Fix [#37085] Hook modifier work when created with Ctrl+H, but not when created via modifier panel

"transform matrix" of the hook was not inited (reset) when assinging and object to it, now use same code for both OBJECT_OT_hook_reset operator and RNA object assignement.

Reviewed by Brecht, thanks.

source/blender/editors/include/ED_object.h

@@ -51,6 +51,7 @@ struct Main;
 struct Mesh;
 struct MetaElem;
 struct ModifierData;
+struct HookModifierData;
 struct Nurb;
 struct Object;
 struct ReportList;
@@ -218,6 +219,9 @@ struct EnumPropertyItem *ED_object_vgroup_selection_itemf_helper(
         int *free,
         const unsigned int selection_mask);
 
+/* object_hook.c */
+void ED_object_hook_reset_do(struct Object *ob, struct HookModifierData *hmd);
+
 #ifdef __cplusplus
 }
 #endif

source/blender/editors/object/object_hook.c

@@ -65,6 +65,7 @@
 #include "ED_curve.h"
 #include "ED_mesh.h"
 #include "ED_screen.h"
+#include "ED_object.h"
 
 #include "WM_types.h"
 #include "WM_api.h"
@@ -689,19 +690,8 @@ void OBJECT_OT_hook_remove(wmOperatorType *ot)
 	ot->prop = prop;
 }
 
-static int object_hook_reset_exec(bContext *C, wmOperator *op)
+void ED_object_hook_reset_do(Object *ob, HookModifierData *hmd)
 {
-	PointerRNA ptr = CTX_data_pointer_get_type(C, "modifier", &RNA_HookModifier);
-	int num = RNA_enum_get(op->ptr, "modifier");
-	Object *ob = NULL;
-	HookModifierData *hmd = NULL;
-
-	object_hook_from_context(C, &ptr, num, &ob, &hmd);
-	if (hmd == NULL) {
-		BKE_report(op->reports, RPT_ERROR, "Could not find hook modifier");
-		return OPERATOR_CANCELLED;
-	}
-	
 	/* reset functionality */
 	if (hmd->object) {
 		bPoseChannel *pchan = BKE_pose_channel_find_name(hmd->object->pose, hmd->subtarget);
@@ -720,7 +710,23 @@ static int object_hook_reset_exec(bContext *C, wmOperator *op)
 			mul_m4_m4m4(hmd->parentinv, hmd->object->imat, ob->obmat);
 		}
 	}
-	
+}
+
+static int object_hook_reset_exec(bContext *C, wmOperator *op)
+{
+	PointerRNA ptr = CTX_data_pointer_get_type(C, "modifier", &RNA_HookModifier);
+	int num = RNA_enum_get(op->ptr, "modifier");
+	Object *ob = NULL;
+	HookModifierData *hmd = NULL;
+
+	object_hook_from_context(C, &ptr, num, &ob, &hmd);
+	if (hmd == NULL) {
+		BKE_report(op->reports, RPT_ERROR, "Could not find hook modifier");
+		return OPERATOR_CANCELLED;
+	}
+
+	ED_object_hook_reset_do(ob, hmd);
+
 	DAG_id_tag_update(&ob->id, OB_RECALC_DATA);
 	WM_event_add_notifier(C, NC_OBJECT | ND_MODIFIER, ob);
 	

source/blender/makesrna/intern/rna_modifier.c

@@ -120,6 +120,8 @@ EnumPropertyItem modifier_type_items[] = {
 #include "BKE_modifier.h"
 #include "BKE_particle.h"
 
+#include "ED_object.h"
+
 static void rna_UVProject_projectors_begin(CollectionPropertyIterator *iter, PointerRNA *ptr)
 {
 	UVProjectModifierData *uvp = (UVProjectModifierData *)ptr->data;
@@ -536,6 +538,14 @@ static int rna_MultiresModifier_filepath_length(PointerRNA *ptr)
 	return strlen((external) ? external->filename : "");
 }
 
+static void rna_HookModifier_object_set(PointerRNA *ptr, PointerRNA value)
+{
+	HookModifierData *hmd = ptr->data;
+
+	hmd->object = (Object *)value.data;
+	ED_object_hook_reset_do((Object *)ptr->id.data, hmd);
+}
+
 static void modifier_object_set(Object *self, Object **ob_p, int type, PointerRNA value)
 {
 	Object *ob = value.data;
@@ -1434,6 +1444,7 @@ static void rna_def_modifier_hook(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "object", PROP_POINTER, PROP_NONE);
 	RNA_def_property_ui_text(prop, "Object", "Parent Object for hook, also recalculates and clears offset");
 	RNA_def_property_flag(prop, PROP_EDITABLE | PROP_ID_SELF_CHECK);
+	RNA_def_property_pointer_funcs(prop, NULL, "rna_HookModifier_object_set", NULL, NULL);
 	RNA_def_property_update(prop, 0, "rna_Modifier_dependency_update");
 	
 	prop = RNA_def_property(srna, "subtarget", PROP_STRING, PROP_NONE);