s_music.cpp

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/*
All original material Copyright (C) 2002-2023 UFO: Alien Invasion.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

 */

#include "s_music.h"
#include "s_local.h"
#include "../cl_shared.h"   /* cl_genericPool */
#include "../../shared/parse.h"
#include "../../ports/system.h"
#include "../../common/filesys.h"   /* for MAX_QPATH */
#include "../../common/common.h"    /* for many */
#include "../../common/scripts.h"
#include "../cl_renderer.h"
#include "../cl_video.h"
#include "../battlescape/cl_camera.h"
#include "../battlescape/cl_localentity.h"
#include "../battlescape/cl_battlescape.h"

enum {
    MUSIC_MAIN,
    MUSIC_GEOSCAPE,
    MUSIC_BATTLESCAPE,
    MUSIC_AIRCOMBAT,

    MUSIC_MAX
};

typedef struct music_s {
    char currentTrack[MAX_QPATH];
    char nextTrack[MAX_QPATH];
    Mix_Music* data;
    int category;
    byte* buffer;
    bool playingStream; 
    bool interruptStream;
    bool playing;
} music_t;

#define MUSIC_MAX_ENTRIES 64
static char* musicArrays[MUSIC_MAX][MUSIC_MAX_ENTRIES] = {{}, {}};
static int musicArrayLength[MUSIC_MAX] = {};
static music_t music = {{}, {}, nullptr, 0, nullptr, false, false, true};
static cvar_t* snd_music;
static cvar_t* snd_music_volume;
static cvar_t* snd_music_play;

void M_ParseMusic (const char* name, const char** text)
{
    int i;

    if (Q_streq(name, "geoscape"))
        i = MUSIC_GEOSCAPE;
    else if (Q_streq(name, "battlescape"))
        i = MUSIC_BATTLESCAPE;
    else if (Q_streq(name, "aircombat"))
        i = MUSIC_AIRCOMBAT;
    else if (Q_streq(name, "main"))
        i = MUSIC_MAIN;
    else {
        Com_Printf("M_ParseMusic: Invalid music id '%s'!\n", name);
        linkedList_t* list;
        Com_ParseList(text, &list);
        LIST_Delete(&list);
        return;
    }

    /* get it's body */
    linkedList_t* list;
    if (!Com_ParseList(text, &list)) {
        Com_Error(ERR_DROP, "M_ParseMusic: error while reading music \"%s\"", name);
    }

    for (linkedList_t* element = list; element != nullptr; element = element->next) {
        if (musicArrayLength[i] >= MUSIC_MAX_ENTRIES) {
            Com_Printf("M_ParseMusic: Too many music entries for category: '%s'!\n", name);
            break;
        }
        musicArrays[i][musicArrayLength[i]] = Mem_PoolStrDup((char*)element->data, cl_genericPool, 0);
        musicArrayLength[i]++;
    }

    LIST_Delete(&list);
}

void M_Stop (void)
{
    /* we should not even have a buffer nor data set - but ... just to be sure */
    if (music.playingStream)
        return;

    if (music.data != nullptr) {
        Mix_HaltMusic();
        Mix_FreeMusic(music.data);
    }

    if (music.buffer)
        FS_FreeFile(music.buffer);

    music.data = nullptr;
    music.buffer = nullptr;
}

static void M_Start (const char* file)
{
    if (Q_strnull(file))
        return;

    if (!s_env.initialized) {
        Com_Printf("M_Start: No sound started!\n");
        return;
    }

    if (music.playingStream || !music.playing)
        return;

    char name[MAX_QPATH];
    Com_StripExtension(file, name, sizeof(name));
    const size_t len = strlen(name);
    if (len + 4 >= MAX_QPATH) {
        Com_Printf("M_Start: MAX_QPATH exceeded: " UFO_SIZE_T "\n", len + 4);
        return;
    }

    /* we are already playing that track */
    if (Q_streq(name, music.currentTrack) && music.data && Mix_PlayingMusic())
        return;

    /* we are still playing some background track - fade it out */
    if (music.data && Mix_PlayingMusic()) {
        if (!Mix_FadeOutMusic(1500))
            M_Stop();
        Q_strncpyz(music.nextTrack, name, sizeof(music.nextTrack));
        return;
    }

    /* make really sure the last track is closed and freed */
    M_Stop();

    /* load it in */
    byte* musicBuf;
    const int size = FS_LoadFile(va("music/%s.ogg", name), &musicBuf);
    if (size == -1) {
        Com_Printf("M_Start: Could not load '%s' background track!\n", name);
        return;
    }

    SDL_RWops* rw = SDL_RWFromMem(musicBuf, size);
    if (!rw) {
        Com_Printf("M_Start: Could not load music: 'music/%s'!\n", name);
        FS_FreeFile(musicBuf);
        return;
    }
#if SDL_VERSION_ATLEAST(2,0,0)
    music.data = Mix_LoadMUS_RW(rw, 1);
#else
    music.data = Mix_LoadMUS_RW(rw);
#endif
    if (!music.data) {
        Com_Printf("M_Start: Could not load music: 'music/%s' (%s)!\n", name, Mix_GetError());
        SDL_FreeRW(rw);
        FS_FreeFile(musicBuf);
        return;
    }

    Q_strncpyz(music.currentTrack, name, sizeof(music.currentTrack));
    music.buffer = musicBuf;
    if (Mix_FadeInMusic(music.data, 1, 1500) == -1)
        Com_Printf("M_Start: Could not play music: 'music/%s' (%s)!\n", name, Mix_GetError());
}

static void M_Play_f (void)
{
    if (Cmd_Argc() == 2)
        Cvar_Set("snd_music", "%s", Cmd_Argv(1));

    M_Start(Cvar_GetString("snd_music"));
}

static void M_RandomTrack_f (void)
{
    if (!s_env.initialized || !music.playing)
        return;

    const int musicTrackCount = FS_BuildFileList("music/*.ogg");
    if (musicTrackCount) {
        int randomID = rand() % musicTrackCount;
        Com_DPrintf(DEBUG_SOUND, "M_RandomTrack_f: random track id: %i/%i\n", randomID, musicTrackCount);

        const char* filename;
        while ((filename = FS_NextFileFromFileList("music/*.ogg")) != nullptr) {
            if (!randomID) {
                const char* musicTrack = Com_SkipPath(filename);
                Com_Printf("..playing next music track: '%s'\n", musicTrack);
                Cvar_Set("snd_music", "%s", musicTrack);
            }
            randomID--;
        }
        FS_NextFileFromFileList(nullptr);
    } else {
        Com_DPrintf(DEBUG_SOUND, "M_RandomTrack_f: No music found!\n");
    }
}

static bool M_PlayRandomByCategory (int category)
{
    if (category != MUSIC_BATTLESCAPE && CL_OnBattlescape())
        return false;
    if (!musicArrayLength[category])
        return false;
    const int rnd = rand() % musicArrayLength[category];
    music.category = category;
    Com_Printf("Music: track changed from %s to %s.\n", music.currentTrack, musicArrays[category][rnd]);
    Cvar_Set("snd_music", "%s", musicArrays[category][rnd]);
    return snd_music->modified;
}

static void M_Change_f (void)
{
    if (!s_env.initialized || !music.playing)
        return;

    if (Cmd_Argc() != 2) {
        Com_Printf("Usage: %s <geoscape|battlescape|main|aircombat>\n", Cmd_Argv(0));
        return;
    }
    const char* type = Cmd_Argv(1);
    int category;
    if (Q_streq(type, "geoscape")) {
        category = MUSIC_GEOSCAPE;
    } else if (Q_streq(type, "battlescape")) {
        category = MUSIC_BATTLESCAPE;
    } else if (Q_streq(type, "main")) {
        category = MUSIC_MAIN;
    } else if (Q_streq(type, "aircombat")) {
        category = MUSIC_AIRCOMBAT;
    } else {
        Com_Printf("Invalid parameter given!\n");
        return;
    }

    if (category != MUSIC_BATTLESCAPE && CL_OnBattlescape()) {
        Com_DPrintf(DEBUG_SOUND, "Not changing music to %s - we are on the battlescape!\n", type);
        return;
    }

    if (!musicArrayLength[category]) {
        Com_Printf("M_Change_f: Could not find any %s themed music tracks!\n", type);
        return;
    }

    M_PlayRandomByCategory(category);
}

static int M_CompleteMusic (const char* partial, const char** match)
{
    int n = 0;
    while (char const* const filename = FS_NextFileFromFileList("music/*.ogg")) {
        if (Cmd_GenericCompleteFunction(filename, partial, match)) {
            Com_Printf("%s\n", filename);
            ++n;
        }
    }
    FS_NextFileFromFileList(nullptr);
    return n;
}

static void M_MusicStreamUpdate (void)
{
    if (music.interruptStream) {
        music.interruptStream = false;
        M_StopMusicStream(nullptr);
    }
}

void M_Frame (void)
{
    if (snd_music_play && snd_music_play->modified) {
        music.playing = snd_music_play->integer != 0;
        snd_music_play->modified = false;
    }
    if (!music.playing) {
        if (Mix_PlayingMusic())
            M_Stop();
        return;
    }
    if (snd_music->modified) {
        M_Start(snd_music->string);
        snd_music->modified = false;
    }
    if (snd_music_volume->modified) {
        Mix_VolumeMusic(snd_music_volume->integer);
        snd_music_volume->modified = false;
    }

    if (music.playingStream) {
        M_MusicStreamUpdate();
    } else if (!Mix_PlayingMusic()) {
        M_Stop(); /* free the allocated memory */
        if (Q_strvalid(music.nextTrack)) {
            M_Start(music.nextTrack);
            music.nextTrack[0] = '\0';
        } else {
            if (!M_PlayRandomByCategory(music.category))
                M_Start(music.currentTrack);
        }
    }
}

static const cmdList_t musicCmds[] = {
    {"music_play", M_Play_f, "Plays a music track."},
    {"music_change", M_Change_f, "Changes the music theme (valid values:battlescape/geoscape/main/aircombat)."},
    {"music_stop", M_Stop, "Stops currently playing music track."},
    {"music_randomtrack", M_RandomTrack_f, "Plays a random music track."},
    {nullptr, nullptr, nullptr}
};

void M_Init (void)
{
    if (Cmd_Exists("music_change"))
        Cmd_RemoveCommand("music_change");
    Cmd_TableAddList(musicCmds);
    Cmd_AddParamCompleteFunction("music_play", M_CompleteMusic);
    snd_music = Cvar_Get("snd_music", "PsymongN3", 0, "Background music track");
    snd_music_volume = Cvar_Get("snd_music_volume", "128", CVAR_ARCHIVE, "Music volume - default is 128.");
    snd_music_volume->modified = true;
    snd_music_play = Cvar_Get ("snd_music_play", "1", CVAR_ARCHIVE, "Enable background music.");
    music.playing = snd_music_play->integer != 0;
}

void M_Shutdown (void)
{
    M_Stop();

    Cmd_TableRemoveList(musicCmds);
}

static void M_MusicStreamCallback (musicStream_t* userdata, byte* stream, int length)
{
    int tries = 0;
    while (1) {
        if (!userdata->playing) {
            music.interruptStream = true;
            return;
        }
        const int availableBytes = (userdata->mixerPos > userdata->samplePos) ? MAX_RAW_SAMPLES - userdata->mixerPos + userdata->samplePos : userdata->samplePos - userdata->mixerPos;
        if (length < availableBytes)
            break;
        if (++tries > 50) {
            userdata->playing = false;
            return;
        }
        Sys_Sleep(10);
    }

    if (userdata->mixerPos + length <= MAX_RAW_SAMPLES) {
        memcpy(stream, userdata->sampleBuf + userdata->mixerPos, length);
        userdata->mixerPos += length;
        userdata->mixerPos %= MAX_RAW_SAMPLES;
    } else {
        const int end = MAX_RAW_SAMPLES - userdata->mixerPos;
        const int start = length - end;
        memcpy(stream, userdata->sampleBuf + userdata->mixerPos, end);
        memcpy(stream, userdata->sampleBuf, start);
        userdata->mixerPos = start;
    }
}

static void M_PlayMusicStream (musicStream_t* userdata)
{
    if (userdata->playing)
        return;

    M_Stop();

    userdata->playing = true;
    music.playingStream = true;
    Mix_HookMusic((void (*)(void*, Uint8*, int)) M_MusicStreamCallback, userdata);
}

void M_AddToSampleBuffer (musicStream_t* userdata, int rate, int samples, const byte* data)
{
    if (!s_env.initialized)
        return;

    M_PlayMusicStream(userdata);

    if (rate != s_env.rate) {
        const float scale = (float)rate / s_env.rate;
        for (int i = 0;; i++) {
            const int src = i * scale;
            short* ptr = (short*)&userdata->sampleBuf[userdata->samplePos];
            if (src >= samples)
                break;
            *ptr = LittleShort(((const short*) data)[src * 2]);
            ptr++;
            *ptr = LittleShort(((const short*) data)[src * 2 + 1]);

            userdata->samplePos += 4;
            userdata->samplePos %= MAX_RAW_SAMPLES;
        }
    } else {
        for (int i = 0; i < samples; i++) {
            short* ptr = (short*)&userdata->sampleBuf[userdata->samplePos];
            *ptr = LittleShort(((const short*) data)[i * 2]);
            ptr++;
            *ptr = LittleShort(((const short*) data)[i * 2 + 1]);

            userdata->samplePos += 4;
            userdata->samplePos %= MAX_RAW_SAMPLES;
        }
    }
}

void M_StopMusicStream (musicStream_t* userdata)
{
    if (userdata != nullptr)
        userdata->playing = false;
    music.playingStream = false;
    music.interruptStream = false;
    Mix_HookMusic(nullptr, nullptr);
}