDIO_PARAM_REPEAT:
         pair->value.repeat = (bool)value;
-        break;
+
-    case AUDIO_PARAM_VOLUME:
+    } else if (SDL_strcmp(param, "volume") == 0) {
-        if (value > 1.0f) {
+        if (value > 1.0f || value < 0.0f) {
             log_warn("Out of range volume for channel %s set", channel);
-            value = 1.0f;
+            value = clampf(value, 0.0f, 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:
+    } else if (SDL_strcmp(param, "panning") == 0) {
-        if (value > 1.0f) {
+        if (value > 1.0f || value < -1.0f) {
             log_warn("Out of range panning for channel %s set", channel);
-            value = 1.0f;
+            value = clampf(value, -1.0f, +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;
+
-    default:
+    } else
         CRY("Audio channel parameter setting failed", "Invalid parameter enum given");
-    }
 }