Adds simple disc control for games that require it

3 files changed, 91 insertions, 3 deletions

diff --git a/core.c b/core.c
index c4c9e13..6aaf05f 100644
--- a/core.c
+++ b/core.c
@@ -28,6 +28,7 @@ static char save_dir[MAX_PATH];
 static char system_dir[MAX_PATH];
 static char temp_rom[MAX_PATH];
 static struct retro_game_info game_info;
+static struct retro_disk_control_ext_callback disk_control_ext;
 
 static uint32_t buttons = 0;
 
@@ -217,6 +218,32 @@ error:
 	return ret;
 }
 
+unsigned disc_get_count(void) {
+	if (disk_control_ext.get_num_images)
+		return disk_control_ext.get_num_images();
+
+	return 0;
+}
+
+unsigned disc_get_index(void) {
+	if (disk_control_ext.get_image_index)
+		return disk_control_ext.get_image_index();
+
+	return 0;
+}
+
+bool disc_switch_index(unsigned index) {
+	bool ret = false;
+	if (!disk_control_ext.set_eject_state || !disk_control_ext.set_image_index)
+		return false;
+
+	disk_control_ext.set_eject_state(true);
+	ret = disk_control_ext.set_image_index(index);
+	disk_control_ext.set_eject_state(false);
+
+	return ret;
+}
+
 static void set_directories(void) {
 	const char *home = getenv("HOME");
 	char cwd[MAX_PATH];
@@ -277,6 +304,16 @@ static bool pa_environment(unsigned cmd, void *data) {
 		}
 		break;
 	}
+	case RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE: { /* 13 */
+		const struct retro_disk_control_callback *var =
+			(const struct retro_disk_control_callback *)data;
+
+		if (var) {
+			memset(&disk_control_ext, 0, sizeof(struct retro_disk_control_ext_callback));
+			memcpy(&disk_control_ext, var, sizeof(struct retro_disk_control_callback));
+		}
+		break;
+	}
 	case RETRO_ENVIRONMENT_GET_VARIABLE: { /* 15 */
 		struct retro_variable *var = (struct retro_variable *)data;
 		if (var && var->key) {
@@ -348,6 +385,21 @@ static bool pa_environment(unsigned cmd, void *data) {
 			options_set_visible(display->key, display->visible);
 		break;
 	}
+	case RETRO_ENVIRONMENT_GET_DISK_CONTROL_INTERFACE_VERSION: { /* 57 */
+		unsigned *out =	(unsigned *)data;
+		if (out)
+			*out = 1;
+		break;
+	}
+	case RETRO_ENVIRONMENT_SET_DISK_CONTROL_EXT_INTERFACE: { /* 58 */
+		const struct retro_disk_control_ext_callback *var =
+			(const struct retro_disk_control_ext_callback *)data;
+
+		if (var) {
+			memcpy(&disk_control_ext, var, sizeof(struct retro_disk_control_ext_callback));
+		}
+		break;
+	}
 	case RETRO_ENVIRONMENT_SET_AUDIO_BUFFER_STATUS_CALLBACK: { /* 62 */
 		const struct retro_audio_buffer_status_callback *cb =
 			(const struct retro_audio_buffer_status_callback *)data;
diff --git a/core.h b/core.h
index aa3c776..67cf4e2 100644
--- a/core.h
+++ b/core.h
@@ -47,6 +47,10 @@ void state_file_name(char *name, size_t size, int slot);
 int state_read(void);
 int state_write(void);
 
+unsigned disc_get_count(void);
+unsigned disc_get_index(void);
+bool disc_switch_index(unsigned index);
+
 int core_load(const char *corefile);
 int core_load_content(const char *path);
 void core_unload(void);
diff --git a/menu.c b/menu.c
index 6ada18c..27d89fb 100644
--- a/menu.c
+++ b/menu.c
@@ -19,6 +19,7 @@ typedef enum
 	MA_MAIN_RESUME_GAME,
 	MA_MAIN_SAVE_STATE,
 	MA_MAIN_LOAD_STATE,
+	MA_MAIN_DISC_CTRL,
 	MA_MAIN_CORE_OPTS,
 	MA_MAIN_RESET_GAME,
 	MA_MAIN_CREDITS,
@@ -210,6 +211,30 @@ static void draw_src_bg(void) {
 	menu_darken_bg(g_menubg_ptr, g_menubg_src_ptr, g_menubg_src_h * g_menubg_src_pp, 0);
 }
 
+static int menu_loop_disc(int id, int keys)
+{
+	static int sel = 0;
+	menu_entry e_menu_disc_options[2] = {0};
+	unsigned disc = disc_get_index() + 1;
+	menu_entry *option = &e_menu_disc_options[0];
+
+	option->name = "Disc";
+	option->beh = MB_OPT_RANGE;
+	option->var = &disc;
+	option->min = 1;
+	option->max = disc_get_count();
+	option->enabled = 1;
+	option->need_to_save = 1;
+	option->selectable = 1;
+
+	me_loop(e_menu_disc_options, &sel);
+
+	if (disc_get_index() + 1 != disc)
+		disc_switch_index(disc - 1);
+
+	return 0;
+}
+
 static int menu_loop_core_options_page(int offset, int keys) {
 	static int sel = 0;
 	menu_entry *e_menu_core_options;
@@ -415,10 +440,11 @@ static int main_menu_handler(int id, int keys)
 static menu_entry e_menu_main[] =
 {
 	mee_handler_id("Resume game",        MA_MAIN_RESUME_GAME, main_menu_handler),
-	mee_handler_id("Save State",         MA_MAIN_SAVE_STATE,  main_menu_handler),
-	mee_handler_id("Load State",         MA_MAIN_LOAD_STATE,  main_menu_handler),
+	mee_handler_id("Save state",         MA_MAIN_SAVE_STATE,  main_menu_handler),
+	mee_handler_id("Load state",         MA_MAIN_LOAD_STATE,  main_menu_handler),
+	mee_handler_id("Disc control",       MA_MAIN_DISC_CTRL,   menu_loop_disc),
 	mee_handler_id("Emulator options",   MA_MAIN_CORE_OPTS,   menu_loop_core_options),
-	mee_handler   ("Audio and Video",    menu_loop_video_options),
+	mee_handler   ("Audio and video",    menu_loop_video_options),
 	mee_handler   ("Controls",           menu_loop_keyconfig),
 	/* mee_handler_id("Cheats",             MA_MAIN_CHEATS,      main_menu_handler), */
 	mee_handler   ("Save config",        menu_loop_config_options),
@@ -467,6 +493,7 @@ void menu_end(void)
 void menu_loop(void)
 {
 	static int sel = 0;
+	bool needs_disc_ctrl = disc_get_count() > 1;
 	plat_video_menu_enter(1);
 
 	me_enable(e_menu_main, MA_MAIN_CORE_OPTS, core_options.visible_len > 0);
@@ -474,11 +501,16 @@ void menu_loop(void)
 	me_enable(e_menu_main, MA_MAIN_SAVE_STATE, state_allowed());
 	me_enable(e_menu_main, MA_MAIN_LOAD_STATE, state_allowed());
 
+	me_enable(e_menu_main, MA_MAIN_DISC_CTRL, needs_disc_ctrl);
+
 #ifdef MMENU
 	if (state_allowed()) {
 		me_enable(e_menu_main, MA_MAIN_SAVE_STATE, mmenu == NULL);
 		me_enable(e_menu_main, MA_MAIN_LOAD_STATE, mmenu == NULL);
 	}
+	if (needs_disc_ctrl) {
+		me_enable(e_menu_main, MA_MAIN_DISC_CTRL, mmenu == NULL);
+	}
 #endif
 	me_loop_d(e_menu_main, &sel, NULL, NULL);