/* * TADSR * * This module uses modified code from Perry Cook's ADSR STK module. * */ #include <stdlib.h>#include <math.h>#include "soundpipe.h" enum{ ATTACK, DECAY, SUSTAIN, RELEASE, CLEAR, KEY_ON, KEY_OFF }; static void make_Envelope(sp_tadsr *e){    e->target = 0.0;    e->value = 0.0;    e->rate = 0.001;    e->state = 1;} static void make_ADSR(sp_tadsr *a){    make_Envelope(a);    a->target = 0.0;    a->value = 0.0;    a->attackRate = 0.001;    a->decayRate = 0.001;    a->sustainLevel = 0.0;    a->releaseRate = 0.01;    a->state = CLEAR;} static void ADSR_keyOn(sp_tadsr *a){    a->target = 1.0;    a->rate = a->attackRate;    a->state = ATTACK;} static void ADSR_keyOff(sp_tadsr *a){    a->target = 0.0;    a->rate = a->releaseRate;    a->state = RELEASE;} static void ADSR_setSustainLevel(sp_data *sp, sp_tadsr *a, SPFLOAT aLevel){    USED(sp);    a->sustainLevel = aLevel;} static void ADSR_setAttackTime(sp_data *sp, sp_tadsr *a, SPFLOAT aTime){    a->attackRate = 1.0 / (aTime * sp->sr);} static void ADSR_setDecayTime(sp_data *sp, sp_tadsr *a, SPFLOAT aTime){    a->decayRate = 1.0 / (aTime * sp->sr);} static void ADSR_setReleaseTime(sp_data *sp, sp_tadsr *a, SPFLOAT aTime){    a->releaseRate = 1.0 / (aTime * sp->sr);} static void ADSR_setAllTimes(sp_data *sp, sp_tadsr *a, SPFLOAT attTime, SPFLOAT decTime,                      SPFLOAT susLevel, SPFLOAT relTime){    ADSR_setAttackTime(sp, a, attTime);    ADSR_setDecayTime(sp, a, decTime);    ADSR_setSustainLevel(sp, a, susLevel);    ADSR_setReleaseTime(sp, a, relTime);} static SPFLOAT ADSR_tick(sp_tadsr *a){    SPFLOAT out = 0;    if (a->state == ATTACK) {        a->value += a->rate;        if (a->value >= a->target) {            a->value = a->target;            a->rate = a->decayRate;            a->target = a->sustainLevel;            a->state = DECAY;        }        out = a->value;    } else if (a->state == DECAY) {        a->value -= a->decayRate;        out = a->value;        if (a->value <= a->sustainLevel) {            a->value = a->sustainLevel;            out = a->sustainLevel;            a->rate = 0.0;            a->state = SUSTAIN;        }    } else if (a->state == RELEASE)  {        a->value -= a->releaseRate;        if (a->value <= 0.0) {            a->value = 0.0;            a->state = CLEAR;        }        out = a->value;    } else if (a->state == SUSTAIN)  {        out = a->sustainLevel;    }    return out;} int sp_tadsr_create(sp_tadsr **p){    *p = malloc(sizeof(sp_tadsr));    return SP_OK;} int sp_tadsr_destroy(sp_tadsr **p){    free(*p);    return SP_OK;} int sp_tadsr_init(sp_data *sp, sp_tadsr *p){    USED(sp);     make_ADSR(p);    p->atk = 0.5;    p->dec = 0.5;    p->sus = 0.0;    p->rel = 0.5;    p->mode = KEY_OFF;    return SP_OK;} int sp_tadsr_compute(sp_data *sp, sp_tadsr *p, SPFLOAT *trig, SPFLOAT *out){    if(*trig != 0) {         if(*trig == 2) {            ADSR_keyOff(p);            p->mode = KEY_OFF;        }else if(p->mode == KEY_OFF) {            ADSR_setAllTimes(sp, p, p->atk, p->dec, p->sus, p->rel);            ADSR_keyOn(p);            p->mode = KEY_ON;        } else {            ADSR_keyOff(p);            p->mode = KEY_OFF;        }    }    *out = ADSR_tick(p);    return SP_OK;}