forked from bartvdbraak/blender
52 lines
1.4 KiB
Plaintext
52 lines
1.4 KiB
Plaintext
/*
|
|
* Copyright 2011, Blender Foundation.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
*/
|
|
|
|
#include "stdosl.h"
|
|
|
|
shader node_brightness(
|
|
color ColorIn = color(0.8, 0.8, 0.8),
|
|
float Brightness = 0.0,
|
|
float Contrast = 0.0,
|
|
output color ColorOut = color(0.8, 0.8, 0.8))
|
|
{
|
|
float delta = Contrast * (1.0/200.0);
|
|
float a = 1.0 - delta * 2.0;
|
|
float b;
|
|
|
|
/* input value is a percentage */
|
|
float bright_factor = Brightness / 100.0;
|
|
|
|
/*
|
|
* The algorithm is by Werner D. Streidt
|
|
* (http://visca.com/ffactory/archives/5-99/msg00021.html)
|
|
* Extracted of OpenCV demhist.c
|
|
*/
|
|
|
|
if (Contrast > 0.0) {
|
|
a = (a < 0.0 ? 1.0/a : 0.0);
|
|
b = a * (bright_factor - delta);
|
|
}
|
|
else {
|
|
delta *= -1.0;
|
|
b = a * (bright_factor + delta);
|
|
}
|
|
|
|
ColorOut = a * ColorIn + b;
|
|
}
|
|
|