Move the audio code to a different file

Makefile

@@ -37,6 +37,7 @@ endif
 VERSION := 0.12.3
 export VERSION
 CONF ?= debug
+SDL_AUDIO_DRIVER ?= sdl
 
 BIN := build/bin
 OBJ := build/obj
@@ -172,7 +173,7 @@ all: cocoa sdl tester libretro
 # Get a list of our source files and their respective object file targets
 
 CORE_SOURCES := $(shell ls Core/*.c)
-SDL_SOURCES := $(shell ls SDL/*.c) $(OPEN_DIALOG)
+SDL_SOURCES := $(shell ls SDL/*.c) $(OPEN_DIALOG) SDL/audio/$(SDL_AUDIO_DRIVER).c
 TESTER_SOURCES := $(shell ls Tester/*.c)
 
 ifeq ($(PLATFORM),Darwin)

SDL/audio/audio.h

@@ -0,0 +1,16 @@
+#ifndef sdl_audio_h
+#define sdl_audio_h
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <Core/gb.h>
+
+bool GB_audio_is_playing(void);
+void GB_audio_set_paused(bool paused);
+void GB_audio_clear_queue(void);
+unsigned GB_audio_get_frequency(void);
+size_t GB_audio_get_queue_length(void);
+void GB_audio_queue_sample(GB_sample_t *sample);
+void GB_audio_init(void);
+
+#endif /* sdl_audio_h */

SDL/audio/sdl.c

@@ -0,0 +1,87 @@
+#include "audio.h"
+#include <SDL.h>
+
+#ifndef _WIN32
+#define AUDIO_FREQUENCY 96000
+#include <unistd.h>
+#else
+#include <Windows.h>
+/* Windows (well, at least my VM) can't handle 96KHz sound well :( */
+
+/* felsqualle says: For SDL 2.0.6+ using the WASAPI driver, the highest freq.
+ we can get is 48000. 96000 also works, but always has some faint crackling in
+ the audio, no matter how high or low I set the buffer length...
+ Not quite satisfied with that solution, because acc. to SDL2 docs,
+ 96k + WASAPI *should* work. */
+
+#define AUDIO_FREQUENCY 48000
+#endif
+
+/* Compatibility with older SDL versions */
+#ifndef SDL_AUDIO_ALLOW_SAMPLES_CHANGE
+#define SDL_AUDIO_ALLOW_SAMPLES_CHANGE 0
+#endif
+
+static SDL_AudioDeviceID device_id;
+static SDL_AudioSpec want_aspec, have_aspec;
+
+bool GB_audio_is_playing(void)
+{
+    return SDL_GetAudioDeviceStatus(device_id) == SDL_AUDIO_PLAYING;
+}
+
+void GB_audio_set_paused(bool paused)
+{
+    GB_audio_clear_queue();
+    SDL_PauseAudioDevice(device_id, paused);
+}
+
+void GB_audio_clear_queue(void)
+{
+    SDL_ClearQueuedAudio(device_id);
+}
+
+unsigned GB_audio_get_frequency(void)
+{
+    return have_aspec.freq;
+}
+
+size_t GB_audio_get_queue_length(void)
+{
+    return SDL_GetQueuedAudioSize(device_id);
+}
+
+void GB_audio_queue_sample(GB_sample_t *sample)
+{
+    SDL_QueueAudio(device_id, sample, sizeof(*sample));
+}
+
+void GB_audio_init(void)
+{
+    /* Configure Audio */
+    memset(&want_aspec, 0, sizeof(want_aspec));
+    want_aspec.freq = AUDIO_FREQUENCY;
+    want_aspec.format = AUDIO_S16SYS;
+    want_aspec.channels = 2;
+    want_aspec.samples = 512;
+    
+    SDL_version _sdl_version;
+    SDL_GetVersion(&_sdl_version);
+    unsigned sdl_version = _sdl_version.major * 1000 + _sdl_version.minor * 100 + _sdl_version.patch;
+    
+#ifndef _WIN32
+    /* SDL 2.0.5 on macOS and Linux introduced a bug where certain combinations of buffer lengths and frequencies
+     fail to produce audio correctly. */
+    if (sdl_version >= 2005) {
+        want_aspec.samples = 2048;
+    }
+#else
+    if (sdl_version < 2006) {
+        /* Since WASAPI audio was introduced in SDL 2.0.6, we have to lower the audio frequency
+         to 44100 because otherwise we would get garbled audio output.*/
+        want_aspec.freq = 44100;
+    }
+#endif
+    
+    device_id = SDL_OpenAudioDevice(0, 0, &want_aspec, &have_aspec, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE | SDL_AUDIO_ALLOW_SAMPLES_CHANGE);
+}

SDL/main.c

@@ -8,27 +8,12 @@
 #include "utils.h"
 #include "gui.h"
 #include "shader.h"
-
+#include "audio/audio.h"
 
 #ifndef _WIN32
-#define AUDIO_FREQUENCY 96000
 #include <unistd.h>
 #else
 #include <Windows.h>
-/* Windows (well, at least my VM) can't handle 96KHz sound well :( */
-
-/* felsqualle says: For SDL 2.0.6+ using the WASAPI driver, the highest freq.
-   we can get is 48000. 96000 also works, but always has some faint crackling in
-   the audio, no matter how high or low I set the buffer length...
-   Not quite satisfied with that solution, because acc. to SDL2 docs,
-   96k + WASAPI *should* work. */
-
-#define AUDIO_FREQUENCY 48000
-#endif
-
-/* Compatibility with older SDL versions */
-#ifndef SDL_AUDIO_ALLOW_SAMPLES_CHANGE
-#define SDL_AUDIO_ALLOW_SAMPLES_CHANGE 0
 #endif
 
 GB_gameboy_t gb;
@@ -42,7 +27,6 @@ static char *filename = NULL;
 static typeof(free) *free_function = NULL;
 static char *battery_save_path_ptr;
 
-SDL_AudioDeviceID device_id;
 
 void set_filename(const char *new_filename, typeof(free) *new_free_function)
 {
@@ -53,8 +37,6 @@ void set_filename(const char *new_filename, typeof(free) *new_free_function)
     free_function = new_free_function;
 }
 
-static SDL_AudioSpec want_aspec, have_aspec;
-
 static char *captured_log = NULL;
 
 static void log_capture_callback(GB_gameboy_t *gb, const char *string, GB_log_attributes attributes)
@@ -127,16 +109,15 @@ static void screen_size_changed(void)
 
 static void open_menu(void)
 {
-    bool audio_playing = SDL_GetAudioDeviceStatus(device_id) == SDL_AUDIO_PLAYING;
+    bool audio_playing = GB_audio_is_playing();
     if (audio_playing) {
-        SDL_PauseAudioDevice(device_id, 1);
+        GB_audio_set_paused(true);
     }
     size_t previous_width = GB_get_screen_width(&gb);
     run_gui(true);
     SDL_ShowCursor(SDL_DISABLE);
     if (audio_playing) {
-        SDL_ClearQueuedAudio(device_id);
+        GB_audio_set_paused(false);
-        SDL_PauseAudioDevice(device_id, 0);
     }
     GB_set_color_correction_mode(&gb, configuration.color_correction_mode);
     GB_set_border_mode(&gb, configuration.border_mode);
@@ -176,7 +157,7 @@ static void handle_events(GB_gameboy_t *gb)
                     GB_set_key_state(gb, (GB_key_t) button, event.type == SDL_JOYBUTTONDOWN);
                 }
                 else if (button == JOYPAD_BUTTON_TURBO) {
-                    SDL_ClearQueuedAudio(device_id);
+                    GB_audio_clear_queue();
                     turbo_down = event.type == SDL_JOYBUTTONDOWN;
                     GB_set_turbo_mode(gb, turbo_down, turbo_down && rewind_down);
                 }
@@ -294,14 +275,7 @@ static void handle_events(GB_gameboy_t *gb)
                                 break;
                             }
 #endif
-                            bool audio_playing = SDL_GetAudioDeviceStatus(device_id) == SDL_AUDIO_PLAYING;
+                            GB_audio_set_paused(GB_audio_is_playing());
-                            if (audio_playing) {
-                                SDL_PauseAudioDevice(device_id, 1);
-                            }
-                            else if (!audio_playing) {
-                                SDL_ClearQueuedAudio(device_id);
-                                SDL_PauseAudioDevice(device_id, 0);
-                            }
                         }
                     break;
                     
@@ -336,7 +310,7 @@ static void handle_events(GB_gameboy_t *gb)
             case SDL_KEYUP: // Fallthrough
                 if (event.key.keysym.scancode == configuration.keys[8]) {
                     turbo_down = event.type == SDL_KEYDOWN;
-                    SDL_ClearQueuedAudio(device_id);
+                    GB_audio_clear_queue();
                     GB_set_turbo_mode(gb, turbo_down, turbo_down && rewind_down);
                 }
                 else if (event.key.keysym.scancode == configuration.keys_2[0]) {
@@ -409,15 +383,15 @@ static void gb_audio_callback(GB_gameboy_t *gb, GB_sample_t *sample)
     if (turbo_down) {
         static unsigned skip = 0;
         skip++;
-        if (skip == have_aspec.freq / 8) {
+        if (skip == GB_audio_get_frequency() / 8) {
             skip = 0;
         }
-        if (skip > have_aspec.freq / 16) {
+        if (skip > GB_audio_get_frequency() / 16) {
             return;
         }
     }
     
-    if (SDL_GetQueuedAudioSize(device_id) / sizeof(*sample) > have_aspec.freq / 4) {
+    if (GB_audio_get_queue_length() / sizeof(*sample) > GB_audio_get_frequency() / 4) {
         return;
     }
     
@@ -426,7 +400,7 @@ static void gb_audio_callback(GB_gameboy_t *gb, GB_sample_t *sample)
         sample->right = sample->right * configuration.volume / 100;
     }
     
-    SDL_QueueAudio(device_id, sample, sizeof(*sample));
+    GB_audio_queue_sample(sample);
     
 }
 
@@ -514,7 +488,7 @@ restart:
         GB_set_vblank_callback(&gb, (GB_vblank_callback_t) vblank);
         GB_set_pixels_output(&gb, active_pixel_buffer);
         GB_set_rgb_encode_callback(&gb, rgb_encode);
-        GB_set_sample_rate(&gb, have_aspec.freq);
+        GB_set_sample_rate(&gb, GB_audio_get_frequency());
         GB_set_color_correction_mode(&gb, configuration.color_correction_mode);
         update_palette();
         if ((unsigned)configuration.border_mode <= GB_BORDER_ALWAYS) {
@@ -675,34 +649,7 @@ int main(int argc, char **argv)
         pixel_format = SDL_AllocFormat(SDL_PIXELFORMAT_ABGR8888);
     }
     
-    
+    GB_audio_init();
-    /* Configure Audio */
-    memset(&want_aspec, 0, sizeof(want_aspec));
-    want_aspec.freq = AUDIO_FREQUENCY;
-    want_aspec.format = AUDIO_S16SYS;
-    want_aspec.channels = 2;
-    want_aspec.samples = 512;
-    
-    SDL_version _sdl_version;
-    SDL_GetVersion(&_sdl_version);
-    unsigned sdl_version = _sdl_version.major * 1000 + _sdl_version.minor * 100 + _sdl_version.patch;
-    
-#ifndef _WIN32
-    /* SDL 2.0.5 on macOS and Linux introduced a bug where certain combinations of buffer lengths and frequencies
-       fail to produce audio correctly. */
-    if (sdl_version >= 2005) {
-        want_aspec.samples = 2048;
-    }
-#else
-    if (sdl_version < 2006) {
-        /* Since WASAPI audio was introduced in SDL 2.0.6, we have to lower the audio frequency
-         to 44100 because otherwise we would get garbled audio output.*/
-        want_aspec.freq = 44100;
-    }
-#endif
-    
-    device_id = SDL_OpenAudioDevice(0, 0, &want_aspec, &have_aspec, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE | SDL_AUDIO_ALLOW_SAMPLES_CHANGE);
-    /* Start Audio */
 
     SDL_EventState(SDL_DROPFILE, SDL_ENABLE);
     
@@ -735,7 +682,7 @@ int main(int argc, char **argv)
     else {
         connect_joypad();
     }
-    SDL_PauseAudioDevice(device_id, 0);
+    GB_audio_set_paused(false);
     run(); // Never returns
     return 0;
 }