ref: 1d92cd1477d44245c151c1f39b15c356019d8359
dir: /src/i_oplmusic.c/
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005 Simon Howard
//
// 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.
//
// DESCRIPTION:
// System interface for music.
//
//-----------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "doomdef.h"
#include "memio.h"
#include "mus2mid.h"
#include "deh_main.h"
#include "m_misc.h"
#include "s_sound.h"
#include "w_wad.h"
#include "z_zone.h"
#include "opl.h"
#define MAXMIDLENGTH (96 * 1024)
#define GENMIDI_NUM_INSTRS 128
#define GENMIDI_HEADER "#OPL_II#"
#define GENMIDI_FLAG_FIXED 0x0000 /* fixed pitch */
#define GENMIDI_FLAG_2VOICE 0x0002 /* double voice (OPL3) */
typedef struct
{
byte tremolo;
byte attack;
byte sustain;
byte waveform;
byte scale;
byte level;
} PACKEDATTR genmidi_op_t;
typedef struct
{
genmidi_op_t modulator;
byte feedback;
genmidi_op_t carrier;
byte unused;
short base_note_offset;
} PACKEDATTR genmidi_voice_t;
typedef struct
{
unsigned short flags;
byte fine_tuning;
byte fixed_note;
genmidi_voice_t opl2_voice;
genmidi_voice_t opl3_voice;
} PACKEDATTR genmidi_instr_t;
typedef struct opl_voice_s opl_voice_t;
struct opl_voice_s
{
// Index of this voice:
int index;
// The operators used by this voice:
int op1, op2;
// Currently-loaded instrument data
genmidi_instr_t *current_instr;
// Next in freelist
opl_voice_t *next;
};
// Operators used by the different voices.
static const int voice_operators[2][OPL_NUM_VOICES] = {
{ 0x00, 0x01, 0x02, 0x08, 0x09, 0x0a, 0x10, 0x11, 0x12 },
{ 0x03, 0x04, 0x05, 0x0b, 0x0c, 0x0d, 0x13, 0x14, 0x15 }
};
static boolean music_initialised = false;
//static boolean musicpaused = false;
static int current_music_volume;
// GENMIDI lump instrument data:
static genmidi_instr_t *main_instrs;
static genmidi_instr_t *percussion_instrs;
// Voices:
static opl_voice_t voices[OPL_NUM_VOICES];
static opl_voice_t *voice_free_list;
// In the initialisation stage, register writes are spaced by reading
// from the register port (0). After initialisation, spacing is
// peformed by reading from the data port instead. I have no idea
// why.
static boolean init_stage_reg_writes = false;
// Configuration file variable, containing the port number for the
// adlib chip.
int snd_mport = 0x388;
static unsigned int GetStatus(void)
{
return OPL_ReadPort(OPL_REGISTER_PORT);
}
// Write an OPL register value
static void WriteRegister(int reg, int value)
{
int i;
OPL_WritePort(OPL_REGISTER_PORT, reg);
// For timing, read the register port six times after writing the
// register number to cause the appropriate delay
for (i=0; i<6; ++i)
{
// An oddity of the Doom OPL code: at startup initialisation,
// the spacing here is performed by reading from the register
// port; after initialisation, the data port is read, instead.
if (init_stage_reg_writes)
{
OPL_ReadPort(OPL_REGISTER_PORT);
}
else
{
OPL_ReadPort(OPL_DATA_PORT);
}
}
OPL_WritePort(OPL_DATA_PORT, value);
// Read the register port 25 times after writing the value to
// cause the appropriate delay
for (i=0; i<24; ++i)
{
GetStatus();
}
}
// Detect the presence of an OPL chip
static boolean DetectOPL(void)
{
int result1, result2;
int i;
// Reset both timers:
WriteRegister(OPL_REG_TIMER_CTRL, 0x60);
// Enable interrupts:
WriteRegister(OPL_REG_TIMER_CTRL, 0x80);
// Read status
result1 = GetStatus();
// Set timer:
WriteRegister(OPL_REG_TIMER1, 0xff);
// Start timer 1:
WriteRegister(OPL_REG_TIMER_CTRL, 0x21);
// Wait for 80 microseconds
// This is how Doom does it:
for (i=0; i<200; ++i)
{
GetStatus();
}
// Read status
result2 = GetStatus();
// Reset both timers:
WriteRegister(OPL_REG_TIMER_CTRL, 0x60);
// Enable interrupts:
WriteRegister(OPL_REG_TIMER_CTRL, 0x80);
return (result1 & 0xe0) == 0x00
&& (result2 & 0xe0) == 0xc0;
}
// Initialise registers on startup
static void InitRegisters(void)
{
int r;
// Initialise level registers
for (r=OPL_REGS_LEVEL; r <= OPL_REGS_LEVEL + OPL_NUM_OPERATORS; ++r)
{
WriteRegister(r, 0x3f);
}
// Initialise other registers
// These two loops write to registers that actually don't exist,
// but this is what Doom does ...
// Similarly, the <= is also intenational.
for (r=OPL_REGS_ATTACK; r <= OPL_REGS_WAVEFORM + OPL_NUM_OPERATORS; ++r)
{
WriteRegister(r, 0x00);
}
// More registers ...
for (r=1; r < OPL_REGS_LEVEL; ++r)
{
WriteRegister(r, 0x00);
}
// Re-initialise the low registers:
// Reset both timers and enable interrupts:
WriteRegister(OPL_REG_TIMER_CTRL, 0x60);
WriteRegister(OPL_REG_TIMER_CTRL, 0x80);
// "Allow FM chips to control the waveform of each operator":
WriteRegister(OPL_REG_WAVEFORM_ENABLE, 0x20);
// Keyboard split point on (?)
WriteRegister(OPL_REG_FM_MODE, 0x40);
}
// Load instrument table from GENMIDI lump:
static boolean LoadInstrumentTable(void)
{
byte *lump;
lump = W_CacheLumpName("GENMIDI", PU_STATIC);
// Check header
if (strncmp((char *) lump, GENMIDI_HEADER, strlen(GENMIDI_HEADER)) != 0)
{
W_ReleaseLumpName("GENMIDI");
return false;
}
main_instrs = (genmidi_instr_t *) (lump + strlen(GENMIDI_HEADER));
percussion_instrs = main_instrs + GENMIDI_NUM_INSTRS;
return true;
}
// Get the next available voice from the freelist.
static opl_voice_t *GetFreeVoice(void)
{
opl_voice_t *result;
// None available?
if (voice_free_list == NULL)
{
return NULL;
}
result = voice_free_list;
voice_free_list = voice_free_list->next;
return result;
}
// Release a voice back to the freelist.
static void ReleaseVoice(opl_voice_t *voice)
{
opl_voice_t **rover;
// Search to the end of the freelist (This is how Doom behaves!)
rover = &voice_free_list;
while (*rover != NULL)
{
rover = &(*rover)->next;
}
*rover = voice;
}
// Load data to the specified operator
static void LoadOperatorData(int operator, genmidi_op_t *data,
boolean max_level)
{
int level;
// The scale and level fields must be combined for the level register.
// For the carrier wave we always set the maximum level.
level = (data->scale & 0xc0) | (data->level & 0x3f);
if (max_level)
{
level |= 0x3f;
}
WriteRegister(OPL_REGS_LEVEL + operator, level);
WriteRegister(OPL_REGS_TREMOLO + operator, data->tremolo);
WriteRegister(OPL_REGS_ATTACK + operator, data->attack);
WriteRegister(OPL_REGS_SUSTAIN + operator, data->sustain);
WriteRegister(OPL_REGS_WAVEFORM + operator, data->waveform);
}
// Set the instrument for a particular voice.
static void SetVoiceInstrument(opl_voice_t *voice, genmidi_voice_t *data)
{
// Doom loads the second operator first, then the first.
LoadOperatorData(voice->op2, &data->carrier, true);
LoadOperatorData(voice->op1, &data->modulator, false);
// Set feedback register that control the connection between the
// two operators. Turn on bits in the upper nybble; I think this
// is for OPL3, where it turns on channel A/B.
WriteRegister(OPL_REGS_FEEDBACK + voice->index,
data->feedback | 0x30);
}
// Initialise the voice table and freelist
static void InitVoices(void)
{
int i;
// Start with an empty free list.
voice_free_list = NULL;
// Initialise each voice.
for (i=0; i<OPL_NUM_VOICES; ++i)
{
voices[i].index = i;
voices[i].op1 = voice_operators[0][i];
voices[i].op2 = voice_operators[1][i];
voices[i].current_instr = NULL;
// Add this voice to the freelist.
ReleaseVoice(&voices[i]);
}
}
// Shutdown music
static void I_OPL_ShutdownMusic(void)
{
if (music_initialised)
{
#ifdef TEST
InitRegisters();
#endif
OPL_Shutdown();
// Release GENMIDI lump
W_ReleaseLumpName("GENMIDI");
music_initialised = false;
}
}
// Initialise music subsystem
static boolean I_OPL_InitMusic(void)
{
if (!OPL_Init(snd_mport))
{
return false;
}
init_stage_reg_writes = true;
// Doom does the detection sequence twice, for some reason:
if (!DetectOPL() || !DetectOPL())
{
printf("Dude. The Adlib isn't responding.\n");
OPL_Shutdown();
return false;
}
// Load instruments from GENMIDI lump:
if (!LoadInstrumentTable())
{
OPL_Shutdown();
return false;
}
InitRegisters();
InitVoices();
// Now that initialisation has finished, switch the
// register writing mode:
init_stage_reg_writes = false;
#ifdef TEST
{
opl_voice_t *voice;
voice = GetFreeVoice();
SetVoiceInstrument(voice, &main_instrs[34].opl2_voice);
// Set level:
WriteRegister(OPL_REGS_LEVEL + voice->op2, 0x94);
// Note on:
WriteRegister(OPL_REGS_FREQ_1 + voice->index, 0x65);
WriteRegister(OPL_REGS_FREQ_2 + voice->index, 0x2b);
}
#endif
music_initialised = true;
return true;
}
// Set music volume (0 - 127)
static void I_OPL_SetMusicVolume(int volume)
{
// Internal state variable.
current_music_volume = volume;
}
// Start playing a mid
static void I_OPL_PlaySong(void *handle, int looping)
{
if (!music_initialised)
{
return;
}
}
static void I_OPL_PauseSong(void)
{
if (!music_initialised)
{
return;
}
}
static void I_OPL_ResumeSong(void)
{
if (!music_initialised)
{
return;
}
}
static void I_OPL_StopSong(void)
{
if (!music_initialised)
{
return;
}
}
static void I_OPL_UnRegisterSong(void *handle)
{
if (!music_initialised)
{
return;
}
}
// Determine whether memory block is a .mid file
static boolean IsMid(byte *mem, int len)
{
return len > 4 && !memcmp(mem, "MThd", 4);
}
static boolean ConvertMus(byte *musdata, int len, char *filename)
{
MEMFILE *instream;
MEMFILE *outstream;
void *outbuf;
size_t outbuf_len;
int result;
instream = mem_fopen_read(musdata, len);
outstream = mem_fopen_write();
result = mus2mid(instream, outstream);
if (result == 0)
{
mem_get_buf(outstream, &outbuf, &outbuf_len);
M_WriteFile(filename, outbuf, outbuf_len);
}
mem_fclose(instream);
mem_fclose(outstream);
return result;
}
static void *I_OPL_RegisterSong(void *data, int len)
{
char *filename;
if (!music_initialised)
{
return NULL;
}
// MUS files begin with "MUS"
// Reject anything which doesnt have this signature
filename = M_TempFile("doom.mid");
if (IsMid(data, len) && len < MAXMIDLENGTH)
{
M_WriteFile(filename, data, len);
}
else
{
// Assume a MUS file and try to convert
ConvertMus(data, len, filename);
}
// ....
// remove file now
remove(filename);
Z_Free(filename);
return NULL;
}
// Is the song playing?
static boolean I_OPL_MusicIsPlaying(void)
{
if (!music_initialised)
{
return false;
}
return false;
}
static snddevice_t music_opl_devices[] =
{
SNDDEVICE_ADLIB,
SNDDEVICE_SB,
};
music_module_t music_opl_module =
{
music_opl_devices,
arrlen(music_opl_devices),
I_OPL_InitMusic,
I_OPL_ShutdownMusic,
I_OPL_SetMusicVolume,
I_OPL_PauseSong,
I_OPL_ResumeSong,
I_OPL_RegisterSong,
I_OPL_UnRegisterSong,
I_OPL_PlaySong,
I_OPL_StopSong,
I_OPL_MusicIsPlaying,
};