song_ripper.cpp

/**
 * GBA SongRipper (c) 2012, 2014 by Bregalad
 * This is free and open source software
 *
 * This program converts a GBA song for the Sappy sound engine into MIDI (.mid) format.
 */

#include "midi.hpp"
#include <algorithm>
#include <forward_list>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cstring>

class Note;

static uint32_t track_ptr[16];
static uint8_t last_cmd[16];
static char last_key[16];
static char last_vel[16];
static int counter[16];
static uint32_t return_ptr[16];
static int key_shift[16];
static bool return_flag[16];
static bool track_completed[16];
static bool end_flag = false;
static bool loop_flag = false;
static uint32_t loop_adr;

static int lfo_delay_ctr[16];
static int lfo_delay[16];
static int lfo_depth[16];
static int lfo_type[16];
static bool lfo_flag[16];
static bool lfo_hack[16];

static unsigned int simultaneous_notes_ctr = 0;
static unsigned int simultaneous_notes_max = 0;

static std::forward_list<Note> notes_playing;

static int bank_number;
static bool bank_used = false;
static bool rc = false;
static bool gs = false;
static bool xg = false;
static bool lv = false;
static bool sv = false;

static MIDI midi(24);
static FILE *inGBA;

static void process_event(int track);

static void print_instructions()
{
	puts(
		"Rips sequence data from a GBA game using Sappy sound engine to MIDI (.mid) format.\n"
		"\nUsage: song_riper infile.gba outfile.mid song_address [-b1 -gm -gs -xg]\n"
		"-b : Bank: forces all patches to be in the specified bank (0-127).\n"
		"In General MIDI, channel 10 is reserved for drums.\n"
		"Unfortunately, we do not want to use any \"drums\" in the output file.\n"
		"I have 3 modes to fix this problem.\n"
		"-rc : Rearrange Channels. This will avoid using the channel 10, and use it at last ressort only if all 16 channels should be used\n"
		"-gs : This will send a GS system exclusive message to tell the player channel 10 is not drums.\n"
		"-xg : This will send a XG system exclusive message, and force banks number which will disable \"drums\".\n"
		"-lv : Linearise volume and velocities. This should be used to have the output \"sound\" like the original song, but shouldn't be used to get an exact dump of sequence data."
		"-sv : Simulate vibrato. This will insert controllers in real time to simulate a vibrato, instead of just when commands are given. Like -lv, this should be used to have the output \"sound\" like the original song, but shouldn't be used to get an exact dump of sequence data.\n\n"
		"It is possible, but not recommended, to use more than one of these flags at a time.\n"
	);
	exit(0);
}

static void add_simultaneous_note()
{
	// Update simultaneous notes max.
	if (++simultaneous_notes_ctr > simultaneous_notes_max)
		simultaneous_notes_max = simultaneous_notes_ctr;
}

// LFO logic on tick
static void process_lfo(int track)
{
	if (sv && lfo_delay_ctr[track] != 0)
	{
		// Decrease counter if it's value was nonzero
		if (--lfo_delay_ctr[track] == 0)
		{
			// If 1->0 transition we need to add a signal to start the LFO
			if (lfo_type[track] == 0)
				// Send a controller 1 if pitch LFO
				midi.add_controller(track, 1, (lfo_depth[track] < 16) ? lfo_depth[track] * 8 : 127);
			else
				// Send a channel aftertouch otherwise
				midi.add_chanaft(track, (lfo_depth[track] < 16) ? lfo_depth[track] * 8 : 127);
			lfo_flag[track] = true;
		}
	}
}

static void start_lfo(int track)
{
	// Reset down delay counter to its initial value
	if (sv && lfo_delay[track] != 0)
		lfo_delay_ctr[track] = lfo_delay[track];
}

static void stop_lfo(int track)
{
	// Cancel a LFO if it was playing,
	if (sv && lfo_flag[track])
	{
		if (lfo_type[track] == 0)
			midi.add_controller(track, 1, 0);
		else
			midi.add_chanaft(track, 0);
		lfo_flag[track] = false;
	}
	else
		lfo_delay_ctr[track] = 0;			// cancel delay counter if it wasn't playing
}

// Note class
// this was needed to properly handle polyphony on all channels...

class Note
{
	MIDI& midi;
	int counter;
	int key;
	int vel;
	int chn;
	bool event_made;

	// Tick counter, if it becomes zero
	// then create key off event
	// this function returns "true" when the note should be freed from memory
	bool tick()
	{
		if (counter > 0 && --counter == 0)
		{
			midi.add_note_off(chn, key, vel);
			stop_lfo(chn);
			simultaneous_notes_ctr--;
			return true;
		}
		else
			return false;
	}
	friend bool countdown_is_over(Note& n);
	friend void make_note_on_event(Note& n);

public:
	// Create note and key on event
	Note(MIDI& midi, int chn, int len, int key, int vel) :
		midi(midi), counter(len), key(key), vel(vel), chn(chn)
	{
		event_made = false;

		start_lfo(chn);
		add_simultaneous_note();
	}
};

bool countdown_is_over(Note& n)
{
	return n.tick() || n.counter < 0;
}

void make_note_on_event(Note& n)
{
	if (!n.event_made)
	{
		midi.add_note_on(n.chn, n.key, n.vel);
		n.event_made = true;
	}
}

static bool tick(int track_amnt)
{
	// Tick all playing notes, and remove notes which
	// have been keyed off OR which are infinite length from the list
	notes_playing.remove_if (countdown_is_over);

	// Process all tracks
	for (int track = 0; track < track_amnt; track++)
	{
		counter[track]--;
		// Process events until counter non-null or pointer null
		// This might not be executed if counter both are non null.
		while (track_ptr[track] != 0 && !end_flag && counter[track] <= 0)
		{
			// Check if we're at loop start point
			if (track == 0 && loop_flag && !return_flag[0] && !track_completed[0] && track_ptr[0] == loop_adr)
				midi.add_marker("loopStart");

			process_event(track);
		}
	}

	for (int track = 0; track < track_amnt; track++)
	{
		process_lfo(track);
	}

	// Compute if all still active channels are completely decoded
	bool all_completed_flag = true;
	for (int i = 0; i < track_amnt; i++)
		all_completed_flag &= track_completed[i];

	// If everything is completed, the main program should quit its loop
	if (all_completed_flag) return false;

	// Make note on events for this tick
	//(it's important they are made after all other events)
	for_each(notes_playing.begin(), notes_playing.end(), make_note_on_event);

	// Increment MIDI time
	midi.clock();
	return true;
}

static uint32_t get_GBA_pointer()
{
	uint32_t p;
	fread(&p, 1, 4, inGBA);
	return p & 0x3FFFFFF;
}

static void process_event(int track)
{
	// Length table for notes and rests
	const int lenTbl[] =
	{
		0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
		16, 17, 18, 19, 20, 21, 22, 23, 24, 28, 30, 32, 36,
		40, 42, 44, 48, 52, 54, 56, 60, 64, 66, 68, 72, 76, 78,
		80, 84, 88, 90, 92, 96
	};

	fseek(inGBA, track_ptr[track], SEEK_SET);
	// Read command
	uint8_t command = fgetc(inGBA);

	track_ptr[track]++;
	uint8_t arg1;
	// Repeat last command, the byte read was in fact the first argument
	if (command < 0x80)
	{
		arg1 = command;
		command = last_cmd[track];
	}

	// Delta time command
	else if (command <= 0xb0)
	{
		counter[track] = lenTbl[command - 0x80];
		return;
	}

	// End track command
	else if (command == 0xb1)
	{
		// Null pointer
		track_ptr[track] = 0;
		track_completed[track] = true;
		return;
	}

	// Jump command
	else if (command == 0xb2)
	{
		track_ptr[track] = get_GBA_pointer();

		// detect the end track
		track_completed[track] = true;
		return;
	}

	// Call command
	else if (command == 0xb3)
	{
		uint32_t addr = get_GBA_pointer();

		// Return address for the track
		return_ptr[track] = track_ptr[track] + 4;
		// Now points to called address
		track_ptr[track] = addr;
		return_flag[track] = true;
		return;
	}

	// Return command
	else if (command == 0xb4)
	{
		if (return_flag[track])
		{
			track_ptr[track] = return_ptr[track];
			return_flag[track] = false;
		}
		return;
	}

	// Tempo change
	else if (command == 0xbb)
	{
		int tempo = 2 * fgetc(inGBA);
		track_ptr[track]++;
		midi.add_tempo(tempo);
		return;
	}

	else
	{
		// Normal command
		last_cmd[track] = command;
		// Need argument
		arg1 = fgetc(inGBA);
		track_ptr[track]++;
	}

	// Note on with specified length command
	if (command >= 0xd0)
	{
		int key, vel, len_ofs = 0;
		// Is arg1 a key value ?
		if (arg1 < 0x80)
		{	// Yes -> use new key value
			key = arg1;
			last_key[track] = key;

			uint8_t arg2 = fgetc(inGBA);
			// Is arg2 a velocity ?
			if (arg2 < 0x80)
			{	// Yes -> use new velocity value
				vel = arg2;
				last_vel[track] = vel;
				track_ptr[track]++;

				uint8_t arg3 = fgetc(inGBA);

				// Is there a length offset ?
				if (arg3 < 0x80)
				{	// Yes -> read it and increment pointer
					len_ofs = arg3;
					track_ptr[track]++;
				}
			}
			else
			{	// No -> use previous velocity value
				vel = last_vel[track];
			}
		}
		else
		{
			// No -> use last value
			key = last_key[track];
			vel = last_vel[track];
			track_ptr[track]--;		// Seek back, as arg 1 is unused and belong to next event !
		}

		// Linearise velocity if needed
		if (lv) vel = sqrt(127.0 * vel);

		notes_playing.push_front( Note(midi, track, lenTbl[command - 0xd0 + 1] + len_ofs, key + key_shift[track], vel) );
		return;
	}

	// Other commands
	switch (command)
	{
		// Key shift
		case 0xbc:
			key_shift[track] = arg1;
			return;

		// Set instrument
		case 0xbd:
			if (bank_used)
			{
				if (!xg)
					midi.add_controller(track, 0, bank_number);
				else
				{
					midi.add_controller(track, 0, bank_number >> 7);
					midi.add_controller(track, 32, bank_number & 0x7f);
				}
			}
			midi.add_pchange(track, arg1);
			return;

		// Set volume
		case 0xbe:
		{	// Linearise volume if needed
			int volume = lv ? (int)sqrt(127.0 * arg1) : arg1;
			midi.add_controller(track, 7, volume);
		}	return;

		// Set panning
		case 0xbf:
			midi.add_controller(track, 10, arg1);
			return;

		// Pitch bend
		case 0xc0:
			midi.add_pitch_bend(track, (char)arg1);
			return;

		// Pitch bend range
		case 0xc1:
			if (sv)
				midi.add_RPN(track, 0, (char)arg1);
			else
				midi.add_controller(track, 20, arg1);
			return;

		// LFO Speed
		case 0xc2:
			if (sv)
				midi.add_NRPN(track, 136, (char)arg1);
			else
				midi.add_controller(track, 21, arg1);
			return;

		// LFO delay
		case 0xc3:
			if (sv)
				lfo_delay[track] = arg1;
			else
				midi.add_controller(track, 26, arg1);
			return;

		// LFO depth
		case 0xc4:
			if (sv)
			{
				if (lfo_delay[track] == 0 && lfo_hack[track])
				{
					if (lfo_type[track]==0)
						midi.add_controller(track, 1, arg1>12 ? 127 : 10 * arg1);
					else
						midi.add_chanaft(track, arg1>12 ? 127 : 10 * arg1);

					lfo_flag[track] = true;
				}
				lfo_depth[track] = arg1;
				// I had a stupid bug with LFO inserting controllers I didn't want at the start of files
				// So I made a terrible quick fix for it, in the mean time I can find something better to prevent it.
				lfo_hack[track] = true;
			}
			else
				midi.add_controller(track, 1, arg1);
			return;

		// LFO type
		case 0xc5:
			if (sv)
				lfo_type[track] = arg1;
			else
				midi.add_controller(track, 22, arg1);
			return;

		// Detune
		case 0xc8:
			if (sv)
				midi.add_RPN(track, 1, (char)arg1);
			else
				midi.add_controller(track, 24, arg1);
			return;

		// Key off
		case 0xce:
		{
			int key, vel = 0;

			// Is arg1 a key value ?
			if (arg1 < 0x80)
			{	// Yes -> use new key value
				key = arg1;
				last_key[track] = key;
			}
			else
			{	// No -> use last value
				key = last_key[track];
				vel = last_vel[track];
				track_ptr[track]--;		// Seek back, as arg 1 is unused and belong to next event !
			}

			midi.add_note_off(track, key + key_shift[track], vel);
			stop_lfo(track);
			simultaneous_notes_ctr --;
		}	return;

		// Key on
		case 0xcf:
		{
			int key, vel;
			// Is arg1 a key value ?
			if (arg1 < 0x80)
			{
				// Yes -> use new key value
				key = arg1;
				last_key[track] = key;

				uint8_t arg2 = fgetc(inGBA);
				// Is arg2 a velocity ?
				if (arg2 < 0x80)
				{
					// Yes -> use new velocity value
					vel = arg2;
					last_vel[track] = vel;
					track_ptr[track]++;
				}
				else	// No -> use previous velocity value
					vel = last_vel[track];
			}
			else
			{
				// No -> use last value
				key = last_key[track];
				vel = last_vel[track];
				track_ptr[track]--;		// Seek back, as arg 1 is unused and belong to next event !
			}
			// Linearise velocity if needed
			if (lv) vel = (int)sqrt(127.0 * vel);

			// Make note of infinite length
			notes_playing.push_front(Note(midi, track, -1, key + key_shift[track], vel));
		}	return;

		default :
			break;
	}
}

static uint32_t parseArguments(const int argv, const char *const args[])
{
	if (argv < 3) print_instructions();

	// Open the input and output files
	inGBA = fopen(args[0], "rb");
	if (!inGBA)
	{
		fprintf(stderr, "Can't open file %s for reading.\n", args[0]);
		exit(0);
	}

	for (int i = 3; i < argv; i++)
	{
		if (args[i][0] == '-')
		{
			if (args[i][1] == 'b')
			{
				if (strlen(args[i]) < 3) print_instructions();
				bank_number = atoi(args[i] + 2);
				bank_used = true;
			}
			else if (args[i][1] == 'r' && args[i][2] == 'c')
				rc = true;
			else if (args[i][1] == 'g' && args[i][2] == 's')
				gs = true;
			else if (args[i][1] == 'x' && args[i][2] == 'g')
				xg = true;
			else if (args[i][1] == 'l' && args[i][2] == 'v')
				lv = true;
			else if (args[i][1] == 's' && args[i][2] == 'v')
				sv = true;
			else
				print_instructions();
		}
		else
			print_instructions();
	}
	// Return base address, parsed correctly in both decimal and hex
	return strtoul(args[2], 0, 0);
}

int main(int argc, char *argv[])
{
	FILE *outMID;
	puts("GBA ROM sequence ripper (c) 2012 Bregalad");
	uint32_t base_address = parseArguments(argc - 1, argv + 1);

	if (fseek(inGBA, base_address, SEEK_SET))
	{
		fprintf(stderr, "Can't seek to the base address 0x%x.\n", base_address);
		exit(0);
	}

	int track_amnt = fgetc(inGBA);
	if (track_amnt < 1 || track_amnt > 16)
	{
		fprintf(stderr, "Invalid amount of tracks %d! (must be 1-16).\n", track_amnt);
		exit(0);
	}
	printf("%u tracks.\n", track_amnt);

	// Open output file once we know the pointer points to correct data
	//(this avoids creating blank files when there is an error)
	outMID = fopen(argv[2], "wb");
	if (!outMID)
	{
		fprintf(stderr, "Can't write to file %s.\n", argv[2]);
		exit(0);
	}

	printf("Converting...");

	if (rc)
	{	// Make the drum channel last in the list, hopefully reducing the risk of it being used
		midi.chn_reorder[9] = 15;
		for (unsigned int j = 10; j < 16; ++j)
			midi.chn_reorder[j] = j-1;
	}

	if (gs)
	{	// GS reset
		const char gs_reset_sysex[] = {0x41, 0x10, 0x42, 0x12, 0x40, 0x00, 0x7f, 0x00, 0x41};
		midi.add_sysex(gs_reset_sysex, sizeof(gs_reset_sysex));
		// Part 10 to normal
		const char part_10_normal_sysex[] = {0x41, 0x10, 0x42, 0x12, 0x40, 0x10, 0x15, 0x00, 0x1b};
		midi.add_sysex(part_10_normal_sysex, sizeof(part_10_normal_sysex));
	}

	if (xg)
	{	// XG reset
		const char xg_sysex[] = {0x43, 0x10, 0x4C, 0x00, 0x00, 0x7E, 0x00};
		midi.add_sysex(xg_sysex, sizeof xg_sysex);
	}

	midi.add_marker("Converted by SequenceRipper 2.0");

	fgetc(inGBA);						// Unknown byte
	fgetc(inGBA);						// Priority
	int8_t reverb = fgetc(inGBA);		// Reverb

	int instr_bank_address = get_GBA_pointer();

	// Read table of pointers
	for (int i = 0; i < track_amnt; i++)
	{
		track_ptr[i] = get_GBA_pointer();

		lfo_depth[i] = 0;
		lfo_delay[i] = 0;
		lfo_flag[i] = false;

		if (reverb < 0)  // add reverb controller on all tracks
			midi.add_controller(i, 91, lv ? (int)sqrt((reverb & 0x7f) * 127.0) : reverb & 0x7f);
	}

	// Search for loop address of track #0
	if (track_amnt > 1)	// If 2 or more track, end of track is before start of track 2
		fseek(inGBA, track_ptr[1] - 9, SEEK_SET);
	else
		// If only a single track, the end is before start of header data
		fseek(inGBA, base_address - 9, SEEK_SET);

	// Read where in track 1 the loop starts
	for (int i = 0; i < 5; i++)
		if (fgetc(inGBA) == 0xb2)
		{
			loop_flag = true;
			loop_adr = get_GBA_pointer();
			break;
		}

	// This is the main loop which will process all channels
	// until they are all inactive
	int i = 100000;
	while (tick(track_amnt))
	{
		if (i-- == 0)
		{	// Security thing to avoid infinite loop in case things goes wrong
			puts("Time out!");
			break;
		}
	}

	// If a loop was detected this is its end
	if (loop_flag) midi.add_marker("loopEnd");

	printf(" Maximum simultaneous notes: %d\n", simultaneous_notes_max);

	printf("Dump complete. Now outputting MIDI file...");
	midi.write(outMID);
	// Close files
	fclose(inGBA);
	puts(" Done!\n");
	return instr_bank_address;
}