From 0c352407d8e7d3c8eb3108a734b5a9746ea14ad7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Steve=20Szil=C3=A1gyi?= <ryd.spes@gmail.com>
Date: Wed, 8 Dec 2021 12:10:56 +0100
Subject: [PATCH] VehicleWheel can now return the surface it's colliding with.

Fixed PR issues.

Update vehicle_body_3d.cpp

Apply suggestions from code review

Co-authored-by: Camille Mohr-Daurat <pouleyKetchoup@gmail.com>
---
 doc/classes/VehicleWheel3D.xml | 7 +++++++
 scene/3d/vehicle_body_3d.cpp   | 8 ++++++--
 scene/3d/vehicle_body_3d.h     | 2 ++
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/doc/classes/VehicleWheel3D.xml b/doc/classes/VehicleWheel3D.xml
index 951f4f827536..17a9e9f7da59 100644
--- a/doc/classes/VehicleWheel3D.xml
+++ b/doc/classes/VehicleWheel3D.xml
@@ -11,6 +11,13 @@
 		<link title="3D Truck Town Demo">https://godotengine.org/asset-library/asset/524</link>
 	</tutorials>
 	<methods>
+		<method name="get_contact_body" qualifiers="const">
+			<return type="Node3D" />
+			<description>
+				Returns the contacting body node if valid in the tree, as [Node3D]. At the moment, [GridMap] is not supported so the node will be always of type [PhysicsBody3D].
+				Returns [code]null[/code] if the wheel is not in contact with a surface, or the contact body is not a [PhysicsBody3D].
+			</description>
+		</method>
 		<method name="get_rpm" qualifiers="const">
 			<return type="float" />
 			<description>
diff --git a/scene/3d/vehicle_body_3d.cpp b/scene/3d/vehicle_body_3d.cpp
index 90db093137ed..5b2d01f8dfc0 100644
--- a/scene/3d/vehicle_body_3d.cpp
+++ b/scene/3d/vehicle_body_3d.cpp
@@ -225,6 +225,10 @@ bool VehicleWheel3D::is_in_contact() const {
 	return m_raycastInfo.m_isInContact;
 }
 
+Node3D *VehicleWheel3D::get_contact_body() const {
+	return m_raycastInfo.m_groundObject;
+}
+
 void VehicleWheel3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_radius", "length"), &VehicleWheel3D::set_radius);
 	ClassDB::bind_method(D_METHOD("get_radius"), &VehicleWheel3D::get_radius);
@@ -257,6 +261,7 @@ void VehicleWheel3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_friction_slip"), &VehicleWheel3D::get_friction_slip);
 
 	ClassDB::bind_method(D_METHOD("is_in_contact"), &VehicleWheel3D::is_in_contact);
+	ClassDB::bind_method(D_METHOD("get_contact_body"), &VehicleWheel3D::get_contact_body);
 
 	ClassDB::bind_method(D_METHOD("set_roll_influence", "roll_influence"), &VehicleWheel3D::set_roll_influence);
 	ClassDB::bind_method(D_METHOD("get_roll_influence"), &VehicleWheel3D::get_roll_influence);
@@ -413,9 +418,8 @@ real_t VehicleBody3D::_ray_cast(int p_idx, PhysicsDirectBodyState3D *s) {
 	ray_params.exclude = exclude;
 	ray_params.collision_mask = get_collision_mask();
 
-	bool col = ss->intersect_ray(ray_params, rr);
-
 	wheel.m_raycastInfo.m_groundObject = nullptr;
+	bool col = ss->intersect_ray(ray_params, rr);
 
 	if (col) {
 		param = source.distance_to(rr.position) / source.distance_to(target);
diff --git a/scene/3d/vehicle_body_3d.h b/scene/3d/vehicle_body_3d.h
index a798c76c1fd3..eb6923df544f 100644
--- a/scene/3d/vehicle_body_3d.h
+++ b/scene/3d/vehicle_body_3d.h
@@ -129,6 +129,8 @@ class VehicleWheel3D : public Node3D {
 
 	bool is_in_contact() const;
 
+	Node3D *get_contact_body() const;
+
 	void set_roll_influence(real_t p_value);
 	real_t get_roll_influence() const;