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/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright 2011 Blender Foundation. */
#include "COM_BrightnessOperation.h"
namespace blender::compositor {
BrightnessOperation::BrightnessOperation()
{
this->add_input_socket(DataType::Color);
this->add_input_socket(DataType::Value);
this->add_input_socket(DataType::Value);
this->add_output_socket(DataType::Color);
input_program_ = nullptr;
use_premultiply_ = false;
flags_.can_be_constant = true;
}
void BrightnessOperation::set_use_premultiply(bool use_premultiply)
{
use_premultiply_ = use_premultiply;
}
void BrightnessOperation::init_execution()
{
input_program_ = this->get_input_socket_reader(0);
input_brightness_program_ = this->get_input_socket_reader(1);
input_contrast_program_ = this->get_input_socket_reader(2);
}
void BrightnessOperation::execute_pixel_sampled(float output[4],
float x,
float y,
PixelSampler sampler)
{
float input_value[4];
float a, b;
float input_brightness[4];
float input_contrast[4];
input_program_->read_sampled(input_value, x, y, sampler);
input_brightness_program_->read_sampled(input_brightness, x, y, sampler);
input_contrast_program_->read_sampled(input_contrast, x, y, sampler);
float brightness = input_brightness[0];
float contrast = input_contrast[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 (use_premultiply_) {
premul_to_straight_v4(input_value);
}
output[0] = a * input_value[0] + b;
output[1] = a * input_value[1] + b;
output[2] = a * input_value[2] + b;
output[3] = input_value[3];
if (use_premultiply_) {
straight_to_premul_v4(output);
}
}
void BrightnessOperation::update_memory_buffer_partial(MemoryBuffer *output,
const rcti &area,
Span<MemoryBuffer *> inputs)
{
float tmp_color[4];
for (BuffersIterator<float> it = output->iterate_with(inputs, area); !it.is_end(); ++it) {
const float *in_color = it.in(0);
const float brightness = *it.in(1) / 100.0f;
const float contrast = *it.in(2);
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`.
*/
float a, b;
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;
}
const float *color;
if (use_premultiply_) {
premul_to_straight_v4_v4(tmp_color, in_color);
color = tmp_color;
}
else {
color = in_color;
}
it.out[0] = a * color[0] + b;
it.out[1] = a * color[1] + b;
it.out[2] = a * color[2] + b;
it.out[3] = color[3];
if (use_premultiply_) {
straight_to_premul_v4(it.out);
}
}
}
void BrightnessOperation::deinit_execution()
{
input_program_ = nullptr;
input_brightness_program_ = nullptr;
input_contrast_program_ = nullptr;
}
} // namespace blender::compositor
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