GPencil: New modifier to generate weights dynamically

his new modifier allows to generate weights base on:

* Angle of the stroke relative to object or world orientation. For example, if the value is 90, the maximum weights will be for vertical lines and minimum for horizontal lines.

* Distance to Target object. The distance calculated is normalized to get valid weights between 0 and 1.0.

The weights are created in an existing vertex group and the data can be replaced or mixed with the existing value to combine different weight effects. The minimum parameter, allows to define the minimum weight generated. This is useful to avoid very low weights.

The generated weights can be used in any modifier. For example, the angle weight value can be used to mimic FreeStyle Caligraphy modifier using the weight with the thickness modifier.

Also some modifier has been changed to inlude a new option to use the weights as factor of the effect.
As result of this change, the fading option has been removed from Thickness and Opacity modifiers because this can be done using the new modifier, it's not logic to repeat the same.

Reviewed By: mendio, filedescriptor

Differential Revision: https://developer.blender.org/D11604

1 files changed, 196 insertions, 60 deletions

diff --git a/source/blender/makesrna/intern/rna_gpencil_modifier.c b/source/blender/makesrna/intern/rna_gpencil_modifier.c
index 3e6048e30c4..f1c05079d9c 100644
--- a/source/blender/makesrna/intern/rna_gpencil_modifier.c
+++ b/source/blender/makesrna/intern/rna_gpencil_modifier.c
@@ -93,6 +93,11 @@ const EnumPropertyItem rna_enum_object_greasepencil_modifier_type_items[] = {
      ICON_MOD_SUBSURF,
      "Subdivide",
      "Subdivide stroke adding more control points"},
+    {eGpencilModifierType_Weight,
+     "GP_WEIGHT",
+     ICON_MOD_VERTEX_WEIGHT,
+     "Vertex Weight",
+     "Generate Vertex Weights"},
     {0, "", 0, N_("Deform"), ""},
     {eGpencilModifierType_Armature,
      "GP_ARMATURE",
@@ -233,6 +238,8 @@ static StructRNA *rna_GpencilModifier_refine(struct PointerRNA *ptr)
       return &RNA_TintGpencilModifier;
     case eGpencilModifierType_Time:
       return &RNA_TimeGpencilModifier;
+    case eGpencilModifierType_Weight:
+      return &RNA_WeightGpencilModifier;
     case eGpencilModifierType_Color:
       return &RNA_ColorGpencilModifier;
     case eGpencilModifierType_Array:
@@ -331,6 +338,8 @@ RNA_GP_MOD_VGROUP_NAME_SET(Offset, vgname);
 RNA_GP_MOD_VGROUP_NAME_SET(Armature, vgname);
 RNA_GP_MOD_VGROUP_NAME_SET(Texture, vgname);
 RNA_GP_MOD_VGROUP_NAME_SET(Tint, vgname);
+RNA_GP_MOD_VGROUP_NAME_SET(Weight, target_vgname);
+RNA_GP_MOD_VGROUP_NAME_SET(Weight, vgname);
 RNA_GP_MOD_VGROUP_NAME_SET(Lineart, vgname);
 
 #  undef RNA_GP_MOD_VGROUP_NAME_SET
@@ -363,8 +372,7 @@ static void greasepencil_modifier_object_set(Object *self,
 RNA_GP_MOD_OBJECT_SET(Armature, object, OB_ARMATURE);
 RNA_GP_MOD_OBJECT_SET(Lattice, object, OB_LATTICE);
 RNA_GP_MOD_OBJECT_SET(Mirror, object, OB_EMPTY);
-RNA_GP_MOD_OBJECT_SET(Opacity, object, OB_EMPTY);
-RNA_GP_MOD_OBJECT_SET(Thick, object, OB_EMPTY);
+RNA_GP_MOD_OBJECT_SET(Weight, object, OB_EMPTY);
 
 #  undef RNA_GP_MOD_OBJECT_SET
 
@@ -538,6 +546,16 @@ static void rna_ThickGpencilModifier_material_set(PointerRNA *ptr,
   rna_GpencilModifier_material_set(ptr, value, ma_target, reports);
 }
 
+static void rna_WeightGpencilModifier_material_set(PointerRNA *ptr,
+                                                   PointerRNA value,
+                                                   struct ReportList *reports)
+{
+  WeightGpencilModifierData *tmd = (WeightGpencilModifierData *)ptr->data;
+  Material **ma_target = &tmd->material;
+
+  rna_GpencilModifier_material_set(ptr, value, ma_target, reports);
+}
+
 static void rna_OffsetGpencilModifier_material_set(PointerRNA *ptr,
                                                    PointerRNA value,
                                                    struct ReportList *reports)
@@ -1143,35 +1161,9 @@ static void rna_def_modifier_gpencilthick(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Thickness Factor", "Factor to multiply the thickness with");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
-  prop = RNA_def_property(srna, "use_fading", PROP_BOOLEAN, PROP_NONE);
-  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_THICK_FADING);
-  RNA_def_property_ui_text(prop, "Fading", "Fading effect");
-  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
-
-  /* Distance reference object */
-  prop = RNA_def_property(srna, "object", PROP_POINTER, PROP_NONE);
-  RNA_def_property_ui_text(prop, "Object", "Object used as distance reference");
-  RNA_def_property_pointer_funcs(prop, NULL, "rna_ThickGpencilModifier_object_set", NULL, NULL);
-  RNA_def_property_flag(prop, PROP_EDITABLE | PROP_ID_SELF_CHECK);
-  RNA_def_property_update(prop, 0, "rna_GpencilModifier_dependency_update");
-
-  prop = RNA_def_property(srna, "fading_start", PROP_FLOAT, PROP_NONE);
-  RNA_def_property_float_sdna(prop, NULL, "fading_start");
-  RNA_def_property_ui_range(prop, 0, 1000.0, 1.0, 2);
-  RNA_def_property_ui_text(prop, "Fading Start", "Start distance of fading effect");
-  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
-
-  prop = RNA_def_property(srna, "fading_end", PROP_FLOAT, PROP_NONE);
-  RNA_def_property_float_sdna(prop, NULL, "fading_end");
-  RNA_def_property_ui_range(prop, 0, 1000.0, 1.0, 2);
-  RNA_def_property_ui_text(prop, "Fading End", "End distance of fading effect");
-  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
-
-  prop = RNA_def_property(srna, "fading_end_factor", PROP_FLOAT, PROP_NONE);
-  RNA_def_property_float_sdna(prop, NULL, "fading_end_factor");
-  RNA_def_property_range(prop, 0.0, FLT_MAX);
-  RNA_def_property_ui_range(prop, 0.0, 10.0, 0.1, 3);
-  RNA_def_property_ui_text(prop, "End Factor", "Fading end thickness factor");
+  prop = RNA_def_property(srna, "use_weight_factor", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_THICK_WEIGHT_FACTOR);
+  RNA_def_property_ui_text(prop, "Weighted", "Use weight to modulate effect");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
   prop = RNA_def_property(srna, "pass_index", PROP_INT, PROP_NONE);
@@ -1440,6 +1432,11 @@ static void rna_def_modifier_gpenciltint(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Strength", "Factor for tinting");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
+  prop = RNA_def_property(srna, "use_weight_factor", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_TINT_WEIGHT_FACTOR);
+  RNA_def_property_ui_text(prop, "Weighted", "Use weight to modulate effect");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
   prop = RNA_def_property(srna, "radius", PROP_FLOAT, PROP_DISTANCE);
   RNA_def_property_float_sdna(prop, NULL, "radius");
   RNA_def_property_range(prop, 1e-6f, FLT_MAX);
@@ -1726,35 +1723,9 @@ static void rna_def_modifier_gpencilopacity(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Hardness", "Factor of stroke hardness");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
-  prop = RNA_def_property(srna, "use_fading", PROP_BOOLEAN, PROP_NONE);
-  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_OPACITY_FADING);
-  RNA_def_property_ui_text(prop, "Fading", "Fading effect");
-  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
-
-  /* Distance reference object */
-  prop = RNA_def_property(srna, "object", PROP_POINTER, PROP_NONE);
-  RNA_def_property_ui_text(prop, "Object", "Object used as distance reference");
-  RNA_def_property_pointer_funcs(prop, NULL, "rna_OpacityGpencilModifier_object_set", NULL, NULL);
-  RNA_def_property_flag(prop, PROP_EDITABLE | PROP_ID_SELF_CHECK);
-  RNA_def_property_update(prop, 0, "rna_GpencilModifier_dependency_update");
-
-  prop = RNA_def_property(srna, "fading_start", PROP_FLOAT, PROP_NONE);
-  RNA_def_property_float_sdna(prop, NULL, "fading_start");
-  RNA_def_property_ui_range(prop, 0, 1000.0, 1.0, 2);
-  RNA_def_property_ui_text(prop, "Fading Start", "Start distance of fading effect");
-  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
-
-  prop = RNA_def_property(srna, "fading_end", PROP_FLOAT, PROP_NONE);
-  RNA_def_property_float_sdna(prop, NULL, "fading_end");
-  RNA_def_property_ui_range(prop, 0, 1000.0, 1.0, 2);
-  RNA_def_property_ui_text(prop, "Fading End", "End distance of fading effect");
-  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
-
-  prop = RNA_def_property(srna, "fading_end_factor", PROP_FLOAT, PROP_NONE);
-  RNA_def_property_float_sdna(prop, NULL, "fading_end_factor");
-  RNA_def_property_range(prop, 0.0, FLT_MAX);
-  RNA_def_property_ui_range(prop, 0.0, 10.0, 0.1, 3);
-  RNA_def_property_ui_text(prop, "End Factor", "Fading end thickness factor");
+  prop = RNA_def_property(srna, "use_weight_factor", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_OPACITY_WEIGHT_FACTOR);
+  RNA_def_property_ui_text(prop, "Weighted", "Use weight to modulate effect");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
   prop = RNA_def_property(srna, "pass_index", PROP_INT, PROP_NONE);
@@ -2733,6 +2704,170 @@ static void rna_def_modifier_gpenciltexture(BlenderRNA *brna)
   RNA_define_lib_overridable(false);
 }
 
+static void rna_def_modifier_gpencilweight(BlenderRNA *brna)
+{
+  StructRNA *srna;
+  PropertyRNA *prop;
+
+  static const EnumPropertyItem mode_items[] = {
+      {GP_WEIGHT_MODE_DISTANCE,
+       "DISTANCE",
+       0,
+       "Distance",
+       "Calculate weights depending on the distance to the target object"},
+      {GP_WEIGHT_MODE_ANGLE,
+       "ANGLE",
+       0,
+       "Angle",
+       "Calculate weights depending on the stroke orientation"},
+      {0, NULL, 0, NULL, NULL},
+  };
+  static const EnumPropertyItem axis_items[] = {
+      {0, "X", 0, "X", ""},
+      {1, "Y", 0, "Y", ""},
+      {2, "Z", 0, "Z", ""},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  static const EnumPropertyItem space_items[] = {
+      {GP_SPACE_LOCAL, "LOCAL", 0, "Local Space", ""},
+      {GP_SPACE_WORLD, "WORLD", 0, "World Space", ""},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  srna = RNA_def_struct(brna, "WeightGpencilModifier", "GpencilModifier");
+  RNA_def_struct_ui_text(srna, "Weight Modifier", "Calculate Vertex Weight dynamically");
+  RNA_def_struct_sdna(srna, "WeightGpencilModifierData");
+  RNA_def_struct_ui_icon(srna, ICON_MOD_VERTEX_WEIGHT);
+
+  RNA_define_lib_overridable(true);
+
+  prop = RNA_def_property(srna, "mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "mode");
+  RNA_def_property_enum_items(prop, mode_items);
+  RNA_def_property_ui_text(prop, "Mode", "");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "target_vertex_group", PROP_STRING, PROP_NONE);
+  RNA_def_property_string_sdna(prop, NULL, "target_vgname");
+  RNA_def_property_ui_text(prop, "Output", "Output Vertex group");
+  RNA_def_property_string_funcs(prop, NULL, NULL, "rna_WeightGpencilModifier_target_vgname_set");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "use_blend", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_WEIGHT_BLEND_DATA);
+  RNA_def_property_ui_text(
+      prop, "Blend", "Blend results with existing weights in output weight group");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "use_invert_output", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_WEIGHT_INVERT_OUTPUT);
+  RNA_def_property_ui_text(prop, "Invert", "Invert weight values");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "angle", PROP_FLOAT, PROP_ANGLE);
+  RNA_def_property_float_sdna(prop, NULL, "angle");
+  RNA_def_property_ui_text(prop, "Angle", "Angle");
+  RNA_def_property_range(prop, 0.0f, DEG2RAD(180.0f));
+  RNA_def_property_update(prop, NC_SCENE, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "axis", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "axis");
+  RNA_def_property_enum_items(prop, axis_items);
+  RNA_def_property_ui_text(prop, "Axis", "");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "space", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "space");
+  RNA_def_property_enum_items(prop, space_items);
+  RNA_def_property_ui_text(prop, "Space", "Coordinates space");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "layer", PROP_STRING, PROP_NONE);
+  RNA_def_property_string_sdna(prop, NULL, "layername");
+  RNA_def_property_ui_text(prop, "Layer", "Layer name");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "material", PROP_POINTER, PROP_NONE);
+  RNA_def_property_flag(prop, PROP_EDITABLE);
+  RNA_def_property_pointer_funcs(prop,
+                                 NULL,
+                                 "rna_WeightGpencilModifier_material_set",
+                                 NULL,
+                                 "rna_GpencilModifier_material_poll");
+  RNA_def_property_ui_text(prop, "Material", "Material used for filtering effect");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "vertex_group", PROP_STRING, PROP_NONE);
+  RNA_def_property_string_sdna(prop, NULL, "vgname");
+  RNA_def_property_ui_text(prop, "Vertex Group", "Vertex group name for modulating the deform");
+  RNA_def_property_string_funcs(prop, NULL, NULL, "rna_WeightGpencilModifier_vgname_set");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  /* Distance reference object */
+  prop = RNA_def_property(srna, "object", PROP_POINTER, PROP_NONE);
+  RNA_def_property_ui_text(prop, "Object", "Object used as distance reference");
+  RNA_def_property_pointer_funcs(prop, NULL, "rna_WeightGpencilModifier_object_set", NULL, NULL);
+  RNA_def_property_flag(prop, PROP_EDITABLE | PROP_ID_SELF_CHECK);
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_dependency_update");
+
+  prop = RNA_def_property(srna, "distance_start", PROP_FLOAT, PROP_NONE);
+  RNA_def_property_float_sdna(prop, NULL, "dist_start");
+  RNA_def_property_ui_range(prop, 0, 1000.0, 1.0, 2);
+  RNA_def_property_ui_text(prop, "Distance Start", "Start value for distance calculation");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "minimum_weight", PROP_FLOAT, PROP_FACTOR);
+  RNA_def_property_float_sdna(prop, NULL, "min_weight");
+  RNA_def_property_ui_text(prop, "Minimum", "Minimum value for vertex weight");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "distance_end", PROP_FLOAT, PROP_NONE);
+  RNA_def_property_float_sdna(prop, NULL, "dist_end");
+  RNA_def_property_ui_range(prop, 0, 1000.0, 1.0, 2);
+  RNA_def_property_ui_text(prop, "Distance End", "End value for distance calculation");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "pass_index", PROP_INT, PROP_NONE);
+  RNA_def_property_int_sdna(prop, NULL, "pass_index");
+  RNA_def_property_range(prop, 0, 100);
+  RNA_def_property_ui_text(prop, "Pass", "Pass index");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "invert_layers", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_WEIGHT_INVERT_LAYER);
+  RNA_def_property_ui_text(prop, "Inverse Layers", "Inverse filter");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "invert_materials", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_WEIGHT_INVERT_MATERIAL);
+  RNA_def_property_ui_text(prop, "Inverse Materials", "Inverse filter");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "invert_material_pass", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_WEIGHT_INVERT_PASS);
+  RNA_def_property_ui_text(prop, "Inverse Pass", "Inverse filter");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "invert_vertex", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_WEIGHT_INVERT_VGROUP);
+  RNA_def_property_ui_text(prop, "Inverse VertexGroup", "Inverse filter");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "layer_pass", PROP_INT, PROP_NONE);
+  RNA_def_property_int_sdna(prop, NULL, "layer_pass");
+  RNA_def_property_range(prop, 0, 100);
+  RNA_def_property_ui_text(prop, "Pass", "Layer pass index");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "invert_layer_pass", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_WEIGHT_INVERT_LAYERPASS);
+  RNA_def_property_ui_text(prop, "Inverse Pass", "Inverse filter");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  RNA_define_lib_overridable(false);
+}
+
 static void rna_def_modifier_gpencillineart(BlenderRNA *brna)
 {
   StructRNA *srna;
@@ -3187,6 +3322,7 @@ void RNA_def_greasepencil_modifier(BlenderRNA *brna)
   rna_def_modifier_gpencilarmature(brna);
   rna_def_modifier_gpencilmultiply(brna);
   rna_def_modifier_gpenciltexture(brna);
+  rna_def_modifier_gpencilweight(brna);
   rna_def_modifier_gpencillineart(brna);
   rna_def_modifier_gpencillength(brna);
 }