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vo_opengl: add hable tone-mapping algorithm 

Developed by John Hable for use in Uncharted 2. Also used by Frictional
Games in SOMA. Originally inspired by a filmic tone mapping algorithm
created by Kodak.

From http://frictionalgames.blogspot.de/2012/09/tech-feature-hdr-lightning.html
This commit is contained in:
Niklas Haas 2016-05-30 12:48:01 +02:00 committed by wm4
parent 48015009b7
commit 15bb05d2fe
4 changed files with 16 additions and 0 deletions
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3
DOCS/man/vo.rst
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@ -1074,6 +1074,9 @@ Available video output drivers are:
reinhard
Reinhard tone mapping algorithm. Very simple continuous curve.
Preserves dynamic range and peak but uses nonlinear contrast.
hable
Similar to ``reinhard`` but preserves dark contrast better (slightly
sigmoidal). Developed by John Hable for use in video games.
gamma
Fits a logarithmic transfer between the tone curves.
linear

1
video/out/opengl/video.c
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@ -385,6 +385,7 @@ const struct m_sub_options gl_video_conf = {
OPT_CHOICE("hdr-tone-mapping", hdr_tone_mapping, 0,
({"clip", TONE_MAPPING_CLIP},
{"reinhard", TONE_MAPPING_REINHARD},
{"hable", TONE_MAPPING_HABLE},
{"gamma", TONE_MAPPING_GAMMA},
{"linear", TONE_MAPPING_LINEAR})),
OPT_FLOAT("tone-mapping-param", tone_mapping_param, 0),

1
video/out/opengl/video.h
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@ -106,6 +106,7 @@ enum prescalers {
enum tone_mapping {
TONE_MAPPING_CLIP,
TONE_MAPPING_REINHARD,
TONE_MAPPING_HABLE,
TONE_MAPPING_GAMMA,
TONE_MAPPING_LINEAR,
};

11
video/out/opengl/video_shaders.c
View File

@ -335,6 +335,17 @@ void pass_tone_map(struct gl_shader_cache *sc, float peak_src, float peak_dst,
break;
}
case TONE_MAPPING_HABLE: {
float A = 0.15, B = 0.50, C = 0.10, D = 0.20, E = 0.02, F = 0.30;
GLSLHF("vec3 hable(vec3 x) {\n");
GLSLHF("return ((x * (%f*x + %f)+%f)/(x * (%f*x + %f) + %f)) - %f;\n",
A, C*B, D*E, A, B, D*F, E/F);
GLSLHF("}\n");
GLSLF("color.rgb = hable(color.rgb) / hable(vec3(%f));\n", scale);
break;
}
case TONE_MAPPING_GAMMA: {
float gamma = isnan(param) ? 1.8 : param;
GLSLF("color.rgb = pow(color.rgb / vec3(%f), vec3(%f));\n",