1 files changed, 51 insertions, 3 deletions

diff --git a/scene/gui/scroll_bar.cpp b/scene/gui/scroll_bar.cpp
index 2ccdbb05a9..6519cde6d3 100644
--- a/scene/gui/scroll_bar.cpp
+++ b/scene/gui/scroll_bar.cpp
@@ -98,7 +98,18 @@ void ScrollBar::_gui_input(Ref<InputEvent> p_event) {
 
 			if (ofs < grabber_ofs) {
 
-				set_value(get_value() - get_page());
+				if (scrolling) {
+					target_scroll = target_scroll - get_page();
+				} else {
+					target_scroll = get_value() - get_page();
+				}
+
+				if (smooth_scroll_enabled) {
+					scrolling = true;
+					set_fixed_process(true);
+				} else {
+					set_value(target_scroll);
+				}
 				return;
 			}
 
@@ -111,8 +122,18 @@ void ScrollBar::_gui_input(Ref<InputEvent> p_event) {
 				drag.value_at_click = get_as_ratio();
 				update();
 			} else {
+				if (scrolling) {
+					target_scroll = target_scroll + get_page();
+				} else {
+					target_scroll = get_value() + get_page();
+				}
 
-				set_value(get_value() + get_page());
+				if (smooth_scroll_enabled) {
+					scrolling = true;
+					set_fixed_process(true);
+				} else {
+					set_value(target_scroll);
+				}
 			}
 
 		} else {
@@ -311,7 +332,22 @@ void ScrollBar::_notification(int p_what) {
 
 	if (p_what == NOTIFICATION_FIXED_PROCESS) {
 
-		if (drag_slave_touching) {
+		if (scrolling) {
+			if (get_value() != target_scroll) {
+				double target = target_scroll - get_value();
+				double dist = sqrt(target * target);
+				double vel = ((target / dist) * 500) * get_fixed_process_delta_time();
+
+				if (vel >= dist) {
+					set_value(target_scroll);
+				} else {
+					set_value(get_value() + vel);
+				}
+			} else {
+				scrolling = false;
+				set_fixed_process(false);
+			}
+		} else if (drag_slave_touching) {
 
 			if (drag_slave_touching_deaccel) {
 
@@ -639,6 +675,14 @@ NodePath ScrollBar::get_drag_slave() const {
 	return drag_slave_path;
 }
 
+void ScrollBar::set_smooth_scroll_enabled(bool p_enable) {
+	smooth_scroll_enabled = p_enable;
+}
+
+bool ScrollBar::is_smooth_scroll_enabled() const {
+	return smooth_scroll_enabled;
+}
+
 #if 0
 
 void ScrollBar::mouse_button(const Point2& p_pos, int b->get_button_index(),bool b->is_pressed(),int p_modifier_mask) {
@@ -795,6 +839,10 @@ ScrollBar::ScrollBar(Orientation p_orientation) {
 	drag_slave_touching = false;
 	drag_slave_touching_deaccel = false;
 
+	scrolling = false;
+	target_scroll = 0;
+	smooth_scroll_enabled = false;
+
 	if (focus_by_default)
 		set_focus_mode(FOCUS_ALL);
 	set_step(0);