Transform: default to user-defined orientation

Previously we tried this but reverted (see 64d40c82c3)
because there wasn't a predictable set of keys to use global-space.

Now the keys are swapped:

- 'GX' always transforms in the user defined orientation.
- 'GXX' always transforms in global space.

As before 'GXXX' cycles back to disabling constraints.

This does have a down side that GXX won't be used for local-space
when the user has global space set.
Also, when global is the user-orientation, pressing GX and GXX
does the same thing.

Note: examples here use GX but could be any transform-mode/axis.

source/blender/editors/transform/transform.c

@@ -992,13 +992,10 @@ static void transform_event_xyz_constraint(TransInfo *t, short key_type, char cm
 			}
 		}
 		else if (!edit_2d) {
-			if (cmode == axis) {
+			if (cmode != axis) {
-				if (t->con.orientation != V3D_MANIP_GLOBAL) {
+				/* First press, constraint to an axis. */
-					stopConstraint(t);
+				t->orientation.index = 1;
-				}
+				const short orientation = t->orientation.types[t->orientation.index];
-				else {
-					short orientation = (t->current_orientation != V3D_MANIP_GLOBAL ?
-					                     t->current_orientation : V3D_MANIP_LOCAL);
 				if (is_plane == false) {
 					setUserConstraint(t, orientation, constraint_axis, msg2);
 				}
@@ -1006,13 +1003,21 @@ static void transform_event_xyz_constraint(TransInfo *t, short key_type, char cm
 					setUserConstraint(t, orientation, constraint_plane, msg3);
 				}
 			}
+			else {
+				/* Successive presses on existing axis, cycle orientation modes. */
+				t->orientation.index = (t->orientation.index + 1) % ARRAY_SIZE(t->orientation.types);
+
+				if (t->orientation.index == 0) {
+					stopConstraint(t);
 				}
 				else {
+					const short orientation = t->orientation.types[t->orientation.index];
 					if (is_plane == false) {
-					setUserConstraint(t, V3D_MANIP_GLOBAL, constraint_axis, msg2);
+						setUserConstraint(t, orientation, constraint_axis, msg2);
 					}
 					else {
-					setUserConstraint(t, V3D_MANIP_GLOBAL, constraint_plane, msg3);
+						setUserConstraint(t, orientation, constraint_plane, msg3);
+					}
 				}
 			}
 		}
@@ -2122,12 +2127,12 @@ void saveTransform(bContext *C, TransInfo *t, wmOperator *op)
 		if (t->spacetype == SPACE_VIEW3D) {
 			if ((prop = RNA_struct_find_property(op->ptr, "constraint_orientation")) &&
 			    !RNA_property_is_set(op->ptr, prop) &&
-			    (t->current_orientation != V3D_MANIP_CUSTOM_MATRIX))
+			    (t->orientation.user != V3D_MANIP_CUSTOM_MATRIX))
 			{
-				t->scene->orientation_type = t->current_orientation;
+				t->scene->orientation_type = t->orientation.user;
-				BLI_assert(((t->scene->orientation_index_custom == -1) && (t->custom_orientation == NULL)) ||
+				BLI_assert(((t->scene->orientation_index_custom == -1) && (t->orientation.custom == NULL)) ||
 				           (BKE_scene_transform_orientation_get_index(
-				                    t->scene, t->custom_orientation) == t->scene->orientation_index_custom));
+				                    t->scene, t->orientation.custom) == t->scene->orientation_index_custom));
 			}
 		}
 	}
@@ -2153,13 +2158,13 @@ void saveTransform(bContext *C, TransInfo *t, wmOperator *op)
 	if ((prop = RNA_struct_find_property(op->ptr, "constraint_axis"))) {
 		/* constraint orientation can be global, even if user selects something else
 		 * so use the orientation in the constraint if set */
-		short orientation = (t->con.mode & CON_APPLY) ? t->con.orientation : t->current_orientation;
+		short orientation = (t->con.mode & CON_APPLY) ? t->con.orientation : t->orientation.user;
 
 		if (orientation == V3D_MANIP_CUSTOM) {
 			const int orientation_index_custom = BKE_scene_transform_orientation_get_index(
-			        t->scene, t->custom_orientation);
+			        t->scene, t->orientation.custom);
 
-			/* Maybe we need a t->con.custom_orientation? Seems like it would always match t->custom_orientation. */
+			/* Maybe we need a t->con.custom_orientation? Seems like it would always match t->orientation.custom. */
 			orientation = V3D_MANIP_CUSTOM + orientation_index_custom;
 			BLI_assert(orientation >= V3D_MANIP_CUSTOM);
 		}
@@ -2420,7 +2425,7 @@ bool initTransform(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
 				t->con.mode |= CON_AXIS2;
 			}
 
-			setUserConstraint(t, t->current_orientation, t->con.mode, "%s");
+			setUserConstraint(t, t->orientation.user, t->con.mode, "%s");
 		}
 	}
 

source/blender/editors/transform/transform.h

@@ -503,8 +503,14 @@ typedef struct TransInfo {
 	/*************** NEW STUFF *********************/
 	short		launch_event; 	/* event type used to launch transform */
 
-	short		current_orientation;
+	/* Always: 'orientation_types[orientation_index]' */
-	TransformOrientation *custom_orientation; /* this gets used when current_orientation is V3D_MANIP_CUSTOM */
+	struct {
+		short		user;
+		short		index;
+		short		types[3];
+		/* this gets used when current_orientation is V3D_MANIP_CUSTOM */
+		TransformOrientation *custom;
+	} orientation;
 	short		gizmo_flag;			/* backup from view3d, to restore on end */
 
 	short		prop_mode;

source/blender/editors/transform/transform_constraints.c

@@ -709,7 +709,7 @@ void setUserConstraint(TransInfo *t, short orientation, int mode, const char fte
 		{
 			char orientation_str[128];
 			BLI_snprintf(orientation_str, sizeof(orientation_str), "%s \"%s\"",
-			             IFACE_("custom orientation"), t->custom_orientation->name);
+			             IFACE_("custom orientation"), t->orientation.custom->name);
 			BLI_snprintf(text, sizeof(text), ftext, orientation_str);
 			setConstraint(t, t->spacemtx, mode, text);
 			break;

source/blender/editors/transform/transform_generics.c

@@ -1395,10 +1395,17 @@ void initTransInfo(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
 			t->around = V3D_AROUND_CURSOR;
 		}
 
-		t->current_orientation = t->scene->orientation_type;
+		t->orientation.user = t->scene->orientation_type;
-		t->custom_orientation = BKE_scene_transform_orientation_find(
+		t->orientation.custom = BKE_scene_transform_orientation_find(
 		        t->scene, t->scene->orientation_index_custom);
 
+		t->orientation.index = 0;
+		ARRAY_SET_ITEMS(
+		        t->orientation.types,
+		        V3D_MANIP_GLOBAL,  /* Value isn't used (first index is no constraint). */
+		        t->orientation.user,
+		        V3D_MANIP_GLOBAL);
+
 		/* exceptional case */
 		if (t->around == V3D_AROUND_LOCAL_ORIGINS) {
 			if (ELEM(t->mode, TFM_ROTATION, TFM_RESIZE, TFM_TRACKBALL)) {
@@ -1489,8 +1496,8 @@ void initTransInfo(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
 	           RNA_property_is_set(op->ptr, prop)))
 	{
 		RNA_property_float_get_array(op->ptr, prop, &t->spacemtx[0][0]);
-		t->current_orientation = V3D_MANIP_CUSTOM_MATRIX;
+		t->orientation.user = V3D_MANIP_CUSTOM_MATRIX;
-		t->custom_orientation = 0;
+		t->orientation.custom = 0;
 	}
 	else if (op && ((prop = RNA_struct_find_property(op->ptr, "constraint_orientation")) &&
 	                RNA_property_is_set(op->ptr, prop)))
@@ -1509,8 +1516,8 @@ void initTransInfo(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
 			}
 		}
 
-		t->current_orientation = orientation;
+		t->orientation.user = orientation;
-		t->custom_orientation = custom_orientation;
+		t->orientation.custom = custom_orientation;
 	}
 
 	if (op && ((prop = RNA_struct_find_property(op->ptr, "release_confirm")) &&

source/blender/editors/transform/transform_orientations.c

@@ -432,7 +432,7 @@ void initTransformOrientation(bContext *C, TransInfo *t)
 	Object *ob = CTX_data_active_object(C);
 	Object *obedit = CTX_data_active_object(C);
 
-	switch (t->current_orientation) {
+	switch (t->orientation.user) {
 		case V3D_MANIP_GLOBAL:
 			unit_m3(t->spacemtx);
 			BLI_strncpy(t->spacename, IFACE_("global"), sizeof(t->spacename));
@@ -492,9 +492,9 @@ void initTransformOrientation(bContext *C, TransInfo *t)
 			BLI_strncpy(t->spacename, IFACE_("custom"), sizeof(t->spacename));
 			break;
 		case V3D_MANIP_CUSTOM:
-			BLI_strncpy(t->spacename, t->custom_orientation->name, sizeof(t->spacename));
+			BLI_strncpy(t->spacename, t->orientation.custom->name, sizeof(t->spacename));
 
-			if (applyTransformOrientation(t->custom_orientation, t->spacemtx, t->spacename)) {
+			if (applyTransformOrientation(t->orientation.custom, t->spacemtx, t->spacename)) {
 				/* pass */
 			}
 			else {