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authorPaul B Mahol <onemda@gmail.com>2017-08-18 09:15:33 +0200
committerPaul B Mahol <onemda@gmail.com>2017-08-19 12:42:24 +0200
commit1146133df8117c96cc6681a062df6df825fcae2d (patch)
tree19cb503e6e87c1ebf223724e9e2afd0cac991eeb /libavutil/eval.c
parente3a4afca07b2753269f5f05c6fd5ca3034734c00 (diff)
avutil/eval: add linear interpolation helper
Diffstat (limited to 'libavutil/eval.c')
-rw-r--r--libavutil/eval.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/libavutil/eval.c b/libavutil/eval.c
index 638259adef..b5f4ea2409 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -155,7 +155,7 @@ struct AVExpr {
e_pow, e_mul, e_div, e_add,
e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc, e_round,
e_sqrt, e_not, e_random, e_hypot, e_gcd,
- e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2
+ e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2, e_lerp,
} type;
double value; // is sign in other types
union {
@@ -208,6 +208,12 @@ static double eval_expr(Parser *p, AVExpr *e)
return e->value * (d >= eval_expr(p, e->param[1]) &&
d <= eval_expr(p, e->param[2]));
}
+ case e_lerp: {
+ double v0 = eval_expr(p, e->param[0]);
+ double v1 = eval_expr(p, e->param[1]);
+ double f = eval_expr(p, e->param[2]);
+ return v0 + (v1 - v0) * f;
+ }
case e_print: {
double x = eval_expr(p, e->param[0]);
int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
@@ -456,6 +462,7 @@ static int parse_primary(AVExpr **e, Parser *p)
else if (strmatch(next, "between"))d->type = e_between;
else if (strmatch(next, "clip" )) d->type = e_clip;
else if (strmatch(next, "atan2" )) d->type = e_atan2;
+ else if (strmatch(next, "lerp" )) d->type = e_lerp;
else {
for (i=0; p->func1_names && p->func1_names[i]; i++) {
if (strmatch(next, p->func1_names[i])) {
@@ -654,6 +661,7 @@ static int verify_expr(AVExpr *e)
&& (!e->param[2] || verify_expr(e->param[2]));
case e_between:
case e_clip:
+ case e_lerp:
return verify_expr(e->param[0]) &&
verify_expr(e->param[1]) &&
verify_expr(e->param[2]);