== Constraints System - Recode 2 ==

Once again, I've recoded the constraints system. This time, the goals were:
* To make it more future-proof by 'modernising' the coding style. The long functions filled with switch statements, have given way to function-pointers with smaller functions for specific purposes.
* To make it support constraints which use multiple targets more readily that it did. In the past, it was assumed that constraints could only have at most one target.

As a result, a lot of code has been shuffled around, and modified. Also, the subversion number has been bumped up.

Known issues:
* PyConstraints, which were the main motivation for supporting multiple-targets, are currently broken. There are some bimport() error that keeps causing problems. I've also temporarily removed the doDriver support, although it may return in another form soon. 
* Constraints BPy-API is currently has a few features which currently don't work yet
* Outliner currently only displays the names of the constraints instead of the fancy subtarget/target/constraint-name display it used to do. What gets displayed here needs further investigation, as the old way was certainly not that great (and is not compatible with the new system too) 

1 files changed, 64 insertions, 23 deletions

diff --git a/source/blender/blenkernel/BKE_constraint.h b/source/blender/blenkernel/BKE_constraint.h
index 39a3cf13087..40fd8c5ed18 100644
--- a/source/blender/blenkernel/BKE_constraint.h
+++ b/source/blender/blenkernel/BKE_constraint.h
@@ -33,22 +33,12 @@
 #ifndef BKE_CONSTRAINT_H
 #define BKE_CONSTRAINT_H
 
-
 struct bConstraint;
+struct bConstraintTarget;
 struct ListBase;
 struct Object;
 struct bConstraintChannel;
 struct bPoseChannel;
-struct bAction;
-struct bArmature;
-
-/* ---------------------------------------------------------------------------- */
-
-/* Constraint target/owner types */
-#define TARGET_OBJECT			1	/*	string is ""				*/
-#define TARGET_BONE				2	/*	string is bone-name		*/
-#define TARGET_VERT				3	/*	string is vertex-group name 	*/
-#define TARGET_CV				4 	/* 	string is vertex-group name - is not available until curves get vgroups */
 
 /* ---------------------------------------------------------------------------- */
 
@@ -65,26 +55,77 @@ typedef struct bConstraintOb {
 
 /* ---------------------------------------------------------------------------- */
 
+/* Constraint Type-Info (shorthand in code = cti):
+ *  This struct provides function pointers for runtime, so that functions can be
+ *  written more generally (with fewer/no special exceptions for various constraints).
+ *
+ *  Callers of these functions must check that they actually point to something useful,
+ *  as some constraints don't define some of these.
+ *
+ *  Warning: it is not too advisable to reorder order of members of this struct,
+ *			as you'll have to edit quite a few ($NUM_CONSTRAINT_TYPES) of these
+ *			structs.
+ */
+typedef struct bConstraintTypeInfo {
+	/* admin/ident */
+	short type;				/* CONSTRAINT_TYPE_### */
+	short size;				/* size in bytes of the struct */
+	char name[32]; 			/* name constraint in interface */
+	char structName[32];	/* name of struct for SDNA */
+	
+	/* data management function pointers - special handling */
+		/* free any data that is allocated separately (optional) */
+	void (*free_data)(struct bConstraint *con);
+		/* adjust pointer to other ID-data using ID_NEW(), but not to targets (optional) */
+	void (*relink_data)(struct bConstraint *con);
+		/* copy any special data that is allocated separately (optional) */
+	void (*copy_data)(struct bConstraint *con, struct bConstraint *src);
+		/* set settings for data that will be used for bConstraint.data (memory already allocated) */
+	void (*new_data)(void *cdata);
+	
+	/* target handling function pointers */
+		/* for multi-target constraints: return that list; otherwise make a temporary list */
+	void (*get_constraint_targets)(struct bConstraint *con, struct ListBase *list);
+		/* for single-target constraints only: flush data back to source data, and the free memory used */
+	void (*flush_constraint_targets)(struct bConstraint *con, struct ListBase *list, short nocopy);
+	
+	/* evaluation */
+		/* set the ct->matrix for the given constraint target (at the given ctime) */
+	void (*get_target_matrix)(struct bConstraint *con, struct bConstraintOb *cob, struct bConstraintTarget *ct, float ctime);
+		/* evaluate the constraint for the given time */
+	void (*evaluate_constraint)(struct bConstraint *con, struct bConstraintOb *cob, struct ListBase *targets);
+} bConstraintTypeInfo;
+
+/* Function Prototypes for bConstraintTypeInfo's */
+bConstraintTypeInfo *constraint_get_typeinfo(struct bConstraint *con);
+bConstraintTypeInfo *get_constraint_typeinfo(int type);
+
+/* ---------------------------------------------------------------------------- */
+/* Useful macros for testing various common flag combinations */
+
+/* Constraint Target Macros */
+#define VALID_CONS_TARGET(ct) ((ct) && (ct->tar))
+
+
+/* ---------------------------------------------------------------------------- */
+
 /* Constraint function prototypes */
 void unique_constraint_name(struct bConstraint *con, struct ListBase *list);
-void *new_constraint_data(short type);
+
 void free_constraints(struct ListBase *conlist);
 void copy_constraints(struct ListBase *dst, struct ListBase *src);
 void relink_constraints(struct ListBase *list);
 void free_constraint_data(struct bConstraint *con);
 
+
 /* Constraint Channel function prototypes */
-struct bConstraintChannel *get_constraint_channel(ListBase *list, const char *name);
-struct bConstraintChannel *verify_constraint_channel(ListBase *list, const char *name);
-void do_constraint_channels(struct ListBase *conbase, struct ListBase *chanbase, float ctime, int onlydrivers);
-void copy_constraint_channels(ListBase *dst, ListBase *src);
+struct bConstraintChannel *get_constraint_channel(struct ListBase *list, const char *name);
+struct bConstraintChannel *verify_constraint_channel(struct ListBase *list, const char *name);
+void do_constraint_channels(struct ListBase *conbase, struct ListBase *chanbase, float ctime, short onlydrivers);
+void copy_constraint_channels(struct ListBase *dst, struct ListBase *src);
 void clone_constraint_channels(struct ListBase *dst, struct ListBase *src);
-void free_constraint_channels(ListBase *chanbase);
+void free_constraint_channels(struct ListBase *chanbase);
 
-/* Target function prototypes  */
-char constraint_has_target(struct bConstraint *con);
-struct Object *get_constraint_target(struct bConstraint *con, char **subtarget);
-void set_constraint_target(struct bConstraint *con, struct Object *ob, char *subtarget);
 
 /* Constraint Evaluation function prototypes */
 struct bConstraintOb *constraints_make_evalob(struct Object *ob, void *subdata, short datatype);
@@ -92,8 +133,8 @@ void constraints_clear_evalob(struct bConstraintOb *cob);
 
 void constraint_mat_convertspace(struct Object *ob, struct bPoseChannel *pchan, float mat[][4], short from, short to);
 
-short get_constraint_target_matrix(struct bConstraint *con, short ownertype, void *ownerdata, float mat[][4], float time);
-void solve_constraints (struct ListBase *conlist, struct bConstraintOb *cob, float ctime);
+void get_constraint_target_matrix(struct bConstraint *con, short ownertype, void *ownerdata, float mat[][4], float ctime);
+void solve_constraints(struct ListBase *conlist, struct bConstraintOb *cob, float ctime);
 
 
 #endif