Game Physics Engine Development, 2nd Edition

7.4 Collision-Like Things 141

virtual unsigned addContact(ParticleContact *contact,

unsigned limit) const;

};

Excerpt from file src/plinks.cpp

unsigned ParticleRod::addContact(ParticleContact *contact,

unsigned limit) const

{

// Find the length of the rod.

real currentLen = currentLength();

// Check if we’re overextended.

if (currentLen == length)

{

return 0;

}

// Otherwise, return the contact.

contact->particle[0] = particle[0];

contact->particle[1] = particle[1];

// Calculate the normal.

Vector3 normal =

particle[1]->getPosition() - particle[0]->getPosition();

normal.normalize();

// The contact normal depends on whether we’re extending or

compressing.

if (currentLen ...