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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_ChromaMatteOperation.h"
#include "BLI_math.h"
namespace blender::compositor {
ChromaMatteOperation::ChromaMatteOperation()
{
addInputSocket(DataType::Color);
addInputSocket(DataType::Color);
addOutputSocket(DataType::Value);
this->m_inputImageProgram = nullptr;
this->m_inputKeyProgram = nullptr;
}
void ChromaMatteOperation::initExecution()
{
this->m_inputImageProgram = this->getInputSocketReader(0);
this->m_inputKeyProgram = this->getInputSocketReader(1);
}
void ChromaMatteOperation::deinitExecution()
{
this->m_inputImageProgram = nullptr;
this->m_inputKeyProgram = nullptr;
}
void ChromaMatteOperation::executePixelSampled(float output[4],
float x,
float y,
PixelSampler sampler)
{
float inKey[4];
float inImage[4];
const float acceptance = this->m_settings->t1; /* in radians */
const float cutoff = this->m_settings->t2; /* in radians */
const float gain = this->m_settings->fstrength;
float x_angle, z_angle, alpha;
float theta, beta;
float kfg;
this->m_inputKeyProgram->readSampled(inKey, x, y, sampler);
this->m_inputImageProgram->readSampled(inImage, x, y, sampler);
/* Store matte(alpha) value in [0] to go with
* #COM_SetAlphaMultiplyOperation and the Value output. */
/* Algorithm from book "Video Demystified", does not include the spill reduction part. */
/* Find theta, the angle that the color space should be rotated based on key. */
/* rescale to -1.0..1.0 */
// inImage[0] = (inImage[0] * 2.0f) - 1.0f; // UNUSED
inImage[1] = (inImage[1] * 2.0f) - 1.0f;
inImage[2] = (inImage[2] * 2.0f) - 1.0f;
// inKey[0] = (inKey[0] * 2.0f) - 1.0f; // UNUSED
inKey[1] = (inKey[1] * 2.0f) - 1.0f;
inKey[2] = (inKey[2] * 2.0f) - 1.0f;
theta = atan2(inKey[2], inKey[1]);
/*rotate the cb and cr into x/z space */
x_angle = inImage[1] * cosf(theta) + inImage[2] * sinf(theta);
z_angle = inImage[2] * cosf(theta) - inImage[1] * sinf(theta);
/*if within the acceptance angle */
/* if kfg is <0 then the pixel is outside of the key color */
kfg = x_angle - (fabsf(z_angle) / tanf(acceptance / 2.0f));
if (kfg > 0.0f) { /* found a pixel that is within key color */
alpha = 1.0f - (kfg / gain);
beta = atan2(z_angle, x_angle);
/* if beta is within the cutoff angle */
if (fabsf(beta) < (cutoff / 2.0f)) {
alpha = 0.0f;
}
/* don't make something that was more transparent less transparent */
if (alpha < inImage[3]) {
output[0] = alpha;
}
else {
output[0] = inImage[3];
}
}
else { /*pixel is outside key color */
output[0] = inImage[3]; /* make pixel just as transparent as it was before */
}
}
} // namespace blender::compositor
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