From 812586a54a13ea618097760fc4514abcb8f49e2c Mon Sep 17 00:00:00 2001
From: Niklas Haas <git@haasn.dev>
Date: Sun, 5 Feb 2023 14:53:19 +0100
Subject: [PATCH] tone_mapping: make HDR metadata available to tone-mappers

By just sticking it inside `pl_hdr_metadata`, happen what may.

We don't need access to the output metadata, so omit it. (This will
probably never change, because this HDR metadata contains scene-derived
values)
---
 meson.build                           | 1 +
 src/include/libplacebo/tone_mapping.h | 5 +++++
 src/shaders/colorspace.c              | 1 +
 src/tone_mapping.c                    | 3 ++-
 4 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/meson.build b/meson.build
index 09f17f9e..8bab6a00 100644
--- a/meson.build
+++ b/meson.build
@@ -12,6 +12,7 @@ project('libplacebo', ['c', 'cpp'],
     5,
     # API version
     {
+      '245': 'add `pl_tone_map_params.hdr`',
       '244': 'add `pl_map_hdr_metadata`',
       '243': 'add `pl_color_space.nominal_min/max`',
       '242': 'add `pl_hdr_metadata.scene_max/avg` and `pl_hdr_metadata.ootf`',
diff --git a/src/include/libplacebo/tone_mapping.h b/src/include/libplacebo/tone_mapping.h
index c198d528..d2508b88 100644
--- a/src/include/libplacebo/tone_mapping.h
+++ b/src/include/libplacebo/tone_mapping.h
@@ -22,6 +22,7 @@
 #include <stdbool.h>
 
 #include <libplacebo/common.h>
+#include <libplacebo/colorspace.h>
 
 PL_API_BEGIN
 
@@ -93,6 +94,10 @@ struct pl_tone_map_params {
     // The desired characteristics of the output, in `output_scaling` units.
     float output_min;
     float output_max;
+
+    // The input HDR metadata. Only used by a select few tone-mapping
+    // functions. (Optional)
+    struct pl_hdr_metadata hdr;
 };
 
 #define pl_tone_map_params(...) (&(struct pl_tone_map_params) { __VA_ARGS__ });
diff --git a/src/shaders/colorspace.c b/src/shaders/colorspace.c
index 92b3afd3..bf5cfcdf 100644
--- a/src/shaders/colorspace.c
+++ b/src/shaders/colorspace.c
@@ -1285,6 +1285,7 @@ static void tone_map(pl_shader sh,
         .input_max = pl_hdr_rescale(PL_HDR_NORM, PL_HDR_SQRT, src_max),
         .output_min = dst_min,
         .output_max = dst_max,
+        .hdr = src->hdr,
     };
 
     enum pl_tone_map_mode mode = params->tone_mapping_mode;
diff --git a/src/tone_mapping.c b/src/tone_mapping.c
index 72e71d01..b3e15625 100644
--- a/src/tone_mapping.c
+++ b/src/tone_mapping.c
@@ -87,7 +87,8 @@ bool pl_tone_map_params_equal(const struct pl_tone_map_params *a,
            a->input_min == b->input_min &&
            a->input_max == b->input_max &&
            a->output_min == b->output_min &&
-           a->output_max == b->output_max;
+           a->output_max == b->output_max &&
+           pl_hdr_metadata_equal(&a->hdr, &b->hdr);
 }
 
 bool pl_tone_map_params_noop(const struct pl_tone_map_params *p)