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| author | Stefano Sabatini <stefasab@gmail.com> | 2023-12-28 19:09:22 +0100 |
|---|---|---|
| committer | Stefano Sabatini <stefasab@gmail.com> | 2024-01-01 20:12:52 +0100 |
| commit | 7769afcab4c2160d39058b21bcfb7923f4b036eb (patch) | |
| tree | af8a24ed600914e9975369a2c2415fa8e6fd6b8c /libavutil/eval.c | |
| parent | 933c7ff0b96f72e71155d91e66f726e0beb4e824 (diff) | |
| download | ffmpeg-7769afcab4c2160d39058b21bcfb7923f4b036eb.tar.gz | |
lavu/eval: add randomi function to compute random value in interval
Diffstat (limited to 'libavutil/eval.c')
| -rw-r--r-- | libavutil/eval.c | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/libavutil/eval.c b/libavutil/eval.c index bad9e4ecb8..dc6b3697bc 100644 --- a/libavutil/eval.c +++ b/libavutil/eval.c @@ -162,7 +162,7 @@ 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; @@ -228,12 +228,22 @@ static double eval_expr(Parser *p, AVExpr *e) av_log(p, level, "%f\n", x); return x; } - 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; - p->var[idx]= r; - return e->value * (r * (1.0/UINT64_MAX)); + +#define COMPUTE_NEXT_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; \ + p->var[idx] = r; \ + + case e_random: { + COMPUTE_NEXT_RANDOM(); + return r * (1.0/UINT64_MAX); + } + case e_randomi: { + double min = eval_expr(p, e->param[1]); + double max = eval_expr(p, e->param[2]); + COMPUTE_NEXT_RANDOM(); + return min + (max - min) * r / UINT64_MAX; } case e_while: { double d = NAN; @@ -461,6 +471,7 @@ 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; @@ -674,6 +685,7 @@ 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]); |