grease_pencil_sculpt_strength.cc

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/* SPDX-FileCopyrightText: 2024 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include "BLI_index_mask.hh"
#include "BLI_task.hh"
 
#include "BKE_context.hh"
#include "BKE_grease_pencil.hh"
#include "BKE_paint.hh"
 
#include "ED_grease_pencil.hh"
#include "ED_view3d.hh"
 
#include "WM_api.hh"
#include "WM_types.hh"
 
#include "grease_pencil_intern.hh"
#include "paint_intern.hh"
 
namespace blender::ed::sculpt_paint::greasepencil {
 
class StrengthOperation : public GreasePencilStrokeOperationCommon {
 public:
  using GreasePencilStrokeOperationCommon::GreasePencilStrokeOperationCommon;
 
  void on_stroke_begin(const bContext &C, const InputSample &start_sample) override;
  void on_stroke_extended(const bContext &C, const InputSample &extension_sample) override;
  void on_stroke_done(const bContext & /*C*/) override {}
};
 
void StrengthOperation::on_stroke_begin(const bContext &C, const InputSample &start_sample)
{
  this->init_stroke(C, start_sample);
  this->init_auto_masking(C, start_sample);
}
 
void StrengthOperation::on_stroke_extended(const bContext &C, const InputSample &extension_sample)
{
  Paint &paint = *BKE_paint_get_active_from_context(&C);
  const Brush &brush = *BKE_paint_brush(&paint);
  const bool invert = this->is_inverted(brush);
 
  this->foreach_editable_drawing_with_automask(
      C, [&](const GreasePencilStrokeParams &params, const IndexMask &point_mask) {
        Array<float2> view_positions = calculate_view_positions(params, point_mask);
        MutableSpan<float> opacities = params.drawing.opacities_for_write();
 
        point_mask.foreach_index(GrainSize(4096), [&](const int64_t point_i) {
          float &opacity = opacities[point_i];
          const float influence = brush_point_influence(
              paint, brush, view_positions[point_i], extension_sample, params.multi_frame_falloff);
          /* Brush influence mapped to opacity by a factor of 0.125. */
          const float delta_opacity = (invert ? -influence : influence) * 0.125f;
          opacity = std::clamp(opacity + delta_opacity, 0.0f, 1.0f);
        });
 
        return true;
      });
  this->stroke_extended(extension_sample);
}
 
std::unique_ptr<GreasePencilStrokeOperation> new_strength_operation(
    const BrushStrokeMode stroke_mode)
{
  return std::make_unique<StrengthOperation>(stroke_mode);
}
 
}  // namespace blender::ed::sculpt_paint::greasepencil