Implement collision impulse in Godot Physics 3D

This commit is contained in:
Lily Garcia 2023-01-07 22:34:28 -05:00
parent e780dc332a
commit 8ee6264cc9
9 changed files with 59 additions and 47 deletions

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@ -152,10 +152,10 @@
</description>
</method>
<method name="get_contact_impulse" qualifiers="const">
<return type="float" />
<return type="Vector3" />
<param index="0" name="contact_idx" type="int" />
<description>
Impulse created by the contact. Only implemented for Bullet physics.
Impulse created by the contact.
</description>
</method>
<method name="get_contact_local_normal" qualifiers="const">

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@ -131,7 +131,7 @@
</description>
</method>
<method name="_get_contact_impulse" qualifiers="virtual const">
<return type="float" />
<return type="Vector3" />
<param index="0" name="contact_idx" type="int" />
<description>
</description>

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@ -94,7 +94,7 @@ public:
EXBIND1RC(Vector3, get_contact_local_position, int)
EXBIND1RC(Vector3, get_contact_local_normal, int)
EXBIND1RC(real_t, get_contact_impulse, int)
EXBIND1RC(Vector3, get_contact_impulse, int)
EXBIND1RC(int, get_contact_local_shape, int)
EXBIND1RC(RID, get_contact_collider, int)
EXBIND1RC(Vector3, get_contact_collider_position, int)

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@ -126,6 +126,7 @@ class GodotBody3D : public GodotCollisionObject3D {
ObjectID collider_instance_id;
RID collider;
Vector3 collider_velocity_at_pos;
Vector3 impulse;
};
Vector<Contact> contacts; //no contacts by default
@ -183,7 +184,7 @@ public:
_FORCE_INLINE_ int get_max_contacts_reported() const { return contacts.size(); }
_FORCE_INLINE_ bool can_report_contacts() const { return !contacts.is_empty(); }
_FORCE_INLINE_ void add_contact(const Vector3 &p_local_pos, const Vector3 &p_local_normal, real_t p_depth, int p_local_shape, const Vector3 &p_collider_pos, int p_collider_shape, ObjectID p_collider_instance_id, const RID &p_collider, const Vector3 &p_collider_velocity_at_pos);
_FORCE_INLINE_ void add_contact(const Vector3 &p_local_pos, const Vector3 &p_local_normal, real_t p_depth, int p_local_shape, const Vector3 &p_collider_pos, int p_collider_shape, ObjectID p_collider_instance_id, const RID &p_collider, const Vector3 &p_collider_velocity_at_pos, const Vector3 &p_impulse);
_FORCE_INLINE_ void add_exception(const RID &p_exception) { exceptions.insert(p_exception); }
_FORCE_INLINE_ void remove_exception(const RID &p_exception) { exceptions.erase(p_exception); }
@ -347,7 +348,7 @@ public:
//add contact inline
void GodotBody3D::add_contact(const Vector3 &p_local_pos, const Vector3 &p_local_normal, real_t p_depth, int p_local_shape, const Vector3 &p_collider_pos, int p_collider_shape, ObjectID p_collider_instance_id, const RID &p_collider, const Vector3 &p_collider_velocity_at_pos) {
void GodotBody3D::add_contact(const Vector3 &p_local_pos, const Vector3 &p_local_normal, real_t p_depth, int p_local_shape, const Vector3 &p_collider_pos, int p_collider_shape, ObjectID p_collider_instance_id, const RID &p_collider, const Vector3 &p_collider_velocity_at_pos, const Vector3 &p_impulse) {
int c_max = contacts.size();
if (c_max == 0) {
@ -387,6 +388,7 @@ void GodotBody3D::add_contact(const Vector3 &p_local_pos, const Vector3 &p_local
c[idx].collider_instance_id = p_collider_instance_id;
c[idx].collider = p_collider;
c[idx].collider_velocity_at_pos = p_collider_velocity_at_pos;
c[idx].impulse = p_impulse;
}
#endif // GODOT_BODY_3D_H

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@ -188,8 +188,9 @@ Vector3 GodotPhysicsDirectBodyState3D::get_contact_local_normal(int p_contact_id
return body->contacts[p_contact_idx].local_normal;
}
real_t GodotPhysicsDirectBodyState3D::get_contact_impulse(int p_contact_idx) const {
return 0.0f; // Only implemented for bullet
Vector3 GodotPhysicsDirectBodyState3D::get_contact_impulse(int p_contact_idx) const {
ERR_FAIL_INDEX_V(p_contact_idx, body->contact_count, Vector3());
return body->contacts[p_contact_idx].impulse;
}
int GodotPhysicsDirectBodyState3D::get_contact_local_shape(int p_contact_idx) const {

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@ -89,7 +89,7 @@ public:
virtual Vector3 get_contact_local_position(int p_contact_idx) const override;
virtual Vector3 get_contact_local_normal(int p_contact_idx) const override;
virtual real_t get_contact_impulse(int p_contact_idx) const override;
virtual Vector3 get_contact_impulse(int p_contact_idx) const override;
virtual int get_contact_local_shape(int p_contact_idx) const override;
virtual RID get_contact_collider(int p_contact_idx) const override;

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@ -364,26 +364,6 @@ bool GodotBodyPair3D::pre_solve(real_t p_step) {
c.rA = global_A - A->get_center_of_mass();
c.rB = global_B - B->get_center_of_mass() - offset_B;
// contact query reporting...
if (A->can_report_contacts()) {
Vector3 crA = A->get_angular_velocity().cross(c.rA) + A->get_linear_velocity();
A->add_contact(global_A, -c.normal, depth, shape_A, global_B, shape_B, B->get_instance_id(), B->get_self(), crA);
}
if (B->can_report_contacts()) {
Vector3 crB = B->get_angular_velocity().cross(c.rB) + B->get_linear_velocity();
B->add_contact(global_B, c.normal, depth, shape_B, global_A, shape_A, A->get_instance_id(), A->get_self(), crB);
}
if (report_contacts_only) {
collided = false;
continue;
}
c.active = true;
do_process = true;
// Precompute normal mass, tangent mass, and bias.
Vector3 inertia_A = inv_inertia_tensor_A.xform(c.rA.cross(c.normal));
Vector3 inertia_B = inv_inertia_tensor_B.xform(c.rB.cross(c.normal));
@ -395,6 +375,29 @@ bool GodotBodyPair3D::pre_solve(real_t p_step) {
c.depth = depth;
Vector3 j_vec = c.normal * c.acc_normal_impulse + c.acc_tangent_impulse;
c.acc_impulse -= j_vec;
// contact query reporting...
if (A->can_report_contacts()) {
Vector3 crA = A->get_angular_velocity().cross(c.rA) + A->get_linear_velocity();
A->add_contact(global_A, -c.normal, depth, shape_A, global_B, shape_B, B->get_instance_id(), B->get_self(), crA, c.acc_impulse);
}
if (B->can_report_contacts()) {
Vector3 crB = B->get_angular_velocity().cross(c.rB) + B->get_linear_velocity();
B->add_contact(global_B, c.normal, depth, shape_B, global_A, shape_A, A->get_instance_id(), A->get_self(), crB, -c.acc_impulse);
}
if (report_contacts_only) {
collided = false;
continue;
}
c.active = true;
do_process = true;
if (collide_A) {
A->apply_impulse(-j_vec, c.rA + A->get_center_of_mass());
}
@ -504,6 +507,7 @@ void GodotBodyPair3D::solve(real_t p_step) {
if (collide_B) {
B->apply_impulse(j, c.rB + B->get_center_of_mass());
}
c.acc_impulse -= j;
c.active = true;
}
@ -550,6 +554,7 @@ void GodotBodyPair3D::solve(real_t p_step) {
if (collide_B) {
B->apply_impulse(jt, c.rB + B->get_center_of_mass());
}
c.acc_impulse -= jt;
c.active = true;
}
@ -745,23 +750,6 @@ bool GodotBodySoftBodyPair3D::pre_solve(real_t p_step) {
c.rA = global_A - transform_A.origin - body->get_center_of_mass();
c.rB = global_B;
if (body->can_report_contacts()) {
Vector3 crA = body->get_angular_velocity().cross(c.rA) + body->get_linear_velocity();
body->add_contact(global_A, -c.normal, depth, body_shape, global_B, 0, soft_body->get_instance_id(), soft_body->get_self(), crA);
}
if (report_contacts_only) {
collided = false;
continue;
}
c.active = true;
do_process = true;
if (body_collides) {
body->set_active(true);
}
// Precompute normal mass, tangent mass, and bias.
Vector3 inertia_A = body_inv_inertia_tensor.xform(c.rA.cross(c.normal));
real_t kNormal = body_inv_mass + node_inv_mass;
@ -778,6 +766,24 @@ bool GodotBodySoftBodyPair3D::pre_solve(real_t p_step) {
if (soft_body_collides) {
soft_body->apply_node_impulse(c.index_B, j_vec);
}
c.acc_impulse -= j_vec;
if (body->can_report_contacts()) {
Vector3 crA = body->get_angular_velocity().cross(c.rA) + body->get_linear_velocity();
body->add_contact(global_A, -c.normal, depth, body_shape, global_B, 0, soft_body->get_instance_id(), soft_body->get_self(), crA, c.acc_impulse);
}
if (report_contacts_only) {
collided = false;
continue;
}
c.active = true;
do_process = true;
if (body_collides) {
body->set_active(true);
}
c.bounce = body->get_bounce();
@ -880,6 +886,7 @@ void GodotBodySoftBodyPair3D::solve(real_t p_step) {
if (soft_body_collides) {
soft_body->apply_node_impulse(c.index_B, j);
}
c.acc_impulse -= j;
c.active = true;
}
@ -924,6 +931,7 @@ void GodotBodySoftBodyPair3D::solve(real_t p_step) {
if (soft_body_collides) {
soft_body->apply_node_impulse(c.index_B, jt);
}
c.acc_impulse -= jt;
c.active = true;
}

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@ -44,6 +44,7 @@ protected:
Vector3 normal;
int index_A = 0, index_B = 0;
Vector3 local_A, local_B;
Vector3 acc_impulse; // accumulated impulse - only one of the object's impulse is needed as impulse_a == -impulse_b
real_t acc_normal_impulse = 0.0; // accumulated normal impulse (Pn)
Vector3 acc_tangent_impulse; // accumulated tangent impulse (Pt)
real_t acc_bias_impulse = 0.0; // accumulated normal impulse for position bias (Pnb)

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@ -95,7 +95,7 @@ public:
virtual Vector3 get_contact_local_position(int p_contact_idx) const = 0;
virtual Vector3 get_contact_local_normal(int p_contact_idx) const = 0;
virtual real_t get_contact_impulse(int p_contact_idx) const = 0;
virtual Vector3 get_contact_impulse(int p_contact_idx) const = 0;
virtual int get_contact_local_shape(int p_contact_idx) const = 0;
virtual RID get_contact_collider(int p_contact_idx) const = 0;