MOD_grease_pencil_tint.cc

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/* SPDX-FileCopyrightText: 2024 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#include "MEM_guardedalloc.h"
 
#include "BLI_math_matrix.hh"
 
#include "DNA_defaults.h"
#include "DNA_material_types.h"
#include "DNA_modifier_types.h"
#include "DNA_scene_types.h"
 
#include "BKE_colorband.hh"
#include "BKE_colortools.hh"
#include "BKE_curves.hh"
#include "BKE_geometry_set.hh"
#include "BKE_grease_pencil.hh"
#include "BKE_lib_query.hh"
#include "BKE_material.hh"
#include "BKE_modifier.hh"
#include "BKE_screen.hh"
 
#include "BLO_read_write.hh"
 
#include "DEG_depsgraph_query.hh"
 
#include "UI_interface.hh"
#include "UI_resources.hh"
 
#include "BLT_translation.hh"
 
#include "WM_types.hh"
 
#include "RNA_access.hh"
#include "RNA_enum_types.hh"
#include "RNA_prototypes.hh"
 
#include "MOD_grease_pencil_util.hh"
#include "MOD_modifiertypes.hh"
#include "MOD_ui_common.hh"
 
namespace blender {
 
using bke::greasepencil::Drawing;
 
static void init_data(ModifierData *md)
{
  auto *tmd = reinterpret_cast<GreasePencilTintModifierData *>(md);
 
  BLI_assert(MEMCMP_STRUCT_AFTER_IS_ZERO(tmd, modifier));
 
  MEMCPY_STRUCT_AFTER(tmd, DNA_struct_default_get(GreasePencilTintModifierData), modifier);
  modifier::greasepencil::init_influence_data(&tmd->influence, true);
 
  /* Add default color ramp. */
  tmd->color_ramp = BKE_colorband_add(false);
  if (tmd->color_ramp) {
    BKE_colorband_init(tmd->color_ramp, true);
    CBData *data = tmd->color_ramp->data;
    data[0].r = data[0].g = data[0].b = data[0].a = 1.0f;
    data[0].pos = 0.0f;
    data[1].r = data[1].g = data[1].b = 0.0f;
    data[1].a = 1.0f;
    data[1].pos = 1.0f;
 
    tmd->color_ramp->tot = 2;
  }
}
 
static void copy_data(const ModifierData *md, ModifierData *target, const int flag)
{
  const auto *tmd = reinterpret_cast<const GreasePencilTintModifierData *>(md);
  auto *ttmd = reinterpret_cast<GreasePencilTintModifierData *>(target);
 
  modifier::greasepencil::free_influence_data(&ttmd->influence);
  MEM_SAFE_FREE(ttmd->color_ramp);
 
  BKE_modifier_copydata_generic(md, target, flag);
  modifier::greasepencil::copy_influence_data(&tmd->influence, &ttmd->influence, flag);
 
  if (tmd->color_ramp) {
    ttmd->color_ramp = static_cast<ColorBand *>(MEM_dupallocN(tmd->color_ramp));
  }
}
 
static void free_data(ModifierData *md)
{
  auto *tmd = reinterpret_cast<GreasePencilTintModifierData *>(md);
  modifier::greasepencil::free_influence_data(&tmd->influence);
 
  MEM_SAFE_FREE(tmd->color_ramp);
}
 
static void foreach_ID_link(ModifierData *md, Object *ob, IDWalkFunc walk, void *user_data)
{
  auto *tmd = reinterpret_cast<GreasePencilTintModifierData *>(md);
  modifier::greasepencil::foreach_influence_ID_link(&tmd->influence, ob, walk, user_data);
  walk(user_data, ob, (ID **)&tmd->object, IDWALK_CB_NOP);
}
 
static bool is_disabled(const Scene * /*scene*/, ModifierData *md, bool /*use_render_params*/)
{
  auto *tmd = reinterpret_cast<GreasePencilTintModifierData *>(md);
  if (tmd->tint_mode == MOD_GREASE_PENCIL_TINT_GRADIENT) {
    return tmd->object == nullptr;
  }
  return false;
}
 
static void update_depsgraph(ModifierData *md, const ModifierUpdateDepsgraphContext *ctx)
{
  auto *tmd = reinterpret_cast<GreasePencilTintModifierData *>(md);
  if (tmd->object != nullptr) {
    DEG_add_object_relation(
        ctx->node, tmd->object, DEG_OB_COMP_TRANSFORM, "Grease Pencil Tint Modifier");
  }
  DEG_add_object_relation(
      ctx->node, ctx->object, DEG_OB_COMP_TRANSFORM, "Grease Pencil Tint Modifier");
}
 
static ColorGeometry4f get_base_color(const ColorGeometry4f &input_color,
                                      const ColorGeometry4f &material_color)
{
  /* When input alpha is zero, replace with material color. */
  return (input_color.a == 0.0f && material_color.a > 0.0f) ? material_color : input_color;
}
 
static ColorGeometry4f apply_uniform_tint(const GreasePencilTintModifierData &tmd,
                                          const ColorGeometry4f &input_color,
                                          const float factor)
{
  const float3 rgb = math::interpolate(
      float3(input_color.r, input_color.g, input_color.b), float3(tmd.color), factor);
  /* Alpha is unchanged. */
  return ColorGeometry4f(rgb[0], rgb[1], rgb[2], input_color.a);
}
 
static ColorGeometry4f apply_gradient_tint(const GreasePencilTintModifierData &tmd,
                                           const float4x4 &matrix,
                                           const float3 &position,
                                           const ColorGeometry4f &input_color,
                                           const float factor)
{
  const float3 gradient_pos = math::transform_point(matrix, position);
  const float gradient_factor = std::clamp(
      math::safe_divide(math::length(gradient_pos), tmd.radius), 0.0f, 1.0f);
 
  float4 gradient_color;
  BKE_colorband_evaluate(tmd.color_ramp, gradient_factor, gradient_color);
 
  const float3 input_rgb = {input_color.r, input_color.g, input_color.b};
  /* GP2 compatibility: ignore vertex group factor and use the plain modifier setting for
   * RGB mixing. */
  const float3 rgb = math::interpolate(
      input_rgb, gradient_color.xyz(), tmd.factor * gradient_color.w);
  /* GP2 compatibility: use vertex group factor for alpha. */
  return ColorGeometry4f(rgb[0], rgb[1], rgb[2], factor);
}
 
static void modify_stroke_color(Object &ob,
                                const GreasePencilTintModifierData &tmd,
                                bke::CurvesGeometry &curves,
                                const IndexMask &curves_mask,
                                const MutableSpan<ColorGeometry4f> vertex_colors)
{
  const bool use_curve = (tmd.influence.flag & GREASE_PENCIL_INFLUENCE_USE_CUSTOM_CURVE);
  const bool use_weight_as_factor = (tmd.flag & MOD_GREASE_PENCIL_TINT_USE_WEIGHT_AS_FACTOR);
  const OffsetIndices<int> points_by_curve = curves.points_by_curve();
 
  bke::AttributeAccessor attributes = curves.attributes();
  const VArray<int> stroke_materials = *attributes.lookup_or_default<int>(
      "material_index", bke::AttrDomain::Curve, 0);
  const VArray<float> vgroup_weights = modifier::greasepencil::get_influence_vertex_weights(
      curves, tmd.influence);
 
  /* Common input color and base factor calculation. */
  auto get_material_color = [&](const int64_t curve_i) {
    const Material *ma = BKE_object_material_get(&ob, stroke_materials[curve_i] + 1);
    const MaterialGPencilStyle *gp_style = ma ? ma->gp_style : nullptr;
    if (!gp_style) {
      return ColorGeometry4f(0.0f, 0.0f, 0.0f, 0.0f);
    }
    return ColorGeometry4f(gp_style->stroke_rgba);
  };
 
  auto get_point_factor = [&](const int64_t point_i) {
    const float weight = vgroup_weights[point_i];
    if (use_weight_as_factor) {
      return weight;
    }
    return tmd.factor * weight;
  };
 
  const GreasePencilTintModifierMode tint_mode = GreasePencilTintModifierMode(tmd.tint_mode);
  switch (tint_mode) {
    case MOD_GREASE_PENCIL_TINT_UNIFORM: {
      curves_mask.foreach_index(GrainSize(512), [&](const int64_t curve_i) {
        const ColorGeometry4f material_color = get_material_color(curve_i);
 
        const IndexRange points = points_by_curve[curve_i];
        for (const int64_t i : points.index_range()) {
          const int64_t point_i = points[i];
          const float curve_input = points.size() >= 2 ? (float(i) / float(points.size() - 1)) :
                                                         0.0f;
          const float curve_factor = use_curve ? BKE_curvemapping_evaluateF(
                                                     tmd.influence.custom_curve, 0, curve_input) :
                                                 1.0f;
          vertex_colors[point_i] = apply_uniform_tint(
              tmd,
              get_base_color(vertex_colors[point_i], material_color),
              get_point_factor(point_i) * curve_factor);
        }
      });
      break;
    }
    case MOD_GREASE_PENCIL_TINT_GRADIENT: {
      if (tmd.object == nullptr) {
        return;
      }
 
      const OffsetIndices<int> points_by_curve = curves.points_by_curve();
      const Span<float3> positions = curves.positions();
      /* Transforms points to the gradient object space. */
      const float4x4 matrix = tmd.object->world_to_object() * ob.object_to_world();
 
      curves_mask.foreach_index(GrainSize(512), [&](const int64_t curve_i) {
        const ColorGeometry4f material_color = get_material_color(curve_i);
 
        const IndexRange points = points_by_curve[curve_i];
        for (const int64_t point_i : points) {
          vertex_colors[point_i] = apply_gradient_tint(
              tmd,
              matrix,
              positions[point_i],
              get_base_color(vertex_colors[point_i], material_color),
              get_point_factor(point_i));
        }
      });
      break;
    }
  }
}
 
static void modify_fill_color(Object &ob,
                              const GreasePencilTintModifierData &tmd,
                              Drawing &drawing,
                              const IndexMask &curves_mask)
{
  const bool use_weight_as_factor = (tmd.flag & MOD_GREASE_PENCIL_TINT_USE_WEIGHT_AS_FACTOR);
  const bke::CurvesGeometry &curves = drawing.strokes();
  const OffsetIndices<int> points_by_curve = curves.points_by_curve();
  const GreasePencilTintModifierMode tint_mode = GreasePencilTintModifierMode(tmd.tint_mode);
 
  /* Check early before getting attribute writers. */
  if (tint_mode == MOD_GREASE_PENCIL_TINT_GRADIENT && tmd.object == nullptr) {
    return;
  }
 
  bke::MutableAttributeAccessor attributes = drawing.strokes_for_write().attributes_for_write();
  /* Fill color per stroke. */
  MutableSpan<ColorGeometry4f> fill_colors = drawing.fill_colors_for_write();
  const VArray<int> stroke_materials = *attributes.lookup_or_default<int>(
      "material_index", bke::AttrDomain::Curve, 0);
  const VArray<float> vgroup_weights = modifier::greasepencil::get_influence_vertex_weights(
      curves, tmd.influence);
 
  /* Common input color and base factor calculation. */
  auto get_material_color = [&](const int64_t curve_i) {
    const Material *ma = BKE_object_material_get(&ob, stroke_materials[curve_i] + 1);
    const MaterialGPencilStyle *gp_style = ma ? ma->gp_style : nullptr;
    if (!gp_style) {
      return ColorGeometry4f(0.0f, 0.0f, 0.0f, 0.0f);
    }
    const bool is_gradient = gp_style->fill_style == GP_MATERIAL_FILL_STYLE_GRADIENT;
    const float4 average_color = math::interpolate(
        float4(gp_style->fill_rgba), float4(gp_style->mix_rgba), is_gradient ? 0.5f : 0.0f);
    return ColorGeometry4f(average_color);
  };
 
  auto get_curve_factor = [&](const int64_t curve_i) {
    /* Use the first stroke point as vertex weight. */
    const IndexRange points = points_by_curve[curve_i];
    const float vgroup_weight_first = vgroup_weights[points.first()];
    float stroke_weight = vgroup_weight_first;
    if (points.is_empty() || (stroke_weight <= 0.0f)) {
      return 0.0f;
    }
    if (use_weight_as_factor) {
      return stroke_weight;
    }
    return tmd.factor * stroke_weight;
  };
 
  switch (tint_mode) {
    case MOD_GREASE_PENCIL_TINT_UNIFORM: {
      curves_mask.foreach_index(GrainSize(512), [&](int64_t curve_i) {
        const ColorGeometry4f material_color = get_material_color(curve_i);
        fill_colors[curve_i] = apply_uniform_tint(
            tmd, get_base_color(fill_colors[curve_i], material_color), get_curve_factor(curve_i));
      });
      break;
    }
    case MOD_GREASE_PENCIL_TINT_GRADIENT: {
      const OffsetIndices<int> points_by_curve = curves.points_by_curve();
      const Span<float3> positions = curves.positions();
      /* Transforms points to the gradient object space. */
      const float4x4 matrix = tmd.object->world_to_object() * ob.object_to_world();
 
      curves_mask.foreach_index(GrainSize(512), [&](int64_t curve_i) {
        const ColorGeometry4f material_color = get_material_color(curve_i);
        /* Use the first stroke point for gradient position. */
        const IndexRange points = points_by_curve[curve_i];
        const float3 pos = points.is_empty() ? float3(0.0f, 0.0f, 0.0f) :
                                               positions[points.first()];
 
        fill_colors[curve_i] = apply_gradient_tint(
            tmd,
            matrix,
            pos,
            get_base_color(fill_colors[curve_i], material_color),
            get_curve_factor(curve_i));
      });
      break;
    }
  }
}
 
static void modify_opacity(const GreasePencilTintModifierData &tmd,
                           bke::CurvesGeometry &curves,
                           const IndexMask &curves_mask)
{
  /* Only when factor is greater than 1. */
  if (tmd.factor <= 1.0f) {
    return;
  }
 
  const OffsetIndices<int> points_by_curve = curves.points_by_curve();
  bke::MutableAttributeAccessor attributes = curves.attributes_for_write();
  bke::SpanAttributeWriter<float> opacities = attributes.lookup_or_add_for_write_span<float>(
      "opacity", bke::AttrDomain::Point);
  if (!opacities) {
    return;
  }
 
  curves_mask.foreach_index(GrainSize(512), [&](const int64_t curve_i) {
    const IndexRange points = points_by_curve[curve_i];
    for (const int64_t point_i : points) {
      opacities.span[point_i] = std::clamp(
          opacities.span[point_i] + tmd.factor - 1.0f, 0.0f, 1.0f);
    }
  });
 
  opacities.finish();
}
 
static void modify_curves(ModifierData &md, const ModifierEvalContext &ctx, Drawing &drawing)
{
  auto &tmd = reinterpret_cast<GreasePencilTintModifierData &>(md);
  bke::CurvesGeometry &curves = drawing.strokes_for_write();
 
  IndexMaskMemory mask_memory;
  const IndexMask curves_mask = modifier::greasepencil::get_filtered_stroke_mask(
      ctx.object, curves, tmd.influence, mask_memory);
 
  /* Factor > 1.0 also affects the opacity of the stroke. */
  modify_opacity(tmd, curves, curves_mask);
 
  switch (tmd.color_mode) {
    case MOD_GREASE_PENCIL_COLOR_STROKE:
      modify_stroke_color(
          *ctx.object, tmd, curves, curves_mask, drawing.vertex_colors_for_write());
      break;
    case MOD_GREASE_PENCIL_COLOR_FILL:
      modify_fill_color(*ctx.object, tmd, drawing, curves_mask);
      break;
    case MOD_GREASE_PENCIL_COLOR_BOTH:
      modify_stroke_color(
          *ctx.object, tmd, curves, curves_mask, drawing.vertex_colors_for_write());
      modify_fill_color(*ctx.object, tmd, drawing, curves_mask);
      break;
    case MOD_GREASE_PENCIL_COLOR_HARDNESS:
      BLI_assert_unreachable();
      break;
  }
}
 
static void modify_geometry_set(ModifierData *md,
                                const ModifierEvalContext *ctx,
                                bke::GeometrySet *geometry_set)
{
  auto *tmd = reinterpret_cast<GreasePencilTintModifierData *>(md);
 
  if (!geometry_set->has_grease_pencil()) {
    return;
  }
  GreasePencil &grease_pencil = *geometry_set->get_grease_pencil_for_write();
  const int frame = grease_pencil.runtime->eval_frame;
 
  IndexMaskMemory mask_memory;
  const IndexMask layer_mask = modifier::greasepencil::get_filtered_layer_mask(
      grease_pencil, tmd->influence, mask_memory);
  const Vector<Drawing *> drawings = modifier::greasepencil::get_drawings_for_write(
      grease_pencil, layer_mask, frame);
  threading::parallel_for_each(drawings,
                               [&](Drawing *drawing) { modify_curves(*md, *ctx, *drawing); });
}
 
static void panel_draw(const bContext *C, Panel *panel)
{
  uiLayout *layout = panel->layout;
 
  PointerRNA ob_ptr;
  PointerRNA *ptr = modifier_panel_get_property_pointers(panel, &ob_ptr);
 
  uiLayoutSetPropSep(layout, true);
 
  const GreasePencilTintModifierMode tint_mode = GreasePencilTintModifierMode(
      RNA_enum_get(ptr, "tint_mode"));
  const bool use_weight_as_factor = RNA_boolean_get(ptr, "use_weight_as_factor");
 
  layout->prop(ptr, "color_mode", UI_ITEM_NONE, std::nullopt, ICON_NONE);
 
  uiLayout *row = &layout->row(true);
  uiLayoutSetActive(row, !use_weight_as_factor);
  row->prop(ptr, "factor", UI_ITEM_NONE, std::nullopt, ICON_NONE);
  row->prop(ptr, "use_weight_as_factor", UI_ITEM_NONE, "", ICON_MOD_VERTEX_WEIGHT);
 
  layout->prop(ptr, "tint_mode", UI_ITEM_R_EXPAND, std::nullopt, ICON_NONE);
  switch (tint_mode) {
    case MOD_GREASE_PENCIL_TINT_UNIFORM:
      layout->prop(ptr, "color", UI_ITEM_NONE, std::nullopt, ICON_NONE);
      break;
    case MOD_GREASE_PENCIL_TINT_GRADIENT:
      uiLayout *col = &layout->column(false);
      uiLayoutSetPropSep(col, false);
      uiTemplateColorRamp(col, ptr, "color_ramp", true);
      layout->separator();
      layout->prop(ptr, "object", UI_ITEM_NONE, std::nullopt, ICON_NONE);
      layout->prop(ptr, "radius", UI_ITEM_NONE, std::nullopt, ICON_NONE);
      break;
  }
 
  if (uiLayout *influence_panel = layout->panel_prop(
          C, ptr, "open_influence_panel", IFACE_("Influence")))
  {
    modifier::greasepencil::draw_layer_filter_settings(C, influence_panel, ptr);
    modifier::greasepencil::draw_material_filter_settings(C, influence_panel, ptr);
    modifier::greasepencil::draw_vertex_group_settings(C, influence_panel, ptr);
    modifier::greasepencil::draw_custom_curve_settings(C, influence_panel, ptr);
  }
 
  modifier_error_message_draw(layout, ptr);
}
 
static void panel_register(ARegionType *region_type)
{
  modifier_panel_register(region_type, eModifierType_GreasePencilTint, panel_draw);
}
 
static void blend_write(BlendWriter *writer, const ID * /*id_owner*/, const ModifierData *md)
{
  const auto *tmd = reinterpret_cast<const GreasePencilTintModifierData *>(md);
 
  BLO_write_struct(writer, GreasePencilTintModifierData, tmd);
  modifier::greasepencil::write_influence_data(writer, &tmd->influence);
  if (tmd->color_ramp) {
    BLO_write_struct(writer, ColorBand, tmd->color_ramp);
  }
}
 
static void blend_read(BlendDataReader *reader, ModifierData *md)
{
  auto *tmd = reinterpret_cast<GreasePencilTintModifierData *>(md);
 
  modifier::greasepencil::read_influence_data(reader, &tmd->influence);
  BLO_read_struct(reader, ColorBand, &tmd->color_ramp);
}
 
}  // namespace blender
 
ModifierTypeInfo modifierType_GreasePencilTint = {
    /*idname*/ "GreasePencilTint",
    /*name*/ N_("Tint"),
    /*struct_name*/ "GreasePencilTintModifierData",
    /*struct_size*/ sizeof(GreasePencilTintModifierData),
    /*srna*/ &RNA_GreasePencilTintModifier,
    /*type*/ ModifierTypeType::NonGeometrical,
    /*flags*/ eModifierTypeFlag_AcceptsGreasePencil | eModifierTypeFlag_SupportsEditmode |
        eModifierTypeFlag_EnableInEditmode | eModifierTypeFlag_SupportsMapping,
    /*icon*/ ICON_MOD_TINT,
 
    /*copy_data*/ blender::copy_data,
 
    /*deform_verts*/ nullptr,
    /*deform_matrices*/ nullptr,
    /*deform_verts_EM*/ nullptr,
    /*deform_matrices_EM*/ nullptr,
    /*modify_mesh*/ nullptr,
    /*modify_geometry_set*/ blender::modify_geometry_set,
 
    /*init_data*/ blender::init_data,
    /*required_data_mask*/ nullptr,
    /*free_data*/ blender::free_data,
    /*is_disabled*/ blender::is_disabled,
    /*update_depsgraph*/ blender::update_depsgraph,
    /*depends_on_time*/ nullptr,
    /*depends_on_normals*/ nullptr,
    /*foreach_ID_link*/ blender::foreach_ID_link,
    /*foreach_tex_link*/ nullptr,
    /*free_runtime_data*/ nullptr,
    /*panel_register*/ blender::panel_register,
    /*blend_write*/ blender::blend_write,
    /*blend_read*/ blender::blend_read,
};