[3.x] Fix 3D moving platform logic

doc/classes/KinematicBody.xml

@@ -95,6 +95,7 @@
 				[code]floor_max_angle[/code] is the maximum angle (in radians) where a slope is still considered a floor (or a ceiling), rather than a wall. The default value equals 45 degrees.
 				If [code]infinite_inertia[/code] is [code]true[/code], body will be able to push [RigidBody] nodes, but it won't also detect any collisions with them. If [code]false[/code], it will interact with [RigidBody] nodes like with [StaticBody].
 				Returns the [code]linear_velocity[/code] vector, rotated and/or scaled if a slide collision occurred. To get detailed information about collisions that occurred, use [method get_slide_collision].
+				When the body touches a moving platform, the platform's velocity is automatically added to the body motion. If a collision occurs due to the platform's motion, it will always be first in the slide collisions.
 			</description>
 		</method>
 		<method name="move_and_slide_with_snap">

doc/classes/KinematicBody2D.xml

@@ -93,6 +93,7 @@
 				[code]floor_max_angle[/code] is the maximum angle (in radians) where a slope is still considered a floor (or a ceiling), rather than a wall. The default value equals 45 degrees.
 				If [code]infinite_inertia[/code] is [code]true[/code], body will be able to push [RigidBody2D] nodes, but it won't also detect any collisions with them. If [code]false[/code], it will interact with [RigidBody2D] nodes like with [StaticBody2D].
 				Returns the [code]linear_velocity[/code] vector, rotated and/or scaled if a slide collision occurred. To get detailed information about collisions that occurred, use [method get_slide_collision].
+				When the body touches a moving platform, the platform's velocity is automatically added to the body motion. If a collision occurs due to the platform's motion, it will always be first in the slide collisions.
 			</description>
 		</method>
 		<method name="move_and_slide_with_snap">

doc/classes/PhysicsServer.xml

@@ -602,6 +602,8 @@
 			<argument index="2" name="motion" type="Vector3" />
 			<argument index="3" name="infinite_inertia" type="bool" />
 			<argument index="4" name="result" type="PhysicsTestMotionResult" default="null" />
+			<argument index="5" name="exclude_raycast_shapes" type="bool" default="true" />
+			<argument index="6" name="exclude" type="Array" default="[  ]" />
 			<description>
 				Returns [code]true[/code] if a collision would result from moving in the given direction from a given point in space. [PhysicsTestMotionResult] can be passed to return additional information in.
 			</description>

modules/bullet/bullet_physics_server.cpp

@@ -856,12 +856,12 @@ PhysicsDirectBodyState *BulletPhysicsServer::body_get_direct_state(RID p_body) {
 	return BulletPhysicsDirectBodyState::get_singleton(body);
 }
 
-bool BulletPhysicsServer::body_test_motion(RID p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, MotionResult *r_result, bool p_exclude_raycast_shapes) {
+bool BulletPhysicsServer::body_test_motion(RID p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, MotionResult *r_result, bool p_exclude_raycast_shapes, const Set<RID> &p_exclude) {
 	RigidBodyBullet *body = rigid_body_owner.get(p_body);
 	ERR_FAIL_COND_V(!body, false);
 	ERR_FAIL_COND_V(!body->get_space(), false);
 
-	return body->get_space()->test_body_motion(body, p_from, p_motion, p_infinite_inertia, r_result, p_exclude_raycast_shapes);
+	return body->get_space()->test_body_motion(body, p_from, p_motion, p_infinite_inertia, r_result, p_exclude_raycast_shapes, p_exclude);
 }
 
 int BulletPhysicsServer::body_test_ray_separation(RID p_body, const Transform &p_transform, bool p_infinite_inertia, Vector3 &r_recover_motion, SeparationResult *r_results, int p_result_max, float p_margin) {

modules/bullet/bullet_physics_server.h

@@ -254,7 +254,7 @@ class BulletPhysicsServer : public PhysicsServer {
 	// this function only works on physics process, errors and returns null otherwise
 	virtual PhysicsDirectBodyState *body_get_direct_state(RID p_body);
 
-	virtual bool body_test_motion(RID p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, MotionResult *r_result = nullptr, bool p_exclude_raycast_shapes = true);
+	virtual bool body_test_motion(RID p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, MotionResult *r_result = nullptr, bool p_exclude_raycast_shapes = true, const Set<RID> &p_exclude = Set<RID>());
 	virtual int body_test_ray_separation(RID p_body, const Transform &p_transform, bool p_infinite_inertia, Vector3 &r_recover_motion, SeparationResult *r_results, int p_result_max, float p_margin = 0.001);
 
 	/* SOFT BODY API */

modules/bullet/godot_result_callbacks.cpp

@@ -142,6 +142,10 @@ bool GodotKinClosestConvexResultCallback::needsCollision(btBroadphaseProxy *prox
 			if (m_self_object->has_collision_exception(gObj) || gObj->has_collision_exception(m_self_object)) {
 				return false;
 			}
+
+			if (m_exclude->has(gObj->get_self())) {
+				return false;
+			}
 		}
 		return true;
 	} else {

modules/bullet/godot_result_callbacks.h

@@ -105,11 +105,13 @@ struct GodotAllConvexResultCallback : public btCollisionWorld::ConvexResultCallb
 struct GodotKinClosestConvexResultCallback : public btCollisionWorld::ClosestConvexResultCallback {
 public:
 	const RigidBodyBullet *m_self_object;
+	const Set<RID> *m_exclude;
 	const bool m_infinite_inertia;
 
-	GodotKinClosestConvexResultCallback(const btVector3 &convexFromWorld, const btVector3 &convexToWorld, const RigidBodyBullet *p_self_object, bool p_infinite_inertia) :
+	GodotKinClosestConvexResultCallback(const btVector3 &convexFromWorld, const btVector3 &convexToWorld, const RigidBodyBullet *p_self_object, bool p_infinite_inertia, const Set<RID> *p_exclude) :
 			btCollisionWorld::ClosestConvexResultCallback(convexFromWorld, convexToWorld),
 			m_self_object(p_self_object),
+			m_exclude(p_exclude),
 			m_infinite_inertia(p_infinite_inertia) {}
 
 	virtual bool needsCollision(btBroadphaseProxy *proxy0) const;

modules/bullet/space_bullet.cpp

@@ -928,7 +928,7 @@ static Ref<SpatialMaterial> red_mat;
 static Ref<SpatialMaterial> blue_mat;
 #endif
 
-bool SpaceBullet::test_body_motion(RigidBodyBullet *p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, PhysicsServer::MotionResult *r_result, bool p_exclude_raycast_shapes) {
+bool SpaceBullet::test_body_motion(RigidBodyBullet *p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, PhysicsServer::MotionResult *r_result, bool p_exclude_raycast_shapes, const Set<RID> &p_exclude) {
 #if debug_test_motion
 	/// Yes I know this is not good, but I've used it as fast debugging hack.
 	/// I'm leaving it here just for speedup the other eventual debugs
@@ -968,7 +968,7 @@ bool SpaceBullet::test_body_motion(RigidBodyBullet *p_body, const Transform &p_f
 	btVector3 initial_recover_motion(0, 0, 0);
 	{ /// Phase one - multi shapes depenetration using margin
 		for (int t(RECOVERING_MOVEMENT_CYCLES); 0 < t; --t) {
-			if (!recover_from_penetration(p_body, body_transform, RECOVERING_MOVEMENT_SCALE, p_infinite_inertia, initial_recover_motion)) {
+			if (!recover_from_penetration(p_body, body_transform, RECOVERING_MOVEMENT_SCALE, p_infinite_inertia, initial_recover_motion, nullptr, p_exclude)) {
 				break;
 			}
 		}
@@ -1020,7 +1020,7 @@ bool SpaceBullet::test_body_motion(RigidBodyBullet *p_body, const Transform &p_f
 				break;
 			}
 
-			GodotKinClosestConvexResultCallback btResult(shape_world_from.getOrigin(), shape_world_to.getOrigin(), p_body, p_infinite_inertia);
+			GodotKinClosestConvexResultCallback btResult(shape_world_from.getOrigin(), shape_world_to.getOrigin(), p_body, p_infinite_inertia, &p_exclude);
 			btResult.m_collisionFilterGroup = p_body->get_collision_layer();
 			btResult.m_collisionFilterMask = p_body->get_collision_mask();
 
@@ -1043,7 +1043,7 @@ bool SpaceBullet::test_body_motion(RigidBodyBullet *p_body, const Transform &p_f
 		btVector3 __rec(0, 0, 0);
 		RecoverResult r_recover_result;
 
-		has_penetration = recover_from_penetration(p_body, body_transform, 1, p_infinite_inertia, __rec, &r_recover_result);
+		has_penetration = recover_from_penetration(p_body, body_transform, 1, p_infinite_inertia, __rec, &r_recover_result, p_exclude);
 
 		// Parse results
 		if (r_result) {
@@ -1195,7 +1195,7 @@ struct RecoverPenetrationBroadPhaseCallback : public btBroadphaseAabbCallback {
 	}
 };
 
-bool SpaceBullet::recover_from_penetration(RigidBodyBullet *p_body, const btTransform &p_body_position, btScalar p_recover_movement_scale, bool p_infinite_inertia, btVector3 &r_delta_recover_movement, RecoverResult *r_recover_result) {
+bool SpaceBullet::recover_from_penetration(RigidBodyBullet *p_body, const btTransform &p_body_position, btScalar p_recover_movement_scale, bool p_infinite_inertia, btVector3 &r_delta_recover_movement, RecoverResult *r_recover_result, const Set<RID> &p_exclude) {
 	// Calculate the cumulative AABB of all shapes of the kinematic body
 	btVector3 aabb_min, aabb_max;
 	bool shapes_found = false;
@@ -1264,6 +1264,12 @@ bool SpaceBullet::recover_from_penetration(RigidBodyBullet *p_body, const btTran
 
 		for (int i = recover_broad_result.results.size() - 1; 0 <= i; --i) {
 			btCollisionObject *otherObject = recover_broad_result.results[i].collision_object;
+
+			CollisionObjectBullet *gObj = static_cast<CollisionObjectBullet *>(otherObject->getUserPointer());
+			if (p_exclude.has(gObj->get_self())) {
+				continue;
+			}
+
 			if (p_infinite_inertia && !otherObject->isStaticOrKinematicObject()) {
 				otherObject->activate(); // Force activation of hitten rigid, soft body
 				continue;

modules/bullet/space_bullet.h

@@ -185,7 +185,7 @@ class SpaceBullet : public RIDBullet {
 	real_t get_linear_damp() const { return linear_damp; }
 	real_t get_angular_damp() const { return angular_damp; }
 
-	bool test_body_motion(RigidBodyBullet *p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, PhysicsServer::MotionResult *r_result, bool p_exclude_raycast_shapes);
+	bool test_body_motion(RigidBodyBullet *p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, PhysicsServer::MotionResult *r_result, bool p_exclude_raycast_shapes, const Set<RID> &p_exclude = Set<RID>());
 	int test_ray_separation(RigidBodyBullet *p_body, const Transform &p_transform, bool p_infinite_inertia, Vector3 &r_recover_motion, PhysicsServer::SeparationResult *r_results, int p_result_max, float p_margin);
 
 private:
@@ -213,7 +213,7 @@ class SpaceBullet : public RIDBullet {
 				local_shape_most_recovered(0) {}
 	};
 
-	bool recover_from_penetration(RigidBodyBullet *p_body, const btTransform &p_body_position, btScalar p_recover_movement_scale, bool p_infinite_inertia, btVector3 &r_delta_recover_movement, RecoverResult *r_recover_result = nullptr);
+	bool recover_from_penetration(RigidBodyBullet *p_body, const btTransform &p_body_position, btScalar p_recover_movement_scale, bool p_infinite_inertia, btVector3 &r_delta_recover_movement, RecoverResult *r_recover_result = nullptr, const Set<RID> &p_exclude = Set<RID>());
 	/// This is an API that recover a kinematic object from penetration
 	/// This allow only Convex Convex test and it always use GJK algorithm, With this API we don't benefit of Bullet special accelerated functions
 	bool RFP_convex_convex_test(const btConvexShape *p_shapeA, const btConvexShape *p_shapeB, btCollisionObject *p_objectB, int p_shapeId_A, int p_shapeId_B, const btTransform &p_transformA, const btTransform &p_transformB, btScalar p_recover_movement_scale, btVector3 &r_delta_recover_movement, RecoverResult *r_recover_result = nullptr);

scene/2d/physics_body_2d.cpp

@@ -1128,7 +1128,7 @@ Vector2 KinematicBody2D::move_and_slide(const Vector2 &p_linear_velocity, const
 	floor_normal = Vector2();
 	floor_velocity = Vector2();
 
-	if (current_floor_velocity != Vector2()) {
+	if (current_floor_velocity != Vector2() && on_floor_body.is_valid()) {
 		Collision floor_collision;
 		Set<RID> exclude;
 		exclude.insert(on_floor_body);

scene/3d/physics_body.cpp

@@ -973,14 +973,14 @@ Ref<KinematicCollision> KinematicBody::_move(const Vector3 &p_motion, bool p_inf
 	return Ref<KinematicCollision>();
 }
 
-bool KinematicBody::move_and_collide(const Vector3 &p_motion, bool p_infinite_inertia, Collision &r_collision, bool p_exclude_raycast_shapes, bool p_test_only, bool p_cancel_sliding) {
+bool KinematicBody::move_and_collide(const Vector3 &p_motion, bool p_infinite_inertia, Collision &r_collision, bool p_exclude_raycast_shapes, bool p_test_only, bool p_cancel_sliding, const Set<RID> &p_exclude) {
 	if (sync_to_physics) {
 		ERR_PRINT("Functions move_and_slide and move_and_collide do not work together with 'sync to physics' option. Please read the documentation.");
 	}
 
 	Transform gt = get_global_transform();
 	PhysicsServer::MotionResult result;
-	bool colliding = PhysicsServer::get_singleton()->body_test_motion(get_rid(), gt, p_motion, p_infinite_inertia, &result, p_exclude_raycast_shapes);
+	bool colliding = PhysicsServer::get_singleton()->body_test_motion(get_rid(), gt, p_motion, p_infinite_inertia, &result, p_exclude_raycast_shapes, p_exclude);
 
 	// Restore direction of motion to be along original motion,
 	// in order to avoid sliding due to recovery,
@@ -1061,8 +1061,11 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
 		}
 	}
 
+	// Hack in order to work with calling from _process as well as from _physics_process; calling from thread is risky
+	float delta = Engine::get_singleton()->is_in_physics_frame() ? get_physics_process_delta_time() : get_process_delta_time();
+
 	Vector3 current_floor_velocity = floor_velocity;
-	if (on_floor && on_floor_body.is_valid()) {
+	if ((on_floor || on_wall) && on_floor_body.is_valid()) {
 		// This approach makes sure there is less delay between the actual body velocity and the one we saved.
 		PhysicsDirectBodyState *bs = PhysicsServer::get_singleton()->body_get_direct_state(on_floor_body);
 		if (bs) {
@@ -1072,17 +1075,26 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
 		}
 	}
 
-	// Hack in order to work with calling from _process as well as from _physics_process; calling from thread is risky
-	Vector3 motion = (current_floor_velocity + body_velocity) * (Engine::get_singleton()->is_in_physics_frame() ? get_physics_process_delta_time() : get_process_delta_time());
-
+	colliders.clear();
 	on_floor = false;
-	on_floor_body = RID();
 	on_ceiling = false;
 	on_wall = false;
-	colliders.clear();
 	floor_normal = Vector3();
 	floor_velocity = Vector3();
 
+	if (current_floor_velocity != Vector3() && on_floor_body.is_valid()) {
+		Collision floor_collision;
+		Set<RID> exclude;
+		exclude.insert(on_floor_body);
+		if (move_and_collide(current_floor_velocity * delta, p_infinite_inertia, floor_collision, true, false, false, exclude)) {
+			colliders.push_back(floor_collision);
+			_set_collision_direction(floor_collision, up_direction, p_floor_max_angle);
+		}
+	}
+
+	on_floor_body = RID();
+	Vector3 motion = body_velocity * delta;
+
 	// No sliding on first attempt to keep floor motion stable when possible,
 	// when stop on slope is enabled.
 	bool sliding_enabled = !p_stop_on_slope;
@@ -1110,33 +1122,18 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
 
 				colliders.push_back(collision);
 
-				if (up_direction == Vector3()) {
-					//all is a wall
-					on_wall = true;
-				} else {
-					if (Math::acos(collision.normal.dot(up_direction)) <= p_floor_max_angle + FLOOR_ANGLE_THRESHOLD) { //floor
-
-						on_floor = true;
-						floor_normal = collision.normal;
-						on_floor_body = collision.collider_rid;
-						floor_velocity = collision.collider_vel;
-
-						if (p_stop_on_slope) {
-							if ((body_velocity_normal + up_direction).length() < 0.01) {
-								Transform gt = get_global_transform();
-								if (collision.travel.length() > margin) {
-									gt.origin -= collision.travel.slide(up_direction);
-								} else {
-									gt.origin -= collision.travel;
-								}
-								set_global_transform(gt);
-								return Vector3();
-							}
+				_set_collision_direction(collision, up_direction, p_floor_max_angle);
+
+				if (on_floor && p_stop_on_slope) {
+					if ((body_velocity_normal + up_direction).length() < 0.01) {
+						Transform gt = get_global_transform();
+						if (collision.travel.length() > margin) {
+							gt.origin -= collision.travel.slide(up_direction);
+						} else {
+							gt.origin -= collision.travel;
 						}
-					} else if (Math::acos(collision.normal.dot(-up_direction)) <= p_floor_max_angle + FLOOR_ANGLE_THRESHOLD) { //ceiling
-						on_ceiling = true;
-					} else {
-						on_wall = true;
+						set_global_transform(gt);
+						return Vector3();
 					}
 				}
 
@@ -1162,6 +1159,11 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
 		}
 	}
 
+	if (!on_floor && !on_wall) {
+		// Add last platform velocity when just left a moving platform.
+		return body_velocity + current_floor_velocity;
+	}
+
 	return body_velocity;
 }
 
@@ -1207,6 +1209,29 @@ Vector3 KinematicBody::move_and_slide_with_snap(const Vector3 &p_linear_velocity
 	return ret;
 }
 
+void KinematicBody::_set_collision_direction(const Collision &p_collision, const Vector3 &p_up_direction, float p_floor_max_angle) {
+	on_floor = false;
+	on_ceiling = false;
+	on_wall = false;
+	if (p_up_direction == Vector3()) {
+		//all is a wall
+		on_wall = true;
+	} else {
+		if (Math::acos(p_collision.normal.dot(p_up_direction)) <= p_floor_max_angle + FLOOR_ANGLE_THRESHOLD) { //floor
+			on_floor = true;
+			floor_normal = p_collision.normal;
+			on_floor_body = p_collision.collider_rid;
+			floor_velocity = p_collision.collider_vel;
+		} else if (Math::acos(p_collision.normal.dot(-p_up_direction)) <= p_floor_max_angle + FLOOR_ANGLE_THRESHOLD) { //ceiling
+			on_ceiling = true;
+		} else {
+			on_wall = true;
+			on_floor_body = p_collision.collider_rid;
+			floor_velocity = p_collision.collider_vel;
+		}
+	}
+}
+
 bool KinematicBody::is_on_floor() const {
 	return on_floor;
 }

scene/3d/physics_body.h

@@ -300,13 +300,14 @@ class KinematicBody : public PhysicsBody {
 
 	Transform last_valid_transform;
 	void _direct_state_changed(Object *p_state);
+	void _set_collision_direction(const Collision &p_collision, const Vector3 &p_up_direction, float p_floor_max_angle);
 
 protected:
 	void _notification(int p_what);
 	static void _bind_methods();
 
 public:
-	bool move_and_collide(const Vector3 &p_motion, bool p_infinite_inertia, Collision &r_collision, bool p_exclude_raycast_shapes = true, bool p_test_only = false, bool p_cancel_sliding = true);
+	bool move_and_collide(const Vector3 &p_motion, bool p_infinite_inertia, Collision &r_collision, bool p_exclude_raycast_shapes = true, bool p_test_only = false, bool p_cancel_sliding = true, const Set<RID> &p_exclude = Set<RID>());
 	bool test_move(const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia);
 
 	bool separate_raycast_shapes(bool p_infinite_inertia, Collision &r_collision);

servers/physics/physics_server_sw.cpp

@@ -860,15 +860,15 @@ bool PhysicsServerSW::body_is_ray_pickable(RID p_body) const {
 	return body->is_ray_pickable();
 }
 
-bool PhysicsServerSW::body_test_motion(RID p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, MotionResult *r_result, bool p_exclude_raycast_shapes) {
+bool PhysicsServerSW::body_test_motion(RID p_body, const Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, MotionResult *r_result, bool p_exclude_raycast_shapes, const Set<RID> &p_exclude) {
 	BodySW *body = body_owner.get(p_body);
 	ERR_FAIL_COND_V(!body, false);
 	ERR_FAIL_COND_V(!body->get_space(), false);
 	ERR_FAIL_COND_V(body->get_space()->is_locked(), false);
 
 	_update_shapes();
 
-	return body->get_space()->test_body_motion(body, p_from, p_motion, p_infinite_inertia, body->get_kinematic_margin(), r_result, p_exclude_raycast_shapes);
+	return body->get_space()->test_body_motion(body, p_from, p_motion, p_infinite_inertia, body->get_kinematic_margin(), r_result, p_exclude_raycast_shapes, p_exclude);
 }
 
 int PhysicsServerSW::body_test_ray_separation(RID p_body, const Transform &p_transform, bool p_infinite_inertia, Vector3 &r_recover_motion, SeparationResult *r_results, int p_result_max, float p_margin) {