Merge pull request #50495 from nekomatata/move-and-slide-fixes-3.x

[3.x] Backport KinematicBody move_and_slide and move_and_collide fixes

doc/classes/Physics2DTestMotionResult.xml

@@ -19,10 +19,16 @@
 		</member>
 		<member name="collider_velocity" type="Vector2" setter="" getter="get_collider_velocity" default="Vector2( 0, 0 )">
 		</member>
+		<member name="collision_depth" type="float" setter="" getter="get_collision_depth" default="0.0">
+		</member>
 		<member name="collision_normal" type="Vector2" setter="" getter="get_collision_normal" default="Vector2( 0, 0 )">
 		</member>
 		<member name="collision_point" type="Vector2" setter="" getter="get_collision_point" default="Vector2( 0, 0 )">
 		</member>
+		<member name="collision_safe_fraction" type="float" setter="" getter="get_collision_safe_fraction" default="0.0">
+		</member>
+		<member name="collision_unsafe_fraction" type="float" setter="" getter="get_collision_unsafe_fraction" default="0.0">
+		</member>
 		<member name="motion" type="Vector2" setter="" getter="get_motion" default="Vector2( 0, 0 )">
 		</member>
 		<member name="motion_remainder" type="Vector2" setter="" getter="get_motion_remainder" default="Vector2( 0, 0 )">

doc/classes/PhysicsTestMotionResult.xml

@@ -19,10 +19,16 @@
 		</member>
 		<member name="collider_velocity" type="Vector3" setter="" getter="get_collider_velocity" default="Vector3( 0, 0, 0 )">
 		</member>
+		<member name="collision_depth" type="float" setter="" getter="get_collision_depth" default="0.0">
+		</member>
 		<member name="collision_normal" type="Vector3" setter="" getter="get_collision_normal" default="Vector3( 0, 0, 0 )">
 		</member>
 		<member name="collision_point" type="Vector3" setter="" getter="get_collision_point" default="Vector3( 0, 0, 0 )">
 		</member>
+		<member name="collision_safe_fraction" type="float" setter="" getter="get_collision_safe_fraction" default="0.0">
+		</member>
+		<member name="collision_unsafe_fraction" type="float" setter="" getter="get_collision_unsafe_fraction" default="0.0">
+		</member>
 		<member name="motion" type="Vector3" setter="" getter="get_motion" default="Vector3( 0, 0, 0 )">
 		</member>
 		<member name="motion_remainder" type="Vector3" setter="" getter="get_motion_remainder" default="Vector3( 0, 0, 0 )">

scene/2d/physics_body_2d.cpp

@@ -1030,7 +1030,7 @@ bool KinematicBody2D::separate_raycast_shapes(bool p_infinite_inertia, Collision
 	}
 }
 
-bool KinematicBody2D::move_and_collide(const Vector2 &p_motion, bool p_infinite_inertia, Collision &r_collision, bool p_exclude_raycast_shapes, bool p_test_only, const Set<RID> &p_exclude) {
+bool KinematicBody2D::move_and_collide(const Vector2 &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.");
 	}
@@ -1039,6 +1039,44 @@ bool KinematicBody2D::move_and_collide(const Vector2 &p_motion, bool p_infinite_
 
 	bool colliding = Physics2DServer::get_singleton()->body_test_motion(get_rid(), gt, p_motion, p_infinite_inertia, margin, &result, p_exclude_raycast_shapes, p_exclude);
 
+	// Restore direction of motion to be along original motion,
+	// in order to avoid sliding due to recovery,
+	// but only if collision depth is low enough to avoid tunneling.
+	if (p_cancel_sliding) {
+		real_t motion_length = p_motion.length();
+		real_t precision = 0.001;
+
+		if (colliding) {
+			// Can't just use margin as a threshold because collision depth is calculated on unsafe motion,
+			// so even in normal resting cases the depth can be a bit more than the margin.
+			precision += motion_length * (result.collision_unsafe_fraction - result.collision_safe_fraction);
+
+			if (result.collision_depth > (real_t)margin + precision) {
+				p_cancel_sliding = false;
+			}
+		}
+
+		if (p_cancel_sliding) {
+			// When motion is null, recovery is the resulting motion.
+			Vector2 motion_normal;
+			if (motion_length > CMP_EPSILON) {
+				motion_normal = p_motion / motion_length;
+			}
+
+			// Check depth of recovery.
+			real_t projected_length = result.motion.dot(motion_normal);
+			Vector2 recovery = result.motion - motion_normal * projected_length;
+			real_t recovery_length = recovery.length();
+			// Fixes cases where canceling slide causes the motion to go too deep into the ground,
+			// because we're only taking rest information into account and not general recovery.
+			if (recovery_length < (real_t)margin + precision) {
+				// Apply adjustment to motion.
+				result.motion = motion_normal * projected_length;
+				result.remainder = p_motion - result.motion;
+			}
+		}
+	}
+
 	if (colliding) {
 		r_collision.collider_metadata = result.collider_metadata;
 		r_collision.collider_shape = result.collider_shape;
@@ -1092,7 +1130,7 @@ Vector2 KinematicBody2D::move_and_slide(const Vector2 &p_linear_velocity, const
 		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, exclude)) {
+		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);
 		}
@@ -1101,14 +1139,17 @@ Vector2 KinematicBody2D::move_and_slide(const Vector2 &p_linear_velocity, const
 	on_floor_body = RID();
 	Vector2 motion = body_velocity * delta;
 
-	while (p_max_slides) {
+	// 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;
+	for (int iteration = 0; iteration < p_max_slides; ++iteration) {
 		Collision collision;
 		bool found_collision = false;
 
 		for (int i = 0; i < 2; ++i) {
 			bool collided;
 			if (i == 0) { //collide
-				collided = move_and_collide(motion, p_infinite_inertia, collision);
+				collided = move_and_collide(motion, p_infinite_inertia, collision, true, false, !sliding_enabled);
 				if (!collided) {
 					motion = Vector2(); //clear because no collision happened and motion completed
 				}
@@ -1124,29 +1165,36 @@ Vector2 KinematicBody2D::move_and_slide(const Vector2 &p_linear_velocity, const
 				found_collision = true;
 
 				colliders.push_back(collision);
-				motion = collision.remainder;
 
 				_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 && collision.travel.length() < 1) {
+					if ((body_velocity_normal + up_direction).length() < 0.01) {
 						Transform2D gt = get_global_transform();
-						gt.elements[2] -= collision.travel.slide(up_direction);
+						if (collision.travel.length() > margin) {
+							gt.elements[2] -= collision.travel.slide(up_direction);
+						} else {
+							gt.elements[2] -= collision.travel;
+						}
 						set_global_transform(gt);
 						return Vector2();
 					}
 				}
 
-				motion = motion.slide(collision.normal);
-				body_velocity = body_velocity.slide(collision.normal);
+				if (sliding_enabled || !on_floor) {
+					motion = collision.remainder.slide(collision.normal);
+					body_velocity = body_velocity.slide(collision.normal);
+				} else {
+					motion = collision.remainder;
+				}
 			}
+
+			sliding_enabled = true;
 		}
 
 		if (!found_collision || motion == Vector2()) {
 			break;
 		}
-
-		--p_max_slides;
 	}
 
 	if (!on_floor && !on_wall) {
@@ -1169,7 +1217,7 @@ Vector2 KinematicBody2D::move_and_slide_with_snap(const Vector2 &p_linear_veloci
 	Collision col;
 	Transform2D gt = get_global_transform();
 
-	if (move_and_collide(p_snap, p_infinite_inertia, col, false, true)) {
+	if (move_and_collide(p_snap, p_infinite_inertia, col, false, true, false)) {
 		bool apply = true;
 		if (up_direction != Vector2()) {
 			if (Math::acos(col.normal.dot(up_direction)) <= p_floor_max_angle + FLOOR_ANGLE_THRESHOLD) {
@@ -1180,9 +1228,12 @@ Vector2 KinematicBody2D::move_and_slide_with_snap(const Vector2 &p_linear_veloci
 				if (p_stop_on_slope) {
 					// move and collide may stray the object a bit because of pre un-stucking,
 					// so only ensure that motion happens on floor direction in this case.
-					col.travel = up_direction * up_direction.dot(col.travel);
+					if (col.travel.length() > margin) {
+						col.travel = up_direction * up_direction.dot(col.travel);
+					} else {
+						col.travel = Vector2();
+					}
 				}
-
 			} else {
 				apply = false;
 			}

scene/2d/physics_body_2d.h

@@ -311,7 +311,7 @@ protected:
 	static void _bind_methods();
 
 public:
-	bool move_and_collide(const Vector2 &p_motion, bool p_infinite_inertia, Collision &r_collision, bool p_exclude_raycast_shapes = true, bool p_test_only = false, const Set<RID> &p_exclude = Set<RID>());
+	bool move_and_collide(const Vector2 &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 Transform2D &p_from, const Vector2 &p_motion, bool p_infinite_inertia = true);
 

scene/3d/physics_body.cpp

@@ -973,7 +973,7 @@ 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 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) {
 	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.");
 	}
@@ -982,6 +982,44 @@ bool KinematicBody::move_and_collide(const Vector3 &p_motion, bool p_infinite_in
 	PhysicsServer::MotionResult result;
 	bool colliding = PhysicsServer::get_singleton()->body_test_motion(get_rid(), gt, p_motion, p_infinite_inertia, &result, p_exclude_raycast_shapes);
 
+	// Restore direction of motion to be along original motion,
+	// in order to avoid sliding due to recovery,
+	// but only if collision depth is low enough to avoid tunneling.
+	if (p_cancel_sliding) {
+		real_t motion_length = p_motion.length();
+		real_t precision = 0.001;
+
+		if (colliding) {
+			// Can't just use margin as a threshold because collision depth is calculated on unsafe motion,
+			// so even in normal resting cases the depth can be a bit more than the margin.
+			precision += motion_length * (result.collision_unsafe_fraction - result.collision_safe_fraction);
+
+			if (result.collision_depth > (real_t)margin + precision) {
+				p_cancel_sliding = false;
+			}
+		}
+
+		if (p_cancel_sliding) {
+			// When motion is null, recovery is the resulting motion.
+			Vector3 motion_normal;
+			if (motion_length > CMP_EPSILON) {
+				motion_normal = p_motion / motion_length;
+			}
+
+			// Check depth of recovery.
+			real_t projected_length = result.motion.dot(motion_normal);
+			Vector3 recovery = result.motion - motion_normal * projected_length;
+			real_t recovery_length = recovery.length();
+			// Fixes cases where canceling slide causes the motion to go too deep into the ground,
+			// because we're only taking rest information into account and not general recovery.
+			if (recovery_length < (real_t)margin + precision) {
+				// Apply adjustment to motion.
+				result.motion = motion_normal * projected_length;
+				result.remainder = p_motion - result.motion;
+			}
+		}
+	}
+
 	if (colliding) {
 		r_collision.collider_metadata = result.collider_metadata;
 		r_collision.collider_shape = result.collider_shape;
@@ -1043,14 +1081,17 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
 	floor_normal = Vector3();
 	floor_velocity = Vector3();
 
-	while (p_max_slides) {
+	// 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;
+	for (int iteration = 0; iteration < p_max_slides; ++iteration) {
 		Collision collision;
 		bool found_collision = false;
 
 		for (int i = 0; i < 2; ++i) {
 			bool collided;
 			if (i == 0) { //collide
-				collided = move_and_collide(motion, p_infinite_inertia, collision);
+				collided = move_and_collide(motion, p_infinite_inertia, collision, true, false, !sliding_enabled);
 				if (!collided) {
 					motion = Vector3(); //clear because no collision happened and motion completed
 				}
@@ -1066,7 +1107,6 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
 				found_collision = true;
 
 				colliders.push_back(collision);
-				motion = collision.remainder;
 
 				if (up_direction == Vector3()) {
 					//all is a wall
@@ -1080,9 +1120,13 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
 						floor_velocity = collision.collider_vel;
 
 						if (p_stop_on_slope) {
-							if ((body_velocity_normal + up_direction).length() < 0.01 && collision.travel.length() < 1) {
+							if ((body_velocity_normal + up_direction).length() < 0.01) {
 								Transform gt = get_global_transform();
-								gt.origin -= collision.travel.slide(up_direction);
+								if (collision.travel.length() > margin) {
+									gt.origin -= collision.travel.slide(up_direction);
+								} else {
+									gt.origin -= collision.travel;
+								}
 								set_global_transform(gt);
 								return Vector3();
 							}
@@ -1094,22 +1138,26 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
 					}
 				}
 
-				motion = motion.slide(collision.normal);
-				body_velocity = body_velocity.slide(collision.normal);
+				if (sliding_enabled || !on_floor) {
+					motion = collision.remainder.slide(collision.normal);
+					body_velocity = body_velocity.slide(collision.normal);
 
-				for (int j = 0; j < 3; j++) {
-					if (locked_axis & (1 << j)) {
-						body_velocity[j] = 0;
+					for (int j = 0; j < 3; j++) {
+						if (locked_axis & (1 << j)) {
+							body_velocity[j] = 0;
+						}
 					}
+				} else {
+					motion = collision.remainder;
 				}
 			}
+
+			sliding_enabled = true;
 		}
 
 		if (!found_collision || motion == Vector3()) {
 			break;
 		}
-
-		--p_max_slides;
 	}
 
 	return body_velocity;
@@ -1127,7 +1175,7 @@ Vector3 KinematicBody::move_and_slide_with_snap(const Vector3 &p_linear_velocity
 	Collision col;
 	Transform gt = get_global_transform();
 
-	if (move_and_collide(p_snap, p_infinite_inertia, col, false, true)) {
+	if (move_and_collide(p_snap, p_infinite_inertia, col, false, true, false)) {
 		bool apply = true;
 		if (up_direction != Vector3()) {
 			if (Math::acos(col.normal.dot(up_direction)) <= p_floor_max_angle + FLOOR_ANGLE_THRESHOLD) {
@@ -1138,7 +1186,11 @@ Vector3 KinematicBody::move_and_slide_with_snap(const Vector3 &p_linear_velocity
 				if (p_stop_on_slope) {
 					// move and collide may stray the object a bit because of pre un-stucking,
 					// so only ensure that motion happens on floor direction in this case.
-					col.travel = col.travel.project(up_direction);
+					if (col.travel.length() > margin) {
+						col.travel = col.travel.project(up_direction);
+					} else {
+						col.travel = Vector3();
+					}
 				}
 			} else {
 				apply = false; //snapped with floor direction, but did not snap to a floor, do not snap.

scene/3d/physics_body.h

@@ -306,7 +306,7 @@ protected:
 	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 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 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/space_sw.cpp

@@ -251,6 +251,8 @@ bool PhysicsDirectSpaceStateSW::cast_motion(const RID &p_shape, const Transform
 
 	bool best_first = true;
 
+	Vector3 motion_normal = p_motion.normalized();
+
 	Vector3 closest_A, closest_B;
 
 	for (int i = 0; i < amount; i++) {
@@ -266,7 +268,7 @@ bool PhysicsDirectSpaceStateSW::cast_motion(const RID &p_shape, const Transform
 		int shape_idx = space->intersection_query_subindex_results[i];
 
 		Vector3 point_A, point_B;
-		Vector3 sep_axis = p_motion.normalized();
+		Vector3 sep_axis = motion_normal;
 
 		Transform col_obj_xform = col_obj->get_transform() * col_obj->get_shape_transform(shape_idx);
 		//test initial overlap, does it collide if going all the way?
@@ -275,35 +277,47 @@ bool PhysicsDirectSpaceStateSW::cast_motion(const RID &p_shape, const Transform
 		}
 
 		//test initial overlap, ignore objects it's inside of.
-		sep_axis = p_motion.normalized();
+		sep_axis = motion_normal;
 
 		if (!CollisionSolverSW::solve_distance(shape, p_xform, col_obj->get_shape(shape_idx), col_obj_xform, point_A, point_B, aabb, &sep_axis)) {
 			continue;
 		}
 
 		//just do kinematic solving
-		real_t low = 0;
-		real_t hi = 1;
-		Vector3 mnormal = p_motion.normalized();
-
+		real_t low = 0.0;
+		real_t hi = 1.0;
+		real_t fraction_coeff = 0.5;
 		for (int j = 0; j < 8; j++) { //steps should be customizable..
+			real_t fraction = low + (hi - low) * fraction_coeff;
 
-			real_t ofs = (low + hi) * 0.5;
-
-			Vector3 sep = mnormal; //important optimization for this to work fast enough
-
-			mshape.motion = xform_inv.basis.xform(p_motion * ofs);
+			mshape.motion = xform_inv.basis.xform(p_motion * fraction);
 
 			Vector3 lA, lB;
-
+			Vector3 sep = motion_normal; //important optimization for this to work fast enough
 			bool collided = !CollisionSolverSW::solve_distance(&mshape, p_xform, col_obj->get_shape(shape_idx), col_obj_xform, lA, lB, aabb, &sep);
 
 			if (collided) {
-				hi = ofs;
+				hi = fraction;
+				if ((j == 0) || (low > 0.0)) { // Did it not collide before?
+					// When alternating or first iteration, use dichotomy.
+					fraction_coeff = 0.5;
+				} else {
+					// When colliding again, converge faster towards low fraction
+					// for more accurate results with long motions that collide near the start.
+					fraction_coeff = 0.25;
+				}
 			} else {
 				point_A = lA;
 				point_B = lB;
-				low = ofs;
+				low = fraction;
+				if ((j == 0) || (hi < 1.0)) { // Did it collide before?
+					// When alternating or first iteration, use dichotomy.
+					fraction_coeff = 0.5;
+				} else {
+					// When not colliding again, converge faster towards high fraction
+					// for more accurate results with long motions that collide near the end.
+					fraction_coeff = 0.75;
+				}
 			}
 		}
 
@@ -894,27 +908,40 @@ bool SpaceSW::test_body_motion(BodySW *p_body, const Transform &p_from, const Ve
 				}
 
 				//just do kinematic solving
-				real_t low = 0;
-				real_t hi = 1;
-
+				real_t low = 0.0;
+				real_t hi = 1.0;
+				real_t fraction_coeff = 0.5;
 				for (int k = 0; k < 8; k++) { //steps should be customizable..
+					real_t fraction = low + (hi - low) * fraction_coeff;
 
-					real_t ofs = (low + hi) * 0.5;
-
-					Vector3 sep = motion_normal; //important optimization for this to work fast enough
-
-					mshape.motion = body_shape_xform_inv.basis.xform(p_motion * ofs);
+					mshape.motion = body_shape_xform_inv.basis.xform(p_motion * fraction);
 
 					Vector3 lA, lB;
-
+					Vector3 sep = motion_normal; //important optimization for this to work fast enough
 					bool collided = !CollisionSolverSW::solve_distance(&mshape, body_shape_xform, col_obj->get_shape(shape_idx), col_obj_xform, lA, lB, motion_aabb, &sep);
 
 					if (collided) {
-						hi = ofs;
+						hi = fraction;
+						if ((k == 0) || (low > 0.0)) { // Did it not collide before?
+							// When alternating or first iteration, use dichotomy.
+							fraction_coeff = 0.5;
+						} else {
+							// When colliding again, converge faster towards low fraction
+							// for more accurate results with long motions that collide near the start.
+							fraction_coeff = 0.25;
+						}
 					} else {
 						point_A = lA;
 						point_B = lB;
-						low = ofs;
+						low = fraction;
+						if ((k == 0) || (hi < 1.0)) { // Did it collide before?
+							// When alternating or first iteration, use dichotomy.
+							fraction_coeff = 0.5;
+						} else {
+							// When not colliding again, converge faster towards high fraction
+							// for more accurate results with long motions that collide near the end.
+							fraction_coeff = 0.75;
+						}
 					}
 				}
 
@@ -1008,6 +1035,9 @@ bool SpaceSW::test_body_motion(BodySW *p_body, const Transform &p_from, const Ve
 				r_result->collision_local_shape = rcd.best_local_shape;
 				r_result->collision_normal = rcd.best_normal;
 				r_result->collision_point = rcd.best_contact;
+				r_result->collision_depth = rcd.best_len;
+				r_result->collision_safe_fraction = safe;
+				r_result->collision_unsafe_fraction = unsafe;
 				//r_result->collider_metadata = rcd.best_object->get_shape_metadata(rcd.best_shape);
 
 				const BodySW *body = static_cast<const BodySW *>(rcd.best_object);

servers/physics_2d/space_2d_sw.cpp

@@ -283,22 +283,38 @@ bool Physics2DDirectSpaceStateSW::cast_motion(const RID &p_shape, const Transfor
 			continue;
 		}
 
-		//just do kinematic solving
-		real_t low = 0;
-		real_t hi = 1;
 		Vector2 mnormal = p_motion.normalized();
 
+		//just do kinematic solving
+		real_t low = 0.0;
+		real_t hi = 1.0;
+		real_t fraction_coeff = 0.5;
 		for (int j = 0; j < 8; j++) { //steps should be customizable..
-
-			real_t ofs = (low + hi) * 0.5;
+			real_t fraction = low + (hi - low) * fraction_coeff;
 
 			Vector2 sep = mnormal; //important optimization for this to work fast enough
-			bool collided = CollisionSolver2DSW::solve(shape, p_xform, p_motion * ofs, col_obj->get_shape(shape_idx), col_obj_xform, Vector2(), nullptr, nullptr, &sep, p_margin);
+			bool collided = CollisionSolver2DSW::solve(shape, p_xform, p_motion * fraction, col_obj->get_shape(shape_idx), col_obj_xform, Vector2(), nullptr, nullptr, &sep, p_margin);
 
 			if (collided) {
-				hi = ofs;
+				hi = fraction;
+				if ((j == 0) || (low > 0.0)) { // Did it not collide before?
+					// When alternating or first iteration, use dichotomy.
+					fraction_coeff = 0.5;
+				} else {
+					// When colliding again, converge faster towards low fraction
+					// for more accurate results with long motions that collide near the start.
+					fraction_coeff = 0.25;
+				}
 			} else {
-				low = ofs;
+				low = fraction;
+				if ((j == 0) || (hi < 1.0)) { // Did it collide before?
+					// When alternating or first iteration, use dichotomy.
+					fraction_coeff = 0.5;
+				} else {
+					// When not colliding again, converge faster towards high fraction
+					// for more accurate results with long motions that collide near the end.
+					fraction_coeff = 0.75;
+				}
 			}
 		}
 
@@ -962,20 +978,35 @@ bool Space2DSW::test_body_motion(Body2DSW *p_body, const Transform2D &p_from, co
 				}
 
 				//just do kinematic solving
-				real_t low = 0;
-				real_t hi = 1;
-
+				real_t low = 0.0;
+				real_t hi = 1.0;
+				real_t fraction_coeff = 0.5;
 				for (int k = 0; k < 8; k++) { //steps should be customizable..
-
-					real_t ofs = (low + hi) * 0.5;
+					real_t fraction = low + (hi - low) * fraction_coeff;
 
 					Vector2 sep = motion_normal; //important optimization for this to work fast enough
-					bool collided = CollisionSolver2DSW::solve(body_shape, body_shape_xform, p_motion * ofs, against_shape, col_obj_shape_xform, Vector2(), nullptr, nullptr, &sep, 0);
+					bool collided = CollisionSolver2DSW::solve(body_shape, body_shape_xform, p_motion * fraction, against_shape, col_obj_shape_xform, Vector2(), nullptr, nullptr, &sep, 0);
 
 					if (collided) {
-						hi = ofs;
+						hi = fraction;
+						if ((k == 0) || (low > 0.0)) { // Did it not collide before?
+							// When alternating or first iteration, use dichotomy.
+							fraction_coeff = 0.5;
+						} else {
+							// When colliding again, converge faster towards low fraction
+							// for more accurate results with long motions that collide near the start.
+							fraction_coeff = 0.25;
+						}
 					} else {
-						low = ofs;
+						low = fraction;
+						if ((k == 0) || (hi < 1.0)) { // Did it collide before?
+							// When alternating or first iteration, use dichotomy.
+							fraction_coeff = 0.5;
+						} else {
+							// When not colliding again, converge faster towards high fraction
+							// for more accurate results with long motions that collide near the end.
+							fraction_coeff = 0.75;
+						}
 					}
 				}
 
@@ -1128,6 +1159,9 @@ bool Space2DSW::test_body_motion(Body2DSW *p_body, const Transform2D &p_from, co
 				r_result->collision_local_shape = rcd.best_local_shape;
 				r_result->collision_normal = rcd.best_normal;
 				r_result->collision_point = rcd.best_contact;
+				r_result->collision_depth = rcd.best_len;
+				r_result->collision_safe_fraction = safe;
+				r_result->collision_unsafe_fraction = unsafe;
 				r_result->collider_metadata = rcd.best_object->get_shape_metadata(rcd.best_shape);
 
 				const Body2DSW *body = static_cast<const Body2DSW *>(rcd.best_object);

servers/physics_2d_server.cpp

@@ -444,6 +444,18 @@ int Physics2DTestMotionResult::get_collider_shape() const {
 	return result.collider_shape;
 }
 
+real_t Physics2DTestMotionResult::get_collision_depth() const {
+	return result.collision_depth;
+}
+
+real_t Physics2DTestMotionResult::get_collision_safe_fraction() const {
+	return result.collision_safe_fraction;
+}
+
+real_t Physics2DTestMotionResult::get_collision_unsafe_fraction() const {
+	return result.collision_unsafe_fraction;
+}
+
 void Physics2DTestMotionResult::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_motion"), &Physics2DTestMotionResult::get_motion);
 	ClassDB::bind_method(D_METHOD("get_motion_remainder"), &Physics2DTestMotionResult::get_motion_remainder);
@@ -454,6 +466,9 @@ void Physics2DTestMotionResult::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_collider_rid"), &Physics2DTestMotionResult::get_collider_rid);
 	ClassDB::bind_method(D_METHOD("get_collider"), &Physics2DTestMotionResult::get_collider);
 	ClassDB::bind_method(D_METHOD("get_collider_shape"), &Physics2DTestMotionResult::get_collider_shape);
+	ClassDB::bind_method(D_METHOD("get_collision_depth"), &Physics2DTestMotionResult::get_collision_depth);
+	ClassDB::bind_method(D_METHOD("get_collision_safe_fraction"), &Physics2DTestMotionResult::get_collision_safe_fraction);
+	ClassDB::bind_method(D_METHOD("get_collision_unsafe_fraction"), &Physics2DTestMotionResult::get_collision_unsafe_fraction);
 
 	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "motion"), "", "get_motion");
 	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "motion_remainder"), "", "get_motion_remainder");
@@ -464,6 +479,9 @@ void Physics2DTestMotionResult::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::_RID, "collider_rid"), "", "get_collider_rid");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "collider"), "", "get_collider");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "collider_shape"), "", "get_collider_shape");
+	ADD_PROPERTY(PropertyInfo(Variant::REAL, "collision_depth"), "", "get_collision_depth");
+	ADD_PROPERTY(PropertyInfo(Variant::REAL, "collision_safe_fraction"), "", "get_collision_safe_fraction");
+	ADD_PROPERTY(PropertyInfo(Variant::REAL, "collision_unsafe_fraction"), "", "get_collision_unsafe_fraction");
 }
 
 ///////////////////////////////////////

servers/physics_2d_server.h

@@ -469,6 +469,9 @@ public:
 		Vector2 collision_point;
 		Vector2 collision_normal;
 		Vector2 collider_velocity;
+		real_t collision_depth = 0.0;
+		real_t collision_safe_fraction = 0.0;
+		real_t collision_unsafe_fraction = 0.0;
 		int collision_local_shape = 0;
 		ObjectID collider_id = 0;
 		RID collider;
@@ -594,6 +597,9 @@ public:
 	RID get_collider_rid() const;
 	Object *get_collider() const;
 	int get_collider_shape() const;
+	real_t get_collision_depth() const;
+	real_t get_collision_safe_fraction() const;
+	real_t get_collision_unsafe_fraction() const;
 };
 
 typedef Physics2DServer *(*CreatePhysics2DServerCallback)();

servers/physics_server.cpp

@@ -392,6 +392,18 @@ int PhysicsTestMotionResult::get_collider_shape() const {
 	return result.collider_shape;
 }
 
+real_t PhysicsTestMotionResult::get_collision_depth() const {
+	return result.collision_depth;
+}
+
+real_t PhysicsTestMotionResult::get_collision_safe_fraction() const {
+	return result.collision_safe_fraction;
+}
+
+real_t PhysicsTestMotionResult::get_collision_unsafe_fraction() const {
+	return result.collision_unsafe_fraction;
+}
+
 void PhysicsTestMotionResult::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_motion"), &PhysicsTestMotionResult::get_motion);
 	ClassDB::bind_method(D_METHOD("get_motion_remainder"), &PhysicsTestMotionResult::get_motion_remainder);
@@ -402,6 +414,9 @@ void PhysicsTestMotionResult::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_collider_rid"), &PhysicsTestMotionResult::get_collider_rid);
 	ClassDB::bind_method(D_METHOD("get_collider"), &PhysicsTestMotionResult::get_collider);
 	ClassDB::bind_method(D_METHOD("get_collider_shape"), &PhysicsTestMotionResult::get_collider_shape);
+	ClassDB::bind_method(D_METHOD("get_collision_depth"), &PhysicsTestMotionResult::get_collision_depth);
+	ClassDB::bind_method(D_METHOD("get_collision_safe_fraction"), &PhysicsTestMotionResult::get_collision_safe_fraction);
+	ClassDB::bind_method(D_METHOD("get_collision_unsafe_fraction"), &PhysicsTestMotionResult::get_collision_unsafe_fraction);
 
 	ADD_PROPERTY(PropertyInfo(Variant::VECTOR3, "motion"), "", "get_motion");
 	ADD_PROPERTY(PropertyInfo(Variant::VECTOR3, "motion_remainder"), "", "get_motion_remainder");
@@ -412,6 +427,9 @@ void PhysicsTestMotionResult::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::_RID, "collider_rid"), "", "get_collider_rid");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "collider"), "", "get_collider");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "collider_shape"), "", "get_collider_shape");
+	ADD_PROPERTY(PropertyInfo(Variant::REAL, "collision_depth"), "", "get_collision_depth");
+	ADD_PROPERTY(PropertyInfo(Variant::REAL, "collision_safe_fraction"), "", "get_collision_safe_fraction");
+	ADD_PROPERTY(PropertyInfo(Variant::REAL, "collision_unsafe_fraction"), "", "get_collision_unsafe_fraction");
 }
 
 ///////////////////////////////////////

servers/physics_server.h

@@ -461,6 +461,9 @@ public:
 		Vector3 collision_point;
 		Vector3 collision_normal;
 		Vector3 collider_velocity;
+		real_t collision_depth = 0.0;
+		real_t collision_safe_fraction = 0.0;
+		real_t collision_unsafe_fraction = 0.0;
 		int collision_local_shape = 0;
 		ObjectID collider_id = 0;
 		RID collider;
@@ -765,6 +768,9 @@ public:
 	RID get_collider_rid() const;
 	Object *get_collider() const;
 	int get_collider_shape() const;
+	real_t get_collision_depth() const;
+	real_t get_collision_safe_fraction() const;
+	real_t get_collision_unsafe_fraction() const;
 };
 
 typedef PhysicsServer *(*CreatePhysicsServerCallback)();