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add comments, correct typo, correct energy computation

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This commit is contained in:
Irlan 2018-04-03 15:02:00 -03:00
parent 676fe352a6
commit 6e0e269f68
1 changed files with 26 additions and 23 deletions
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49
include/bounce/dynamics/cloth/spring_cloth.h
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@ -50,7 +50,7 @@ struct b3SpringClothDef
// Cloth mesh
b3Mesh* mesh;
// Cloth density in kg/m^2
// Cloth density in kg/m^3
float32 density;
// Streching stiffness
@ -130,55 +130,59 @@ public:
b3SpringCloth();
~b3SpringCloth();
//
// Initialize this cloth from a definition.
void Initialize(const b3SpringClothDef& def);
//
// Return the cloth mesh used to initialize this cloth.
b3Mesh* GetMesh() const;
//
// Set the gravitational force applied to this cloth.
// This force is applied at each time step.
void SetGravity(const b3Vec3& gravity);
//
// Return the gravitational force applied to this cloth.
const b3Vec3& GetGravity() const;
//
// Set the type of a given point mass.
void SetType(u32 i, b3MassType type);
//
// Return the type of a given point mass.
b3MassType GetType(u32 i) const;
// Note, the position will be changed only after performing a time step.
// 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);
//
// Return the position of a given point mass.
const b3Vec3& GetPosition(u32 i) const;
//
// Apply a force to a given point mass.
void ApplyForce(u32 i, const b3Vec3& force);
//
float32 GetKineticEnergy() const;
// Return the kinetic (or dynamic) energy in this system.
float32 GetEnergy() const;
//
// Add a shape to the list of shapes in this cloth.
// The cloth will be able to respond to collisions with each shape in the list of shapes.
void AddShape(b3Shape* shape);
//
// Return the number of shapes added to this cloth.
u32 GetShapeCount() const;
//
// Return the list of shapes added to this cloth.
b3Shape** GetShapes();
//
// Return the statistics of the last time step.
const b3SpringClothStep& GetStep() const;
//
// Perform a time step (marches time forward).
void Step(float32 dt);
//
// Set the positions of the mesh vertices to the positions of their associated point masses.
void Apply() const;
//
// Debug draw the cloth mesh.
void Draw(b3Draw* draw) const;
protected:
friend class b3SpringSolver;
@ -280,15 +284,14 @@ inline void b3SpringCloth::ApplyForce(u32 i, const b3Vec3& force)
m_f[i] += force;
}
inline float32 b3SpringCloth::GetKineticEnergy() const
inline float32 b3SpringCloth::GetEnergy() const
{
float32 E = 0.0f;
for (u32 i = 0; i < m_massCount; ++i)
{
b3Vec3 P = m_m[i] * m_v[i];
E += b3Dot(P, m_v[i]);
E += m_m[i] * b3Dot(m_v[i], m_v[i]);
}
return E;
return 0.5f * E;
}
inline u32 b3SpringCloth::GetShapeCount() const