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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 2012, Blender Foundation.
*/
#include "COM_KeyingOperation.h"
#include "MEM_guardedalloc.h"
#include "BLI_listbase.h"
#include "BLI_math.h"
namespace blender::compositor {
static float get_pixel_saturation(const float pixelColor[4],
float screen_balance,
int primary_channel)
{
const int other_1 = (primary_channel + 1) % 3;
const int other_2 = (primary_channel + 2) % 3;
const int min_channel = MIN2(other_1, other_2);
const int max_channel = MAX2(other_1, other_2);
const float val = screen_balance * pixelColor[min_channel] +
(1.0f - screen_balance) * pixelColor[max_channel];
return (pixelColor[primary_channel] - val) * fabsf(1.0f - val);
}
KeyingOperation::KeyingOperation()
{
this->addInputSocket(DataType::Color);
this->addInputSocket(DataType::Color);
this->addOutputSocket(DataType::Value);
this->m_screenBalance = 0.5f;
this->m_pixelReader = nullptr;
this->m_screenReader = nullptr;
}
void KeyingOperation::initExecution()
{
this->m_pixelReader = this->getInputSocketReader(0);
this->m_screenReader = this->getInputSocketReader(1);
}
void KeyingOperation::deinitExecution()
{
this->m_pixelReader = nullptr;
this->m_screenReader = nullptr;
}
void KeyingOperation::executePixelSampled(float output[4], float x, float y, PixelSampler sampler)
{
float pixel_color[4];
float screen_color[4];
this->m_pixelReader->readSampled(pixel_color, x, y, sampler);
this->m_screenReader->readSampled(screen_color, x, y, sampler);
const int primary_channel = max_axis_v3(screen_color);
const float min_pixel_color = min_fff(pixel_color[0], pixel_color[1], pixel_color[2]);
if (min_pixel_color > 1.0f) {
/* overexposure doesn't happen on screen itself and usually happens
* on light sources in the shot, this need to be checked separately
* because saturation and falloff calculation is based on the fact
* that pixels are not overexposed
*/
output[0] = 1.0f;
}
else {
float saturation = get_pixel_saturation(pixel_color, this->m_screenBalance, primary_channel);
float screen_saturation = get_pixel_saturation(
screen_color, this->m_screenBalance, primary_channel);
if (saturation < 0) {
/* means main channel of pixel is different from screen,
* assume this is completely a foreground
*/
output[0] = 1.0f;
}
else if (saturation >= screen_saturation) {
/* matched main channels and higher saturation on pixel
* is treated as completely background
*/
output[0] = 0.0f;
}
else {
/* nice alpha falloff on edges */
float distance = 1.0f - saturation / screen_saturation;
output[0] = distance;
}
}
}
} // namespace blender::compositor
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