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Fix point gravity calculation

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Removing the + 1 in point gravity formula when using distance scale to
make it more accurate for standard gravitation.

Fixes precession in orbits for games using gravitation.

Also moved gravity calculation to area to use it for both rigid bodies
and soft bodies in 3D (same change in 2D for consistency).

Co-authored-by: Ryan Peach <ryan.peach@keysight.com>
This commit is contained in:
PouleyKetchoupp 2021-08-24 09:30:31 -07:00
parent 770a1d00a3
commit 9c9e528e3e
9 changed files with 63 additions and 53 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

20
servers/physics_2d/area_2d_sw.cpp
View file

@ -274,6 +274,26 @@ void Area2DSW::call_queries() {
}
}
void Area2DSW::compute_gravity(const Vector2 &p_position, Vector2 &r_gravity) const {
if (is_gravity_point()) {
const real_t gravity_distance_scale = get_gravity_distance_scale();
Vector2 v = get_transform().xform(get_gravity_vector()) - p_position;
if (gravity_distance_scale > 0) {
const real_t v_length = v.length();
if (v_length > 0) {
const real_t v_scaled = v_length * gravity_distance_scale;
r_gravity = (v.normalized() * (get_gravity() / (v_scaled * v_scaled)));
} else {
r_gravity = Vector2();
}
} else {
r_gravity = v.normalized() * get_gravity();
}
} else {
r_gravity = get_gravity_vector() * get_gravity();
}
}
Area2DSW::Area2DSW() :
CollisionObject2DSW(TYPE_AREA),
monitor_query_list(this),

8
servers/physics_2d/area_2d_sw.h
View file

@ -34,7 +34,6 @@
#include "collision_object_2d_sw.h"
#include "core/templates/self_list.h"
#include "servers/physics_server_2d.h"
//#include "servers/physics_3d/query_sw.h"
class Space2DSW;
class Body2DSW;
@ -94,17 +93,12 @@ class Area2DSW : public CollisionObject2DSW {
Map<BodyKey, BodyState> monitored_bodies;
Map<BodyKey, BodyState> monitored_areas;
//virtual void shape_changed_notify(Shape2DSW *p_shape);
//virtual void shape_deleted_notify(Shape2DSW *p_shape);
Set<Constraint2DSW *> constraints;
virtual void _shapes_changed();
void _queue_monitor_update();
public:
//_FORCE_INLINE_ const Matrix32& get_inverse_transform() const { return inverse_transform; }
//_FORCE_INLINE_ SpaceSW* get_owner() { return owner; }
void set_monitor_callback(ObjectID p_id, const StringName &p_method);
_FORCE_INLINE_ bool has_monitor_callback() const { return monitor_callback_id.is_valid(); }
@ -161,6 +155,8 @@ public:
void call_queries();
void compute_gravity(const Vector2 &p_position, Vector2 &r_gravity) const;
Area2DSW();
~Area2DSW();
};

21
servers/physics_2d/body_2d_sw.cpp
View file

@ -352,17 +352,10 @@ void Body2DSW::set_space(Space2DSW *p_space) {
first_integration = false;
}
void Body2DSW::_compute_area_gravity_and_dampenings(const Area2DSW *p_area) {
if (p_area->is_gravity_point()) {
if (p_area->get_gravity_distance_scale() > 0) {
Vector2 v = p_area->get_transform().xform(p_area->get_gravity_vector()) - get_transform().get_origin();
gravity += v.normalized() * (p_area->get_gravity() / Math::pow(v.length() * p_area->get_gravity_distance_scale() + 1, 2));
} else {
gravity += (p_area->get_transform().xform(p_area->get_gravity_vector()) - get_transform().get_origin()).normalized() * p_area->get_gravity();
}
} else {
gravity += p_area->get_gravity_vector() * p_area->get_gravity();
}
void Body2DSW::_compute_area_gravity_and_damping(const Area2DSW *p_area) {
Vector2 area_gravity;
p_area->compute_gravity(get_transform().get_origin(), area_gravity);
gravity += area_gravity;
area_linear_damp += p_area->get_linear_damp();
area_angular_damp += p_area->get_angular_damp();
@ -391,7 +384,7 @@ void Body2DSW::integrate_forces(real_t p_step) {
switch (mode) {
case PhysicsServer2D::AREA_SPACE_OVERRIDE_COMBINE:
case PhysicsServer2D::AREA_SPACE_OVERRIDE_COMBINE_REPLACE: {
_compute_area_gravity_and_dampenings(aa[i].area);
_compute_area_gravity_and_damping(aa[i].area);
stopped = mode == PhysicsServer2D::AREA_SPACE_OVERRIDE_COMBINE_REPLACE;
} break;
case PhysicsServer2D::AREA_SPACE_OVERRIDE_REPLACE:
@ -399,7 +392,7 @@ void Body2DSW::integrate_forces(real_t p_step) {
gravity = Vector2(0, 0);
area_angular_damp = 0;
area_linear_damp = 0;
_compute_area_gravity_and_dampenings(aa[i].area);
_compute_area_gravity_and_damping(aa[i].area);
stopped = mode == PhysicsServer2D::AREA_SPACE_OVERRIDE_REPLACE;
} break;
default: {
@ -408,7 +401,7 @@ void Body2DSW::integrate_forces(real_t p_step) {
}
}
if (!stopped) {
_compute_area_gravity_and_dampenings(def_area);
_compute_area_gravity_and_damping(def_area);
}
gravity *= gravity_scale;

2
servers/physics_2d/body_2d_sw.h
View file

@ -125,7 +125,7 @@ class Body2DSW : public CollisionObject2DSW {
uint64_t island_step;
_FORCE_INLINE_ void _compute_area_gravity_and_dampenings(const Area2DSW *p_area);
_FORCE_INLINE_ void _compute_area_gravity_and_damping(const Area2DSW *p_area);
friend class PhysicsDirectBodyState2DSW; // i give up, too many functions to expose

20
servers/physics_3d/area_3d_sw.cpp
View file

@ -304,6 +304,26 @@ void Area3DSW::call_queries() {
}
}
void Area3DSW::compute_gravity(const Vector3 &p_position, Vector3 &r_gravity) const {
if (is_gravity_point()) {
const real_t gravity_distance_scale = get_gravity_distance_scale();
Vector3 v = get_transform().xform(get_gravity_vector()) - p_position;
if (gravity_distance_scale > 0) {
const real_t v_length = v.length();
if (v_length > 0) {
const real_t v_scaled = v_length * gravity_distance_scale;
r_gravity = (v.normalized() * (get_gravity() / (v_scaled * v_scaled)));
} else {
r_gravity = Vector3();
}
} else {
r_gravity = v.normalized() * get_gravity();
}
} else {
r_gravity = get_gravity_vector() * get_gravity();
}
}
Area3DSW::Area3DSW() :
CollisionObject3DSW(TYPE_AREA),
monitor_query_list(this),

9
servers/physics_3d/area_3d_sw.h
View file

@ -34,7 +34,6 @@
#include "collision_object_3d_sw.h"
#include "core/templates/self_list.h"
#include "servers/physics_server_3d.h"
//#include "servers/physics_3d/query_sw.h"
class Space3DSW;
class Body3DSW;
@ -101,18 +100,12 @@ class Area3DSW : public CollisionObject3DSW {
Map<BodyKey, BodyState> monitored_bodies;
Map<BodyKey, BodyState> monitored_areas;
//virtual void shape_changed_notify(ShapeSW *p_shape);
//virtual void shape_deleted_notify(ShapeSW *p_shape);
Set<Constraint3DSW *> constraints;
virtual void _shapes_changed();
void _queue_monitor_update();
public:
//_FORCE_INLINE_ const Transform& get_inverse_transform() const { return inverse_transform; }
//_FORCE_INLINE_ SpaceSW* get_owner() { return owner; }
void set_monitor_callback(ObjectID p_id, const StringName &p_method);
_FORCE_INLINE_ bool has_monitor_callback() const { return monitor_callback_id.is_valid(); }
@ -184,6 +177,8 @@ public:
void call_queries();
void compute_gravity(const Vector3 &p_position, Vector3 &r_gravity) const;
Area3DSW();
~Area3DSW();
};

21
servers/physics_3d/body_3d_sw.cpp
View file

@ -379,17 +379,10 @@ void Body3DSW::set_space(Space3DSW *p_space) {
first_integration = true;
}
void Body3DSW::_compute_area_gravity_and_dampenings(const Area3DSW *p_area) {
if (p_area->is_gravity_point()) {
if (p_area->get_gravity_distance_scale() > 0) {
Vector3 v = p_area->get_transform().xform(p_area->get_gravity_vector()) - get_transform().get_origin();
gravity += v.normalized() * (p_area->get_gravity() / Math::pow(v.length() * p_area->get_gravity_distance_scale() + 1, 2));
} else {
gravity += (p_area->get_transform().xform(p_area->get_gravity_vector()) - get_transform().get_origin()).normalized() * p_area->get_gravity();
}
} else {
gravity += p_area->get_gravity_vector() * p_area->get_gravity();
}
void Body3DSW::_compute_area_gravity_and_damping(const Area3DSW *p_area) {
Vector3 area_gravity;
p_area->compute_gravity(get_transform().get_origin(), area_gravity);
gravity += area_gravity;
area_linear_damp += p_area->get_linear_damp();
area_angular_damp += p_area->get_angular_damp();
@ -431,7 +424,7 @@ void Body3DSW::integrate_forces(real_t p_step) {
switch (mode) {
case PhysicsServer3D::AREA_SPACE_OVERRIDE_COMBINE:
case PhysicsServer3D::AREA_SPACE_OVERRIDE_COMBINE_REPLACE: {
_compute_area_gravity_and_dampenings(aa[i].area);
_compute_area_gravity_and_damping(aa[i].area);
stopped = mode == PhysicsServer3D::AREA_SPACE_OVERRIDE_COMBINE_REPLACE;
} break;
case PhysicsServer3D::AREA_SPACE_OVERRIDE_REPLACE:
@ -439,7 +432,7 @@ void Body3DSW::integrate_forces(real_t p_step) {
gravity = Vector3(0, 0, 0);
area_angular_damp = 0;
area_linear_damp = 0;
_compute_area_gravity_and_dampenings(aa[i].area);
_compute_area_gravity_and_damping(aa[i].area);
stopped = mode == PhysicsServer3D::AREA_SPACE_OVERRIDE_REPLACE;
} break;
default: {
@ -449,7 +442,7 @@ void Body3DSW::integrate_forces(real_t p_step) {
}
if (!stopped) {
_compute_area_gravity_and_dampenings(def_area);
_compute_area_gravity_and_damping(def_area);
}
gravity *= gravity_scale;

2
servers/physics_3d/body_3d_sw.h
View file

@ -122,7 +122,7 @@ class Body3DSW : public CollisionObject3DSW {
uint64_t island_step;
_FORCE_INLINE_ void _compute_area_gravity_and_dampenings(const Area3DSW *p_area);
_FORCE_INLINE_ void _compute_area_gravity_and_damping(const Area3DSW *p_area);
_FORCE_INLINE_ void _update_transform_dependant();

13
servers/physics_3d/soft_body_3d_sw.cpp
View file

@ -964,16 +964,9 @@ void SoftBody3DSW::apply_forces(bool p_has_wind_forces) {
}
void SoftBody3DSW::_compute_area_gravity(const Area3DSW *p_area) {
if (p_area->is_gravity_point()) {
if (p_area->get_gravity_distance_scale() > 0) {
Vector3 v = p_area->get_transform().xform(p_area->get_gravity_vector()) - get_transform().get_origin();
gravity += v.normalized() * (p_area->get_gravity() / Math::pow(v.length() * p_area->get_gravity_distance_scale() + 1, 2));
} else {
gravity += (p_area->get_transform().xform(p_area->get_gravity_vector()) - get_transform().get_origin()).normalized() * p_area->get_gravity();
}
} else {
gravity += p_area->get_gravity_vector() * p_area->get_gravity();
}
Vector3 area_gravity;
p_area->compute_gravity(get_transform().get_origin(), area_gravity);
gravity += area_gravity;
}
Vector3 SoftBody3DSW::_compute_area_windforce(const Area3DSW *p_area, const Face *p_face) {