== PyConstraints ==

At last! The ability to code constraints in Python. This opens up many interesting rigging possibilities, as well as making prototyping constraints easier.

* A PyConstraint script must begin with the line 
#BPYCONSTRAINT
* It must also define a doConstraint function, which performs the core actions of the constraint.
* PyConstraints use IDProperties to store custom properties for each PyConstraint instance. The scripter can choose which of these ID-Properties to expose to a user to control the behaviour of the constraint. This must be done using the Draw.PupBlock method.

Credits to Joe Eager (joeedh) for coding the original patch on which this is based. I've made heavy revisions to large parts of the patch.

For more detailed information, and some demo scripts, see the following page:
http://aligorith.googlepages.com/pyconstraints2

1 files changed, 129 insertions, 8 deletions

diff --git a/source/blender/src/editconstraint.c b/source/blender/src/editconstraint.c
index 2eef0f55978..32cfde2eb86 100644
--- a/source/blender/src/editconstraint.c
+++ b/source/blender/src/editconstraint.c
@@ -45,6 +45,7 @@
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
 #include "DNA_screen_types.h"
+#include "DNA_text_types.h"
 #include "DNA_view3d_types.h"
 
 #include "BKE_action.h"
@@ -52,6 +53,7 @@
 #include "BKE_constraint.h"
 #include "BKE_depsgraph.h"
 #include "BKE_global.h"
+#include "BKE_main.h"
 #include "BKE_ipo.h"
 #include "BKE_object.h"
 #include "BKE_utildefines.h"
@@ -65,6 +67,8 @@
 #include "BIF_space.h"
 #include "BIF_toolbox.h"
 
+#include "BPY_extern.h"
+
 #include "blendef.h"
 #include "nla.h"
 #include "mydevice.h"
@@ -247,7 +251,14 @@ char *get_con_subtarget_name(bConstraint *con, Object *target)
 	 * to the name for this constraints subtarget ... NULL otherwise
 	 */
 	switch (con->type) {
-
+		case CONSTRAINT_TYPE_PYTHON:
+		{
+			bPythonConstraint *data = con->data;
+			if (data->flag & PYCON_USETARGETS) {
+				if (data->tar==target) return data->subtarget;
+			}
+		}
+		break;
 		case CONSTRAINT_TYPE_ACTION:
 		{
 			bActionConstraint *data = con->data;
@@ -376,6 +387,51 @@ static void test_constraints (Object *owner, const char* substring)
 			curcon->flag &= ~CONSTRAINT_DISABLE;
 			
 			switch (curcon->type){
+				case CONSTRAINT_TYPE_PYTHON:
+				{
+					bPythonConstraint *data = curcon->data;
+					float dummy_matrix[4][4];
+					
+					/* is there are valid script? */
+					if (!data->text) {
+						curcon->flag |= CONSTRAINT_DISABLE;
+						break;
+					}
+					else if (!BPY_is_pyconstraint(data->text)) {
+						curcon->flag |= CONSTRAINT_DISABLE;
+						break;
+					}
+					data->flag &= ~PYCON_SCRIPTERROR;
+					
+					/* does the constraint require target input? */
+					if (BPY_pyconstraint_targets(data, dummy_matrix))
+						data->flag |= PYCON_USETARGETS;
+					else
+						data->flag &= ~PYCON_USETARGETS;
+					
+					/* check whether we have a valid target */
+					if (data->flag & PYCON_USETARGETS) {
+						/* validate target */
+						if (!exist_object(data->tar)) {
+							data->tar = NULL;
+							curcon->flag |= CONSTRAINT_DISABLE;
+							break;
+						}
+						
+						if ( (data->tar == owner) &&
+							 (!get_named_bone(get_armature(owner), 
+											  data->subtarget))) {
+							curcon->flag |= CONSTRAINT_DISABLE;
+							break;
+						}
+					}
+					else {
+						/* don't hold onto target */
+						data->tar = NULL;
+						BLI_strncpy(data->subtarget, "", 32);
+					}
+				}
+					break;
 				case CONSTRAINT_TYPE_ACTION:
 				{
 					bActionConstraint *data = curcon->data;
@@ -688,21 +744,21 @@ void add_constraint(int only_IK)
 	else {
 		if(pchanact) {
 			if(pchansel)
-				nr= pupmenu("Add Constraint to Active Bone%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|Track To%x3|Floor%x4|Locked Track%x5|Stretch To%x7|Action%x16");
+				nr= pupmenu("Add Constraint to Active Bone%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|%l|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|%l|Track To%x3|Floor%x4|Locked Track%x5|Stretch To%x7|Action%x16|%l|Script%x18");
 			else if(obsel && obsel->type==OB_CURVE)
-				nr= pupmenu("Add Constraint to Active Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|Track To%x3|Floor%x4|Locked Track%x5|Follow Path%x6|Clamp To%x17|Stretch To%x7|Action%x16");
+				nr= pupmenu("Add Constraint to Active Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|%l|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|%l|Track To%x3|Floor%x4|Locked Track%x5|Follow Path%x6|Clamp To%x17|Stretch To%x7|Action%x16|%l|Script%x18");
 			else if(obsel)
-				nr= pupmenu("Add Constraint to Active Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|Track To%x3|Floor%x4|Locked Track%x5|Stretch To%x7|Action%x16");
+				nr= pupmenu("Add Constraint to Active Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|%l|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|%l|Track To%x3|Floor%x4|Locked Track%x5|Stretch To%x7|Action%x16|%l|Script%x18");
 			else
-				nr= pupmenu("Add Constraint to New Empty Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|Track To%x3|Floor%x4|Locked Track%x5|Stretch To%x7");
+				nr= pupmenu("Add Constraint to New Empty Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|%l|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|%l|Track To%x3|Floor%x4|Locked Track%x5|Stretch To%x7|%l|Script%x18");
 		}
 		else {
 			if(obsel && obsel->type==OB_CURVE)
-				nr= pupmenu("Add Constraint to Active Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|Track To%x3|Floor%x4|Locked Track%x5|Follow Path%x6|Clamp To%x17");
+				nr= pupmenu("Add Constraint to Active Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|%l|Track To%x3|Floor%x4|Locked Track%x5|Follow Path%x6|Clamp To%x17|%l|Script%x18");
 			else if(obsel)
-				nr= pupmenu("Add Constraint to Active Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|Track To%x3|Floor%x4|Locked Track%x5");
+				nr= pupmenu("Add Constraint to Active Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|%l|Track To%x3|Floor%x4|Locked Track%x5|%l|Script%x18");
 			else
-				nr= pupmenu("Add Constraint to New Empty Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|Track To%x3|Floor%x4|Locked Track%x5");
+				nr= pupmenu("Add Constraint to New Empty Object%t|Copy Location%x1|Copy Rotation%x2|Copy Scale%x8|Limit Location%x13|Limit Rotation%x14|Limit Scale%x15|%l|Track To%x3|Floor%x4|Locked Track%x5|%l|Script%x18");
 		}
 	}
 	
@@ -762,6 +818,21 @@ void add_constraint(int only_IK)
 			cu->flag |= CU_PATH;
 			con = add_new_constraint(CONSTRAINT_TYPE_CLAMPTO);
 		}
+		else if(nr==18) {	
+			char *menustr;
+			int scriptint= 0, dummy_active=0;
+			
+			/* popup a list of usable scripts */
+			menustr = buildmenu_pyconstraints(NULL, &dummy_active);
+			scriptint = pupmenu(menustr);
+			MEM_freeN(menustr);
+			
+			/* only add constraint if a script was chosen */
+			if (scriptint) {
+				con = add_new_constraint(CONSTRAINT_TYPE_PYTHON);
+				validate_pyconstraint_cb(con->data, &scriptint);
+			}
+		}
 		
 		if(con==NULL) return;	/* paranoia */
 		
@@ -921,3 +992,53 @@ void rename_constraint(Object *ob, bConstraint *con, char *oldname)
 	
 }
 
+/* ********************** CONSTRAINT-SPECIFIC STUFF ********************* */
+/* ------------- PyConstraints ------------------ */
+
+/* this callback sets the text-file to be used for selected menu item */
+void validate_pyconstraint_cb(void *arg1, void *arg2)
+{
+	bPythonConstraint *data = arg1;
+	Text *text;
+	int index = *((int *)arg2);
+	int i;
+	
+	/* innovative use of a for loop to search */
+	for (text=G.main->text.first, i=1; text && index!=i; i++, text=text->id.next);
+	data->text = text;
+}
+
+/* this returns a string for the list of usable pyconstraint script names */
+char *buildmenu_pyconstraints(Text *con_text, int *pyconindex)
+{
+	Text *text;
+	char *menustr = MEM_callocN(128, "menustr pyconstraints");
+	char *name, stmp[128];
+	int buf = 128;
+	int used = strlen("Scripts: %t") + 1;
+	int i;
+		
+	sprintf(menustr, "%s", "Scripts: %t");
+	
+	for (text=G.main->text.first, i=1; text; i++, text=text->id.next) {
+		/* this is important to ensure that right script is shown as active */
+		if (text == con_text) *pyconindex = i;
+		
+		/* menu entry is length of name + 3(len(|%X)) + 6 characters for the int.*/
+		if (BPY_is_pyconstraint(text)) {
+			name= text->id.name;
+			if (strlen(name)+used+10 >= buf) {
+				char *newbuf = MEM_callocN(buf+128, "menustr pyconstraints 2");
+				memcpy(newbuf, menustr, used);
+				MEM_freeN(menustr);
+				menustr = newbuf;
+				buf += 128;
+			}
+			sprintf(stmp, "|%s%%x%d", name, i);
+			strcat(menustr, stmp);
+			used += strlen(name)+10;
+		}
+	}
+	
+	return menustr;
+}