Game Physics Engine Development, 2nd Edition

314 Chapter 13 Generating Contacts

)

{

// Make sure we have contacts.

if (data->contactsLeft <= 0) return 0;

// Check for intersection.

if (!IntersectionTests::boxAndHalfSpace(box, plane))

{

return 0;

}

// We have an intersection, so find the intersection points. We can

make

// do with only checking vertices. If the box is resting on a plane

// or on an edge, it will be reported as four or two contact points.

// Go through each combination of + and - for each half-size.

static real mults[8][3] = {{1,1,1},{-1,1,1},{1,-1,1},{-1,-1,1},

{1,1,-1},{-1,1,-1},{1,-1,-1},{-1,-1,-1}};

Contact* contact = data->contacts;

unsigned contactsUsed = 0;

for (unsigned i = 0; i