From 285b816f1fc2a52eae8d9e27e70d499fb26428c0 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>
(cherry picked from commit 0c352407d8e7d3c8eb3108a734b5a9746ea14ad7)
---
 doc/classes/VehicleWheel.xml | 7 +++++++
 scene/3d/vehicle_body.cpp    | 9 +++++++--
 scene/3d/vehicle_body.h      | 2 ++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/doc/classes/VehicleWheel.xml b/doc/classes/VehicleWheel.xml
index ef3418b419c..f9ee35d61e3 100644
--- a/doc/classes/VehicleWheel.xml
+++ b/doc/classes/VehicleWheel.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="Spatial" />
+			<description>
+				Returns the contacting body node if valid in the tree, as [Spatial]. At the moment, [GridMap] is not supported so the node will be always of type [PhysicsBody].
+				Returns [code]null[/code] if the wheel is not in contact with a surface, or the contact body is not a [PhysicsBody].
+			</description>
+		</method>
 		<method name="get_rpm" qualifiers="const">
 			<return type="float" />
 			<description>
diff --git a/scene/3d/vehicle_body.cpp b/scene/3d/vehicle_body.cpp
index 7d814f74526..4f55783ded8 100644
--- a/scene/3d/vehicle_body.cpp
+++ b/scene/3d/vehicle_body.cpp
@@ -217,6 +217,10 @@ bool VehicleWheel::is_in_contact() const {
 	return m_raycastInfo.m_isInContact;
 }
 
+Spatial *VehicleWheel::get_contact_body() const {
+	return m_raycastInfo.m_groundObject;
+}
+
 void VehicleWheel::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_radius", "length"), &VehicleWheel::set_radius);
 	ClassDB::bind_method(D_METHOD("get_radius"), &VehicleWheel::get_radius);
@@ -249,6 +253,7 @@ void VehicleWheel::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_friction_slip"), &VehicleWheel::get_friction_slip);
 
 	ClassDB::bind_method(D_METHOD("is_in_contact"), &VehicleWheel::is_in_contact);
+	ClassDB::bind_method(D_METHOD("get_contact_body"), &VehicleWheel::get_contact_body);
 
 	ClassDB::bind_method(D_METHOD("set_roll_influence", "roll_influence"), &VehicleWheel::set_roll_influence);
 	ClassDB::bind_method(D_METHOD("get_roll_influence"), &VehicleWheel::get_roll_influence);
@@ -357,6 +362,7 @@ VehicleWheel::VehicleWheel() {
 	m_suspensionRelativeVelocity = 0;
 	m_clippedInvContactDotSuspension = 1.0;
 	m_raycastInfo.m_isInContact = false;
+	m_raycastInfo.m_groundObject = nullptr;
 	m_raycastInfo.m_suspensionLength = 0.0;
 
 	body = nullptr;
@@ -423,9 +429,8 @@ real_t VehicleBody::_ray_cast(int p_idx, PhysicsDirectBodyState *s) {
 
 	PhysicsDirectSpaceState *ss = s->get_space_state();
 
-	bool col = ss->intersect_ray(source, target, rr, exclude, get_collision_mask());
-
 	wheel.m_raycastInfo.m_groundObject = nullptr;
+	bool col = ss->intersect_ray(source, target, rr, exclude, get_collision_mask());
 
 	if (col) {
 		param = source.distance_to(rr.position) / source.distance_to(target);
diff --git a/scene/3d/vehicle_body.h b/scene/3d/vehicle_body.h
index f8de693856c..b3eed665113 100644
--- a/scene/3d/vehicle_body.h
+++ b/scene/3d/vehicle_body.h
@@ -129,6 +129,8 @@ public:
 
 	bool is_in_contact() const;
 
+	Spatial *get_contact_body() const;
+
 	void set_roll_influence(float p_value);
 	float get_roll_influence() const;