ref: 96de5819111e6f89e310981e49fa52e8b9cae653
dir: /h/line.h/
typedef struct {
SPFLOAT a, dur, b;
SPFLOAT val, incr;
uint32_t sdur, stime;
int init;
} sp_line;
int sp_line_create(sp_line **p);
int sp_line_destroy(sp_line **p);
int sp_line_init(sp_data *sp, sp_line *p);
int sp_line_compute(sp_data *sp, sp_line *p, SPFLOAT *in, SPFLOAT *out);