COM_DoubleEdgeMaskOperation.cc

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/* SPDX-FileCopyrightText: 2011 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <cstdlib>
 
#include "BLI_math_vector.hh"
#include "BLI_span.hh"
#include "BLI_task.hh"
 
#include "COM_DoubleEdgeMaskOperation.h"
#include "COM_JumpFloodingAlgorithm.h"
 
/* Exact copies of the functions in compositor_double_edge_mask_compute_boundary.glsl and
 * compositor_double_edge_mask_compute_gradient.glsl but adapted for CPU. See those files for more
 * information. */
 
namespace blender::compositor {
 
static float load_mask(const float *input, int2 texel, int2 size)
{
  const int2 clamped_texel = math::clamp(texel, int2(0), size - 1);
  return input[size_t(clamped_texel.y) * size.x + clamped_texel.x];
}
 
static float load_mask(const float *input, int2 texel, int2 size, float fallback)
{
  if (texel.x < 0 || texel.x >= size.x || texel.y < 0 || texel.y >= size.y) {
    return fallback;
  }
  return input[size_t(texel.y) * size.x + texel.x];
}
 
void DoubleEdgeMaskOperation::compute_boundary(const float *inner_mask,
                                               const float *outer_mask,
                                               MutableSpan<int2> inner_boundary,
                                               MutableSpan<int2> outer_boundary)
{
  const int2 size = int2(this->get_width(), this->get_height());
  threading::parallel_for(IndexRange(size.y), 1, [&](const IndexRange sub_y_range) {
    for (const int64_t y : sub_y_range) {
      for (const int64_t x : IndexRange(size.x)) {
        int2 texel = int2(x, y);
 
        bool has_inner_non_masked_neighbors = false;
        bool has_outer_non_masked_neighbors = false;
        for (int j = -1; j <= 1; j++) {
          for (int i = -1; i <= 1; i++) {
            int2 offset = int2(i, j);
 
            if (offset == int2(0)) {
              continue;
            }
 
            if (load_mask(inner_mask, texel + offset, size) == 0.0f) {
              has_inner_non_masked_neighbors = true;
            }
 
            float boundary_fallback = include_edges_of_image_ ? 0.0f : 1.0f;
            if (load_mask(outer_mask, texel + offset, size, boundary_fallback) == 0.0f) {
              has_outer_non_masked_neighbors = true;
            }
 
            if (has_inner_non_masked_neighbors && has_outer_non_masked_neighbors) {
              break;
            }
          }
        }
 
        bool is_inner_masked = load_mask(inner_mask, texel, size) > 0.0f;
        bool is_outer_masked = load_mask(outer_mask, texel, size) > 0.0f;
 
        bool is_inner_boundary = is_inner_masked && has_inner_non_masked_neighbors &&
                                 (is_outer_masked || include_all_inner_edges_);
        bool is_outer_boundary = is_outer_masked && !is_inner_masked &&
                                 has_outer_non_masked_neighbors;
 
        int2 inner_jump_flooding_value = initialize_jump_flooding_value(texel, is_inner_boundary);
        int2 outer_jump_flooding_value = initialize_jump_flooding_value(texel, is_outer_boundary);
 
        const size_t output_index = size_t(texel.y) * size.x + texel.x;
        inner_boundary[output_index] = inner_jump_flooding_value;
        outer_boundary[output_index] = outer_jump_flooding_value;
      }
    }
  });
}
 
void DoubleEdgeMaskOperation::compute_gradient(const float *inner_mask_buffer,
                                               const float *outer_mask_buffer,
                                               MutableSpan<int2> flooded_inner_boundary,
                                               MutableSpan<int2> flooded_outer_boundary,
                                               float *output_mask)
{
  const int2 size = int2(this->get_width(), this->get_height());
  threading::parallel_for(IndexRange(size.y), 1, [&](const IndexRange sub_y_range) {
    for (const int64_t y : sub_y_range) {
      for (const int64_t x : IndexRange(size.x)) {
        int2 texel = int2(x, y);
        const size_t index = size_t(texel.y) * size.x + texel.x;
 
        float inner_mask = inner_mask_buffer[index];
        if (inner_mask != 0.0f) {
          output_mask[index] = 1.0f;
          continue;
        }
 
        float outer_mask = outer_mask_buffer[index];
        if (outer_mask == 0.0f) {
          output_mask[index] = 0.0f;
          continue;
        }
 
        int2 inner_boundary_texel = flooded_inner_boundary[index];
        int2 outer_boundary_texel = flooded_outer_boundary[index];
        float distance_to_inner = math::distance(float2(texel), float2(inner_boundary_texel));
        float distance_to_outer = math::distance(float2(texel), float2(outer_boundary_texel));
 
        float gradient = distance_to_outer / (distance_to_outer + distance_to_inner);
 
        output_mask[index] = gradient;
      }
    }
  });
}
 
void DoubleEdgeMaskOperation::compute_double_edge_mask(const float *inner_mask,
                                                       const float *outer_mask,
                                                       float *output_mask)
{
  const int2 size = int2(this->get_width(), this->get_height());
  Array<int2> inner_boundary(size_t(size.x) * size.y);
  Array<int2> outer_boundary(size_t(size.x) * size.y);
  compute_boundary(inner_mask, outer_mask, inner_boundary, outer_boundary);
  Array<int2> flooded_inner_boundary = jump_flooding(inner_boundary, size);
  Array<int2> flooded_outer_boundary = jump_flooding(outer_boundary, size);
  compute_gradient(
      inner_mask, outer_mask, flooded_inner_boundary, flooded_outer_boundary, output_mask);
}
 
DoubleEdgeMaskOperation::DoubleEdgeMaskOperation()
{
  this->add_input_socket(DataType::Value);
  this->add_input_socket(DataType::Value);
  this->add_output_socket(DataType::Value);
  include_all_inner_edges_ = false;
  include_edges_of_image_ = false;
  flags_.can_be_constant = true;
  is_output_rendered_ = false;
}
 
void DoubleEdgeMaskOperation::get_area_of_interest(int /*input_idx*/,
                                                   const rcti & /*output_area*/,
                                                   rcti &r_input_area)
{
  r_input_area = this->get_canvas();
}
 
void DoubleEdgeMaskOperation::update_memory_buffer(MemoryBuffer *output,
                                                   const rcti & /*area*/,
                                                   Span<MemoryBuffer *> inputs)
{
  if (!is_output_rendered_) {
    MemoryBuffer *input_inner_mask = inputs[0];
    MemoryBuffer *input_outer_mask = inputs[1];
    if (input_inner_mask->is_a_single_elem() && input_outer_mask->is_a_single_elem()) {
      output->clear();
      is_output_rendered_ = true;
      return;
    }
 
    /* Ensure full buffers to work with no strides. */
    MemoryBuffer *inner_mask = input_inner_mask->is_a_single_elem() ? input_inner_mask->inflate() :
                                                                      input_inner_mask;
    MemoryBuffer *outer_mask = input_outer_mask->is_a_single_elem() ? input_outer_mask->inflate() :
                                                                      input_outer_mask;
 
    BLI_assert(output->get_width() == this->get_width());
    BLI_assert(output->get_height() == this->get_height());
    compute_double_edge_mask(
        inner_mask->get_buffer(), outer_mask->get_buffer(), output->get_buffer());
    is_output_rendered_ = true;
 
    if (inner_mask != input_inner_mask) {
      delete inner_mask;
    }
    if (outer_mask != input_outer_mask) {
      delete outer_mask;
    }
  }
}
 
}  // namespace blender::compositor