void kdtreebenthin::draw<1>(scene& scene, ray4* r, hit4* hit4)
{
unsigned int signx = movemask(r->D().x());
unsigned int signy = movemask(r->D().y());
unsigned int signz = movemask(r->D().z());
//If the traversal direction is not same for all rays we
// do a single ray traversal
if (((signx - 1) < 14) // sign of x is 0xF or 0
|| ((signy - 1) < 14) // sign of y is 0xF or 0
|| ((signz - 1) < 14)) { // sign of z is 0xF or 0
hit hit[4];
for (int i = 0; i < 4; ++i) {
vec3f d(r->D().x()[i], r->D().y()[i], r->D().z()[i]);
ray ray(r->O(), d);
hit[i].prim = -1;
draw(scene, ray, hit[i]);
}
hit4->prim = ssei(hit[0].prim, hit[1].prim, hit[2].prim, hit[3].prim);
hit4->u = ssef(hit[0].u, hit[1].u, hit[2].u, hit[3].u);
hit4->v = ssef(hit[0].v, hit[1].v, hit[2].v, hit[3].v);
return;
}
ssef tnear, tfar;
_boundingBox.clip(*r, tnear, tfar);
if (movemask(tnear >= tfar) == 0xF)
return;
const unsigned int dir[3][2] = {
{ signx & 1 , 1 - (signx & 1) },
{ signy & 1 , 1 - (signy & 1) },
{ signz & 1 , 1 - (signz & 1) } };
ssef far[MAX_STACK_SIZE];
ssef near[MAX_STACK_SIZE];
int nodes[MAX_STACK_SIZE];
//push dummyNode onto stack which will cause us to exit
nodes[0] = 0;
far[0] = BPRAY_INF;
uint32_t stackptr = 1;
kdnode* currNode = _nodes + 1;
int activemask = 0xF;
#if MAILBOX
static uint64_t rayid = 0;
__sync_add_and_fetch(&rayid, 1);
#endif
while (true) {
if (!currNode->isLeaf()) {
const int axis = currNode->getAxis();
const int front = currNode->getLeft() + dir[axis][0];
const int back = currNode->getLeft() + dir[axis][1];
const ssef dist = currNode->getSplit() - r->O()[axis];
const ssef t = dist * r->rcpD()[axis];
currNode = _nodes + back;
if (!(movemask(tnear <= t) & activemask)) continue;
currNode = _nodes + front;
if (!(movemask(tfar >= t) & activemask)) continue;
nodes[stackptr] = back;
near[stackptr] = max(tnear, t);
far[stackptr] = tfar;
tfar = min(tfar, t);
activemask &= movemask(tnear <= tfar);
++stackptr;
} else {
int primidx = currNode->getPrimitiveOffset();
int primcount = currNode->getNumPrims();
for (int i = 0; i != primcount; ++i) {
int t = _prims[primidx + i];
//prefetch
int t2 = _prims[primidx + i + 1];
_mm_prefetch((char*)&scene._accels[t2], _MM_HINT_T0);
#if MAILBOX
//mailboxing
if (mbox.find(scene, rayid, t)) continue;
#endif
scene.intersect(t, *r, *hit4);
#if MAILBOX
mbox.add(scene, rayid, t);
#endif
}
if (movemask(tfar < r->tfar) == 0) return;
--stackptr;
currNode = nodes[stackptr] + _nodes;
tfar = far[stackptr];
tnear = near[stackptr];
activemask = movemask(tnear <= tfar);
}
}
}
void kdtree::draw(scene& scene, ray& ray, hit& hit)
{
float tentry, texit;
if (!_boundingBox.intersect(ray, tentry, texit))
return;
ray.tfar = texit;
if (tentry < 0.f) tentry = 0.f;
stackitem stack[MAX_STACK_SIZE];
//push dummy element
stack[0].node = 0;
stack[0].texit = BPRAY_INF;
uint32_t stackptr = 1;
kdnode* currNode = _nodes + 1;
static uint64_t rayid = 0;
++rayid;
while (true) {
if (!currNode->isLeaf()) {
int axis = currNode->getAxis();
float dist = currNode->getSplit() - ray.O()[axis];
int left = currNode->getLeft();
if (dist <= tentry * ray.D()[axis]) { // right node traversed first
if (dist >= texit * ray.D()[axis]) {
stack[stackptr].node = left;
stack[stackptr].texit = texit;
++stackptr;
texit = dist * ray.rcpD()[axis];
}
currNode = _nodes + left + 1;
}
else { //left node traversed first
if (dist <= texit * ray.D()[axis]) { // exit in right
stack[stackptr].node = left + 1;
stack[stackptr].texit = texit;
++stackptr;
texit = dist * ray.rcpD()[axis];
}
currNode = _nodes + left;
}
}
else {
int primidx = currNode->getPrimitiveOffset();
int primcount = currNode->getNumPrims();
for (int i = 0; i != primcount; ++i) {
int t = _prims[primidx + i];
//prefetch
int t2 = _prims[primidx + i + 1];
_mm_prefetch((char*)&scene._accels[t2], _MM_HINT_T0);
//mailboxing
if (mbox.find(scene, rayid, t)) continue;
scene.intersect(t, ray, hit);
mbox.add(scene, rayid, t);
}
if (ray.tfar < texit) return;
--stackptr;
tentry = texit;
currNode = stack[stackptr].node + _nodes;
texit = stack[stackptr].texit;
}
}
}