Drivers Editing: Added "Copy/Paste" buttons beside "Add Variable" for copying all variables from one driver to another

This was a feature request from a few years back (IIRC from ZanQdo?) to make it
easier to reuse one set of driver variables across several different drivers.

Dev Notes:
* Finally it's done! All that trouble for two little buttons.
* Grr... cmake... grrr!

4 files changed, 158 insertions, 9 deletions

diff --git a/source/blender/editors/space_graph/graph_buttons.c b/source/blender/editors/space_graph/graph_buttons.c
index f8b081eda20..5846a439b3c 100644
--- a/source/blender/editors/space_graph/graph_buttons.c
+++ b/source/blender/editors/space_graph/graph_buttons.c
@@ -516,7 +516,7 @@ static void driver_delete_var_cb(bContext *UNUSED(C), void *driver_v, void *dvar
 	DriverVar *dvar = (DriverVar *)dvar_v;
 	
 	/* remove the active variable */
-	driver_free_variable(driver, dvar);
+	driver_free_variable_ex(driver, dvar);
 }
 
 /* callback to report why a driver variable is invalid */
@@ -825,14 +825,26 @@ static void graph_panel_drivers(const bContext *C, Panel *pa)
 		uiItemL(row, valBuf, ICON_NONE);
 	}
 	
-	/* add driver variables */
-	col = uiLayoutColumn(pa->layout, false);
-	block = uiLayoutGetBlock(col);
-	but = uiDefIconTextBut(block, UI_BTYPE_BUT, B_IPO_DEPCHANGE, ICON_ZOOMIN, IFACE_("Add Variable"),
-	               0, 0, 10 * UI_UNIT_X, UI_UNIT_Y,
-	               NULL, 0.0, 0.0, 0, 0,
-	               TIP_("Driver variables ensure that all dependencies will be accounted for and that drivers will update correctly"));
-	UI_but_func_set(but, driver_add_var_cb, driver, NULL);
+	/* add/copy/paste driver variables */
+	{
+		uiLayout *row;
+		
+		/* add driver variable */
+		row = uiLayoutRow(pa->layout, false);
+		block = uiLayoutGetBlock(row);
+		but = uiDefIconTextBut(block, UI_BTYPE_BUT, B_IPO_DEPCHANGE, ICON_ZOOMIN, IFACE_("Add Variable"),
+	                           0, 0, 10 * UI_UNIT_X, UI_UNIT_Y,
+	                           NULL, 0.0, 0.0, 0, 0,
+	                           TIP_("Driver variables ensure that all dependencies will be accounted for and that drivers will update correctly"));
+		UI_but_func_set(but, driver_add_var_cb, driver, NULL);
+		
+		/* copy/paste (as sub-row) */
+		row = uiLayoutRow(row, true);
+		block = uiLayoutGetBlock(row);
+		
+		uiItemO(row, "", ICON_COPYDOWN, "GRAPH_OT_driver_variables_copy");
+		uiItemO(row, "", ICON_PASTEDOWN, "GRAPH_OT_driver_variables_paste");
+	}
 	
 	/* loop over targets, drawing them */
 	for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
diff --git a/source/blender/editors/space_graph/graph_edit.c b/source/blender/editors/space_graph/graph_edit.c
index dd2ec2401a5..a54b7e141f3 100644
--- a/source/blender/editors/space_graph/graph_edit.c
+++ b/source/blender/editors/space_graph/graph_edit.c
@@ -54,6 +54,7 @@
 
 #include "BLT_translation.h"
 
+#include "BKE_depsgraph.h"
 #include "BKE_fcurve.h"
 #include "BKE_global.h"
 #include "BKE_nla.h"
@@ -2610,3 +2611,130 @@ void GRAPH_OT_fmodifier_paste(wmOperatorType *ot)
 }
 
 /* ************************************************************************** */
+/* Drivers */
+
+/* ******************** Copy Driver Vars Operator *********************** */
+
+static int graph_driver_vars_copy_exec(bContext *C, wmOperator *op)
+{
+	bAnimContext ac;
+	bAnimListElem *ale;
+	bool ok = false;
+	
+	/* get editor data */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return OPERATOR_CANCELLED;
+	
+	/* clear buffer first */
+	ANIM_driver_vars_copybuf_free();
+	
+	/* get the active F-Curve */
+	ale = get_active_fcurve_channel(&ac);
+	
+	/* if this exists, call the copy driver vars API function */
+	if (ale && ale->data) {
+		FCurve *fcu = (FCurve *)ale->data;
+		
+		ok = ANIM_driver_vars_copy(op->reports, fcu);
+		
+		/* free temp data now */
+		MEM_freeN(ale);
+	}
+	
+	/* successful or not? */
+	if (ok == 0)
+		return OPERATOR_CANCELLED;
+	else
+		return OPERATOR_FINISHED;
+}
+ 
+void GRAPH_OT_driver_variables_copy(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Copy Driver Variables";
+	ot->idname = "GRAPH_OT_driver_variables_copy";
+	ot->description = "Copy the driver variables of the active F-Curve";
+	
+	/* api callbacks */
+	ot->exec = graph_driver_vars_copy_exec;
+	ot->poll = graphop_active_fcurve_poll; 
+	
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}
+
+/* ******************** Paste Driver Vars Operator *********************** */
+
+static int graph_driver_vars_paste_exec(bContext *C, wmOperator *op)
+{
+	bAnimContext ac;
+	
+	ListBase anim_data = {NULL, NULL};
+	bAnimListElem *ale;
+	int filter;
+	
+	const bool replace = RNA_boolean_get(op->ptr, "replace");
+	bool ok = false;
+	
+	/* get editor data */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return OPERATOR_CANCELLED;
+	
+	/* filter data */
+	filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_ACTIVE | ANIMFILTER_FOREDIT | ANIMFILTER_NODUPLIS);
+	ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
+	
+	/* paste modifiers */
+	for (ale = anim_data.first; ale; ale = ale->next) {
+		FCurve *fcu = (FCurve *)ale->data;
+		bool paste_ok;
+		
+		printf("pasting vars to %p -> %p\n", fcu, fcu->driver);
+		paste_ok = ANIM_driver_vars_paste(op->reports, fcu, replace);
+		
+		if (paste_ok) {
+			//ale->update |= ANIM_UPDATE_DEPS;
+			printf("now we have: %d vars\n",  BLI_listbase_count(&fcu->driver->variables));
+			ok = true;
+		}
+	}
+	
+	// XXX: something causes a crash after adding the copies (to empty list), if we do an update immediately
+	if (ok) {
+		DAG_relations_tag_update(CTX_data_main(C));
+		//ANIM_animdata_update(&ac, &anim_data);
+	}
+	ANIM_animdata_freelist(&anim_data);
+	
+	/* successful or not? */
+	if (ok) {
+		/* set notifier that keyframes have changed */
+		WM_event_add_notifier(C, NC_SCENE | ND_FRAME, CTX_data_scene(C));
+		return OPERATOR_FINISHED;
+	}
+	else {
+		return OPERATOR_CANCELLED;
+	}
+}
+ 
+void GRAPH_OT_driver_variables_paste(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Paste Driver Variables";
+	ot->idname = "GRAPH_OT_driver_variables_paste";
+	ot->description = "Add copied driver variables to the active driver";
+	
+	/* api callbacks */
+	ot->exec = graph_driver_vars_paste_exec;
+	ot->poll = graphop_active_fcurve_poll;
+	
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+	
+	/* properties */
+	RNA_def_boolean(ot->srna, "only_active", true, "Only Active", "Only paste F-Modifiers on active F-Curve");
+	RNA_def_boolean(ot->srna, "replace", false, "Replace Existing", 
+	                "Replace existing F-Modifiers, instead of just appending to the end of the existing list");
+}
+
+/* ************************************************************************** */
diff --git a/source/blender/editors/space_graph/graph_intern.h b/source/blender/editors/space_graph/graph_intern.h
index a478a86a5e2..b6b711e129f 100644
--- a/source/blender/editors/space_graph/graph_intern.h
+++ b/source/blender/editors/space_graph/graph_intern.h
@@ -148,6 +148,11 @@ void GRAPH_OT_fmodifier_paste(struct wmOperatorType *ot);
 
 /* ----------- */
 
+void GRAPH_OT_driver_variables_copy(struct wmOperatorType *ot);
+void GRAPH_OT_driver_variables_paste(struct wmOperatorType *ot);
+
+/* ----------- */
+
 void GRAPH_OT_ghost_curves_create(struct wmOperatorType *ot);
 void GRAPH_OT_ghost_curves_clear(struct wmOperatorType *ot);
 
diff --git a/source/blender/editors/space_graph/graph_ops.c b/source/blender/editors/space_graph/graph_ops.c
index 59215531ac0..7ffa8250067 100644
--- a/source/blender/editors/space_graph/graph_ops.c
+++ b/source/blender/editors/space_graph/graph_ops.c
@@ -458,6 +458,10 @@ void graphedit_operatortypes(void)
 	WM_operatortype_append(GRAPH_OT_fmodifier_add);
 	WM_operatortype_append(GRAPH_OT_fmodifier_copy);
 	WM_operatortype_append(GRAPH_OT_fmodifier_paste);
+	
+	/* Drivers */
+	WM_operatortype_append(GRAPH_OT_driver_variables_copy);
+	WM_operatortype_append(GRAPH_OT_driver_variables_paste);
 }
 
 void ED_operatormacros_graph(void)