sequencer/intern/modifiers/MOD_mask.cc

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/* SPDX-FileCopyrightText: 2025 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#include "BLI_math_base.h"
#include "BLI_math_matrix.hh"
 
#include "BLT_translation.hh"
 
#include "DNA_scene_types.h"
#include "DNA_sequence_types.h"
 
#include "SEQ_modifier.hh"
#include "SEQ_render.hh"
#include "SEQ_transform.hh"
 
#include "UI_interface.hh"
#include "UI_interface_layout.hh"
 
#include "modifier.hh"
 
namespace blender::seq {
 
struct MaskApplyOp {
  template<typename ImageT, typename MaskSampler>
  void apply(ImageT *image, MaskSampler &mask, int image_x, IndexRange y_range)
  {
    image += y_range.first() * image_x * 4;
    for (int64_t y : y_range) {
      mask.begin_row(y);
      for ([[maybe_unused]] int64_t x : IndexRange(image_x)) {
        float m = mask.load_mask_min();
 
        if constexpr (std::is_same_v<ImageT, uchar>) {
          /* Byte buffer is straight, so only affect on alpha itself, this is
           * the only way to alpha-over byte strip after applying mask modifier. */
          image[3] = uchar(image[3] * m);
        }
        else if constexpr (std::is_same_v<ImageT, float>) {
          /* Float buffers are premultiplied, so need to premul color as well to make it
           * easy to alpha-over masked strip. */
          float4 pix(image);
          pix *= m;
          *reinterpret_cast<float4 *>(image) = pix;
        }
        image += 4;
      }
    }
  }
};
 
static void maskmodifier_apply(ModifierApplyContext &context,
                               StripModifierData * /*smd*/,
                               ImBuf *mask)
{
  if (mask == nullptr || (mask->byte_buffer.data == nullptr && mask->float_buffer.data == nullptr))
  {
    return;
  }
 
  MaskApplyOp op;
  apply_modifier_op(op, context.image, mask, context.transform);
 
  /* Image has gained transparency. */
  context.image->planes = R_IMF_PLANES_RGBA;
}
 
static void maskmodifier_panel_draw(const bContext *C, Panel *panel)
{
  uiLayout *layout = panel->layout;
  PointerRNA *ptr = UI_panel_custom_data_get(panel);
 
  draw_mask_input_type_settings(C, layout, ptr);
}
 
static void maskmodifier_register(ARegionType *region_type)
{
  modifier_panel_register(region_type, eSeqModifierType_Mask, maskmodifier_panel_draw);
}
 
StripModifierTypeInfo seqModifierType_Mask = {
    /*idname*/ "Mask",
    /*name*/ CTX_N_(BLT_I18NCONTEXT_ID_SEQUENCE, "Mask"),
    /*struct_name*/ "SequencerMaskModifierData",
    /*struct_size*/ sizeof(SequencerMaskModifierData),
    /*init_data*/ nullptr,
    /*free_data*/ nullptr,
    /*copy_data*/ nullptr,
    /*apply*/ maskmodifier_apply,
    /*panel_register*/ maskmodifier_register,
    /*blend_write*/ nullptr,
    /*blend_read*/ nullptr,
};
 
};  // namespace blender::seq