struct envelope_t
{
	/* 'Real world' AHDSR values */
	double attack;
	double attack_hold;
	double decay;
	double sustain;
	double release;

	/* AHDR values in samples */
	double attack_s;
	double attack_hold_s;
	double decay_s;
	double release_s;
};

void env_init(struct envelope_t *env, double attack, double attack_hold, double decay, double sustain, double release);
double env_getamplitude(struct envelope_t *env, uint32_t sample, uint32_t released);