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/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright 2012 Blender Foundation. */
#include "COM_KeyingOperation.h"
namespace blender::compositor {
static float get_pixel_saturation(const float pixel_color[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 * pixel_color[min_channel] +
(1.0f - screen_balance) * pixel_color[max_channel];
return (pixel_color[primary_channel] - val) * fabsf(1.0f - val);
}
KeyingOperation::KeyingOperation()
{
this->add_input_socket(DataType::Color);
this->add_input_socket(DataType::Color);
this->add_output_socket(DataType::Value);
screen_balance_ = 0.5f;
pixel_reader_ = nullptr;
screen_reader_ = nullptr;
}
void KeyingOperation::init_execution()
{
pixel_reader_ = this->get_input_socket_reader(0);
screen_reader_ = this->get_input_socket_reader(1);
}
void KeyingOperation::deinit_execution()
{
pixel_reader_ = nullptr;
screen_reader_ = nullptr;
}
void KeyingOperation::execute_pixel_sampled(float output[4],
float x,
float y,
PixelSampler sampler)
{
float pixel_color[4];
float screen_color[4];
pixel_reader_->read_sampled(pixel_color, x, y, sampler);
screen_reader_->read_sampled(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, screen_balance_, primary_channel);
float screen_saturation = get_pixel_saturation(screen_color, screen_balance_, 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;
}
}
}
void KeyingOperation::update_memory_buffer_partial(MemoryBuffer *output,
const rcti &area,
Span<MemoryBuffer *> inputs)
{
for (BuffersIterator<float> it = output->iterate_with(inputs, area); !it.is_end(); ++it) {
const float *pixel_color = it.in(0);
const float *screen_color = it.in(1);
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.
*/
it.out[0] = 1.0f;
}
else {
const float saturation = get_pixel_saturation(pixel_color, screen_balance_, primary_channel);
const float screen_saturation = get_pixel_saturation(
screen_color, screen_balance_, primary_channel);
if (saturation < 0) {
/* Means main channel of pixel is different from screen,
* assume this is completely a foreground.
*/
it.out[0] = 1.0f;
}
else if (saturation >= screen_saturation) {
/* Matched main channels and higher saturation on pixel
* is treated as completely background.
*/
it.out[0] = 0.0f;
}
else {
/* Nice alpha falloff on edges. */
const float distance = 1.0f - saturation / screen_saturation;
it.out[0] = distance;
}
}
}
}
} // namespace blender::compositor
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