GPencil: Curvature support for length modifier

Extend the stroke following an approximated circluar/helical curve.

This can be used as an effect for lineart or on its own as helix generator.

Reviewed By: Sebastian Parborg (zeddb), Hans Goudey (HooglyBoogly), YimingWu (NicksBest), Antonio Vazquez (antoniov), Henrik Dick (weasel)

Differential Revision: https://developer.blender.org/D11668

# 请为您的变更输入提交说明。以 '#' 开始的行将被忽略，而一个空的提交
# 说明将会终止提交。
#
# 位于分支 master
# 您的分支与上游分支 'origin/master' 一致。
#
# 要提交的变更：
#	修改：     source/blender/blenkernel/BKE_gpencil_geom.h
#	修改：     source/blender/blenkernel/intern/gpencil_geom.cc
#	修改：     source/blender/gpencil_modifiers/intern/MOD_gpencillength.c
#	修改：     source/blender/makesdna/DNA_gpencil_modifier_defaults.h
#	修改：     source/blender/makesdna/DNA_gpencil_modifier_types.h
#	修改：     source/blender/makesrna/intern/rna_gpencil_modifier.c
#

1 files changed, 64 insertions, 11 deletions

diff --git a/source/blender/makesrna/intern/rna_gpencil_modifier.c b/source/blender/makesrna/intern/rna_gpencil_modifier.c
index 4fa33424994..d5ef7cf2651 100644
--- a/source/blender/makesrna/intern/rna_gpencil_modifier.c
+++ b/source/blender/makesrna/intern/rna_gpencil_modifier.c
@@ -74,6 +74,11 @@ const EnumPropertyItem rna_enum_object_greasepencil_modifier_type_items[] = {
      ICON_MOD_DASH,
      "Dot Dash",
      "Generate dot-dash styled strokes"},
+    {eGpencilModifierType_Length,
+     "GP_LENGTH",
+     ICON_MOD_LENGTH,
+     "Length",
+     "Extend or shrink strokes"},
     {eGpencilModifierType_Lineart,
      "GP_LINEART",
      ICON_MOD_LINEART,
@@ -120,11 +125,6 @@ const EnumPropertyItem rna_enum_object_greasepencil_modifier_type_items[] = {
      ICON_MOD_LATTICE,
      "Lattice",
      "Deform strokes using lattice"},
-    {eGpencilModifierType_Length,
-     "GP_LENGTH",
-     ICON_MOD_LENGTH,
-     "Length",
-     "Extend or shrink strokes"},
     {eGpencilModifierType_Noise, "GP_NOISE", ICON_MOD_NOISE, "Noise", "Add noise to strokes"},
     {eGpencilModifierType_Offset,
      "GP_OFFSET",
@@ -3278,14 +3278,29 @@ static void rna_def_modifier_gpencillength(BlenderRNA *brna)
 
   prop = RNA_def_property(srna, "start_factor", PROP_FLOAT, PROP_NONE);
   RNA_def_property_float_sdna(prop, NULL, "start_fac");
-  RNA_def_property_ui_range(prop, -10.0f, 10.0f, 0.1, 1);
-  RNA_def_property_ui_text(prop, "Start Factor", "Length difference for each segment");
+  RNA_def_property_ui_range(prop, -10.0f, 10.0f, 0.1, 2);
+  RNA_def_property_ui_text(
+      prop, "Start Factor", "Added length to the start of each stroke relative to its length");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
   prop = RNA_def_property(srna, "end_factor", PROP_FLOAT, PROP_NONE);
   RNA_def_property_float_sdna(prop, NULL, "end_fac");
-  RNA_def_property_ui_range(prop, -10.0f, 10.0f, 0.1, 1);
-  RNA_def_property_ui_text(prop, "End Factor", "Length difference for each segment");
+  RNA_def_property_ui_range(prop, -10.0f, 10.0f, 0.1, 2);
+  RNA_def_property_ui_text(
+      prop, "End Factor", "Added length to the end of each stroke relative to its length");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "start_length", PROP_FLOAT, PROP_DISTANCE);
+  RNA_def_property_float_sdna(prop, NULL, "start_fac");
+  RNA_def_property_ui_range(prop, -100.0f, 100.0f, 0.1f, 3);
+  RNA_def_property_ui_text(
+      prop, "Start Factor", "Absolute added length to the start of each stroke");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "end_length", PROP_FLOAT, PROP_DISTANCE);
+  RNA_def_property_float_sdna(prop, NULL, "end_fac");
+  RNA_def_property_ui_range(prop, -100.0f, 100.0f, 0.1f, 3);
+  RNA_def_property_ui_text(prop, "End Factor", "Absolute added length to the end of each stroke");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
   prop = RNA_def_property(srna, "overshoot_factor", PROP_FLOAT, PROP_FACTOR);
@@ -3293,8 +3308,8 @@ static void rna_def_modifier_gpencillength(BlenderRNA *brna)
   RNA_def_property_range(prop, 0.0f, 1.0f);
   RNA_def_property_ui_text(
       prop,
-      "Overshoot Factor",
-      "Defines how precise must follow the stroke trajectory for the overshoot extremes");
+      "Used Length",
+      "Defines what portion of the stroke is used for the calculation of the extension");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
   prop = RNA_def_property(srna, "mode", PROP_ENUM, PROP_NONE);
@@ -3303,6 +3318,44 @@ static void rna_def_modifier_gpencillength(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Mode", "Mode to define length");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
+  prop = RNA_def_property(srna, "use_curvature", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_LENGTH_USE_CURVATURE);
+  RNA_def_property_ui_text(prop, "Use Curvature", "Follow the curvature of the stroke");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "invert_curvature", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_LENGTH_INVERT_CURVATURE);
+  RNA_def_property_ui_text(
+      prop, "Invert Curvature", "Invert the curvature of the stroke's extension");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "point_density", PROP_FLOAT, PROP_NONE);
+  RNA_def_property_range(prop, 0.1f, 1000.0f);
+  RNA_def_property_ui_range(prop, 0.1f, 1000.0f, 1.0f, 1);
+  RNA_def_property_ui_scale_type(prop, PROP_SCALE_CUBIC);
+  RNA_def_property_ui_text(
+      prop, "Point Density", "Multiplied by Start/End for the total added point count");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "segment_influence", PROP_FLOAT, PROP_FACTOR);
+  RNA_def_property_range(prop, -2.0f, 3.0f);
+  RNA_def_property_ui_range(prop, 0.0f, 1.0f, 0.1f, 2);
+  RNA_def_property_ui_text(prop,
+                           "Segment Influence",
+                           "Factor to determine how much the length of the individual segments "
+                           "should influence the final computed curvature. Higher factors makes "
+                           "small segments influence the overall curvature less");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "max_angle", PROP_FLOAT, PROP_ANGLE);
+  RNA_def_property_ui_text(prop,
+                           "Filter Angle",
+                           "Ignore points on the stroke that deviate from their neighbors by more "
+                           "than this angle when determining the extrapolation shape");
+  RNA_def_property_range(prop, 0.0f, DEG2RAD(180.0f));
+  RNA_def_property_ui_range(prop, 0.0f, DEG2RAD(179.5f), 10.0f, 1);
+  RNA_def_property_update(prop, NC_SCENE, "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");