From e89c4c22dee54533450feb4032bc5d608dbb2ddc Mon Sep 17 00:00:00 2001
From: Emmanuel Barroga <emmanuelbarroga@gmail.com>
Date: Tue, 13 Aug 2019 03:11:24 -0700
Subject: [PATCH] Add scrollwheel input to spin slider

Adds the ability to adjust the editor's spin slider using the mouse scrollwheel.
---
 editor/editor_spin_slider.cpp | 29 +++++++++++++++++++++++++++--
 editor/editor_spin_slider.h   |  1 +
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/editor/editor_spin_slider.cpp b/editor/editor_spin_slider.cpp
index 379b8a2980b7..743149aba97f 100644
--- a/editor/editor_spin_slider.cpp
+++ b/editor/editor_spin_slider.cpp
@@ -132,20 +132,39 @@ void EditorSpinSlider::_gui_input(const Ref<InputEvent> &p_event) {
 void EditorSpinSlider::_grabber_gui_input(const Ref<InputEvent> &p_event) {
 
 	Ref<InputEventMouseButton> mb = p_event;
+
+	if (grabbing_grabber) {
+		if (mb.is_valid()) {
+
+			if (mb->get_button_index() == BUTTON_WHEEL_UP) {
+				set_value(get_value() + get_step());
+				mousewheel_over_grabber = true;
+			} else if (mb->get_button_index() == BUTTON_WHEEL_DOWN) {
+				set_value(get_value() - get_step());
+				mousewheel_over_grabber = true;
+			}
+		}
+	}
+
 	if (mb.is_valid() && mb->get_button_index() == BUTTON_LEFT) {
 
 		if (mb->is_pressed()) {
 
 			grabbing_grabber = true;
-			grabbing_ratio = get_as_ratio();
-			grabbing_from = grabber->get_transform().xform(mb->get_position()).x;
+			if (!mousewheel_over_grabber) {
+				grabbing_ratio = get_as_ratio();
+				grabbing_from = grabber->get_transform().xform(mb->get_position()).x;
+			}
 		} else {
 			grabbing_grabber = false;
+			mousewheel_over_grabber = false;
 		}
 	}
 
 	Ref<InputEventMouseMotion> mm = p_event;
 	if (mm.is_valid() && grabbing_grabber) {
+		if (mousewheel_over_grabber)
+			return;
 
 		float grabbing_ofs = (grabber->get_transform().xform(mm->get_position()).x - grabbing_from) / float(grabber_range);
 		set_as_ratio(grabbing_ratio + grabbing_ofs);
@@ -261,6 +280,11 @@ void EditorSpinSlider::_notification(int p_what) {
 
 				grabber->set_size(Size2(0, 0));
 				grabber->set_position(get_global_position() + grabber_rect.position + grabber_rect.size * 0.5 - grabber->get_size() * 0.5);
+
+				if (mousewheel_over_grabber) {
+					Input::get_singleton()->warp_mouse_position(grabber->get_position() + grabber_rect.size);
+				}
+
 				grabber_range = width;
 			}
 		}
@@ -456,6 +480,7 @@ EditorSpinSlider::EditorSpinSlider() {
 	grabber->connect("gui_input", this, "_grabber_gui_input");
 	mouse_over_spin = false;
 	mouse_over_grabber = false;
+	mousewheel_over_grabber = false;
 	grabbing_grabber = false;
 	grabber_range = 1;
 	value_input = memnew(LineEdit);
diff --git a/editor/editor_spin_slider.h b/editor/editor_spin_slider.h
index d91380e175ff..2dc6e2c2f202 100644
--- a/editor/editor_spin_slider.h
+++ b/editor/editor_spin_slider.h
@@ -48,6 +48,7 @@ class EditorSpinSlider : public Range {
 
 	bool mouse_over_spin;
 	bool mouse_over_grabber;
+	bool mousewheel_over_grabber;
 
 	bool grabbing_grabber;
 	int grabbing_from;