From 4dc5213b0913a2585f75dfd03b497ca2efc093de Mon Sep 17 00:00:00 2001 From: Stefano Sabatini Date: Thu, 28 Dec 2023 19:09:22 +0100 Subject: [PATCH] lavu/eval: add randomi function to compute random value in interval --- libavutil/eval.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/libavutil/eval.c b/libavutil/eval.c index 344bebbf69..e94597ccf4 100644 --- a/libavutil/eval.c +++ b/libavutil/eval.c @@ -164,7 +164,7 @@ struct AVExpr { 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_lerp, - e_sgn, + e_sgn, e_randomi } type; double value; // is sign in other types int const_index; @@ -230,13 +230,23 @@ static double eval_expr(Parser *p, AVExpr *e) av_log(p, level, "%f\n", x); return x; } - case e_random:{ +#define COMPUTE_RANDOM(seed_) (seed_)*1664525+1013904223 + case e_random:{ int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1); uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx]; - r= r*1664525+1013904223; + r = COMPUTE_RANDOM(r); p->var[idx]= r; return e->value * (r * (1.0/UINT64_MAX)); } + case e_randomi: { + int idx = av_clip(eval_expr(p, e->param[0]), 0, VARS-1); + uint64_t r = isnan(p->var[idx]) ? 0 : p->var[idx]; + r = COMPUTE_RANDOM(r); + p->var[idx] = r; + double min = eval_expr(p, e->param[1]); + double max = eval_expr(p, e->param[2]); + return min + (max - min) * r / UINT64_MAX; + } case e_while: { double d = NAN; while (eval_expr(p, e->param[0])) @@ -463,6 +473,7 @@ static int parse_primary(AVExpr **e, Parser *p) else if (strmatch(next, "pow" )) d->type = e_pow; else if (strmatch(next, "print" )) d->type = e_print; else if (strmatch(next, "random")) d->type = e_random; + else if (strmatch(next, "randomi")) d->type = e_randomi; else if (strmatch(next, "hypot" )) d->type = e_hypot; else if (strmatch(next, "gcd" )) d->type = e_gcd; else if (strmatch(next, "if" )) d->type = e_if; @@ -676,6 +687,7 @@ static int verify_expr(AVExpr *e) case e_between: case e_clip: case e_lerp: + case e_randomi: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && verify_expr(e->param[2]); -- 2.34.1