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optimization, friction force

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This commit is contained in:
Irlan 2018-06-28 19:52:11 -03:00
parent 2485f92ba4
commit 3d3d9f0910
7 changed files with 139 additions and 71 deletions
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2
include/bounce/dynamics/cloth/cloth_solver.h
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@ -26,7 +26,7 @@ class b3StackAllocator;
class b3Particle;
class b3Force;
struct b3BodyContact;
class b3BodyContact;
struct b3DenseVec3;
struct b3DiagMat33;

1
include/bounce/dynamics/cloth/force.h
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@ -29,6 +29,7 @@ class b3Particle;
// Force types
enum b3ForceType
{
e_frictionForce,
e_springForce,
};

36
include/bounce/dynamics/cloth/particle.h
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@ -21,6 +21,7 @@
#include <bounce/common/math/transform.h>
#include <bounce/common/template/list.h>
#include <bounce/dynamics/cloth/force.h>
class b3Shape;
class b3Cloth;
@ -57,15 +58,43 @@ struct b3ParticleDef
void* userData;
};
// A contact between a particle and a solid
struct b3BodyContact
class b3FrictionForce : public b3Force
{
public:
b3FrictionForce() { }
~b3FrictionForce() { }
void Apply(const b3ClothSolverData* data);
b3Particle* m_p;
float32 m_kd;
};
// A contact between a particle and a solid
class b3BodyContact
{
public:
b3BodyContact()
{
}
~b3BodyContact()
{
}
b3Particle* p1;
b3Shape* s2;
float32 s;
bool f1_active, f2_active;
b3FrictionForce f1, f2;
bool n_active, t1_active, t2_active;
b3Vec3 n, t1, t2;
float32 Fn, Ft1, Ft2;
bool n_active, t1_active, t2_active;
};
// A cloth particle.
@ -115,6 +144,7 @@ private:
friend class b3ClothSolver;
friend class b3Force;
friend class b3SpringForce;
friend class b3FrictionForce;
b3Particle(const b3ParticleDef& def, b3Cloth* cloth);
~b3Particle();

65
src/bounce/dynamics/cloth/cloth.cpp
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@ -33,8 +33,6 @@
#define B3_CLOTH_BENDING 0
#define B3_CLOTH_FRICTION 1
static B3_FORCE_INLINE u32 b3NextIndex(u32 i)
{
return i + 1 < 3 ? i + 1 : 0;
@ -217,7 +215,7 @@ b3Cloth::b3Cloth(const b3ClothDef& def, b3World* world) : m_particleBlocks(sizeo
b3SpringForceDef fd;
fd.Initialize(p1, p2, def.bending, def.damping);
CreateForce(fd);
}
@ -236,7 +234,7 @@ b3Cloth::b3Cloth(const b3ClothDef& def, b3World* world) : m_particleBlocks(sizeo
b3SpringForceDef fd;
fd.Initialize(p1, p2, def.structural, def.damping);
CreateForce(fd);
}
}
@ -485,6 +483,8 @@ void b3Cloth::UpdateContacts()
b3BodyContact c0 = *c;
// Create a new contact
c->f1_active = false;
c->f2_active = false;
c->n_active = false;
c->t1_active = false;
c->t2_active = false;
@ -565,8 +565,6 @@ void b3Cloth::UpdateContacts()
continue;
}
#if B3_CLOTH_FRICTION == 1
// A friction force requires an associated normal force.
if (c0.n_active == false)
{
@ -577,6 +575,7 @@ void b3Cloth::UpdateContacts()
b3Vec3 n = c->n;
float32 u = s->GetFriction();
float32 normalForce = c0.Fn;
float32 maxFrictionForce = u * normalForce;
// Relative velocity
b3Vec3 dv = p->m_velocity;
@ -593,12 +592,6 @@ void b3Cloth::UpdateContacts()
c->t1 = t1;
c->t2 = t2;
}
else
{
c->t1_active = true;
c->t2_active = true;
continue;
}
b3Vec3 ts[2];
ts[0] = c->t1;
@ -616,6 +609,18 @@ void b3Cloth::UpdateContacts()
Ft0[0] = c0.Ft1;
Ft0[1] = c0.Ft2;
bool f_active[2];
f_active[0] = c->f1_active;
f_active[1] = c->f2_active;
bool f_active0[2];
f_active0[0] = c0.f1_active;
f_active0[1] = c0.f2_active;
b3FrictionForce* sf[2];
sf[0] = &c->f1;
sf[1] = &c->f2;
for (u32 k = 0; k < 2; ++k)
{
b3Vec3 t = ts[k];
@ -628,27 +633,33 @@ void b3Cloth::UpdateContacts()
// Lock particle on surface
t_active[k] = true;
}
if (t_active0[k] == true && t_active[k] == true)
{
// The contact persists
float32 maxForce = u * normalForce;
float32 frictionForce = Ft0[k];
if (Ft0[k] * Ft0[k] > maxForce * maxForce)
// Dynamic friction
if (frictionForce * frictionForce > maxFrictionForce * maxFrictionForce)
{
// Unlock particle off surface
t_active[k] = false;
//t_active[k] = false;
// Apply dynamic friction
//f_active[k] = true;
//sf[k]->m_type = e_frictionForce;
//sf[k]->m_p = p;
//sf[k]->m_kd = 100.0f;
}
}
}
c->f1_active = f_active[0];
c->f2_active = f_active[1];
c->t1_active = t_active[0];
c->t2_active = t_active[1];
#endif
}
}
void b3Cloth::Solve(float32 dt, const b3Vec3& gravity)
@ -659,7 +670,7 @@ void b3Cloth::Solve(float32 dt, const b3Vec3& gravity)
b3ClothSolverDef solverDef;
solverDef.stack = &m_world->m_stackAllocator;
solverDef.particleCapacity = m_particleList.m_count;
solverDef.forceCapacity = m_forceList.m_count;
solverDef.forceCapacity = m_forceList.m_count + (2 * m_particleList.m_count);
solverDef.contactCapacity = m_particleList.m_count;
b3ClothSolver solver(solverDef);
@ -676,6 +687,16 @@ void b3Cloth::Solve(float32 dt, const b3Vec3& gravity)
for (b3Particle* p = m_particleList.m_head; p; p = p->m_next)
{
if (p->m_contact.f1_active)
{
solver.Add(&p->m_contact.f1);
}
if (p->m_contact.f2_active)
{
solver.Add(&p->m_contact.f2);
}
if (p->m_contact.n_active)
{
solver.Add(&p->m_contact);

7
src/bounce/dynamics/cloth/cloth_solver.cpp
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@ -268,11 +268,8 @@ void b3ClothSolver::Solve(float32 dt, const b3Vec3& gravity)
{
m_particles[i]->m_position = sx[i];
m_particles[i]->m_velocity = sv[i];
}
// Cache x to improve convergence
for (u32 i = 0; i < m_particleCount; ++i)
{
// Cache x to improve convergence
m_particles[i]->m_x = x[i];
}

21
src/bounce/dynamics/cloth/particle.cpp
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@ -18,6 +18,25 @@
#include <bounce/dynamics/cloth/particle.h>
#include <bounce/dynamics/cloth/cloth.h>
#include <bounce/dynamics/cloth/cloth_solver.h>
#include <bounce/dynamics/cloth/dense_vec3.h>
#include <bounce/dynamics/cloth/sparse_sym_mat33.h>
void b3FrictionForce::Apply(const b3ClothSolverData* data)
{
b3DenseVec3& v = *data->v;
b3DenseVec3& f = *data->f;
b3SparseSymMat33& dfdv = *data->dfdv;
u32 i = m_p->m_solverId;
f[i] += -m_kd * v[i];
b3Mat33 I; I.SetIdentity();
b3Mat33 Jv = -m_kd * I;
dfdv(i, i) += Jv;
}
b3Particle::b3Particle(const b3ParticleDef& def, b3Cloth* cloth)
{
@ -34,6 +53,8 @@ b3Particle::b3Particle(const b3ParticleDef& def, b3Cloth* cloth)
m_x.SetZero();
m_vertex = ~0;
m_contact.f1_active = false;
m_contact.f2_active = false;
m_contact.n_active = false;
m_contact.t1_active = false;
m_contact.t2_active = false;

78
src/bounce/dynamics/cloth/spring_force.cpp
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@ -69,54 +69,52 @@ void b3SpringForce::Apply(const b3ClothSolverData* data)
b3Mat33 I; I.SetIdentity();
b3Vec3 dx = x1 - x2;
m_f.SetZero();
float32 L = b3Length(dx);
b3Mat33 Jx;
if (L >= m_L0)
if (m_ks > 0.0f)
{
b3Vec3 n = dx / L;
b3Vec3 dx = x1 - x2;
// Tension
m_f = -m_ks * (L - m_L0) * n;
float32 L = b3Length(dx);
// Jacobian
Jx = -m_ks * (b3Outer(dx, dx) + (1.0f - m_L0 / L) * (I - b3Outer(dx, dx)));
}
else
{
m_f.SetZero();
Jx.SetZero();
if (L >= m_L0)
{
b3Vec3 n = dx / L;
// Apply tension
m_f += -m_ks * (L - m_L0) * n;
// Jacobian
b3Mat33 Jx11 = -m_ks * (b3Outer(dx, dx) + (1.0f - m_L0 / L) * (I - b3Outer(dx, dx)));
b3Mat33 Jx12 = -Jx11;
//b3Mat33 Jx21 = Jx12;
b3Mat33 Jx22 = Jx11;
dfdx(i1, i1) += Jx11;
dfdx(i1, i2) += Jx12;
//dfdx(i2, i1) += Jx21;
dfdx(i2, i2) += Jx22;
}
}
// Damping
b3Vec3 dv = v1 - v2;
if (m_kd > 0.0f)
{
// Apply damping
b3Vec3 dv = v1 - v2;
m_f += -m_kd * dv;
b3Mat33 Jv = -m_kd * I;
m_f += -m_kd * dv;
b3Mat33 Jv11 = -m_kd * I;
b3Mat33 Jv12 = -Jv11;
//b3Mat33 Jv21 = Jv12;
b3Mat33 Jv22 = Jv11;
dfdv(i1, i1) += Jv11;
dfdv(i1, i2) += Jv12;
//dfdv(i2, i1) += Jv21;
dfdv(i2, i2) += Jv22;
}
f[i1] += m_f;
f[i2] -= m_f;
b3Mat33 Jx11 = Jx;
b3Mat33 Jx12 = -Jx11;
//b3Mat33 Jx21 = Jx12;
b3Mat33 Jx22 = Jx11;
dfdx(i1, i1) += Jx11;
dfdx(i1, i2) += Jx12;
//dfdx(i2, i1) += Jx21;
dfdx(i2, i2) += Jx22;
b3Mat33 Jv11 = Jv;
b3Mat33 Jv12 = -Jv11;
//b3Mat33 Jv21 = Jv12;
b3Mat33 Jv22 = Jv11;
dfdv(i1, i1) += Jv11;
dfdv(i1, i2) += Jv12;
//dfdv(i2, i1) += Jv21;
dfdv(i2, i2) += Jv22;
}