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/*
* 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.
*
* Copyright 2011, Blender Foundation.
*/
#include "COM_BrightnessOperation.h"
BrightnessOperation::BrightnessOperation()
{
this->addInputSocket(COM_DT_COLOR);
this->addInputSocket(COM_DT_VALUE);
this->addInputSocket(COM_DT_VALUE);
this->addOutputSocket(COM_DT_COLOR);
this->m_inputProgram = NULL;
this->m_use_premultiply = false;
}
void BrightnessOperation::setUsePremultiply(bool use_premultiply)
{
this->m_use_premultiply = use_premultiply;
}
void BrightnessOperation::initExecution()
{
this->m_inputProgram = this->getInputSocketReader(0);
this->m_inputBrightnessProgram = this->getInputSocketReader(1);
this->m_inputContrastProgram = this->getInputSocketReader(2);
}
void BrightnessOperation::executePixelSampled(float output[4],
float x,
float y,
PixelSampler sampler)
{
float inputValue[4];
float a, b;
float inputBrightness[4];
float inputContrast[4];
this->m_inputProgram->readSampled(inputValue, x, y, sampler);
this->m_inputBrightnessProgram->readSampled(inputBrightness, x, y, sampler);
this->m_inputContrastProgram->readSampled(inputContrast, x, y, sampler);
float brightness = inputBrightness[0];
float contrast = inputContrast[0];
brightness /= 100.0f;
float delta = contrast / 200.0f;
/*
* The algorithm is by Werner D. Streidt
* (http://visca.com/ffactory/archives/5-99/msg00021.html)
* Extracted of OpenCV demhist.c
*/
if (contrast > 0) {
a = 1.0f - delta * 2.0f;
a = 1.0f / max_ff(a, FLT_EPSILON);
b = a * (brightness - delta);
}
else {
delta *= -1;
a = max_ff(1.0f - delta * 2.0f, 0.0f);
b = a * brightness + delta;
}
if (this->m_use_premultiply) {
premul_to_straight_v4(inputValue);
}
output[0] = a * inputValue[0] + b;
output[1] = a * inputValue[1] + b;
output[2] = a * inputValue[2] + b;
output[3] = inputValue[3];
if (this->m_use_premultiply) {
straight_to_premul_v4(output);
}
}
void BrightnessOperation::deinitExecution()
{
this->m_inputProgram = NULL;
this->m_inputBrightnessProgram = NULL;
this->m_inputContrastProgram = NULL;
}
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