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)

9 files changed, 216 insertions, 19 deletions

diff --git a/source/blender/editors/armature/armature_add.c b/source/blender/editors/armature/armature_add.c
index 6afc5a357c8..847b45d612c 100644
--- a/source/blender/editors/armature/armature_add.c
+++ b/source/blender/editors/armature/armature_add.c
@@ -83,6 +83,15 @@ EditBone *ED_armature_edit_bone_add(bArmature *arm, const char *name)
 	bone->segments = 1;
 	bone->layer = arm->layer;
 	
+	bone->roll1 = 0.0f;
+	bone->roll2 = 0.0f;
+	bone->curveInX = 0.0f;
+	bone->curveInY = 0.0f;
+	bone->curveOutX = 0.0f;
+	bone->curveOutY = 0.0f;
+	bone->scaleIn = 1.0f;
+	bone->scaleOut = 1.0f;
+
 	return bone;
 }
 
@@ -890,6 +899,16 @@ static int armature_extrude_exec(bContext *C, wmOperator *op)
 					newbone->segments = 1;
 					newbone->layer = ebone->layer;
 					
+					newbone->roll1 = ebone->roll1;
+					newbone->roll2 = ebone->roll2;
+					newbone->curveInX = ebone->curveInX;
+					newbone->curveInY = ebone->curveInY;
+					newbone->curveOutX = ebone->curveOutX;
+					newbone->curveOutY = ebone->curveOutY;
+					newbone->scaleIn = ebone->scaleIn;
+					newbone->scaleOut = ebone->scaleOut;
+
+
 					BLI_strncpy(newbone->name, ebone->name, sizeof(newbone->name));
 					
 					if (flipbone && forked) {   // only set if mirror edit
diff --git a/source/blender/editors/armature/armature_intern.h b/source/blender/editors/armature/armature_intern.h
index ac150b9af74..02aefce3464 100644
--- a/source/blender/editors/armature/armature_intern.h
+++ b/source/blender/editors/armature/armature_intern.h
@@ -170,6 +170,11 @@ typedef struct tPChanFCurveLink {
 	float oldangle;
 	float oldaxis[3];
 	
+	float roll1, roll2;             /* old bbone values (to be restored along with the transform properties) */
+	float curveInX, curveInY;       /* (NOTE: we haven't renamed these this time, as their names are already long enough) */
+	float curveOutX, curveOutY;
+	float scaleIn, scaleOut;
+	
 	struct IDProperty *oldprops;    /* copy of custom properties at start of operator (to be restored before each modal step) */
 } tPChanFCurveLink;
 
diff --git a/source/blender/editors/armature/armature_utils.c b/source/blender/editors/armature/armature_utils.c
index 85c6835a8bb..d73536e5ba7 100644
--- a/source/blender/editors/armature/armature_utils.c
+++ b/source/blender/editors/armature/armature_utils.c
@@ -456,7 +456,16 @@ EditBone *make_boneList(ListBase *edbo, ListBase *bones, EditBone *parent, Bone
 		eBone->rad_tail = curBone->rad_tail;
 		eBone->segments = curBone->segments;
 		eBone->layer = curBone->layer;
-		
+
+		eBone->roll1 = curBone->roll1;
+		eBone->roll2 = curBone->roll2;
+		eBone->curveInX = curBone->curveInX;
+		eBone->curveInY = curBone->curveInY;
+		eBone->curveOutX = curBone->curveOutX;
+		eBone->curveOutY = curBone->curveOutY;
+		eBone->scaleIn = curBone->scaleIn;
+		eBone->scaleOut = curBone->scaleOut;
+
 		if (curBone->prop)
 			eBone->prop = IDP_CopyProperty(curBone->prop);
 		
@@ -611,7 +620,17 @@ void ED_armature_from_edit(bArmature *arm)
 		newBone->rad_tail = eBone->rad_tail;
 		newBone->segments = eBone->segments;
 		newBone->layer = eBone->layer;
-		
+
+		newBone->roll1 = eBone->roll1;
+		newBone->roll2 = eBone->roll2;
+		newBone->curveInX = eBone->curveInX;
+		newBone->curveInY = eBone->curveInY;
+		newBone->curveOutX = eBone->curveOutX;
+		newBone->curveOutY = eBone->curveOutY;
+		newBone->scaleIn = eBone->scaleIn;
+		newBone->scaleOut = eBone->scaleOut;
+
+
 		if (eBone->prop)
 			newBone->prop = IDP_CopyProperty(eBone->prop);
 	}
diff --git a/source/blender/editors/armature/editarmature_retarget.c b/source/blender/editors/armature/editarmature_retarget.c
index 7c09ad49f35..fa7bf6e7ad4 100644
--- a/source/blender/editors/armature/editarmature_retarget.c
+++ b/source/blender/editors/armature/editarmature_retarget.c
@@ -1451,6 +1451,15 @@ static EditBone *add_editbonetolist(char *name, ListBase *list)
 	bone->segments = 1;
 	bone->layer =  1; //arm->layer;
 	
+	bone->roll1 = 0.0f;
+	bone->roll2 = 0.0f;
+	bone->curveInX = 0.0f;
+	bone->curveInY = 0.0f;
+	bone->curveOutX = 0.0f;
+	bone->curveOutY = 0.0f;
+	bone->scaleIn = 1.0f;
+	bone->scaleOut = 1.0f;
+
 	return bone;
 }
 #endif
diff --git a/source/blender/editors/armature/pose_slide.c b/source/blender/editors/armature/pose_slide.c
index 9ef46c63f0f..cd0ea23e2d3 100644
--- a/source/blender/editors/armature/pose_slide.c
+++ b/source/blender/editors/armature/pose_slide.c
@@ -303,8 +303,8 @@ static void pose_slide_apply_vec3(tPoseSlideOp *pso, tPChanFCurveLink *pfl, floa
 	MEM_freeN(path);
 }
 
-/* helper for apply() - perform sliding for custom properties */
-static void pose_slide_apply_props(tPoseSlideOp *pso, tPChanFCurveLink *pfl)
+/* helper for apply() - perform sliding for custom properties or bbone properties */
+static void pose_slide_apply_props(tPoseSlideOp *pso, tPChanFCurveLink *pfl, const char prop_prefix[])
 {
 	PointerRNA ptr = {{NULL}};
 	LinkData *ld;
@@ -313,8 +313,10 @@ static void pose_slide_apply_props(tPoseSlideOp *pso, tPChanFCurveLink *pfl)
 	/* setup pointer RNA for resolving paths */
 	RNA_pointer_create(NULL, &RNA_PoseBone, pfl->pchan, &ptr);
 	
-	/* custom properties are just denoted using ["..."][etc.] after the end of the base path, 
-	 * so just check for opening pair after the end of the path
+	/* - custom properties are just denoted using ["..."][etc.] after the end of the base path, 
+	 *   so just check for opening pair after the end of the path
+	 * - bbone properties are similar, but they always start with a prefix "bbone_*",
+	 *   so a similar method should work here for those too
 	 */
 	for (ld = pfl->fcurves.first; ld; ld = ld->next) {
 		FCurve *fcu = (FCurve *)ld->data;
@@ -328,7 +330,7 @@ static void pose_slide_apply_props(tPoseSlideOp *pso, tPChanFCurveLink *pfl)
 		 *	- pPtr is the chunk of the path which is left over
 		 */
 		bPtr = strstr(fcu->rna_path, pfl->pchan_path) + len;
-		pPtr = strstr(bPtr, "[\"");   /* dummy " for texteditor bugs */
+		pPtr = strstr(bPtr, prop_prefix);
 		
 		if (pPtr) {
 			/* use RNA to try and get a handle on this property, then, assuming that it is just
@@ -517,9 +519,16 @@ static void pose_slide_apply(bContext *C, tPoseSlideOp *pso)
 			}
 		}
 		
+		if (pchan->flag & POSE_BBONE_SHAPE) {
+			/* bbone properties - they all start a "bbone_" prefix */
+			pose_slide_apply_props(pso, pfl, "bbone_"); 
+		}
+		
 		if (pfl->oldprops) {
-			/* not strictly a transform, but contributes to the pose produced in many rigs */
-			pose_slide_apply_props(pso, pfl);
+			/* not strictly a transform, but custom properties contribute to the pose produced in many rigs
+			 * (e.g. the facial rigs used in Sintel)
+			 */
+			pose_slide_apply_props(pso, pfl, "[\"");  /* dummy " for texteditor bugs */
 		}
 	}
 	
diff --git a/source/blender/editors/armature/pose_transform.c b/source/blender/editors/armature/pose_transform.c
index 01e16df9f08..df906a3638a 100644
--- a/source/blender/editors/armature/pose_transform.c
+++ b/source/blender/editors/armature/pose_transform.c
@@ -367,10 +367,26 @@ static bPoseChannel *pose_bone_do_paste(Object *ob, bPoseChannel *chan, const bo
 				axis_angle_to_quat(pchan->quat, chan->rotAxis, pchan->rotAngle);
 		}
 		
+		/* B-Bone posing options should also be included... */
+		pchan->curveInX = chan->curveInX;
+		pchan->curveInY = chan->curveInY;
+		pchan->curveOutX = chan->curveOutX;
+		pchan->curveOutY = chan->curveOutY;
+		
+		pchan->roll1 = chan->roll1;
+		pchan->roll2 = chan->roll2;
+		pchan->scaleIn = chan->scaleIn;
+		pchan->scaleOut = chan->scaleOut;
+		
 		/* paste flipped pose? */
 		if (flip) {
 			pchan->loc[0] *= -1;
 			
+			pchan->curveInX *= -1;
+			pchan->curveOutX *= -1;
+			pchan->roll1 *= -1; // XXX?
+			pchan->roll2 *= -1; // XXX?
+			
 			/* has to be done as eulers... */
 			if (pchan->rotmode > 0) {
 				pchan->eul[1] *= -1;
@@ -540,6 +556,9 @@ static void pchan_clear_scale(bPoseChannel *pchan)
 		pchan->size[1] = 1.0f;
 	if ((pchan->protectflag & OB_LOCK_SCALEZ) == 0)
 		pchan->size[2] = 1.0f;
+	
+	pchan->scaleIn = 1.0f;
+	pchan->scaleOut = 1.0f;
 }
 
 /* clear location of pose-channel */
@@ -650,6 +669,15 @@ static void pchan_clear_rot(bPoseChannel *pchan)
 			zero_v3(pchan->eul);
 		}
 	}
+	
+	/* Clear also Bendy Bone stuff - Roll is obvious, but Curve X/Y stuff is also kindof rotational in nature... */
+	pchan->roll1 = 0.0f;
+	pchan->roll2 = 0.0f;
+	
+	pchan->curveInX = 0.0f;
+	pchan->curveInY = 0.0f;
+	pchan->curveOutX = 0.0f;
+	pchan->curveOutY = 0.0f;
 }
 
 /* clear loc/rot/scale of pose-channel */
diff --git a/source/blender/editors/armature/pose_utils.c b/source/blender/editors/armature/pose_utils.c
index 2ba1eedd33b..b960bec3603 100644
--- a/source/blender/editors/armature/pose_utils.c
+++ b/source/blender/editors/armature/pose_utils.c
@@ -71,7 +71,7 @@ static void fcurves_to_pchan_links_get(ListBase *pfLinks, Object *ob, bAction *a
 	ListBase curves = {NULL, NULL};
 	int transFlags = action_get_item_transforms(act, ob, pchan, &curves);
 	
-	pchan->flag &= ~(POSE_LOC | POSE_ROT | POSE_SIZE);
+	pchan->flag &= ~(POSE_LOC | POSE_ROT | POSE_SIZE | POSE_BBONE_SHAPE);
 	
 	/* check if any transforms found... */
 	if (transFlags) {
@@ -96,6 +96,8 @@ static void fcurves_to_pchan_links_get(ListBase *pfLinks, Object *ob, bAction *a
 			pchan->flag |= POSE_ROT;
 		if (transFlags & ACT_TRANS_SCALE)
 			pchan->flag |= POSE_SIZE;
+		if (transFlags & ACT_TRANS_BBONE)
+			pchan->flag |= POSE_BBONE_SHAPE;
 			
 		/* store current transforms */
 		copy_v3_v3(pfl->oldloc, pchan->loc);
@@ -105,6 +107,16 @@ static void fcurves_to_pchan_links_get(ListBase *pfLinks, Object *ob, bAction *a
 		copy_v3_v3(pfl->oldaxis, pchan->rotAxis);
 		pfl->oldangle = pchan->rotAngle;
 		
+		/* store current bbone values */
+		pfl->roll1 = pchan->roll1;
+		pfl->roll2 = pchan->roll2;
+		pfl->curveInX = pchan->curveInX;
+		pfl->curveInY = pchan->curveInY;
+		pfl->curveOutX = pchan->curveOutX;
+		pfl->curveOutY = pchan->curveOutY;
+		pfl->scaleIn = pchan->scaleIn;
+		pfl->scaleOut = pchan->scaleOut;
+		
 		/* make copy of custom properties */
 		if (pchan->prop && (transFlags & ACT_TRANS_PROP))
 			pfl->oldprops = IDP_CopyProperty(pchan->prop);
@@ -133,6 +145,7 @@ void poseAnim_mapping_get(bContext *C, ListBase *pfLinks, Object *ob, bAction *a
 			fcurves_to_pchan_links_get(pfLinks, ob, act, pchan);
 		}
 		CTX_DATA_END;
+		
 	}
 }
 
@@ -199,6 +212,16 @@ void poseAnim_mapping_reset(ListBase *pfLinks)
 		copy_v3_v3(pchan->rotAxis, pfl->oldaxis);
 		pchan->rotAngle = pfl->oldangle;
 		
+		/* store current bbone values */
+		pchan->roll1 = pfl->roll1;
+		pchan->roll2 = pfl->roll2;
+		pchan->curveInX = pfl->curveInX;
+		pchan->curveInY = pfl->curveInY;
+		pchan->curveOutX = pfl->curveOutX;
+		pchan->curveOutY = pfl->curveOutY;
+		pchan->scaleIn = pfl->scaleIn;
+		pchan->scaleOut = pfl->scaleOut;
+		
 		/* just overwrite values of properties from the stored copies (there should be some) */
 		if (pfl->oldprops)
 			IDP_SyncGroupValues(pfl->pchan->prop, pfl->oldprops);
diff --git a/source/blender/editors/include/ED_armature.h b/source/blender/editors/include/ED_armature.h
index 15c68378b9a..904132b8876 100644
--- a/source/blender/editors/include/ED_armature.h
+++ b/source/blender/editors/include/ED_armature.h
@@ -74,7 +74,10 @@ typedef struct EditBone {
 	float xwidth, length, zwidth;  /* put them in order! transform uses this as scale */
 	float ease1, ease2;
 	float rad_head, rad_tail;
-	
+	float roll1, roll2;
+	float curveOutX, curveOutY;
+	float curveInX, curveInY;
+	float scaleIn, scaleOut;
 	float oldlength;        /* for envelope scaling */
 	
 	short segments;
diff --git a/source/blender/editors/space_view3d/drawarmature.c b/source/blender/editors/space_view3d/drawarmature.c
index 5cda721be44..f7c1e2ee981 100644
--- a/source/blender/editors/space_view3d/drawarmature.c
+++ b/source/blender/editors/space_view3d/drawarmature.c
@@ -53,6 +53,7 @@
 #include "BKE_global.h"
 #include "BKE_modifier.h"
 #include "BKE_nla.h"
+#include "BKE_curve.h"
 
 
 #include "BIF_gl.h"
@@ -1093,20 +1094,101 @@ static void draw_line_bone(int armflag, int boneflag, short constflag, unsigned
 	glPopMatrix();
 }
 
-static void draw_b_bone_boxes(const short dt, bPoseChannel *pchan, float xwidth, float length, float zwidth)
+/* A partial copy of b_bone_spline_setup(), with just the parts for previewing editmode curve settings 
+ *
+ * This assumes that prev/next bones don't have any impact (since they should all still be in the "straight"
+ * position here anyway), and that we can simply apply the bbone settings to get the desired effect...
+ */
+static void ebone_spline_preview(EditBone *ebone, Mat4 result_array[MAX_BBONE_SUBDIV])
+{
+	float h1[3], h2[3], length, hlength1, hlength2, roll1 = 0.0f, roll2 = 0.0f;
+	float mat3[3][3];
+	float data[MAX_BBONE_SUBDIV + 1][4], *fp;
+	int a;
+	
+	length = ebone->length;
+	
+	hlength1 = ebone->ease1 * length * 0.390464f; /* 0.5f * sqrt(2) * kappa, the handle length for near-perfect circles */
+	hlength2 = ebone->ease2 * length * 0.390464f;
+	
+	/* find the handle points, since this is inside bone space, the
+	 * first point = (0, 0, 0)
+	 * last point =  (0, length, 0)
+	 *
+	 * we also just apply all the "extra effects", since they're the whole reason we're doing this...
+	 */
+	h1[0] = ebone->curveInX;
+	h1[1] = hlength1;
+	h1[2] = ebone->curveInY;
+	roll1 = ebone->roll1;
+	
+	h2[0] = ebone->curveOutX;
+	h2[1] = -hlength2;
+	h2[2] = ebone->curveOutY;
+	roll2 = ebone->roll2;
+	
+	/* make curve */
+	if (ebone->segments > MAX_BBONE_SUBDIV)
+		ebone->segments = MAX_BBONE_SUBDIV;
+
+	BKE_curve_forward_diff_bezier(0.0f,  h1[0],                               h2[0],                               0.0f,   data[0],     MAX_BBONE_SUBDIV, 4 * sizeof(float));
+	BKE_curve_forward_diff_bezier(0.0f,  h1[1],                               length + h2[1],                      length, data[0] + 1, MAX_BBONE_SUBDIV, 4 * sizeof(float));
+	BKE_curve_forward_diff_bezier(0.0f,  h1[2],                               h2[2],                               0.0f,   data[0] + 2, MAX_BBONE_SUBDIV, 4 * sizeof(float));
+	BKE_curve_forward_diff_bezier(roll1, roll1 + 0.390464f * (roll2 - roll1), roll2 - 0.390464f * (roll2 - roll1), roll2,  data[0] + 3, MAX_BBONE_SUBDIV, 4 * sizeof(float));
+
+	equalize_bbone_bezier(data[0], ebone->segments); /* note: does stride 4! */
+
+	/* make transformation matrices for the segments for drawing */
+	for (a = 0, fp = data[0]; a < ebone->segments; a++, fp += 4) {
+		sub_v3_v3v3(h1, fp + 4, fp);
+		vec_roll_to_mat3(h1, fp[3], mat3); /* fp[3] is roll */
+		
+		copy_m4_m3(result_array[a].mat, mat3);
+		copy_v3_v3(result_array[a].mat[3], fp);
+		
+		/* "extra" scale facs... */
+		{
+			const int num_segments = ebone->segments;
+			
+			const float scaleFactorIn  = 1.0f + (ebone->scaleIn  - 1.0f) * ((float)(num_segments - a) / (float)num_segments);
+			const float scaleFactorOut = 1.0f + (ebone->scaleOut - 1.0f) * ((float)(a + 1)            / (float)num_segments);
+			
+			const float scalefac = scaleFactorIn * scaleFactorOut;
+			float bscalemat[4][4], bscale[3];
+			
+			bscale[0] = scalefac;
+			bscale[1] = 1.0f;
+			bscale[2] = scalefac;
+			
+			size_to_mat4(bscalemat, bscale);
+			
+			/* Note: don't multiply by inverse scale mat here, as it causes problems with scaling shearing and breaking segment chains */
+			mul_m4_series(result_array[a].mat, result_array[a].mat, bscalemat);
+		}
+	}
+}
+
+static void draw_b_bone_boxes(const short dt, bPoseChannel *pchan, EditBone *ebone, float xwidth, float length, float zwidth)
 {
 	int segments = 0;
 	
 	if (pchan) 
 		segments = pchan->bone->segments;
+	else if (ebone)
+		segments = ebone->segments;
 	
-	if ((segments > 1) && (pchan)) {
+	if (segments > 1) {
 		float dlen = length / (float)segments;
 		Mat4 bbone[MAX_BBONE_SUBDIV];
 		int a;
-
-		b_bone_spline_setup(pchan, 0, bbone);
-
+		
+		if (pchan) {
+			b_bone_spline_setup(pchan, 0, bbone);
+		}
+		else if (ebone) {
+			ebone_spline_preview(ebone, bbone);
+		}
+		
 		for (a = 0; a < segments; a++) {
 			glPushMatrix();
 			glMultMatrixf(bbone[a].mat);
@@ -1177,7 +1259,7 @@ static void draw_b_bone(const short dt, int armflag, int boneflag, short constfl
 		else
 			UI_ThemeColor(TH_BONE_SOLID);
 		
-		draw_b_bone_boxes(OB_SOLID, pchan, xwidth, length, zwidth);
+		draw_b_bone_boxes(OB_SOLID, pchan, ebone, xwidth, length, zwidth);
 		
 		/* disable solid drawing */
 		GPU_basic_shader_bind(GPU_SHADER_USE_COLOR);
@@ -1190,7 +1272,7 @@ static void draw_b_bone(const short dt, int armflag, int boneflag, short constfl
 				if (set_pchan_glColor(PCHAN_COLOR_CONSTS, boneflag, constflag)) {
 					glEnable(GL_BLEND);
 					
-					draw_b_bone_boxes(OB_SOLID, pchan, xwidth, length, zwidth);
+					draw_b_bone_boxes(OB_SOLID, pchan, ebone, xwidth, length, zwidth);
 					
 					glDisable(GL_BLEND);
 				}
@@ -1200,7 +1282,7 @@ static void draw_b_bone(const short dt, int armflag, int boneflag, short constfl
 			}
 		}
 		
-		draw_b_bone_boxes(OB_WIRE, pchan, xwidth, length, zwidth);
+		draw_b_bone_boxes(OB_WIRE, pchan, ebone, xwidth, length, zwidth);
 	}
 }