Fix #35368:

* Editing number of segments for particle hair did not update the viewport.
* Hidden particles were confusing, the paths were drawn but without the points.
  Now it draws the path faded to indicate that they are hidden/locked.
* Select tips/roots operators now have options to select/deselect/toggle/invert.

release/scripts/startup/bl_ui/space_view3d.py

@@ -1437,14 +1437,32 @@ class VIEW3D_MT_particle_specials(Menu):
         particle_edit = context.tool_settings.particle_edit
 
         layout.operator("particle.rekey")
+        layout.operator("particle.delete")
+        layout.operator("particle.remove_doubles")
 
-        layout.separator()
         if particle_edit.select_mode == 'POINT':
             layout.operator("particle.subdivide")
+
+        layout.operator("particle.weight_set")
+        layout.separator()
+
+        layout.operator("particle.mirror")
+
+        if particle_edit.select_mode == 'POINT':
+            layout.separator()
             layout.operator("particle.select_roots")
             layout.operator("particle.select_tips")
 
-        layout.operator("particle.remove_doubles")
+            layout.separator()
+
+            layout.operator("particle.select_more")
+            layout.operator("particle.select_less")
+
+            layout.separator()
+
+            layout.operator("particle.select_all").action = 'TOGGLE'
+            layout.operator("particle.select_linked")
+            layout.operator("particle.select_all", text="Inverse").action = 'INVERT'
 
 
 class VIEW3D_MT_particle_showhide(ShowHideMenu, Menu):

source/blender/editors/physics/particle_edit.c

@@ -376,6 +376,9 @@ typedef struct PEData {
 	int invert;
 	int tot;
 	float vec[3];
+
+	int select_action;
+	int select_toggle_action;
 } PEData;
 
 static void PE_set_data(bContext *C, PEData *data)
@@ -1332,6 +1335,34 @@ static void toggle_key_select(PEData *data, int point_index, int key_index)
 
 /************************ de select all operator ************************/
 
+static void select_action_apply(PTCacheEditPoint *point, PTCacheEditKey *key, int action)
+{
+	switch (action) {
+	case SEL_SELECT:
+		if ((key->flag & PEK_SELECT) == 0) {
+			key->flag |= PEK_SELECT;
+			point->flag |= PEP_EDIT_RECALC;
+		}
+		break;
+	case SEL_DESELECT:
+		if (key->flag & PEK_SELECT) {
+			key->flag &= ~PEK_SELECT;
+			point->flag |= PEP_EDIT_RECALC;
+		}
+		break;
+	case SEL_INVERT:
+		if ((key->flag & PEK_SELECT) == 0) {
+			key->flag |= PEK_SELECT;
+			point->flag |= PEP_EDIT_RECALC;
+		}
+		else {
+			key->flag &= ~PEK_SELECT;
+			point->flag |= PEP_EDIT_RECALC;
+		}
+		break;
+	}
+}
+
 static int pe_select_all_exec(bContext *C, wmOperator *op)
 {
 	Scene *scene= CTX_data_scene(C);
@@ -1355,30 +1386,7 @@ static int pe_select_all_exec(bContext *C, wmOperator *op)
 
 	LOOP_VISIBLE_POINTS {
 		LOOP_VISIBLE_KEYS {
-			switch (action) {
+			select_action_apply(point, key, action);
-			case SEL_SELECT:
-				if ((key->flag & PEK_SELECT) == 0) {
-					key->flag |= PEK_SELECT;
-					point->flag |= PEP_EDIT_RECALC;
-				}
-				break;
-			case SEL_DESELECT:
-				if (key->flag & PEK_SELECT) {
-					key->flag &= ~PEK_SELECT;
-					point->flag |= PEP_EDIT_RECALC;
-				}
-				break;
-			case SEL_INVERT:
-				if ((key->flag & PEK_SELECT) == 0) {
-					key->flag |= PEK_SELECT;
-					point->flag |= PEP_EDIT_RECALC;
-				}
-				else {
-					key->flag &= ~PEK_SELECT;
-					point->flag |= PEP_EDIT_RECALC;
-				}
-				break;
-			}
 		}
 	}
 
@@ -1445,22 +1453,39 @@ int PE_mouse_particles(bContext *C, const int mval[2], bool extend, bool deselec
 	return OPERATOR_FINISHED;
 }
 
-/************************ select first operator ************************/
+/************************ select root operator ************************/
 
 static void select_root(PEData *data, int point_index)
 {
-	if (data->edit->points[point_index].flag & PEP_HIDE)
+	PTCacheEditPoint *point = data->edit->points + point_index;
+	PTCacheEditKey *key = point->keys;
+
+	if (point->flag & PEP_HIDE)
 		return;
 	
-	data->edit->points[point_index].keys->flag |= PEK_SELECT;
+	if (data->select_action != SEL_TOGGLE)
-	data->edit->points[point_index].flag |= PEP_EDIT_RECALC; /* redraw selection only */
+		select_action_apply(point, key, data->select_action);
+	else if (key->flag & PEK_SELECT)
+		data->select_toggle_action = SEL_DESELECT;
 }
 
-static int select_roots_exec(bContext *C, wmOperator *UNUSED(op))
+static int select_roots_exec(bContext *C, wmOperator *op)
 {
 	PEData data;
+	int action = RNA_enum_get(op->ptr, "action");
 
 	PE_set_data(C, &data);
+
+	if (action == SEL_TOGGLE) {
+		data.select_action = SEL_TOGGLE;
+		data.select_toggle_action = SEL_SELECT;
+
+		foreach_point(&data, select_root);
+
+		action = data.select_toggle_action;
+	}
+
+	data.select_action = action;
 	foreach_point(&data, select_root);
 
 	PE_update_selection(data.scene, data.ob, 1);
@@ -1482,26 +1507,44 @@ void PARTICLE_OT_select_roots(wmOperatorType *ot)
 
 	/* flags */
 	ot->flag = OPTYPE_REGISTER|OPTYPE_UNDO;
+
+	/* properties */
+	WM_operator_properties_select_action(ot, SEL_SELECT);
 }
 
-/************************ select last operator ************************/
+/************************ select tip operator ************************/
 
 static void select_tip(PEData *data, int point_index)
 {
 	PTCacheEditPoint *point = data->edit->points + point_index;
+	PTCacheEditKey *key = &point->keys[point->totkey - 1];
 	
 	if (point->flag & PEP_HIDE)
 		return;
 	
-	point->keys[point->totkey - 1].flag |= PEK_SELECT;
+	if (data->select_action != SEL_TOGGLE)
-	point->flag |= PEP_EDIT_RECALC; /* redraw selection only */
+		select_action_apply(point, key, data->select_action);
+	else if (key->flag & PEK_SELECT)
+		data->select_toggle_action = SEL_DESELECT;
 }
 
-static int select_tips_exec(bContext *C, wmOperator *UNUSED(op))
+static int select_tips_exec(bContext *C, wmOperator *op)
 {
 	PEData data;
+	int action = RNA_enum_get(op->ptr, "action");
 
 	PE_set_data(C, &data);
+
+	if (action == SEL_TOGGLE) {
+		data.select_action = SEL_TOGGLE;
+		data.select_toggle_action = SEL_SELECT;
+
+		foreach_point(&data, select_tip);
+
+		action = data.select_toggle_action;
+	}
+
+	data.select_action = action;
 	foreach_point(&data, select_tip);
 
 	PE_update_selection(data.scene, data.ob, 1);
@@ -1523,6 +1566,9 @@ void PARTICLE_OT_select_tips(wmOperatorType *ot)
 
 	/* flags */
 	ot->flag = OPTYPE_REGISTER|OPTYPE_UNDO;
+
+	/* properties */
+	WM_operator_properties_select_action(ot, SEL_SELECT);
 }
 
 /************************ select linked operator ************************/

source/blender/editors/space_view3d/drawobject.c

@@ -4785,11 +4785,10 @@ static void draw_ptcache_edit(Scene *scene, View3D *v3d, PTCacheEdit *edit)
 	UI_GetThemeColor3fv(TH_VERTEX, nosel_col);
 
 	/* draw paths */
-	if (timed) {
+	steps = (*edit->pathcache)->steps + 1;
-		glEnable(GL_BLEND);
+
-		steps = (*edit->pathcache)->steps + 1;
+	glEnable(GL_BLEND);
-		pathcol = MEM_callocN(steps * 4 * sizeof(float), "particle path color data");
+	pathcol = MEM_callocN(steps * 4 * sizeof(float), "particle path color data");
-	}
 
 	glEnableClientState(GL_VERTEX_ARRAY);
 	glEnableClientState(GL_COLOR_ARRAY);
@@ -4804,11 +4803,19 @@ static void draw_ptcache_edit(Scene *scene, View3D *v3d, PTCacheEdit *edit)
 	}
 
 	cache = edit->pathcache;
-	for (i = 0; i < totpoint; i++) {
+	for (i = 0, point = edit->points; i < totpoint; i++, point++) {
 		path = cache[i];
 		glVertexPointer(3, GL_FLOAT, sizeof(ParticleCacheKey), path->co);
 
-		if (timed) {
+		if (point->flag & PEP_HIDE) {
+			for (k = 0, pcol = pathcol; k < steps; k++, pcol += 4) {
+				copy_v3_v3(pcol, path->col);
+				pcol[3] = 0.25f;
+			}
+
+			glColorPointer(4, GL_FLOAT, 4 * sizeof(float), pathcol);
+		}
+		else if (timed) {
 			for (k = 0, pcol = pathcol, pkey = path; k < steps; k++, pkey++, pcol += 4) {
 				copy_v3_v3(pcol, pkey->col);
 				pcol[3] = 1.0f - fabsf((float)(CFRA) -pkey->time) / (float)pset->fade_frames;

source/blender/makesrna/intern/rna_particle.c

@@ -2294,7 +2294,7 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "hair_step", PROP_INT, PROP_NONE);
 	RNA_def_property_range(prop, 2, 50);
 	RNA_def_property_ui_text(prop, "Segments", "Number of hair segments");
-	RNA_def_property_update(prop, 0, "rna_Particle_redo");
+	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 
 	/*TODO: not found in UI, readonly? */

source/blender/windowmanager/WM_api.h

@@ -243,6 +243,7 @@ void		WM_operator_properties_gesture_border(struct wmOperatorType *ot, bool exte
 void        WM_operator_properties_mouse_select(struct wmOperatorType *ot);
 void		WM_operator_properties_gesture_straightline(struct wmOperatorType *ot, bool cursor);
 void		WM_operator_properties_select_all(struct wmOperatorType *ot);
+void		WM_operator_properties_select_action(struct wmOperatorType *ot, int default_action);
 
 bool        WM_operator_check_ui_enabled(const struct bContext *C, const char *idname);
 wmOperator *WM_operator_last_redo(const struct bContext *C);

source/blender/windowmanager/intern/wm_operators.c

@@ -1109,9 +1109,9 @@ void WM_operator_properties_filesel(wmOperatorType *ot, int filter, short type,
 	RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
 }
 
-void WM_operator_properties_select_all(wmOperatorType *ot)
+void WM_operator_properties_select_action(wmOperatorType *ot, int default_action)
 {
-	static EnumPropertyItem select_all_actions[] = {
+	static EnumPropertyItem select_actions[] = {
 		{SEL_TOGGLE, "TOGGLE", 0, "Toggle", "Toggle selection for all elements"},
 		{SEL_SELECT, "SELECT", 0, "Select", "Select all elements"},
 		{SEL_DESELECT, "DESELECT", 0, "Deselect", "Deselect all elements"},
@@ -1119,7 +1119,12 @@ void WM_operator_properties_select_all(wmOperatorType *ot)
 		{0, NULL, 0, NULL, NULL}
 	};
 
-	RNA_def_enum(ot->srna, "action", select_all_actions, SEL_TOGGLE, "Action", "Selection action to execute");
+	RNA_def_enum(ot->srna, "action", select_actions, default_action, "Action", "Selection action to execute");
+}
+
+void WM_operator_properties_select_all(wmOperatorType *ot)
+{
+	WM_operator_properties_select_action(ot, SEL_TOGGLE);
 }
 
 void WM_operator_properties_border(wmOperatorType *ot)