htpp

commit c9640681dcbeee20d52f1627ed95270aadd13650
parent 4514baace016476895d4cecea332b79d100e995f
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri,  6 Dec 2019 15:13:06 +0100

Upd how image exposure is handled

The pixel is now multiplied by the exposure priorly to its tone mapping.

Diffstat:
M
doc/htpp.1.txt
 | 
2
+-
M
src/htpp.c
 | 
6
+++---

2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/doc/htpp.1.txt b/doc/htpp.1.txt
@@ -35,7 +35,7 @@ standard input.
 *htpp* tone maps the high dynamic range colors of the _input_ image with the
 following filmic tone mapping operator [2]:
 
-    out-color = f(in-color) / f(white-scale) * exposure
+    out-color = f(in-color * exposure) / f(white-scale)
 
 with:
 
diff --git a/src/htpp.c b/src/htpp.c
@@ -277,9 +277,9 @@ filmic_tone_mapping(double pixel[3], const double exposure, const double Ymax)
   const double white_scale = TONE_MAP(W);
   ASSERT(pixel);
 
-  pixel[0] = TONE_MAP(pixel[0]) / white_scale * exposure;
-  pixel[1] = TONE_MAP(pixel[1]) / white_scale * exposure;
-  pixel[2] = TONE_MAP(pixel[2]) / white_scale * exposure;
+  pixel[0] = TONE_MAP(pixel[0]*exposure) / white_scale;
+  pixel[1] = TONE_MAP(pixel[1]*exposure) / white_scale;
+  pixel[2] = TONE_MAP(pixel[2]*exposure) / white_scale;
   #undef TONE_MAP
   return pixel;
 }