Port emulation of The Voice

Standalone O2EM can emulate The Voice expansion module using wav sound
samples that the user must place in a specific folder, similarly to
what happens with the bios. The libretro port of O2EM, however, didn't
include The Voice support, as the corresponding code was simply
disabled.

This commit ports The Voice emulation to work in a libretro context,
using libretro-common's own mixer to load and play the sound samples,
which should be placed in a 'voice' folder under the usual 'System'
folder.

Makefile

@@ -589,7 +589,7 @@ WARNINGS := -Wall \
 	-fno-strict-overflow
 endif
 
-FLAGS += -D__LIBRETRO__ $(WARNINGS)
+FLAGS += -D__LIBRETRO__ -DHAVE_RWAV $(WARNINGS)
 
 CFLAGS += $(FLAGS)
 

Makefile.common

@@ -27,7 +27,27 @@ SOURCES_C := \
 	$(CORE_DIR)/src/vkeyb/ui.c \
 	$(CORE_DIR)/src/vkeyb/vkeyb.c \
 	$(CORE_DIR)/src/vkeyb/vkeyb_config.c \
-	$(CORE_DIR)/src/vkeyb/vkeyb_layout.c
+	$(CORE_DIR)/src/vkeyb/vkeyb_layout.c \
+	$(LIBRETRO_COMM_DIR)/audio/audio_mixer.c \
+	$(LIBRETRO_COMM_DIR)/audio/conversion/float_to_s16.c \
+	$(LIBRETRO_COMM_DIR)/audio/resampler/audio_resampler.c \
+	$(LIBRETRO_COMM_DIR)/audio/resampler/drivers/sinc_resampler.c \
+	$(LIBRETRO_COMM_DIR)/compat/compat_posix_string.c \
+	$(LIBRETRO_COMM_DIR)/compat/compat_strl.c \
+	$(LIBRETRO_COMM_DIR)/compat/fopen_utf8.c \
+	$(LIBRETRO_COMM_DIR)/encodings/encoding_utf.c \
+	$(LIBRETRO_COMM_DIR)/features/features_cpu.c \
+	$(LIBRETRO_COMM_DIR)/file/config_file.c \
+	$(LIBRETRO_COMM_DIR)/file/config_file_userdata.c \
+	$(LIBRETRO_COMM_DIR)/file/file_path.c \
+	$(LIBRETRO_COMM_DIR)/file/file_path_io.c \
+	$(LIBRETRO_COMM_DIR)/formats/wav/rwav.c \
+	$(LIBRETRO_COMM_DIR)/lists/string_list.c \
+	$(LIBRETRO_COMM_DIR)/memmap/memalign.c \
+	$(LIBRETRO_COMM_DIR)/streams/file_stream.c \
+	$(LIBRETRO_COMM_DIR)/string/stdstring.c \
+	$(LIBRETRO_COMM_DIR)/time/rtime.c \
+	$(LIBRETRO_COMM_DIR)/vfs/vfs_implementation.c
 
 ifeq ($(DEBUG),1)
 SOURCES_C += $(CORE_DIR)/src/debug.c

README.md

@@ -3,4 +3,6 @@ libretro-o2em
 
 Port of O2EM to libretro.
 
-Place "o2rom.bin" (required) in your RetroArch/libretro "System Directory" folder.
+Place "o2rom.bin" (required) in your RetroArch/libretro "System Directory" folder.
+
+If you wish to use The Voice emulation, unzip the voice samples into a folder named "voice" under your RetroArch/libretro "System Directory" folder. There are two sets of voice samples: mainsamp.zip, which are the main voice samples, and sidsamp.zip which are the samples used by the game Sid the Spellbinder. You only need the latter if you want voice in that specific game.

libretro.c

@@ -30,6 +30,11 @@
 
 #include "wrapalleg.h"
 
+#include <audio/audio_mixer.h>
+#include <audio/conversion/float_to_s16.h>
+#include <file/file_path.h>
+#include <retro_miscellaneous.h>
+
 static retro_log_printf_t log_cb;
 static retro_video_refresh_t video_cb;
 static retro_input_poll_t input_poll_cb;
@@ -110,7 +115,7 @@ struct ButtonsState
 // Last state of the buttons for joypad 1
 struct ButtonsState last_btn_state = { false, false, false, false,
                                        false, false,
-                                       false, false };
+                                       false, false };
 
 void retro_set_environment(retro_environment_t cb)
 {
@@ -613,6 +618,22 @@ static void upate_audio(void)
       }
    }
 
+   if (get_voice_status())
+   {
+      float fbuf[SOUND_BUFFER_LEN * 2 * sizeof(float)];
+      int16_t ibuf[SOUND_BUFFER_LEN * 2 * sizeof(int16_t)];
+
+      memset(fbuf, 0, length * 2 * sizeof(float));
+      audio_mixer_mix(fbuf, length, audio_volume / 100.0, true);
+      convert_float_to_s16(ibuf, fbuf, length * 2);
+
+      for (int i = 0; i < length; i++)
+      {
+         audioOutBuffer[i*2] += ibuf[i*2];
+         audioOutBuffer[i*2 + 1] += ibuf[i*2 + 1];
+      }
+   }
+
    audio_batch_cb(audioOutBuffer, length);
 }
 
@@ -895,7 +916,7 @@ void retro_cheat_set(unsigned index, bool enabled, const char *code)
 
 bool retro_load_game(const struct retro_game_info *info)
 {
-    char bios_file_path[256];
+    char bios_file_path[PATH_MAX_LENGTH];
     const char *full_path, *system_directory_c;
     enum retro_pixel_format fmt = RETRO_PIXEL_FORMAT_RGB565;
     struct retro_input_descriptor desc[] = {
@@ -952,14 +973,7 @@ bool retro_load_game(const struct retro_game_info *info)
     }
     else
     {
-#ifdef _WIN32
-      char slash = '\\';
-#else
-      char slash = '/';
-#endif
-
-       snprintf(bios_file_path, sizeof(bios_file_path), "%s%c%s", system_directory_c, slash, bios_file);
-
+       fill_pathname_join(bios_file_path, system_directory_c, bios_file, PATH_MAX_LENGTH);
        if (!does_file_exist(bios_file_path))
        {
           if (log_cb)
@@ -1022,7 +1036,14 @@ bool retro_load_game(const struct retro_game_info *info)
     if (!load_cart(full_path))
        return false;
 
-    //if (app_data.voice) load_voice_samples(path2);
+    if (app_data.voice)
+    {
+       audio_mixer_init(44100);
+
+       char voice_path[PATH_MAX_LENGTH];
+       fill_pathname_join(voice_path, system_directory_c, "voice", PATH_MAX_LENGTH);
+       init_voice(voice_path);
+    }
 
     init_display();
 
@@ -1275,6 +1296,8 @@ void retro_deinit(void)
       free(mbmp_prev);
       mbmp_prev = NULL;
    }
+
+   audio_mixer_done();
 }
 
 void retro_reset(void)