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)

3 files changed, 47 insertions, 17 deletions

diff --git a/source/blender/makesdna/DNA_action_types.h b/source/blender/makesdna/DNA_action_types.h
index 96d7ec3128c..4d82e4528d6 100644
--- a/source/blender/makesdna/DNA_action_types.h
+++ b/source/blender/makesdna/DNA_action_types.h
@@ -199,7 +199,8 @@ typedef struct bPoseChannel {
 	char constflag;                 /* for quick detecting which constraints affect this channel */
 	char selectflag;                /* copy of bone flag, so you can work with library armatures, not for runtime use */
 	char drawflag;
-	char pad0[5];
+	char bboneflag;
+	char pad0[4];
 
 	struct Bone         *bone;      /* set on read file or rebuild pose */
 	struct bPoseChannel *parent;    /* set on read file or rebuild pose */
@@ -242,7 +243,16 @@ typedef struct bPoseChannel {
 	float ikstretch;
 	float ikrotweight;              /* weight of joint rotation constraint */
 	float iklinweight;              /* weight of joint stretch constraint */
-
+	
+	/* curved bones settings - these are for animating, and are applied on top of the copies in pchan->bone */
+	float roll1, roll2;
+	float curveInX, curveInY;
+	float curveOutX, curveOutY;
+	float scaleIn, scaleOut;
+	
+	struct bPoseChannel *bbone_prev; /* next/prev bones to use as handle references when calculating bbones (optional) */
+	struct bPoseChannel *bbone_next;
+	
 	void        *temp;              /* use for outliner */
 } bPoseChannel;
 
@@ -253,17 +263,17 @@ typedef enum ePchan_Flag {
 	POSE_LOC        =   (1 << 0),
 	POSE_ROT        =   (1 << 1),
 	POSE_SIZE       =   (1 << 2),
-	/* old IK/cache stuff... */
-#if 0
-	POSE_IK_MAT     =   (1 << 3),
-	POSE_UNUSED2    =   (1 << 4),
-	POSE_UNUSED3    =   (1 << 5),
-	POSE_UNUSED4    =   (1 << 6),
-	POSE_UNUSED5    =   (1 << 7),
-	/* has Standard IK */
-	POSE_HAS_IK     =   (1 << 8),
-#endif
-	/* IK/Pose solving*/
+	
+	/* old IK/cache stuff
+	 * - used to be here from (1 << 3) to (1 << 8) 
+	 *   but has been repurposed since 2.77.2
+	 *   as they haven't been used in over 10 years
+	 */
+	
+	/* has BBone deforms */
+	POSE_BBONE_SHAPE =  (1 << 3),
+	
+	/* IK/Pose solving */
 	POSE_CHAIN      =   (1 << 9),
 	POSE_DONE       =   (1 << 10),
 	/* visualization */
@@ -318,6 +328,16 @@ typedef enum ePchan_DrawFlag {
 #define PCHAN_CUSTOM_DRAW_SIZE(pchan) \
 	(pchan)->custom_scale * (((pchan)->drawflag & PCHAN_DRAW_NO_CUSTOM_BONE_SIZE) ? 1.0f : (pchan)->bone->length)
 
+/* PoseChannel->bboneflag */
+typedef enum ePchan_BBoneFlag {
+	/* Use custom reference bones (for roll and handle alignment), instead of immediate neighbours */
+	PCHAN_BBONE_CUSTOM_HANDLES    = (1 << 1),
+	/* Evaluate start handle as being "relative" */
+	PCHAN_BBONE_CUSTOM_START_REL  = (1 << 2),
+	/* Evaluate end handle as being "relative" */
+	PCHAN_BBONE_CUSTOM_END_REL    = (1 << 3),
+} ePchan_BBoneFlag;
+
 /* PoseChannel->rotmode and Object->rotmode */
 typedef enum eRotationModes {
 	/* quaternion rotations (default, and for older Blender versions) */
diff --git a/source/blender/makesdna/DNA_armature_types.h b/source/blender/makesdna/DNA_armature_types.h
index b995e6917a9..cda6441f0ae 100644
--- a/source/blender/makesdna/DNA_armature_types.h
+++ b/source/blender/makesdna/DNA_armature_types.h
@@ -68,11 +68,18 @@ typedef struct Bone {
 	float        xwidth, length, zwidth; /*  width: for block bones. keep in this order, transform! */
 	float        ease1, ease2;           /*  length of bezier handles */
 	float        rad_head, rad_tail;     /* radius for head/tail sphere, defining deform as well, parent->rad_tip overrides rad_head */
-
+	
+	float        roll1, roll2;           /* curved bones settings - these define the "restpose" for a curved bone */
+	float		 curveInX, curveInY;
+	float		 curveOutX, curveOutY;
+	float		 scaleIn, scaleOut;
+	
 	float        size[3];        /*  patch for upward compat, UNUSED! */
 	int          layer;          /* layers that bone appears on */
 	short        segments;       /*  for B-bones */
-	short        pad[1];
+	
+	short		 pad1;
+
 } Bone;
 
 typedef struct bArmature {
@@ -204,7 +211,8 @@ typedef enum eBone_Flag {
 	BONE_TRANSFORM_CHILD        = (1 << 20),  /* Indicates that a parent is also being transformed */
 	BONE_UNSELECTABLE           = (1 << 21),  /* bone cannot be selected */
 	BONE_NO_LOCAL_LOCATION      = (1 << 22),  /* bone location is in armature space */
-	BONE_RELATIVE_PARENTING     = (1 << 23)   /* object child will use relative transform (like deform) */
+	BONE_RELATIVE_PARENTING     = (1 << 23),  /* object child will use relative transform (like deform) */
+	BONE_ADD_PARENT_END_ROLL    = (1 << 24)   /* it will add the parent end roll to the inroll */
 	
 } eBone_Flag;
 
diff --git a/source/blender/makesdna/DNA_constraint_types.h b/source/blender/makesdna/DNA_constraint_types.h
index 86991245068..5fcd374b21f 100644
--- a/source/blender/makesdna/DNA_constraint_types.h
+++ b/source/blender/makesdna/DNA_constraint_types.h
@@ -516,7 +516,9 @@ typedef enum eBConstraint_Flags {
 		/* indicates that constraint was added locally (i.e.  didn't come from the proxy-lib) */
 	CONSTRAINT_PROXY_LOCAL = (1<<8),
 		/* indicates that constraint is temporarily disabled (only used in GE) */
-	CONSTRAINT_OFF = (1<<9)
+	CONSTRAINT_OFF = (1<<9),
+		/* use bbone curve shape when calculating headtail values */
+	CONSTRAINT_BBONE_SHAPE = (1<<10),
 } eBConstraint_Flags;
 
 /* bConstraint->ownspace/tarspace */