Bendy Bones: Advanced B-Bones for Easier + Simple Rigging

This commit/patch/branch brings a bunch of powerful new options for B-Bones and
for working with B-Bones, making it easier for animators to create their own
rigs, using fewer bones (which also means hopefully lighter + faster rigs ;)
This functionality was first demoed by Daniel at BConf15

Some highlights from this patch include:
* You can now directly control the shape of B-Bones using a series of properties
  instead of being restricted to trying to indirectly control them through the
  neighbouring bones.  See the "Bendy Bones" panel...

* B-Bones can be shaped in EditMode to define a "curved rest pose" for the bone.
  This is useful for things like eyebrows and mouths/eyelids

* You can now make B-Bones use custom bones as their reference bone handles,
  instead of only using the parent/child bones. To do so, enable the
  "Use Custom Reference Handles" toggle. If none are specified, then the BBone will
  only use the Bendy Bone properties.

* Constraints Head/Tail option can now slide along the B-Bone shape, instead of
  just linearly interpolating between the endpoints of the bone.

For more details, see:
* http://aligorith.blogspot.co.nz/2016/05/bendy-bones-dev-update.html
* http://aligorith.blogspot.co.nz/2016/05/an-in-depth-look-at-how-b-bones-work.html



-- Credits --
Original Idea: Daniel M Lara (pepeland)
Original Patch/Research: Jose Molina
Additional Development + Polish: Joshua Leung (aligorith)
Testing/Feedback: Daniel M Lara (pepeland), Juan Pablo Bouza (jpbouza)

1 files changed, 44 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_pose.c b/source/blender/makesrna/intern/rna_pose.c
index 5bbc2b49a0d..fb7d5141a6d 100644
--- a/source/blender/makesrna/intern/rna_pose.c
+++ b/source/blender/makesrna/intern/rna_pose.c
@@ -872,6 +872,50 @@ static void rna_def_pose_channel(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Rotation Mode", "");
 	RNA_def_property_update(prop, NC_OBJECT | ND_POSE, "rna_Pose_update");
 	
+	/* Curved bones settings - Applied on top of restpose values */
+	rna_def_bone_curved_common(srna, true);
+	
+	/* Custom BBone next/prev sources */
+	prop = RNA_def_property(srna, "use_bbone_custom_handles", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "bboneflag", PCHAN_BBONE_CUSTOM_HANDLES);
+	RNA_def_property_ui_text(prop, "Use Custom Handle References", 
+	                         "Use custom reference bones as handles for B-Bones instead of next/previous bones, "
+	                         "leave these blank to use only B-Bone offset properties to control the shape");
+	RNA_def_property_editable_func(prop, "rna_PoseChannel_proxy_editable");
+	RNA_def_property_update(prop, NC_OBJECT | ND_POSE, "rna_Pose_update");
+	
+	prop = RNA_def_property(srna, "bbone_custom_handle_start", PROP_POINTER, PROP_NONE);
+	RNA_def_property_pointer_sdna(prop, NULL, "bbone_prev");
+	RNA_def_property_struct_type(prop, "PoseBone");
+	RNA_def_property_flag(prop, PROP_EDITABLE);
+	RNA_def_property_ui_text(prop, "B-Bone Start Handle",
+	                         "Bone that serves as the start handle for the B-Bone curve");
+	RNA_def_property_editable_func(prop, "rna_PoseChannel_proxy_editable");
+	RNA_def_property_update(prop, NC_OBJECT | ND_POSE, "rna_Pose_update");
+	
+	prop = RNA_def_property(srna, "use_bbone_relative_start_handle", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "bboneflag", PCHAN_BBONE_CUSTOM_START_REL);
+	RNA_def_property_ui_text(prop, "Relative B-Bone Start Handle", 
+	                         "Use treat custom start handle position as a relative value");
+	RNA_def_property_editable_func(prop, "rna_PoseChannel_proxy_editable");
+	RNA_def_property_update(prop, NC_OBJECT | ND_POSE, "rna_Pose_update");
+	
+	prop = RNA_def_property(srna, "bbone_custom_handle_end", PROP_POINTER, PROP_NONE);
+	RNA_def_property_pointer_sdna(prop, NULL, "bbone_next");
+	RNA_def_property_struct_type(prop, "PoseBone");
+	RNA_def_property_flag(prop, PROP_EDITABLE);
+	RNA_def_property_ui_text(prop, "B-Bone End Handle",
+	                         "Bone that serves as the end handle for the B-Bone curve");
+	RNA_def_property_editable_func(prop, "rna_PoseChannel_proxy_editable");
+	RNA_def_property_update(prop, NC_OBJECT | ND_POSE, "rna_Pose_update");
+	
+	prop = RNA_def_property(srna, "use_bbone_relative_end_handle", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "bboneflag", PCHAN_BBONE_CUSTOM_END_REL);
+	RNA_def_property_ui_text(prop, "Relative B-Bone End Handle", 
+	                         "Use treat custom end handle position as a relative value");
+	RNA_def_property_editable_func(prop, "rna_PoseChannel_proxy_editable");
+	RNA_def_property_update(prop, NC_OBJECT | ND_POSE, "rna_Pose_update");
+	
 	/* transform matrices - should be read-only since these are set directly by AnimSys evaluation */
 	prop = RNA_def_property(srna, "matrix_channel", PROP_FLOAT, PROP_MATRIX);
 	RNA_def_property_float_sdna(prop, NULL, "chan_mat");