void BVHN<N>::clearBarrier(NodeRef& node)
{
if (node.isBarrier())
node.clearBarrier();
else if (!node.isLeaf()) {
Node* n = node.node();
for (size_t c=0; c<N; c++)
clearBarrier(n->child(c));
}
}
void BVHN<N>::clearBarrier(NodeRef& node)
{
if (node.isBarrier())
node.clearBarrier();
else if (!node.isLeaf()) {
BaseNode* n = node.baseNode(BVH_FLAG_ALIGNED_NODE); // FIXME: flags should be stored in BVH
for (size_t c=0; c<N; c++)
clearBarrier(n->child(c));
}
}
typename BVHN<N>::NodeRef BVHN<N>::layoutLargeNodesRecursion(NodeRef& node, FastAllocator::ThreadLocal& allocator)
{
if (node.isBarrier()) {
node.clearBarrier();
return node;
}
else if (node.isNode())
{
Node* oldnode = node.node();
Node* newnode = (BVHN::Node*) allocator.malloc(sizeof(BVHN::Node),byteNodeAlignment);
*newnode = *oldnode;
for (size_t c=0; c<N; c++)
newnode->child(c) = layoutLargeNodesRecursion(oldnode->child(c),allocator);
return encodeNode(newnode);
}
else return node;
}
BVH4::NodeRef BVH4::layoutLargeNodesRecursion(NodeRef& node)
{
if (node.isBarrier()) {
node.clearBarrier();
return node;
}
else if (node.isNode())
{
Node* oldnode = node.node();
Node* newnode = (BVH4::Node*) alloc.threadLocal2()->alloc0.malloc(sizeof(BVH4::Node)); // FIXME: optimize access to threadLocal2
*newnode = *oldnode;
for (size_t c=0; c<BVH4::N; c++)
newnode->child(c) = layoutLargeNodesRecursion(oldnode->child(c));
return encodeNode(newnode);
}
else return node;
}
size_t BVHNRotate<4>::rotate(NodeRef parentRef, size_t depth)
{
/*! nothing to rotate if we reached a leaf node. */
if (parentRef.isBarrier()) return 0;
if (parentRef.isLeaf()) return 0;
Node* parent = parentRef.node();
/*! rotate all children first */
vint4 cdepth;
for (size_t c=0; c<4; c++)
cdepth[c] = (int)rotate(parent->child(c),depth+1);
/* compute current areas of all children */
vfloat4 sizeX = parent->upper_x-parent->lower_x;
vfloat4 sizeY = parent->upper_y-parent->lower_y;
vfloat4 sizeZ = parent->upper_z-parent->lower_z;
vfloat4 childArea = sizeX*(sizeY + sizeZ) + sizeY*sizeZ;
/*! get node bounds */
BBox<vfloat4> child1_0,child1_1,child1_2,child1_3;
parent->bounds(child1_0,child1_1,child1_2,child1_3);
/*! Find best rotation. We pick a first child (child1) and a sub-child
(child2child) of a different second child (child2), and swap child1
and child2child. We perform the best such swap. */
float bestArea = 0;
size_t bestChild1 = -1, bestChild2 = -1, bestChild2Child = -1;
for (size_t c2=0; c2<4; c2++)
{
/*! ignore leaf nodes as we cannot descent into them */
if (parent->child(c2).isBarrier()) continue;
if (parent->child(c2).isLeaf()) continue;
Node* child2 = parent->child(c2).node();
/*! transpose child bounds */
BBox<vfloat4> child2c0,child2c1,child2c2,child2c3;
child2->bounds(child2c0,child2c1,child2c2,child2c3);
/*! put child1_0 at each child2 position */
float cost00 = halfArea3f(merge(child1_0,child2c1,child2c2,child2c3));
float cost01 = halfArea3f(merge(child2c0,child1_0,child2c2,child2c3));
float cost02 = halfArea3f(merge(child2c0,child2c1,child1_0,child2c3));
float cost03 = halfArea3f(merge(child2c0,child2c1,child2c2,child1_0));
vfloat4 cost0 = vfloat4(cost00,cost01,cost02,cost03);
vfloat4 min0 = vreduce_min(cost0);
int pos0 = (int)__bsf(movemask(min0 == cost0));
/*! put child1_1 at each child2 position */
float cost10 = halfArea3f(merge(child1_1,child2c1,child2c2,child2c3));
float cost11 = halfArea3f(merge(child2c0,child1_1,child2c2,child2c3));
float cost12 = halfArea3f(merge(child2c0,child2c1,child1_1,child2c3));
float cost13 = halfArea3f(merge(child2c0,child2c1,child2c2,child1_1));
vfloat4 cost1 = vfloat4(cost10,cost11,cost12,cost13);
vfloat4 min1 = vreduce_min(cost1);
int pos1 = (int)__bsf(movemask(min1 == cost1));
/*! put child1_2 at each child2 position */
float cost20 = halfArea3f(merge(child1_2,child2c1,child2c2,child2c3));
float cost21 = halfArea3f(merge(child2c0,child1_2,child2c2,child2c3));
float cost22 = halfArea3f(merge(child2c0,child2c1,child1_2,child2c3));
float cost23 = halfArea3f(merge(child2c0,child2c1,child2c2,child1_2));
vfloat4 cost2 = vfloat4(cost20,cost21,cost22,cost23);
vfloat4 min2 = vreduce_min(cost2);
int pos2 = (int)__bsf(movemask(min2 == cost2));
/*! put child1_3 at each child2 position */
float cost30 = halfArea3f(merge(child1_3,child2c1,child2c2,child2c3));
float cost31 = halfArea3f(merge(child2c0,child1_3,child2c2,child2c3));
float cost32 = halfArea3f(merge(child2c0,child2c1,child1_3,child2c3));
float cost33 = halfArea3f(merge(child2c0,child2c1,child2c2,child1_3));
vfloat4 cost3 = vfloat4(cost30,cost31,cost32,cost33);
vfloat4 min3 = vreduce_min(cost3);
int pos3 = (int)__bsf(movemask(min3 == cost3));
/*! find best other child */
vfloat4 area0123 = vfloat4(extract<0>(min0),extract<0>(min1),extract<0>(min2),extract<0>(min3)) - vfloat4(childArea[c2]);
int pos[4] = { pos0,pos1,pos2,pos3 };
const size_t mbd = BVH4::maxBuildDepth;
vbool4 valid = vint4(int(depth+1))+cdepth <= vint4(mbd); // only select swaps that fulfill depth constraints
valid &= vint4(c2) != vint4(step);
if (none(valid)) continue;
size_t c1 = select_min(valid,area0123);
float area = area0123[c1];
if (c1 == c2) continue; // can happen if bounds are NANs
/*! accept a swap when it reduces cost and is not swapping a node with itself */
if (area < bestArea) {
bestArea = area;
bestChild1 = c1;
bestChild2 = c2;
bestChild2Child = pos[c1];
}
}
/*! if we did not find a swap that improves the SAH then do nothing */
if (bestChild1 == size_t(-1)) return 1+reduce_max(cdepth);
/*! perform the best found tree rotation */
Node* child2 = parent->child(bestChild2).node();
BVH4::swap(parent,bestChild1,child2,bestChild2Child);
parent->set(bestChild2,child2->bounds());
BVH4::compact(parent);
BVH4::compact(child2);
/*! This returned depth is conservative as the child that was
* pulled up in the tree could have been on the critical path. */
cdepth[bestChild1]++; // bestChild1 was pushed down one level
return 1+reduce_max(cdepth);
}
