// TODO this function needs more commenting.
static void
processContactComponents(cpSpace *space, cpFloat dt)
{
cpArray *bodies = space->bodies;
cpArray *newBodies = cpArrayNew(bodies->num);
cpArray *rogueBodies = cpArrayNew(16);
cpArray *arbiters = space->arbiters;
cpArray *constraints = space->constraints;
cpArray *components = cpArrayNew(bodies->num/8);
cpFloat dv = space->idleSpeedThreshold;
cpFloat dvsq = (dv ? dv*dv : cpvdot(space->gravity, space->gravity)*dt*dt);
// update idling
for(int i=0; i<bodies->num; i++){
cpBody *body = (cpBody*)bodies->arr[i];
cpFloat thresh = (dvsq ? body->m*dvsq : 0.0f);
body->node.idleTime = (cpBodyKineticEnergy(body) > thresh ? 0.0f : body->node.idleTime + dt);
}
// iterate graph edges and build forests
for(int i=0; i<arbiters->num; i++){
cpArbiter *arb = (cpArbiter*)arbiters->arr[i];
mergeBodies(space, components, rogueBodies, arb->private_a->body, arb->private_b->body);
}
for(int j=0; j<constraints->num; j++){
cpConstraint *constraint = (cpConstraint *)constraints->arr[j];
mergeBodies(space, components, rogueBodies, constraint->a, constraint->b);
}
// iterate bodies and add them to their components
for(int i=0; i<bodies->num; i++)
addToComponent((cpBody*)bodies->arr[i], components);
for(int i=0; i<rogueBodies->num; i++)
addToComponent((cpBody*)rogueBodies->arr[i], components);
// iterate components, copy or deactivate
for(int i=0; i<components->num; i++){
cpBody *root = (cpBody*)components->arr[i];
if(componentActive(root, space->sleepTimeThreshold)){
cpBody *body = root, *next;
do {
next = body->node.next;
if(!cpBodyIsRogue(body)) cpArrayPush(newBodies, body);
body->node.next = NULL;
body->node.parent = NULL;
body->node.rank = 0;
} while((body = next) != root);
} else {
cpBody *body = root, *next;
do {
next = body->node.next;
for(cpShape *shape = body->shapesList; shape; shape = shape->next){
removeShapeRaw(shape, space->activeShapes);
addShapeRaw(shape, space->staticShapes);
}
} while((body = next) != root);
cpArrayPush(space->sleepingComponents, root);
}
}
space->bodies = newBodies;
cpArrayFree(bodies);
cpArrayFree(rogueBodies);
cpArrayFree(components);
}
cpFloat Body::kineticEnergy()
{
return cpBodyKineticEnergy(body);
}
