Rigging Goodies: Spline IK Constraint

At last, this commit introduces the Spline IK Constraint to Blender. Spline IK is a constraint that makes n bones follow the shape of a specified curve. 

Simply add a chain of bones, add a curve, add a Spline IK Constraint to the tip bone and set the number of bones in the chain to make it work. Or, try the following test file:
http://download.blender.org/ftp/incoming/250_splineik_spine01.blend

Screenshots of this in action (as proof):
http://download.blender.org/ftp/incoming/b250_splineik_001_before.png
http://download.blender.org/ftp/incoming/b250_splineik_001_after.png

I've implemented this in a similar way to how standard IK solvers are done. However, this code is currently not an IK plugin, since I imagine that it would be useful to be able to combine the 2 types of IK. This can be easily changed though :)

Finally, a few notes on what to expect still:
* Constraint blending currently doesn't affect this. Getting that to work correctly will take a bit more work still.
* Options for not affecting the root joint (to make it easier to attach the chain to a stump or whatever), and non-uniform scaling options have yet to be added. I've marked the places where they can be added though
* Control over the twisting of the chain still needs investigation. 

Have fun!

1 files changed, 27 insertions, 16 deletions

diff --git a/source/blender/makesdna/DNA_action_types.h b/source/blender/makesdna/DNA_action_types.h
index 8d590692794..7067c967da3 100644
--- a/source/blender/makesdna/DNA_action_types.h
+++ b/source/blender/makesdna/DNA_action_types.h
@@ -159,20 +159,30 @@ typedef struct bPoseChannel {
 
 /* PoseChannel (transform) flags */
 typedef enum ePchan_Flag {
-	POSE_LOC		=	0x0001,
-	POSE_ROT		=	0x0002,
-	POSE_SIZE		=	0x0004,
-	POSE_IK_MAT		=	0x0008,
-	POSE_UNUSED2	=	0x0010,
-	POSE_UNUSED3	=	0x0020,
-	POSE_UNUSED4	=	0x0040,
-	POSE_UNUSED5	=	0x0080,
-	POSE_HAS_IK		=	0x0100,
-	POSE_CHAIN		=	0x0200,
-	POSE_DONE		=   0x0400,
-	POSE_KEY		=	0x1000,
-	POSE_STRIDE		=	0x2000,
-	POSE_IKTREE		=   0x4000,
+		/* has transforms */
+	POSE_LOC		=	(1<<0),
+	POSE_ROT		=	(1<<1),
+	POSE_SIZE		=	(1<<2),
+		/* old IK/cache stuff... */
+	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),
+		/* IK/Pose solving*/
+	POSE_CHAIN		=	(1<<9),
+	POSE_DONE		=   (1<<10),
+		/* visualisation */
+	POSE_KEY		=	(1<<11),
+	POSE_STRIDE		=	(1<<12),
+		/* standard IK solving */
+	POSE_IKTREE		=   (1<<13),
+		/* has Spline IK */
+	POSE_HAS_IKS	= 	(1<<14),
+		/* spline IK solving */
+	POSE_IKSPLINE	= 	(1<<15),
 } ePchan_Flag;
 
 /* PoseChannel constflag (constraint detection) */
@@ -183,7 +193,9 @@ typedef enum ePchan_ConstFlag {
 	PCHAN_HAS_ACTION	= (1<<2),
 	PCHAN_HAS_TARGET	= (1<<3),
 		/* only for drawing Posemode too */
-	PCHAN_HAS_STRIDE	= (1<<4)
+	PCHAN_HAS_STRIDE	= (1<<4),
+		/* spline IK */
+	PCHAN_HAS_SPLINEIK	= (1<<5),
 } ePchan_ConstFlag;
 
 /* PoseChannel->ikflag */
@@ -202,7 +214,6 @@ typedef enum ePchan_IkFlag {
 	BONE_IK_NO_XDOF_TEMP = (1<<10),
 	BONE_IK_NO_YDOF_TEMP = (1<<11),
 	BONE_IK_NO_ZDOF_TEMP = (1<<12),
-
 } ePchan_IkFlag;
 
 /* PoseChannel->rotmode and Object->rotmode */