== Constraints System ==

After just over a week of coding, I've finished doing a major refactor/cleanup of the constraints code. In the process, quite a few old kludges and ugly hacks have been removed. Also, some new features which will greatly benefit riggers have been implemented.

=== What's New ===
* The long-awaited ``ChildOf Constraint'':
This allows you to animate parent influences, and choose which transformation channels the parent affects the child on (i.e. no translation/rotation/scaling). It should be noted that disabling some combinations may not totally work as expected. Also, the 'Set Inverse' and 'Clear Inverse' buttons at the bottom of this constraint's panel set/clear the inverse correction for the parent's effects. Use these to make the owner not stick/be glued to the parent.
* Constraint/Target Evaluation Spaces:
In some constraints, there are now 1-2 combo boxes at the bottom of their panel, which allows you to pick which `co-ordinate space' they are evaluated in. This is much more flexible than the old 'local' options for bones only were.
* Action Constraint - Loc/Rot/Size Inputs
The Action Constraint can finally use the target's location/rotation/scaling transforms as input, to control the owner of the constraint. This should work much more reliably than it used to. The target evaluation should now also be more accurate due to the new space conversion stuff.
* Transform - No longer in Crazy Space (TM)
Transforming objects/bones with constraints applied should no longer occur in Crazy Space. They are now correctly inverse-corrected. This also applies to old-style object tracking.

=== General Code Changes ===
* solve_constraints is now in constraints.c. I've removed the old `blend consecutive constraints of same type' junk, which made the code more complex than it needed to be.
* evaluate_constraint is now only passed the constraint, and two matrices. A few unused variables have been removed from here.
* A tempolary struct, bConstraintOb, is now passed to solve_constraints instead of relying on an ugly, static workobject in some cases. This works much better.
* Made the formatting of constraint code consistent
* There's a version patch for older files so that constraint settings are correctly converted to the new system. This is currently done for MajorVersion <= 244, and SubVersion < 3. I've bumped up the subversion to 3 for this purpose. However, with the imminent 2.45 release, this may need to be adjusted accordingly.
* LocEulSizeToMat4 and LocQuatSizeToMat4 now work in the order Size, Rot, Location. I've also added a few other math functions.
* Mat4BlendMat4 is now in arithb. I've modified it's method slightly, to use other arithb functions, instead of its crazy blending scheme. 
* Moved some of the RigidBodyJoint constraint's code out of blenkernel, and into src. It shouldn't be setting its target in its data initialisation function based + accessing scene stuff where it was doing so.

=== Future Work ===
* Geometry to act as targets for constraints. A space has been reserved for this already. 
* Tidy up UI buttons of constraints

1 files changed, 100 insertions, 70 deletions

diff --git a/source/blender/makesdna/DNA_constraint_types.h b/source/blender/makesdna/DNA_constraint_types.h
index 3179d1035ff..a1a136b8836 100644
--- a/source/blender/makesdna/DNA_constraint_types.h
+++ b/source/blender/makesdna/DNA_constraint_types.h
@@ -25,7 +25,7 @@
  *
  * The Original Code is: all of this file.
  *
- * Contributor(s): none yet.
+ * Contributor(s): 2007, Joshua Leung, major recode
  *
  * ***** END GPL/BL DUAL LICENSE BLOCK *****
  * Constraint DNA data
@@ -45,24 +45,29 @@ struct PyObject;
 #endif
 
 /* channels reside in Object or Action (ListBase) constraintChannels */
-typedef struct bConstraintChannel{
+typedef struct bConstraintChannel {
 	struct bConstraintChannel *next, *prev;
 	Ipo			*ipo;
 	short		flag;
 	char		name[30];
 } bConstraintChannel;
 
-typedef struct bConstraint{
+/* A Constraint */
+typedef struct bConstraint {
 	struct bConstraint *next, *prev;
 	void		*data;		/*	Constraint data	(a valid constraint type) */
 	short		type;		/*	Constraint type	*/
-	short		flag;		/*	Flag */
-	short		reserved1;	
+	short		flag;		/*	Flag - General Settings	*/
+	
+	char 		ownspace;	/* 	Space that owner should be evaluated in 	*/
+	char		tarspace;	/* 	Space that target should be evaluated in 	*/
+	
 	char		name[30];	/*	Constraint name	*/
-
-	float		enforce;
+	
+	float		enforce;	/* 	Amount of influence exherted by constraint (0.0-1.0) */
 } bConstraint;
 
+
 /* Python Script Constraint */
 typedef struct bPythonConstraint {
 	Object *tar;			/* object to use as target (if required) */
@@ -75,8 +80,9 @@ typedef struct bPythonConstraint {
 	int pad;
 } bPythonConstraint;
 
-/* Single-target subobject constraints */
-typedef struct bKinematicConstraint{
+/* Single-target subobject constraints ---------------------  */
+/* Inverse-Kinematics (IK) constraint */
+typedef struct bKinematicConstraint {
 	Object		*tar;
 	short		iterations;		/* Maximum number of iterations to try */
 	short		flag;			/* Like CONSTRAINT_IK_TIP */
@@ -89,7 +95,8 @@ typedef struct bKinematicConstraint{
 	int			pad;
 } bKinematicConstraint;
 
-typedef struct bTrackToConstraint{
+/* Track To Constraint */
+typedef struct bTrackToConstraint {
 	Object		*tar;
 	int			reserved1; /* I'll be using reserved1 and reserved2 as Track and Up flags, not sure if that's what they were intented for anyway. Not sure either if it would create backward incompatibility if I were to rename them. - theeth*/
 	int			reserved2;
@@ -98,21 +105,24 @@ typedef struct bTrackToConstraint{
 	char		subtarget[32];
 } bTrackToConstraint;
 
-typedef struct bRotateLikeConstraint{
+/* Copy Rotation Constraint */
+typedef struct bRotateLikeConstraint {
 	Object		*tar;
 	int			flag;
 	int			reserved1;
 	char		subtarget[32];
 } bRotateLikeConstraint;
 
-typedef struct bLocateLikeConstraint{
+/* Copy Location Constraint */
+typedef struct bLocateLikeConstraint {
 	Object		*tar;
 	int			flag;
 	int			reserved1;
 	char		subtarget[32];
 } bLocateLikeConstraint;
 
-typedef struct bMinMaxConstraint{
+/* Floor Constraint */
+typedef struct bMinMaxConstraint {
 	Object		*tar;
 	int			minmaxflag;
 	float			offset;
@@ -122,17 +132,19 @@ typedef struct bMinMaxConstraint{
 	char		subtarget[32];
 } bMinMaxConstraint;
 
-typedef struct bSizeLikeConstraint{
+/* Copy Scale Constraint */
+typedef struct bSizeLikeConstraint {
 	Object		*tar;
 	int			flag;
 	int			reserved1;
 	char		subtarget[32];
 } bSizeLikeConstraint;
 
-typedef struct bActionConstraint{
+/* Action Constraint */
+typedef struct bActionConstraint {
 	Object		*tar;
 	short		type;
-	short		local;
+	short		local;	/* was used in versions prior to the Constraints recode */
 	int		start;
 	int		end;
 	float		min;
@@ -143,7 +155,7 @@ typedef struct bActionConstraint{
 } bActionConstraint;
 
 /* Locked Axis Tracking constraint */
-typedef struct bLockTrackConstraint{
+typedef struct bLockTrackConstraint {
 	Object		*tar;
 	int			trackflag;
 	int			lockflag;
@@ -151,7 +163,7 @@ typedef struct bLockTrackConstraint{
 } bLockTrackConstraint;
 
 /* Follow Path constraints */
-typedef struct bFollowPathConstraint{
+typedef struct bFollowPathConstraint {
 	Object		*tar;	/* Must be path object */
 	float		offset; /* Offset in time on the path (in frame) */
 	int			followflag;
@@ -159,26 +171,8 @@ typedef struct bFollowPathConstraint{
 	int			upflag;
 } bFollowPathConstraint;
 
-/* Distance Limiting constraints */
-typedef struct bDistanceLimitConstraint{
-	Object	*tar;
-	char		subtarget[32];
-	float		pad1;
-	float		pad2;
-	float		distance;
-	float		offset[3];
-} bDistanceLimitConstraint;	
-
-
-/* Zero-target constraints */
-typedef struct bRotationConstraint{
-	float xmin, xmax;
-	float ymin, ymax;
-	float zmin, zmax;
-} bRotationConstraint;
-
 /* Stretch to constraint */
-typedef struct bStretchToConstraint{
+typedef struct bStretchToConstraint {
 	Object		*tar;
 	int			volmode; 
 	int         plane;
@@ -187,33 +181,8 @@ typedef struct bStretchToConstraint{
 	char		subtarget[32];
 } bStretchToConstraint;
 
-/* transform limiting constraints - zero target */
-typedef struct bLocLimitConstraint{
-	float 		xmin, xmax;
-	float 		ymin, ymax;
-	float		zmin, zmax;
-	short 		flag;
-	short 		flag2;
-} bLocLimitConstraint;
-
-typedef struct bRotLimitConstraint{
-	float		xmin, xmax;
-	float		ymin, ymax;
-	float		zmin, zmax;
-	short 		flag;
-	short		pad1;
-} bRotLimitConstraint;
-
-typedef struct bSizeLimitConstraint{
-	float 		xmin, xmax;
-	float		ymin, ymax;
-	float 		zmin, zmax;
-	short 		flag;
-	short		pad1;
-} bSizeLimitConstraint;
-
 /* Rigid Body constraint */
-typedef struct bRigidBodyJointConstraint{
+typedef struct bRigidBodyJointConstraint {
 	Object		*tar;
 	Object		*child;
 	int         type;
@@ -232,16 +201,53 @@ typedef struct bRigidBodyJointConstraint{
 	short		pad2;
 } bRigidBodyJointConstraint;
 
-/* ClampTo Constraint */
+/* Clamp-To Constraint */
 typedef struct bClampToConstraint {
 	Object 		*tar;			/* 'target' must be a curve */
 	int			flag;			/* which axis/plane to compare owner's location on  */
 	int			pad;
 } bClampToConstraint;
 
+/* Child Of Constraint */
+typedef struct bChildOfConstraint {
+	Object 		*tar;			/* object which may/may not be the parent */
+	int 		flag;			/* settings */
+	int			pad;
+	float		invmat[4][4];	/* parent-inverse matrix to use */
+	char 		subtarget[32];	/* string to specify a subobject target */
+} bChildOfConstraint;
+
+/* transform limiting constraints - zero target ----------------------------  */
+/* Limit Location Constraint */
+typedef struct bLocLimitConstraint {
+	float 		xmin, xmax;
+	float 		ymin, ymax;
+	float		zmin, zmax;
+	short 		flag;
+	short 		flag2;
+} bLocLimitConstraint;
+
+/* Limit Rotation Constraint */
+typedef struct bRotLimitConstraint {
+	float		xmin, xmax;
+	float		ymin, ymax;
+	float		zmin, zmax;
+	short 		flag;
+	short		pad1;
+} bRotLimitConstraint;
+
+/* Limit Scaling Constraint */
+typedef struct bSizeLimitConstraint {
+	float 		xmin, xmax;
+	float		ymin, ymax;
+	float 		zmin, zmax;
+	short 		flag;
+	short		pad1;
+} bSizeLimitConstraint;
+
 /* bConstraint.type */
 #define CONSTRAINT_TYPE_NULL		0
-#define CONSTRAINT_TYPE_CHILDOF		1	/* Unimplemented */
+#define CONSTRAINT_TYPE_CHILDOF		1	/* Unimplemented non longer :) - during constraints recode, Aligorith */
 #define CONSTRAINT_TYPE_TRACKTO		2	
 #define CONSTRAINT_TYPE_KINEMATIC	3	
 #define CONSTRAINT_TYPE_FOLLOWPATH	4
@@ -251,10 +257,10 @@ typedef struct bClampToConstraint {
 #define CONSTRAINT_TYPE_ROTLIKE		8	
 #define CONSTRAINT_TYPE_LOCLIKE		9	
 #define CONSTRAINT_TYPE_SIZELIKE	10
-#define CONSTRAINT_TYPE_PYTHON		11	/* Unimplemented */
+#define CONSTRAINT_TYPE_PYTHON		11	/* Unimplemented no longer :) - Aligorith. Scripts */
 #define CONSTRAINT_TYPE_ACTION		12
 #define CONSTRAINT_TYPE_LOCKTRACK	13	/* New Tracking constraint that locks an axis in place - theeth */
-#define CONSTRAINT_TYPE_DISTANCELIMIT	14 
+#define CONSTRAINT_TYPE_DISTANCELIMIT	14 /* was never properly coded - removed! */
 #define CONSTRAINT_TYPE_STRETCHTO	15  /* claiming this to be mine :) is in tuhopuu bjornmose */ 
 #define CONSTRAINT_TYPE_MINMAX      16  /* floor constraint */
 #define CONSTRAINT_TYPE_RIGIDBODYJOINT 17 /* rigidbody constraint */
@@ -268,9 +274,19 @@ typedef struct bClampToConstraint {
 		/* flags 0x2 and 0x8 were used in past, skip this */
 		/* to indicate which Ipo should be shown, maybe for 3d access later too */
 #define CONSTRAINT_ACTIVE		0x10
-		/* only for Pose, evaluates constraints in posechannel local space */
-#define CONSTRAINT_LOCAL		0x20
-
+		/* flag 0x20 was used to indicate that a constraint was evaluated using a 'local' hack for posebones only  */
+		/* to indicate that the owner's space should only be changed into ownspace, but not out of it */
+#define CONSTRAINT_SPACEONCE	0x40
+
+/* bConstraint.ownspace/tarspace */
+	/* default for all - worldspace */
+#define CONSTRAINT_SPACE_WORLD			0
+	/* for objects (relative to parent/without parent influence), for bones (along normals of bone, without parent/restposi) */
+#define CONSTRAINT_SPACE_LOCAL			1
+	/* for posechannels - pose space  */
+#define CONSTRAINT_SPACE_POSE			2
+	/* for posechannels - local with parent  */
+#define CONSTRAINT_SPACE_PARLOCAL		3
 
 /* bConstraintChannel.flag */
 #define CONSTRAINT_CHANNEL_SELECT		0x01
@@ -334,6 +350,7 @@ typedef struct bClampToConstraint {
 #define PLANE_Y		0x01
 #define PLANE_Z		0x02
 
+/* Clamp-To Constraint ->flag */
 #define CLAMPTO_AUTO	0
 #define CLAMPTO_X		1
 #define	CLAMPTO_Y		2
@@ -364,12 +381,25 @@ typedef struct bClampToConstraint {
 #define LIMIT_YROT 0x02
 #define LIMIT_ZROT 0x04
 
+/* not used anymore - for older Limit Location constraints only */
 #define LIMIT_NOPARENT 0x01
 
 /* python constraint -> flag */
 #define PYCON_USETARGETS	0x01
 #define PYCON_SCRIPTERROR	0x02
 
+/* ChildOf Constraint -> flag */
+#define CHILDOF_LOCX 	0x001
+#define CHILDOF_LOCY	0x002
+#define CHILDOF_LOCZ	0x004
+#define CHILDOF_ROTX	0x008
+#define CHILDOF_ROTY	0x010
+#define CHILDOF_ROTZ	0x020
+#define CHILDOF_SIZEX	0x040
+#define CHILDOF_SIZEY	0x080
+#define CHILDOF_SIZEZ	0x100
+
+/* Rigid-Body Constraint */
 #define CONSTRAINT_DRAW_PIVOT 0x40
 
 /* important: these defines need to match up with PHY_DynamicTypes headerfile */