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Merge pull request #39084 from madmiraal/backport-37314 

[3.2] Better damping implementation for Bullet rigid bodies
This commit is contained in:
Rémi Verschelde 2020-07-02 13:26:03 +02:00 committed by GitHub
parent 3247ac4b0e 5d8b0649be
commit 44a516986d
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GPG Key ID: 4AEE18F83AFDEB23
6 changed files with 80 additions and 28 deletions
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2
modules/bullet/SCsub
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@ -203,6 +203,8 @@ if env["builtin_bullet"]:
# if env['target'] == "debug" or env['target'] == "release_debug":
# env_bullet.Append(CPPDEFINES=['BT_DEBUG'])
env_bullet.Append(CPPDEFINES=["BT_USE_OLD_DAMPING_METHOD"])
env_thirdparty = env_bullet.Clone()
env_thirdparty.disable_warnings()
env_thirdparty.add_source_files(env.modules_sources, thirdparty_sources)

40
modules/bullet/rigid_body_bullet.cpp
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@ -503,15 +503,18 @@ void RigidBodyBullet::set_param(PhysicsServer::BodyParameter p_param, real_t p_v
}
case PhysicsServer::BODY_PARAM_LINEAR_DAMP:
linearDamp = p_value;
btBody->setDamping(linearDamp, angularDamp);
// Mark for updating total linear damping.
scratch_space_override_modificator();
break;
case PhysicsServer::BODY_PARAM_ANGULAR_DAMP:
angularDamp = p_value;
btBody->setDamping(linearDamp, angularDamp);
// Mark for updating total angular damping.
scratch_space_override_modificator();
break;
case PhysicsServer::BODY_PARAM_GRAVITY_SCALE:
gravity_scale = p_value;
/// The Bullet gravity will be is set by reload_space_override_modificator
// The Bullet gravity will be is set by reload_space_override_modificator.
// Mark for updating total gravity scale.
scratch_space_override_modificator();
break;
default:
@ -902,21 +905,20 @@ void RigidBodyBullet::on_exit_area(AreaBullet *p_area) {
}
void RigidBodyBullet::reload_space_override_modificator() {
// Make sure that kinematic bodies have their total gravity calculated
if (!is_active() && PhysicsServer::BODY_MODE_KINEMATIC != mode)
return;
Vector3 newGravity(space->get_gravity_direction() * space->get_gravity_magnitude());
real_t newLinearDamp(linearDamp);
real_t newAngularDamp(angularDamp);
Vector3 newGravity(0.0, 0.0, 0.0);
real_t newLinearDamp = MAX(0.0, linearDamp);
real_t newAngularDamp = MAX(0.0, angularDamp);
AreaBullet *currentArea;
// Variable used to calculate new gravity for gravity point areas, it is pointed by currentGravity pointer
Vector3 support_gravity(0, 0, 0);
int countCombined(0);
for (int i = areaWhereIamCount - 1; 0 <= i; --i) {
bool stopped = false;
for (int i = areaWhereIamCount - 1; (0 <= i) && !stopped; --i) {
currentArea = areasWhereIam[i];
@ -965,7 +967,6 @@ void RigidBodyBullet::reload_space_override_modificator() {
newGravity += support_gravity;
newLinearDamp += currentArea->get_spOv_linearDamp();
newAngularDamp += currentArea->get_spOv_angularDamp();
++countCombined;
break;
case PhysicsServer::AREA_SPACE_OVERRIDE_COMBINE_REPLACE:
/// This area adds its gravity/damp values to whatever has been calculated
@ -974,32 +975,31 @@ void RigidBodyBullet::reload_space_override_modificator() {
newGravity += support_gravity;
newLinearDamp += currentArea->get_spOv_linearDamp();
newAngularDamp += currentArea->get_spOv_angularDamp();
++countCombined;
goto endAreasCycle;
stopped = true;
break;
case PhysicsServer::AREA_SPACE_OVERRIDE_REPLACE:
/// This area replaces any gravity/damp, even the default one, and
/// stops taking into account the rest of the areas.
newGravity = support_gravity;
newLinearDamp = currentArea->get_spOv_linearDamp();
newAngularDamp = currentArea->get_spOv_angularDamp();
countCombined = 1;
goto endAreasCycle;
stopped = true;
break;
case PhysicsServer::AREA_SPACE_OVERRIDE_REPLACE_COMBINE:
/// This area replaces any gravity/damp calculated so far, but keeps
/// calculating the rest of the areas, down to the default one.
newGravity = support_gravity;
newLinearDamp = currentArea->get_spOv_linearDamp();
newAngularDamp = currentArea->get_spOv_angularDamp();
countCombined = 1;
break;
}
}
endAreasCycle:
if (1 < countCombined) {
newGravity /= countCombined;
newLinearDamp /= countCombined;
newAngularDamp /= countCombined;
// Add default gravity and damping from space.
if (!stopped) {
newGravity += space->get_gravity_direction() * space->get_gravity_magnitude();
newLinearDamp += space->get_linear_damp();
newAngularDamp += space->get_angular_damp();
}
btVector3 newBtGravity;

10
modules/bullet/space_bullet.cpp
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@ -353,6 +353,8 @@ SpaceBullet::SpaceBullet() :
godotFilterCallback(NULL),
gravityDirection(0, -1, 0),
gravityMagnitude(10),
linear_damp(0.0),
angular_damp(0.0),
contactDebugCount(0),
delta_time(0.) {
@ -390,8 +392,11 @@ void SpaceBullet::set_param(PhysicsServer::AreaParameter p_param, const Variant
update_gravity();
break;
case PhysicsServer::AREA_PARAM_LINEAR_DAMP:
linear_damp = p_value;
break;
case PhysicsServer::AREA_PARAM_ANGULAR_DAMP:
break; // No damp
angular_damp = p_value;
break;
case PhysicsServer::AREA_PARAM_PRIORITY:
// Priority is always 0, the lower
break;
@ -412,8 +417,9 @@ Variant SpaceBullet::get_param(PhysicsServer::AreaParameter p_param) {
case PhysicsServer::AREA_PARAM_GRAVITY_VECTOR:
return gravityDirection;
case PhysicsServer::AREA_PARAM_LINEAR_DAMP:
return linear_damp;
case PhysicsServer::AREA_PARAM_ANGULAR_DAMP:
return 0; // No damp
return angular_damp;
case PhysicsServer::AREA_PARAM_PRIORITY:
return 0; // Priority is always 0, the lower
case PhysicsServer::AREA_PARAM_GRAVITY_IS_POINT:

6
modules/bullet/space_bullet.h
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@ -108,6 +108,9 @@ class SpaceBullet : public RIDBullet {
Vector3 gravityDirection;
real_t gravityMagnitude;
real_t linear_damp;
real_t angular_damp;
Vector<AreaBullet *> areas;
Vector<Vector3> contactDebug;
@ -177,6 +180,9 @@ public:
void update_gravity();
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);
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);

34
thirdparty/bullet/0001-old-damping-def.patch vendored Normal file
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@ -0,0 +1,34 @@
diff --git a/thirdparty/bullet/BulletDynamics/Dynamics/btRigidBody.cpp b/thirdparty/bullet/BulletDynamics/Dynamics/btRigidBody.cpp
index 9e8705b001..f1b50b39c8 100644
--- a/thirdparty/bullet/BulletDynamics/Dynamics/btRigidBody.cpp
+++ b/thirdparty/bullet/BulletDynamics/Dynamics/btRigidBody.cpp
@@ -136,8 +136,13 @@ void btRigidBody::setGravity(const btVector3& acceleration)
void btRigidBody::setDamping(btScalar lin_damping, btScalar ang_damping)
{
- m_linearDamping = btClamped(lin_damping, (btScalar)btScalar(0.0), (btScalar)btScalar(1.0));
- m_angularDamping = btClamped(ang_damping, (btScalar)btScalar(0.0), (btScalar)btScalar(1.0));
+#ifdef BT_USE_OLD_DAMPING_METHOD
+ m_linearDamping = btMax(lin_damping, btScalar(0.0));
+ m_angularDamping = btMax(ang_damping, btScalar(0.0));
+#else
+ m_linearDamping = btClamped(lin_damping, btScalar(0.0), btScalar(1.0));
+ m_angularDamping = btClamped(ang_damping, btScalar(0.0), btScalar(1.0));
+#endif
}
///applyDamping damps the velocity, using the given m_linearDamping and m_angularDamping
@@ -146,10 +151,9 @@ void btRigidBody::applyDamping(btScalar timeStep)
//On new damping: see discussion/issue report here: http://code.google.com/p/bullet/issues/detail?id=74
//todo: do some performance comparisons (but other parts of the engine are probably bottleneck anyway
-//#define USE_OLD_DAMPING_METHOD 1
-#ifdef USE_OLD_DAMPING_METHOD
- m_linearVelocity *= GEN_clamped((btScalar(1.) - timeStep * m_linearDamping), (btScalar)btScalar(0.0), (btScalar)btScalar(1.0));
- m_angularVelocity *= GEN_clamped((btScalar(1.) - timeStep * m_angularDamping), (btScalar)btScalar(0.0), (btScalar)btScalar(1.0));
+#ifdef BT_USE_OLD_DAMPING_METHOD
+ m_linearVelocity *= btMax((btScalar(1.0) - timeStep * m_linearDamping), btScalar(0.0));
+ m_angularVelocity *= btMax((btScalar(1.0) - timeStep * m_angularDamping), btScalar(0.0));
#else
m_linearVelocity *= btPow(btScalar(1) - m_linearDamping, timeStep);
m_angularVelocity *= btPow(btScalar(1) - m_angularDamping, timeStep);

16
thirdparty/bullet/BulletDynamics/Dynamics/btRigidBody.cpp vendored
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@ -136,8 +136,13 @@ void btRigidBody::setGravity(const btVector3& acceleration)
void btRigidBody::setDamping(btScalar lin_damping, btScalar ang_damping)
{
m_linearDamping = btClamped(lin_damping, (btScalar)btScalar(0.0), (btScalar)btScalar(1.0));
m_angularDamping = btClamped(ang_damping, (btScalar)btScalar(0.0), (btScalar)btScalar(1.0));
#ifdef BT_USE_OLD_DAMPING_METHOD
m_linearDamping = btMax(lin_damping, btScalar(0.0));
m_angularDamping = btMax(ang_damping, btScalar(0.0));
#else
m_linearDamping = btClamped(lin_damping, btScalar(0.0), btScalar(1.0));
m_angularDamping = btClamped(ang_damping, btScalar(0.0), btScalar(1.0));
#endif
}
///applyDamping damps the velocity, using the given m_linearDamping and m_angularDamping
@ -146,10 +151,9 @@ void btRigidBody::applyDamping(btScalar timeStep)
//On new damping: see discussion/issue report here: http://code.google.com/p/bullet/issues/detail?id=74
//todo: do some performance comparisons (but other parts of the engine are probably bottleneck anyway
//#define USE_OLD_DAMPING_METHOD 1
#ifdef USE_OLD_DAMPING_METHOD
m_linearVelocity *= GEN_clamped((btScalar(1.) - timeStep * m_linearDamping), (btScalar)btScalar(0.0), (btScalar)btScalar(1.0));
m_angularVelocity *= GEN_clamped((btScalar(1.) - timeStep * m_angularDamping), (btScalar)btScalar(0.0), (btScalar)btScalar(1.0));
#ifdef BT_USE_OLD_DAMPING_METHOD
m_linearVelocity *= btMax((btScalar(1.0) - timeStep * m_linearDamping), btScalar(0.0));
m_angularVelocity *= btMax((btScalar(1.0) - timeStep * m_angularDamping), btScalar(0.0));
#else
m_linearVelocity *= btPow(btScalar(1) - m_linearDamping, timeStep);
m_angularVelocity *= btPow(btScalar(1) - m_angularDamping, timeStep);