release/scripts/startup/bl_ui/space_view3d.py

@@ -522,7 +522,8 @@ class _draw_tool_settings_context_mode:
 
         if curves_tool == 'COMB':
             layout.prop(brush, "falloff_shape", expand=True)
-            layout.popover("VIEW3D_PT_tools_brush_falloff")
+            layout.popover("VIEW3D_PT_tools_brush_falloff", text="Brush Falloff")
+            layout.popover("VIEW3D_PT_curves_sculpt_parameter_falloff", text="Curve Falloff")
         elif curves_tool == 'ADD':
             layout.prop(brush, "falloff_shape", expand=True)
             layout.prop(brush.curves_sculpt_settings, "add_amount")
@@ -7944,6 +7945,28 @@ class VIEW3D_PT_curves_sculpt_add_shape(Panel):
         col.prop(brush.curves_sculpt_settings, "points_per_curve", text="Points")
 
 
+class VIEW3D_PT_curves_sculpt_parameter_falloff(Panel):
+    # Only for popover, these are dummy values.
+    bl_space_type = 'VIEW_3D'
+    bl_region_type = 'WINDOW'
+    bl_label = "Curves Sculpt Parameter Falloff"
+
+    def draw(self, context):
+        layout = self.layout
+
+        settings = UnifiedPaintPanel.paint_settings(context)
+        brush = settings.brush
+
+        layout.template_curve_mapping(brush.curves_sculpt_settings, "curve_parameter_falloff")
+        row = layout.row(align=True)
+        row.operator("brush.sculpt_curves_falloff_preset", icon='SMOOTHCURVE', text="").shape = 'SMOOTH'
+        row.operator("brush.sculpt_curves_falloff_preset", icon='SPHERECURVE', text="").shape = 'ROUND'
+        row.operator("brush.sculpt_curves_falloff_preset", icon='ROOTCURVE', text="").shape = 'ROOT'
+        row.operator("brush.sculpt_curves_falloff_preset", icon='SHARPCURVE', text="").shape = 'SHARP'
+        row.operator("brush.sculpt_curves_falloff_preset", icon='LINCURVE', text="").shape = 'LINE'
+        row.operator("brush.sculpt_curves_falloff_preset", icon='NOCURVE', text="").shape = 'MAX'
+
+
 class VIEW3D_PT_curves_sculpt_grow_shrink_scaling(Panel):
     # Only for popover, these are dummy values.
     bl_space_type = 'VIEW_3D'
@@ -8221,6 +8244,7 @@ classes = (
     TOPBAR_PT_gpencil_vertexcolor,
     TOPBAR_PT_annotation_layers,
     VIEW3D_PT_curves_sculpt_add_shape,
+    VIEW3D_PT_curves_sculpt_parameter_falloff,
     VIEW3D_PT_curves_sculpt_grow_shrink_scaling,
     VIEW3D_PT_viewport_debug,
 )

source/blender/blenkernel/intern/brush.cc

@@ -100,6 +100,8 @@ static void brush_copy_data(Main * /*bmain*/, ID *id_dst, const ID *id_src, cons
   if (brush_src->curves_sculpt_settings != nullptr) {
     brush_dst->curves_sculpt_settings = MEM_cnew<BrushCurvesSculptSettings>(
         __func__, *(brush_src->curves_sculpt_settings));
+    brush_dst->curves_sculpt_settings->curve_parameter_falloff = BKE_curvemapping_copy(
+        brush_src->curves_sculpt_settings->curve_parameter_falloff);
   }
 
   /* enable fake user by default */
@@ -130,6 +132,7 @@ static void brush_free_data(ID *id)
     MEM_SAFE_FREE(brush->gpencil_settings);
   }
   if (brush->curves_sculpt_settings != nullptr) {
+    BKE_curvemapping_free(brush->curves_sculpt_settings->curve_parameter_falloff);
     MEM_freeN(brush->curves_sculpt_settings);
   }
 
@@ -255,6 +258,7 @@ static void brush_blend_write(BlendWriter *writer, ID *id, const void *id_addres
   }
   if (brush->curves_sculpt_settings) {
     BLO_write_struct(writer, BrushCurvesSculptSettings, brush->curves_sculpt_settings);
+    BKE_curvemapping_blend_write(writer, brush->curves_sculpt_settings->curve_parameter_falloff);
   }
   if (brush->gradient) {
     BLO_write_struct(writer, ColorBand, brush->gradient);
@@ -337,6 +341,12 @@ static void brush_blend_read_data(BlendDataReader *reader, ID *id)
   }
 
   BLO_read_data_address(reader, &brush->curves_sculpt_settings);
+  if (brush->curves_sculpt_settings) {
+    BLO_read_data_address(reader, &brush->curves_sculpt_settings->curve_parameter_falloff);
+    if (brush->curves_sculpt_settings->curve_parameter_falloff) {
+      BKE_curvemapping_blend_read(reader, brush->curves_sculpt_settings->curve_parameter_falloff);
+    }
+  }
 
   brush->preview = nullptr;
   brush->icon_imbuf = nullptr;
@@ -1583,6 +1593,7 @@ void BKE_brush_init_curves_sculpt_settings(Brush *brush)
   settings->minimum_length = 0.01f;
   settings->curve_length = 0.3f;
   settings->density_add_attempts = 100;
+  settings->curve_parameter_falloff = BKE_curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);
 }
 
 struct Brush *BKE_brush_first_search(struct Main *bmain, const eObjectMode ob_mode)

source/blender/blenloader/intern/versioning_300.cc

@@ -3952,6 +3952,15 @@ void blo_do_versions_300(FileData *fd, Library * /*lib*/, Main *bmain)
       }
     }
 
+    LISTBASE_FOREACH (Brush *, brush, &bmain->brushes) {
+      if (brush->ob_mode == OB_MODE_SCULPT_CURVES) {
+        if (brush->curves_sculpt_settings->curve_parameter_falloff == nullptr) {
+          brush->curves_sculpt_settings->curve_parameter_falloff = BKE_curvemapping_add(
+              1, 0.0f, 0.0f, 1.0f, 1.0f);
+        }
+      }
+    }
+
     /* Keep this block, even when empty. */
   }
 }

source/blender/editors/sculpt_paint/curves_sculpt_comb.cc

@@ -18,6 +18,7 @@
 #include "BKE_attribute_math.hh"
 #include "BKE_brush.h"
 #include "BKE_bvhutils.h"
+#include "BKE_colortools.h"
 #include "BKE_context.h"
 #include "BKE_crazyspace.hh"
 #include "BKE_curves.hh"
@@ -69,6 +70,8 @@ class CombOperation : public CurvesSculptStrokeOperation {
   /** Solver for length and collision constraints. */
   CurvesConstraintSolver constraint_solver_;
 
+  Array<float> curve_lengths_;
+
   friend struct CombOperationExecutor;
 
  public:
@@ -146,6 +149,17 @@ struct CombOperationExecutor {
       }
       self_->constraint_solver_.initialize(
           *curves_orig_, curve_selection_, curves_id_orig_->flag & CV_SCULPT_COLLISION_ENABLED);
+
+      self_->curve_lengths_.reinitialize(curves_orig_->curves_num());
+      const Span<float> segment_lengths = self_->constraint_solver_.segment_lengths();
+      const OffsetIndices points_by_curve = curves_orig_->points_by_curve();
+      threading::parallel_for(curve_selection_.index_range(), 512, [&](const IndexRange range) {
+        for (const int curve_i : curve_selection_.slice(range)) {
+          const IndexRange points = points_by_curve[curve_i];
+          const Span<float> lengths = segment_lengths.slice(points.drop_back(1));
+          self_->curve_lengths_[curve_i] = std::accumulate(lengths.begin(), lengths.end(), 0.0f);
+        }
+      });
       /* Combing does nothing when there is no mouse movement, so return directly. */
       return;
     }
@@ -204,11 +218,23 @@ struct CombOperationExecutor {
     const float brush_radius_re = brush_radius_base_re_ * brush_radius_factor_;
     const float brush_radius_sq_re = pow2f(brush_radius_re);
 
+    CurveMapping &curve_parameter_falloff_mapping =
+        *brush_->curves_sculpt_settings->curve_parameter_falloff;
+    BKE_curvemapping_init(&curve_parameter_falloff_mapping);
+
+    const Span<float> segment_lengths = self_->constraint_solver_.segment_lengths();
+
     threading::parallel_for(curve_selection_.index_range(), 256, [&](const IndexRange range) {
       for (const int curve_i : curve_selection_.slice(range)) {
         bool curve_changed = false;
         const IndexRange points = points_by_curve[curve_i];
+
+        const float total_length = self_->curve_lengths_[curve_i];
+        const float total_length_inv = safe_divide(1.0f, total_length);
+        float current_length = 0.0f;
         for (const int point_i : points.drop_front(1)) {
+          current_length += segment_lengths[point_i - 1];
+
           const float3 old_pos_cu = deformation.positions[point_i];
           const float3 old_symm_pos_cu = math::transform_point(brush_transform_inv, old_pos_cu);
 
@@ -228,8 +254,12 @@ struct CombOperationExecutor {
           /* A falloff that is based on how far away the point is from the stroke. */
           const float radius_falloff = BKE_brush_curve_strength(
               brush_, distance_to_brush_re, brush_radius_re);
+          const float curve_parameter = current_length * total_length_inv;
+          const float curve_falloff = BKE_curvemapping_evaluateF(
+              &curve_parameter_falloff_mapping, 0, curve_parameter);
           /* Combine the falloff and brush strength. */
-          const float weight = brush_strength_ * radius_falloff * point_factors_[point_i];
+          const float weight = brush_strength_ * curve_falloff * radius_falloff *
+                               point_factors_[point_i];
 
           /* Offset the old point position in screen space and transform it back into 3D space.
            */
@@ -304,15 +334,26 @@ struct CombOperationExecutor {
     const float brush_radius_sq_cu = pow2f(brush_radius_cu);
     const float3 brush_diff_cu = brush_end_cu - brush_start_cu;
 
+    CurveMapping &curve_parameter_falloff_mapping =
+        *brush_->curves_sculpt_settings->curve_parameter_falloff;
+    BKE_curvemapping_init(&curve_parameter_falloff_mapping);
+
     const bke::crazyspace::GeometryDeformation deformation =
         bke::crazyspace::get_evaluated_curves_deformation(*ctx_.depsgraph, *curves_ob_orig_);
     const OffsetIndices points_by_curve = curves_orig_->points_by_curve();
+    const Span<float> segment_lengths = self_->constraint_solver_.segment_lengths();
 
     threading::parallel_for(curve_selection_.index_range(), 256, [&](const IndexRange range) {
       for (const int curve_i : curve_selection_.slice(range)) {
         bool curve_changed = false;
         const IndexRange points = points_by_curve[curve_i];
+
+        const float total_length = self_->curve_lengths_[curve_i];
+        const float total_length_inv = safe_divide(1.0f, total_length);
+        float current_length = 0.0f;
         for (const int point_i : points.drop_front(1)) {
+          current_length += segment_lengths[point_i - 1];
+
           const float3 pos_old_cu = deformation.positions[point_i];
 
           /* Compute distance to the brush. */
@@ -328,8 +369,12 @@ struct CombOperationExecutor {
           /* A falloff that is based on how far away the point is from the stroke. */
           const float radius_falloff = BKE_brush_curve_strength(
               brush_, distance_to_brush_cu, brush_radius_cu);
+          const float curve_parameter = current_length * total_length_inv;
+          const float curve_falloff = BKE_curvemapping_evaluateF(
+              &curve_parameter_falloff_mapping, 0, curve_parameter);
           /* Combine the falloff and brush strength. */
-          const float weight = brush_strength_ * radius_falloff * point_factors_[point_i];
+          const float weight = brush_strength_ * curve_falloff * radius_falloff *
+                               point_factors_[point_i];
 
           const float3 translation_eval_cu = weight * brush_diff_cu;
           const float3 translation_orig_cu = deformation.translation_from_deformed_to_original(

source/blender/editors/sculpt_paint/curves_sculpt_intern.hh

@@ -163,6 +163,11 @@ struct CurvesConstraintSolver {
                   const IndexMask curve_selection,
                   const Mesh *surface,
                   const CurvesSurfaceTransforms &transforms);
+
+  Span<float> segment_lengths() const
+  {
+    return segment_lengths_;
+  }
 };
 
 }  // namespace blender::ed::sculpt_paint

source/blender/editors/sculpt_paint/paint_intern.h

@@ -373,6 +373,7 @@ void paint_sample_color(
 void paint_stroke_operator_properties(struct wmOperatorType *ot);
 
 void BRUSH_OT_curve_preset(struct wmOperatorType *ot);
+void BRUSH_OT_sculpt_curves_falloff_preset(struct wmOperatorType *ot);
 
 void PAINT_OT_face_select_linked(struct wmOperatorType *ot);
 void PAINT_OT_face_select_linked_pick(struct wmOperatorType *ot);

source/blender/editors/sculpt_paint/paint_ops.cc

@@ -1421,6 +1421,7 @@ void ED_operatortypes_paint(void)
   WM_operatortype_append(BRUSH_OT_add_gpencil);
   WM_operatortype_append(BRUSH_OT_scale_size);
   WM_operatortype_append(BRUSH_OT_curve_preset);
+  WM_operatortype_append(BRUSH_OT_sculpt_curves_falloff_preset);
   WM_operatortype_append(BRUSH_OT_reset);
   WM_operatortype_append(BRUSH_OT_stencil_control);
   WM_operatortype_append(BRUSH_OT_stencil_fit_image_aspect);

source/blender/editors/sculpt_paint/paint_utils.c

@@ -25,6 +25,7 @@
 #include "BLT_translation.h"
 
 #include "BKE_brush.h"
+#include "BKE_colortools.h"
 #include "BKE_context.h"
 #include "BKE_customdata.h"
 #include "BKE_image.h"
@@ -569,9 +570,6 @@ static bool brush_curve_preset_poll(bContext *C)
   return br && br->curve;
 }
 
-void BRUSH_OT_curve_preset(wmOperatorType *ot)
-{
-  PropertyRNA *prop;
 static const EnumPropertyItem prop_shape_items[] = {
     {CURVE_PRESET_SHARP, "SHARP", 0, "Sharp", ""},
     {CURVE_PRESET_SMOOTH, "SMOOTH", 0, "Smooth", ""},
@@ -582,6 +580,8 @@ void BRUSH_OT_curve_preset(wmOperatorType *ot)
     {0, NULL, 0, NULL, NULL},
 };
 
+void BRUSH_OT_curve_preset(wmOperatorType *ot)
+{
   ot->name = "Preset";
   ot->description = "Set brush shape";
   ot->idname = "BRUSH_OT_curve_preset";
@@ -589,6 +589,38 @@ void BRUSH_OT_curve_preset(wmOperatorType *ot)
   ot->exec = brush_curve_preset_exec;
   ot->poll = brush_curve_preset_poll;
 
+  PropertyRNA *prop;
+  prop = RNA_def_enum(ot->srna, "shape", prop_shape_items, CURVE_PRESET_SMOOTH, "Mode", "");
+  RNA_def_property_translation_context(prop,
+                                       BLT_I18NCONTEXT_ID_CURVE_LEGACY); /* Abusing id_curve :/ */
+}
+
+static bool brush_sculpt_curves_falloff_preset_poll(bContext *C)
+{
+  Brush *br = BKE_paint_brush(BKE_paint_get_active_from_context(C));
+  return br && br->curves_sculpt_settings && br->curves_sculpt_settings->curve_parameter_falloff;
+}
+
+static int brush_sculpt_curves_falloff_preset_exec(bContext *C, wmOperator *op)
+{
+  Brush *brush = BKE_paint_brush(BKE_paint_get_active_from_context(C));
+  CurveMapping *mapping = brush->curves_sculpt_settings->curve_parameter_falloff;
+  mapping->preset = RNA_enum_get(op->ptr, "shape");
+  CurveMap *map = mapping->cm;
+  BKE_curvemap_reset(map, &mapping->clipr, mapping->preset, CURVEMAP_SLOPE_POSITIVE);
+  return OPERATOR_FINISHED;
+}
+
+void BRUSH_OT_sculpt_curves_falloff_preset(wmOperatorType *ot)
+{
+  ot->name = "Curve Falloff Preset";
+  ot->description = "Set Curve Falloff Preset";
+  ot->idname = "BRUSH_OT_sculpt_curves_falloff_preset";
+
+  ot->exec = brush_sculpt_curves_falloff_preset_exec;
+  ot->poll = brush_sculpt_curves_falloff_preset_poll;
+
+  PropertyRNA *prop;
   prop = RNA_def_enum(ot->srna, "shape", prop_shape_items, CURVE_PRESET_SMOOTH, "Mode", "");
   RNA_def_property_translation_context(prop,
                                        BLT_I18NCONTEXT_ID_CURVE_LEGACY); /* Abusing id_curve :/ */

source/blender/makesdna/DNA_brush_types.h

@@ -162,7 +162,8 @@ typedef struct BrushCurvesSculptSettings {
   int density_add_attempts;
   /** #eBrushCurvesSculptDensityMode. */
   uint8_t density_mode;
-  char _pad[7];
+  char _pad[3];
+  struct CurveMapping *curve_parameter_falloff;
 } BrushCurvesSculptSettings;
 
 typedef struct Brush {

source/blender/makesrna/intern/rna_brush.c

@@ -2106,6 +2106,12 @@ static void rna_def_curves_sculpt_options(BlenderRNA *brna)
   RNA_def_property_enum_items(prop, density_mode_items);
   RNA_def_property_ui_text(
       prop, "Density Mode", "Determines whether the brush adds or removes curves");
+
+  prop = RNA_def_property(srna, "curve_parameter_falloff", PROP_POINTER, PROP_NONE);
+  RNA_def_property_struct_type(prop, "CurveMapping");
+  RNA_def_property_ui_text(prop,
+                           "Curve Parameter Falloff",
+                           "Falloff that is applied from the tip to the root of each curve");
 }
 
 static void rna_def_brush(BlenderRNA *brna)