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Ensure move_and_slide() is consistent between the 2D and 3D versions.
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In the 3D version:
- Partially revert godotengine#20908 that was reverted in the 2D version as part
  of godotengine#21653. This ensures that the Vector returned is always perpendicular
  to the surface collided with; and not the floor_normal Vector passed to
  the function when on a floor.
- Include an update of the floor velocity before multiplying by the time
  delta, which was added to the 2D version as part of commit 13a8014.

In the 2D version:
- Use the Vector2.slide() function instead of Vector2.tangent() to adjust
  the amount of motion the stop_on_slope undoes to ensure that it is in the
  right direction. This is a implementation of the 3D approach from godotengine#30588.
- Combine the !found_collision and motion == Vector2() checks for break.
- Other minor formating changes to make the functions look identical.

Also renamed some variables to align with their use.
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@madmiraal
madmiraal committed Dec 2, 2019
1 parent e64a663 commit 750f343
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Showing 2 changed files with 34 additions and 39 deletions.
34 changes: 15 additions & 19 deletions scene/2d/physics_body_2d.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1214,18 +1214,20 @@ bool KinematicBody2D::move_and_collide(const Vector2 &p_motion, bool p_infinite_

Vector2 KinematicBody2D::move_and_slide(const Vector2 &p_linear_velocity, const Vector2 &p_floor_direction, bool p_stop_on_slope, int p_max_slides, float p_floor_max_angle, bool p_infinite_inertia) {

Vector2 floor_motion = floor_velocity;
Vector2 body_velocity = p_linear_velocity;
Vector2 body_velocity_normal = body_velocity.normalized();

Vector2 current_floor_velocity = floor_velocity;
if (on_floor && on_floor_body.is_valid()) {
//this approach makes sure there is less delay between the actual body velocity and the one we saved
Physics2DDirectBodyState *bs = Physics2DServer::get_singleton()->body_get_direct_state(on_floor_body);
if (bs) {
floor_motion = bs->get_linear_velocity();
current_floor_velocity = bs->get_linear_velocity();
}
}

// Hack in order to work with calling from _process as well as from _physics_process; calling from thread is risky
Vector2 motion = (floor_motion + p_linear_velocity) * (Engine::get_singleton()->is_in_physics_frame() ? get_physics_process_delta_time() : get_process_delta_time());
Vector2 lv = p_linear_velocity;
Vector2 motion = (current_floor_velocity + body_velocity) * (Engine::get_singleton()->is_in_physics_frame() ? get_physics_process_delta_time() : get_process_delta_time());

on_floor = false;
on_floor_body = RID();
Expand All @@ -1234,14 +1236,12 @@ Vector2 KinematicBody2D::move_and_slide(const Vector2 &p_linear_velocity, const
colliders.clear();
floor_velocity = Vector2();

Vector2 lv_n = p_linear_velocity.normalized();

while (p_max_slides) {

Collision collision;
bool found_collision = false;

for (int i = 0; i < 2; i++) {
for (int i = 0; i < 2; ++i) {
bool collided;
if (i == 0) { //collide
collided = move_and_collide(motion, p_infinite_inertia, collision);
Expand Down Expand Up @@ -1273,36 +1273,32 @@ Vector2 KinematicBody2D::move_and_slide(const Vector2 &p_linear_velocity, const
floor_velocity = collision.collider_vel;

if (p_stop_on_slope) {
if ((lv_n + p_floor_direction).length() < 0.01 && collision.travel.length() < 1) {
if ((body_velocity_normal + p_floor_direction).length() < 0.01 && collision.travel.length() < 1) {
Transform2D gt = get_global_transform();
gt.elements[2] -= collision.travel.project(p_floor_direction.tangent());
gt.elements[2] -= collision.travel.slide(p_floor_direction);
set_global_transform(gt);
return Vector2();
}
}

} else if (Math::acos(collision.normal.dot(-p_floor_direction)) <= p_floor_max_angle + FLOOR_ANGLE_THRESHOLD) { //ceiling
on_ceiling = true;
} else {
on_wall = true;
}
}

Vector2 n = collision.normal;
motion = motion.slide(n);
lv = lv.slide(n);
motion = motion.slide(collision.normal);
body_velocity = body_velocity.slide(collision.normal);
}
}

if (!found_collision) {
break;
}
p_max_slides--;
if (motion == Vector2())
if (!found_collision || motion == Vector2())
break;

--p_max_slides;
}

return lv;
return body_velocity;
}

Vector2 KinematicBody2D::move_and_slide_with_snap(const Vector2 &p_linear_velocity, const Vector2 &p_snap, const Vector2 &p_floor_direction, bool p_stop_on_slope, int p_max_slides, float p_floor_max_angle, bool p_infinite_inertia) {
Expand Down
39 changes: 19 additions & 20 deletions scene/3d/physics_body.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1142,25 +1142,34 @@ bool KinematicBody::move_and_collide(const Vector3 &p_motion, bool p_infinite_in

Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Vector3 &p_floor_direction, bool p_stop_on_slope, int p_max_slides, float p_floor_max_angle, bool p_infinite_inertia) {

Vector3 lv = p_linear_velocity;
Vector3 body_velocity = p_linear_velocity;
Vector3 body_velocity_normal = body_velocity.normalized();

for (int i = 0; i < 3; i++) {
if (locked_axis & (1 << i)) {
lv[i] = 0;
body_velocity[i] = 0;
}
}

Vector3 current_floor_velocity = floor_velocity;
if (on_floor && 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) {
current_floor_velocity = bs->get_linear_velocity();
}
}

// Hack in order to work with calling from _process as well as from _physics_process; calling from thread is risky
Vector3 motion = (floor_velocity + lv) * (Engine::get_singleton()->is_in_physics_frame() ? get_physics_process_delta_time() : get_process_delta_time());
Vector3 motion = (current_floor_velocity + body_velocity) * (Engine::get_singleton()->is_in_physics_frame() ? get_physics_process_delta_time() : get_process_delta_time());

on_floor = false;
on_floor_body = RID();
on_ceiling = false;
on_wall = false;
colliders.clear();
floor_velocity = Vector3();

Vector3 lv_n = p_linear_velocity.normalized();

while (p_max_slides) {

Collision collision;
Expand All @@ -1187,7 +1196,6 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
colliders.push_back(collision);
motion = collision.remainder;

bool is_on_slope = false;
if (p_floor_direction == Vector3()) {
//all is a wall
on_wall = true;
Expand All @@ -1199,35 +1207,26 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
floor_velocity = collision.collider_vel;

if (p_stop_on_slope) {
if ((lv_n + p_floor_direction).length() < 0.01 && collision.travel.length() < 1) {
if ((body_velocity_normal + p_floor_direction).length() < 0.01 && collision.travel.length() < 1) {
Transform gt = get_global_transform();
gt.origin -= collision.travel.slide(p_floor_direction);
set_global_transform(gt);
return Vector3();
}
}

is_on_slope = true;

} else if (Math::acos(collision.normal.dot(-p_floor_direction)) <= p_floor_max_angle + FLOOR_ANGLE_THRESHOLD) { //ceiling
on_ceiling = true;
} else {
on_wall = true;
}
}

if (p_stop_on_slope && is_on_slope) {
motion = motion.slide(p_floor_direction);
lv = lv.slide(p_floor_direction);
} else {
Vector3 n = collision.normal;
motion = motion.slide(n);
lv = lv.slide(n);
}
motion = motion.slide(collision.normal);
body_velocity = body_velocity.slide(collision.normal);

for (int j = 0; j < 3; j++) {
if (locked_axis & (1 << j)) {
lv[j] = 0;
body_velocity[j] = 0;
}
}
}
Expand All @@ -1239,7 +1238,7 @@ Vector3 KinematicBody::move_and_slide(const Vector3 &p_linear_velocity, const Ve
--p_max_slides;
}

return lv;
return body_velocity;
}

Vector3 KinematicBody::move_and_slide_with_snap(const Vector3 &p_linear_velocity, const Vector3 &p_snap, const Vector3 &p_floor_direction, bool p_stop_on_slope, int p_max_slides, float p_floor_max_angle, bool p_infinite_inertia) {
Expand Down

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