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kinematic cloth

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This commit is contained in:
Irlan
2018-05-18 19:26:49 -03:00
parent c949c001f4
commit 66228785fc
3 changed files with 90 additions and 44 deletions
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40
include/bounce/dynamics/cloth/spring_cloth.h
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@ -22,6 +22,7 @@
#include <bounce/common/math/mat33.h>
#include <bounce/common/template/array.h>
// Number of maximum shapes per cloth.
#define B3_CLOTH_SHAPE_CAPACITY 32
class b3StackAllocator;
@ -63,6 +64,8 @@ struct b3SpringClothDef
float32 kd;
// Mass radius
// Typically this is value is small and is intended for correcting visual artifacts when
// the cloth is colliding against a solid.
float32 r;
// Acceleration due to gravity (m/s^2)
@ -97,10 +100,12 @@ struct b3Spring
};
// Static masses have zero mass and velocity, and therefore they can't move.
// Kinematic masses are't moved by external and internal forces but can be moved by contact forces.
// Dynamic masses have non-zero mass and can move due to internal and external forces.
enum class b3MassType : u32
{
e_staticMass,
e_kinematicMass,
e_dynamicMass
};
@ -140,6 +145,9 @@ public:
// Units are m/s^2.
void SetGravity(const b3Vec3& gravity);
// Return the number of masses in this cloth.
u32 GetMassCount() const;
// Return the gravitational acceleration applied to this cloth.
const b3Vec3& GetGravity() const;
@ -152,11 +160,17 @@ public:
// Set the position of a given point mass.
// This function will have effect on the position of the point mass
// after performing a time step.
void SetPosition(u32 i, const b3Vec3& translation);
void SetPosition(u32 i, const b3Vec3& position);
// Return the position of a given point mass.
const b3Vec3& GetPosition(u32 i) const;
// Set the velocity of a given point mass.
void SetVelocity(u32 i, const b3Vec3& velocity);
// Return the velocity of a given point mass.
const b3Vec3& GetVelocity(u32 i) const;
// Apply a force to a given point mass.
void ApplyForce(u32 i, const b3Vec3& force);
@ -237,6 +251,11 @@ inline void b3SpringCloth::SetGravity(const b3Vec3& gravity)
m_gravity = gravity;
}
inline u32 b3SpringCloth::GetMassCount() const
{
return m_massCount;
}
inline b3MassType b3SpringCloth::GetType(u32 i) const
{
B3_ASSERT(i < m_massCount);
@ -246,6 +265,7 @@ inline b3MassType b3SpringCloth::GetType(u32 i) const
inline void b3SpringCloth::SetType(u32 i, b3MassType type)
{
B3_ASSERT(i < m_massCount);
if (m_types[i] == type)
{
return;
@ -276,6 +296,24 @@ inline const b3Vec3& b3SpringCloth::GetPosition(u32 i) const
return m_x[i];
}
inline void b3SpringCloth::SetVelocity(u32 i, const b3Vec3& velocity)
{
B3_ASSERT(i < m_massCount);
if (m_types[i] == b3MassType::e_staticMass)
{
return;
}
m_v[i] = velocity;
}
inline const b3Vec3& b3SpringCloth::GetVelocity(u32 i) const
{
B3_ASSERT(i < m_massCount);
return m_v[i];
}
inline void b3SpringCloth::ApplyForce(u32 i, const b3Vec3& force)
{
B3_ASSERT(i < m_massCount);

21
src/bounce/dynamics/cloth/spring_cloth.cpp
View File

@ -400,7 +400,7 @@ void b3SpringCloth::GetTension(b3Array<b3Vec3>& T) const
for (u32 i = 0; i < T.Count(); ++i)
{
if (m_types[i] == b3MassType::e_staticMass)
if (m_types[i] != b3MassType::e_dynamicMass)
{
T[i].SetZero();
}
@ -677,11 +677,26 @@ void b3SpringCloth::Draw() const
for (u32 i = 0; i < m->vertexCount; ++i)
{
b3MassContact* c = m_contacts + i;
if (m_types[i] == b3MassType::e_staticMass)
{
b3Draw_draw->DrawPoint(m_x[i], 4.0f, b3Color_white);
}
if (m_types[i] == b3MassType::e_kinematicMass)
{
b3Draw_draw->DrawPoint(m_x[i], 4.0f, b3Color_blue);
}
if (m_types[i] == b3MassType::e_dynamicMass)
{
b3Draw_draw->DrawPoint(m_x[i], 4.0f, b3Color_green);
}
b3MassContact* c = m_contacts + i;
if (c->lockN)
{
b3Draw_draw->DrawPoint(m_x[i], 6.0f, b3Color_green);
b3Draw_draw->DrawPoint(m_x[i], 6.0f, b3Color_yellow);
b3Draw_draw->DrawSegment(m_x[i], m_x[i] + c->n, b3Color_yellow);

73
src/bounce/dynamics/cloth/spring_solver.cpp
View File

@ -104,7 +104,10 @@ void b3SpringSolver::Solve(b3DenseVec3& f)
// Update state
for (u32 i = 0; i < m_massCount; ++i)
{
m_v[i] += x[i];
if (m_types[i] == b3MassType::e_dynamicMass)
{
m_v[i] += x[i];
}
// dx = h * (v0 + dv) + y = h * v1 + y
m_x[i] += m_h * m_v[i] + m_y[i];
@ -365,54 +368,44 @@ void b3SpringSolver::Compute_S(b3Mat33* out)
{
for (u32 i = 0; i < m_massCount; ++i)
{
switch (m_types[i])
{
case b3MassType::e_staticMass:
out[i].SetIdentity();
if (m_types[i] == b3MassType::e_staticMass)
{
out[i].SetZero();
break;
continue;
}
case b3MassType::e_dynamicMass:
b3MassContact* c = m_contacts + i;
if (c->lockN == true)
{
if (m_contacts[i].lockN == true)
b3Vec3 n = c->n;
b3Mat33 S = b3Mat33_identity - b3Outer(n, n);
if (c->lockT1 == true && c->lockT2 == true)
{
b3Vec3 n = m_contacts[i].n;
b3Mat33 S = b3Mat33_identity - b3Outer(n, n);
if (m_contacts[i].lockT1 == true && m_contacts[i].lockT2 == true)
S.SetZero();
}
else
{
if (c->lockT1 == true)
{
S.SetZero();
}
else
{
if (m_contacts[i].lockT1 == true)
{
b3Vec3 t1 = m_contacts[i].t1;
b3Vec3 t1 = c->t1;
S -= b3Outer(t1, t1);
}
if (m_contacts[i].lockT2 == true)
{
b3Vec3 t2 = m_contacts[i].t2;
S -= b3Outer(t2, t2);
}
S -= b3Outer(t1, t1);
}
out[i] = S;
break;
if (c->lockT2 == true)
{
b3Vec3 t2 = c->t2;
S -= b3Outer(t2, t2);
}
}
out[i].SetIdentity();
break;
}
default:
{
B3_ASSERT(false);
break;
}
out[i] = S;
}
}
}
@ -461,7 +454,7 @@ void b3SpringSolver::Solve(b3DenseVec3& dv, b3DenseVec3& e, u32& iterations, con
// delta0 = dot(filter(b), P * filter(b))
b3DenseVec3 S_b(m_massCount);
b3Filter(S_b, b, S, m_massCount);
// P * filter(b)
b3DenseVec3 P_S_b(m_massCount);
for (u32 i = 0; i < m_massCount; ++i)
@ -529,7 +522,7 @@ void b3SpringSolver::Solve(b3DenseVec3& dv, b3DenseVec3& e, u32& iterations, con
// deltaNew = dot(r, s)
deltaNew = b3Dot(r, s);
B3_ASSERT(b3IsValid(deltaNew));
// beta = deltaNew / deltaOld
float32 beta = deltaNew / deltaOld;