test/source/blender/compositor/operations/COM_TonemapOperation.cc

/* SPDX-FileCopyrightText: 2011 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

#include "COM_TonemapOperation.h"

#include "COM_ExecutionSystem.h"

#include "IMB_colormanagement.hh"

namespace blender::compositor {

TonemapOperation::TonemapOperation()
{
  this->add_input_socket(DataType::Color, ResizeMode::Align);
  this->add_output_socket(DataType::Color);
  data_ = nullptr;
  cached_instance_ = nullptr;
  flags_.can_be_constant = true;
}

void TonemapOperation::get_area_of_interest(const int input_idx,
                                            const rcti & /*output_area*/,
                                            rcti &r_input_area)
{
  BLI_assert(input_idx == 0);
  r_input_area = get_input_operation(input_idx)->get_canvas();
}

struct Luminance {
  float sum;
  float color_sum[3];
  float log_sum;
  float min;
  float max;
  int num_pixels;
};

static Luminance calc_area_luminance(const MemoryBuffer *input, const rcti &area)
{
  Luminance lum = {0};
  for (const float *elem : input->get_buffer_area(area)) {
    const float lu = IMB_colormanagement_get_luminance(elem);
    lum.sum += lu;
    add_v3_v3(lum.color_sum, elem);
    lum.log_sum += logf(std::max(lu, 0.0f) + 1e-5f);
    lum.max = std::max(lu, lum.max);
    lum.min = std::min(lu, lum.min);
    lum.num_pixels++;
  }
  return lum;
}

void TonemapOperation::update_memory_buffer_started(MemoryBuffer *output,
                                                    const rcti & /*area*/,
                                                    Span<MemoryBuffer *> inputs)
{
  MemoryBuffer *input_img = inputs[0];
  if (input_img->is_a_single_elem()) {
    copy_v4_v4(output->get_elem(0, 0), input_img->get_elem(0, 0));
    return;
  }

  if (cached_instance_ == nullptr) {
    Luminance lum = {0};
    const MemoryBuffer *input = inputs[0];
    exec_system_->execute_work<Luminance>(
        input->get_rect(),
        [=](const rcti &split) { return calc_area_luminance(input, split); },
        lum,
        [](Luminance &join, const Luminance &chunk) {
          join.sum += chunk.sum;
          add_v3_v3(join.color_sum, chunk.color_sum);
          join.log_sum += chunk.log_sum;
          join.max = std::max(join.max, chunk.max);
          join.min = std::min(join.min, chunk.min);
          join.num_pixels += chunk.num_pixels;
        });

    AvgLogLum *avg = new AvgLogLum();
    avg->lav = lum.sum / lum.num_pixels;
    mul_v3_v3fl(avg->cav, lum.color_sum, 1.0f / lum.num_pixels);
    const float max_log = log(double(lum.max) + 1e-5);
    const float min_log = log(double(lum.min) + 1e-5);
    const float avg_log = lum.log_sum / lum.num_pixels;
    avg->auto_key = (max_log > min_log) ? ((max_log - avg_log) / (max_log - min_log)) : 1.0f;
    const float al = exp(double(avg_log));
    avg->al = (al == 0.0f) ? 0.0f : (data_->key / al);
    avg->igm = (data_->gamma == 0.0f) ? 1 : (1.0f / data_->gamma);
    cached_instance_ = avg;
  }
}

void TonemapOperation::update_memory_buffer_partial(MemoryBuffer *output,
                                                    const rcti &area,
                                                    Span<MemoryBuffer *> inputs)
{
  MemoryBuffer *input_img = inputs[0];

  if (input_img->is_a_single_elem()) {
    return;
  }

  AvgLogLum *avg = cached_instance_;
  const float igm = avg->igm;
  const float offset = data_->offset;
  for (BuffersIterator<float> it = output->iterate_with(inputs, area); !it.is_end(); ++it) {
    copy_v4_v4(it.out, it.in(0));
    mul_v3_fl(it.out, avg->al);
    float dr = it.out[0] + offset;
    float dg = it.out[1] + offset;
    float db = it.out[2] + offset;
    it.out[0] /= ((dr == 0.0f) ? 1.0f : dr);
    it.out[1] /= ((dg == 0.0f) ? 1.0f : dg);
    it.out[2] /= ((db == 0.0f) ? 1.0f : db);
    if (igm != 0.0f) {
      it.out[0] = powf(std::max(it.out[0], 0.0f), igm);
      it.out[1] = powf(std::max(it.out[1], 0.0f), igm);
      it.out[2] = powf(std::max(it.out[2], 0.0f), igm);
    }
  }
}

void PhotoreceptorTonemapOperation::update_memory_buffer_partial(MemoryBuffer *output,
                                                                 const rcti &area,
                                                                 Span<MemoryBuffer *> inputs)
{
  MemoryBuffer *input_img = inputs[0];
  if (input_img->is_a_single_elem()) {
    copy_v4_v4(output->get_elem(0, 0), input_img->get_elem(0, 0));
    return;
  }

  AvgLogLum *avg = cached_instance_;
  const NodeTonemap *ntm = data_;
  const float f = expf(-data_->f);
  const float m = (ntm->m > 0.0f) ? ntm->m : (0.3f + 0.7f * powf(avg->auto_key, 1.4f));
  const float ic = 1.0f - ntm->c;
  const float ia = 1.0f - ntm->a;
  for (BuffersIterator<float> it = output->iterate_with(inputs, area); !it.is_end(); ++it) {
    copy_v4_v4(it.out, it.in(0));
    const float L = IMB_colormanagement_get_luminance(it.out);
    float I_l = it.out[0] + ic * (L - it.out[0]);
    float I_g = avg->cav[0] + ic * (avg->lav - avg->cav[0]);
    float I_a = I_l + ia * (I_g - I_l);
    it.out[0] /= (it.out[0] + powf(f * I_a, m));
    I_l = it.out[1] + ic * (L - it.out[1]);
    I_g = avg->cav[1] + ic * (avg->lav - avg->cav[1]);
    I_a = I_l + ia * (I_g - I_l);
    it.out[1] /= (it.out[1] + powf(f * I_a, m));
    I_l = it.out[2] + ic * (L - it.out[2]);
    I_g = avg->cav[2] + ic * (avg->lav - avg->cav[2]);
    I_a = I_l + ia * (I_g - I_l);
    it.out[2] /= (it.out[2] + powf(f * I_a, m));
  }
}

}  // namespace blender::compositor