Rewrite of the stage module.

[cantaveria.git] / seq.c

/*
   Cantaveria - action adventure platform game
   Copyright (C) 2009 2010 Evan Rinehart

   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.
   51 Franklin Street, Fifth Floor
   Boston, MA  02110-1301, USA

   evanrinehart@gmail.com
*/
#include <stdio.h>
#include <stdlib.h>

#include <list.h>
#include <util.h>
#include <audio.h>
#include <midi.h>
#include <seq.h>

int tick;
int terr;
int loop_start;
int enable = 0;

int bpm = 120;
int tpb = 384;

//event lists
list* sequence;
list* blank_events;
list* immediate_events;

list* next_event;
list* event_after_loop;



void advance_event(event* now){
        if(now->type == EVX_LOOPEND){
                next_event = event_after_loop;
                tick = loop_start;
        }
        else{
                next_event = next_event->next;
        }
}

event* dequeue_event(){
        if(next_event == NULL) return NULL;

        event* e = next_event->item;
        if(e->tick <= tick){
                advance_event(e);

                if(e->type == EVX_TEMPOCHANGE){
                        bpm = e->val1;
                }

                if(e->type == EVX_TICKSPERBEAT){
                        tpb = e->val1;
                }

                if(e->type == EVX_LOOPSTART){
                        loop_start = e->tick;
                        event_after_loop = next_event;
                }

                return e;
        }
        else{
                return NULL;
        }
}

int samples_until_next(int max){
        int N = 2646000;
        int D = bpm*tpb;

        if(next_event == NULL) return max;

        event* e = next_event->item;
        if(e->tick - tick > max * D / N) return max;

        int d = (e->tick-tick)*N/D;
        return d < max ? d : max;
}

event* seq_advance(int max, int* used){
        int N = bpm*tpb;     // bpm * tpb
        int D = 2646000;   // srate * 60
        event* e;

        int u = samples_until_next(max);

        if(!enable){
                *used = max;
                return NULL;
        }

        *used = u;
        e = dequeue_event();

        terr += N * u;
        tick += terr/D;
        terr %= D;

        return e;
}




/* *** */
static event* make_event(int type, int chan, int val1, int val2){
        event* e;
        if(blank_events->next){
                e = pop(blank_events);
        }
        else{
                e = xmalloc(sizeof(event));
        }

        e->type = type;
        e->chan = chan;
        e->val1= val1;
        e->val2= val2;
        e->tick = 0;
        return e;
}

void recycle_event(event* e){
        push(blank_events, e);
}


void seq_instant(int type, int chan, int val1, int val2){
        event* e = make_event(type, chan, val1, val2);
        audio_lock();
                append(immediate_events, e);
        audio_unlock();
}


void seq_play_sound(int id){
        seq_instant(0x90, 15, id, 0);
}



event* seq_get_immediate(){
        event* e = pop(immediate_events);
        if(e != NULL){
                recycle_event(e);
                return e;
        }
        else{
                return NULL;
        }
}



void seq_enqueue(int when, int type, int chan, int val1, int val2){
        event* e = make_event(type, chan, val1, val2);
        e->tick = when;
        seq_append(e);
}

void seq_clear(){
        list* ptr = sequence->next;
        while(ptr){
                free(ptr->item);
                ptr = ptr->next;
        }
        recycle(sequence);
        sequence = empty();
}


void seq_append(event* e){
        append(sequence, e);
}

void seq_init(){
        blank_events = empty();
        immediate_events = empty();
        sequence = empty();

        loop_start = 0;

        next_event = sequence->next;
}

void seq_load(list* events){
        audio_lock();
                tick = 0;
                terr = 0;
                sequence = events;
                next_event = sequence->next;
                event_after_loop = next_event;
                loop_start = 0;
        audio_unlock();
}

void seq_seek(list* target){
        event* e = target->item;
        audio_lock();
                next_event = target;
                tick = e->tick;
        audio_unlock();
}

list* seq_tell(){
        return next_event;
}

void seq_enable(){
        enable = 1;
}

void seq_disable(){
        seq_instant(EVX_MUSICCUT, 0, 0, 0);
        enable = 0;
}