Add ability to get barycentric coordinates from ray

core/core_bind.cpp

@@ -961,6 +961,11 @@ Vector3 Geometry3D::get_closest_point_to_segment_uncapped(const Vector3 &p_point
 	return ::Geometry3D::get_closest_point_to_segment_uncapped(p_point, s);
 }
 
+Vector3 Geometry3D::get_triangle_barycentric_coords(const Vector3 &p_point, const Vector3 &p_v0, const Vector3 &p_v1, const Vector3 &p_v2) {
+	Vector3 res = ::Geometry3D::triangle_get_barycentric_coords(p_v0, p_v1, p_v2, p_point);
+	return res;
+}
+
 Variant Geometry3D::ray_intersects_triangle(const Vector3 &p_from, const Vector3 &p_dir, const Vector3 &p_v0, const Vector3 &p_v1, const Vector3 &p_v2) {
 	Vector3 res;
 	if (::Geometry3D::ray_intersects_triangle(p_from, p_dir, p_v0, p_v1, p_v2, &res)) {
@@ -1034,6 +1039,8 @@ void Geometry3D::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("get_closest_point_to_segment_uncapped", "point", "s1", "s2"), &Geometry3D::get_closest_point_to_segment_uncapped);
 
+	ClassDB::bind_method(D_METHOD("get_triangle_barycentric_coords", "point", "a", "b", "c"), &Geometry3D::get_triangle_barycentric_coords);
+
 	ClassDB::bind_method(D_METHOD("ray_intersects_triangle", "from", "dir", "a", "b", "c"), &Geometry3D::ray_intersects_triangle);
 	ClassDB::bind_method(D_METHOD("segment_intersects_triangle", "from", "to", "a", "b", "c"), &Geometry3D::segment_intersects_triangle);
 	ClassDB::bind_method(D_METHOD("segment_intersects_sphere", "from", "to", "sphere_position", "sphere_radius"), &Geometry3D::segment_intersects_sphere);

core/core_bind.h

@@ -326,6 +326,7 @@ class Geometry3D : public Object {
 	Vector<Vector3> get_closest_points_between_segments(const Vector3 &p1, const Vector3 &p2, const Vector3 &q1, const Vector3 &q2);
 	Vector3 get_closest_point_to_segment(const Vector3 &p_point, const Vector3 &p_a, const Vector3 &p_b);
 	Vector3 get_closest_point_to_segment_uncapped(const Vector3 &p_point, const Vector3 &p_a, const Vector3 &p_b);
+	Vector3 get_triangle_barycentric_coords(const Vector3 &p_point, const Vector3 &p_v0, const Vector3 &p_v1, const Vector3 &p_v2);
 	Variant ray_intersects_triangle(const Vector3 &p_from, const Vector3 &p_dir, const Vector3 &p_v0, const Vector3 &p_v1, const Vector3 &p_v2);
 	Variant segment_intersects_triangle(const Vector3 &p_from, const Vector3 &p_to, const Vector3 &p_v0, const Vector3 &p_v1, const Vector3 &p_v2);
 

doc/classes/Geometry3D.xml

@@ -73,6 +73,17 @@
 				Given the two 3D segments ([param p1], [param p2]) and ([param q1], [param q2]), finds those two points on the two segments that are closest to each other. Returns a [PackedVector3Array] that contains this point on ([param p1], [param p2]) as well the accompanying point on ([param q1], [param q2]).
 			</description>
 		</method>
+		<method name="get_triangle_barycentric_coords">
+			<return type="Vector3" />
+			<param index="0" name="point" type="Vector3" />
+			<param index="1" name="a" type="Vector3" />
+			<param index="2" name="b" type="Vector3" />
+			<param index="3" name="c" type="Vector3" />
+			<description>
+				Returns a [Vector3] containing weights based on how close a 3D position ([param point]) is to a triangle's different vertices ([param a], [param b] and [param c]). This is useful for interpolating between the data of different vertices in a triangle. One example use case is using this to smoothly rotate over a mesh instead of relying solely on face normals.
+				[url=https://en.wikipedia.org/wiki/Barycentric_coordinate_system]Here is a more detailed explanation of barycentric coordinates.[/url]
+			</description>
+		</method>
 		<method name="ray_intersects_triangle">
 			<return type="Variant" />
 			<param index="0" name="from" type="Vector3" />

doc/classes/PhysicsDirectSpaceState3D.xml

@@ -67,6 +67,8 @@
 				[code]collider_id[/code]: The colliding object's ID.
 				[code]normal[/code]: The object's surface normal at the intersection point, or [code]Vector3(0, 0, 0)[/code] if the ray starts inside the shape and [member PhysicsRayQueryParameters3D.hit_from_inside] is [code]true[/code].
 				[code]position[/code]: The intersection point.
+				[code]face_index[/code]: The face index at the intersection point.
+				[b]Note:[/b] Returns a valid number only if the intersected shape is a [ConcavePolygonShape3D]. Otherwise, [code]-1[/code] is returned.
 				[code]rid[/code]: The intersecting object's [RID].
 				[code]shape[/code]: The shape index of the colliding shape.
 				If the ray did not intersect anything, then an empty dictionary is returned instead.

doc/classes/RayCast3D.xml

@@ -59,6 +59,12 @@
 				Returns the shape ID of the first object that the ray intersects, or [code]0[/code] if no object is intersecting the ray (i.e. [method is_colliding] returns [code]false[/code]).
 			</description>
 		</method>
+		<method name="get_collision_face_index" qualifiers="const">
+			<return type="int" />
+			<description>
+				Returns the collision object's face index at the collision point, or [code]-1[/code] if the shape intersecting the ray is not a [ConcavePolygonShape3D].
+			</description>
+		</method>
 		<method name="get_collision_mask_value" qualifiers="const">
 			<return type="bool" />
 			<param index="0" name="layer_number" type="int" />

scene/3d/ray_cast_3d.cpp

@@ -104,6 +104,10 @@ Vector3 RayCast3D::get_collision_normal() const {
 	return collision_normal;
 }
 
+int RayCast3D::get_collision_face_index() const {
+	return collision_face_index;
+}
+
 void RayCast3D::set_enabled(bool p_enabled) {
 	enabled = p_enabled;
 	update_gizmos();
@@ -232,6 +236,7 @@ void RayCast3D::_update_raycast_state() {
 		against_rid = rr.rid;
 		collision_point = rr.position;
 		collision_normal = rr.normal;
+		collision_face_index = rr.face_index;
 		against_shape = rr.shape;
 	} else {
 		collided = false;
@@ -321,6 +326,7 @@ void RayCast3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_collider_shape"), &RayCast3D::get_collider_shape);
 	ClassDB::bind_method(D_METHOD("get_collision_point"), &RayCast3D::get_collision_point);
 	ClassDB::bind_method(D_METHOD("get_collision_normal"), &RayCast3D::get_collision_normal);
+	ClassDB::bind_method(D_METHOD("get_collision_face_index"), &RayCast3D::get_collision_face_index);
 
 	ClassDB::bind_method(D_METHOD("add_exception_rid", "rid"), &RayCast3D::add_exception_rid);
 	ClassDB::bind_method(D_METHOD("add_exception", "node"), &RayCast3D::add_exception);

scene/3d/ray_cast_3d.h

@@ -45,6 +45,7 @@ class RayCast3D : public Node3D {
 	int against_shape = 0;
 	Vector3 collision_point;
 	Vector3 collision_normal;
+	int collision_face_index = -1;
 
 	Vector3 target_position = Vector3(0, -1, 0);
 	HashSet<RID> exclude;
@@ -122,6 +123,7 @@ class RayCast3D : public Node3D {
 	int get_collider_shape() const;
 	Vector3 get_collision_point() const;
 	Vector3 get_collision_normal() const;
+	int get_collision_face_index() const;
 
 	void add_exception_rid(const RID &p_rid);
 	void add_exception(const CollisionObject3D *p_node);

servers/physics_3d/godot_body_pair_3d.cpp

@@ -168,7 +168,6 @@ void GodotBodyPair3D::validate_contacts() {
 // adjust the velocity of A down so that it will just slightly intersect the collider instead of blowing right past it.
 bool GodotBodyPair3D::_test_ccd(real_t p_step, GodotBody3D *p_A, int p_shape_A, const Transform3D &p_xform_A, GodotBody3D *p_B, int p_shape_B, const Transform3D &p_xform_B) {
 	GodotShape3D *shape_A_ptr = p_A->get_shape(p_shape_A);
-	GodotShape3D *shape_B_ptr = p_B->get_shape(p_shape_B);
 
 	Vector3 motion = p_A->get_linear_velocity() * p_step;
 	real_t mlen = motion.length();
@@ -221,7 +220,8 @@ bool GodotBodyPair3D::_test_ccd(real_t p_step, GodotBody3D *p_A, int p_shape_A,
 		Vector3 local_to = from_inv.xform(to);
 
 		Vector3 rpos, rnorm;
-		if (shape_B_ptr->intersect_segment(local_from, local_to, rpos, rnorm, true)) {
+		int fi = -1;
+		if (p_B->get_shape(p_shape_B)->intersect_segment(local_from, local_to, rpos, rnorm, fi, true)) {
 			float hit_length = local_from.distance_to(rpos);
 			if (hit_length < segment_hit_length) {
 				segment_support_idx = i;

servers/physics_3d/godot_collision_solver_3d.cpp

@@ -106,7 +106,8 @@ bool GodotCollisionSolver3D::solve_separation_ray(const GodotShape3D *p_shape_A,
 	to = ai.xform(to);
 
 	Vector3 p, n;
-	if (!p_shape_B->intersect_segment(from, to, p, n, true)) {
+	int fi = -1;
+	if (!p_shape_B->intersect_segment(from, to, p, n, fi, true)) {
 		return false;
 	}
 

servers/physics_3d/godot_shape_3d.cpp

@@ -126,7 +126,7 @@ Vector3 GodotWorldBoundaryShape3D::get_support(const Vector3 &p_normal) const {
 	return p_normal * 1e15;
 }
 
-bool GodotWorldBoundaryShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotWorldBoundaryShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	bool inters = plane.intersects_segment(p_begin, p_end, &r_result);
 	if (inters) {
 		r_normal = plane.normal;
@@ -207,7 +207,7 @@ void GodotSeparationRayShape3D::get_supports(const Vector3 &p_normal, int p_max,
 	}
 }
 
-bool GodotSeparationRayShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotSeparationRayShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	return false; //simply not possible
 }
 
@@ -275,7 +275,7 @@ void GodotSphereShape3D::get_supports(const Vector3 &p_normal, int p_max, Vector
 	r_type = FEATURE_POINT;
 }
 
-bool GodotSphereShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotSphereShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	return Geometry3D::segment_intersects_sphere(p_begin, p_end, Vector3(), radius, &r_result, &r_normal);
 }
 
@@ -417,7 +417,7 @@ void GodotBoxShape3D::get_supports(const Vector3 &p_normal, int p_max, Vector3 *
 	r_supports[0] = point;
 }
 
-bool GodotBoxShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotBoxShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	AABB aabb_ext(-half_extents, half_extents * 2.0);
 
 	return aabb_ext.intersects_segment(p_begin, p_end, &r_result, &r_normal);
@@ -551,7 +551,7 @@ void GodotCapsuleShape3D::get_supports(const Vector3 &p_normal, int p_max, Vecto
 	}
 }
 
-bool GodotCapsuleShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotCapsuleShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	Vector3 norm = (p_end - p_begin).normalized();
 	real_t min_d = 1e20;
 
@@ -743,7 +743,7 @@ void GodotCylinderShape3D::get_supports(const Vector3 &p_normal, int p_max, Vect
 	}
 }
 
-bool GodotCylinderShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotCylinderShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	return Geometry3D::segment_intersects_cylinder(p_begin, p_end, height, radius, &r_result, &r_normal, 1);
 }
 
@@ -975,7 +975,7 @@ void GodotConvexPolygonShape3D::get_supports(const Vector3 &p_normal, int p_max,
 	r_type = FEATURE_POINT;
 }
 
-bool GodotConvexPolygonShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotConvexPolygonShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	const Geometry3D::MeshData::Face *faces = mesh.faces.ptr();
 	int fc = mesh.faces.size();
 
@@ -1252,7 +1252,7 @@ void GodotFaceShape3D::get_supports(const Vector3 &p_normal, int p_max, Vector3
 	r_supports[0] = vertex[vert_support_idx];
 }
 
-bool GodotFaceShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotFaceShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	bool c = Geometry3D::segment_intersects_triangle(p_begin, p_end, vertex[0], vertex[1], vertex[2], &r_result);
 	if (c) {
 		r_normal = Plane(vertex[0], vertex[1], vertex[2]).normal;
@@ -1362,12 +1362,14 @@ void GodotConcavePolygonShape3D::_cull_segment(int p_idx, _SegmentCullParams *p_
 
 		Vector3 res;
 		Vector3 normal;
-		if (face->intersect_segment(p_params->from, p_params->to, res, normal, true)) {
+		int face_index = params_bvh->face_index;
+		if (face->intersect_segment(p_params->from, p_params->to, res, normal, face_index, true)) {
 			real_t d = p_params->dir.dot(res) - p_params->dir.dot(p_params->from);
 			if ((d > 0) && (d < p_params->min_d)) {
 				p_params->min_d = d;
 				p_params->result = res;
 				p_params->normal = normal;
+				p_params->face_index = face_index;
 				p_params->collisions++;
 			}
 		}
@@ -1381,7 +1383,7 @@ void GodotConcavePolygonShape3D::_cull_segment(int p_idx, _SegmentCullParams *p_
 	}
 }
 
-bool GodotConcavePolygonShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotConcavePolygonShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_result, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	if (faces.size() == 0) {
 		return false;
 	}
@@ -1411,6 +1413,7 @@ bool GodotConcavePolygonShape3D::intersect_segment(const Vector3 &p_begin, const
 	if (params.collisions > 0) {
 		r_result = params.result;
 		r_normal = params.normal;
+		r_face_index = params.face_index;
 		return true;
 	} else {
 		return false;
@@ -1734,9 +1737,11 @@ struct _HeightmapGridCullState {
 _FORCE_INLINE_ bool _heightmap_face_cull_segment(_HeightmapSegmentCullParams &p_params) {
 	Vector3 res;
 	Vector3 normal;
-	if (p_params.face->intersect_segment(p_params.from, p_params.to, res, normal, true)) {
+	int fi = -1;
+	if (p_params.face->intersect_segment(p_params.from, p_params.to, res, normal, fi, true)) {
 		p_params.result = res;
 		p_params.normal = normal;
+
 		return true;
 	}
 
@@ -1940,7 +1945,7 @@ bool GodotHeightMapShape3D::_intersect_grid_segment(ProcessFunction &p_process,
 	return false;
 }
 
-bool GodotHeightMapShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_point, Vector3 &r_normal, bool p_hit_back_faces) const {
+bool GodotHeightMapShape3D::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_point, Vector3 &r_normal, int &r_face_index, bool p_hit_back_faces) const {
 	if (heights.is_empty()) {
 		return false;
 	}