bool BVH4BuilderFast::splitParallel(BuildRecord ¤t, BuildRecord &leftChild, BuildRecord &rightChild, const size_t threadID, const size_t numThreads)
{
const unsigned int items = current.end - current.begin;
assert(items >= BUILD_RECORD_SPLIT_THRESHOLD);
/* mark as leaf if leaf threshold reached */
if (items <= QBVH_BUILDER_LEAF_ITEM_THRESHOLD) {
current.createLeaf();
return false;
}
/* use primitive array temporarily for parallel splits */
PrimRef* tmp = (PrimRef*) primAllocator.base();
/* parallel binning of centroids */
g_state->parallelBinner.bin(current,prims,tmp,threadID,numThreads);
/* find best split */
Split split;
g_state->parallelBinner.best(split);
/* if we cannot find a valid split, enforce an arbitrary split */
if (unlikely(split.pos == -1)) split_fallback(prims,current,leftChild,rightChild);
/* parallel partitioning of items */
else g_state->parallelBinner.partition(tmp,prims,split,leftChild,rightChild,threadID,numThreads);
if (leftChild.items() <= QBVH_BUILDER_LEAF_ITEM_THRESHOLD) leftChild.createLeaf();
if (rightChild.items() <= QBVH_BUILDER_LEAF_ITEM_THRESHOLD) rightChild.createLeaf();
return true;
}
bool BVH4BuilderFast::splitSequential(BuildRecord& current, BuildRecord& leftChild, BuildRecord& rightChild)
{
/* mark as leaf if leaf threshold reached */
if (current.items() <= QBVH_BUILDER_LEAF_ITEM_THRESHOLD) {
current.createLeaf();
return false;
}
/* calculate binning function */
Mapping<16> mapping(current.bounds);
/* binning of centroids */
Binner<16> binner;
binner.bin(prims,current.begin,current.end,mapping);
/* find best split */
Split split;
binner.best(split,mapping);
/* if we cannot find a valid split, enforce an arbitrary split */
if (unlikely(split.pos == -1)) split_fallback(prims,current,leftChild,rightChild);
/* partitioning of items */
else binner.partition(prims, current.begin, current.end, split, mapping, leftChild, rightChild);
if (leftChild.items() <= QBVH_BUILDER_LEAF_ITEM_THRESHOLD) leftChild.createLeaf();
if (rightChild.items() <= QBVH_BUILDER_LEAF_ITEM_THRESHOLD) rightChild.createLeaf();
return true;
}
__forceinline void BVH4BuilderTopLevel::split(BuildRecord& current, BuildRecord& left, BuildRecord& right, const size_t mode, const size_t threadID, const size_t numThreads)
{
if (mode == BUILD_TOP_LEVEL && current.items() >= BUILD_RECORD_SPLIT_THRESHOLD)
return split_parallel(current,left,right,threadID,numThreads);
else
return split_sequential(current,left,right);
}
void BVH4BuilderFast::createTriangle4vLeaf(const BVH4BuilderFast* This, BuildRecord& current, Allocator& leafAlloc, size_t threadID)
{
size_t items = current.items();
size_t start = current.begin;
assert(items<=4);
/* allocate leaf node */
Triangle4v* accel = (Triangle4v*) leafAlloc.malloc(sizeof(Triangle4v));
*(NodeRef*)current.parentNode = This->bvh->encodeLeaf((char*)accel,1);
ssei vgeomID = -1, vprimID = -1, vmask = -1;
sse3f v0 = zero, v1 = zero, v2 = zero;
for (size_t i=0; i<items; i++)
{
const size_t geomID = This->prims[start+i].geomID();
const size_t primID = This->prims[start+i].primID();
const TriangleMesh* __restrict__ const mesh = This->scene->getTriangleMesh(geomID);
const TriangleMesh::Triangle& tri = mesh->triangle(primID);
const Vec3fa& p0 = mesh->vertex(tri.v[0]);
const Vec3fa& p1 = mesh->vertex(tri.v[1]);
const Vec3fa& p2 = mesh->vertex(tri.v[2]);
vgeomID [i] = geomID;
vprimID [i] = primID;
vmask [i] = mesh->mask;
v0.x[i] = p0.x; v0.y[i] = p0.y; v0.z[i] = p0.z;
v1.x[i] = p1.x; v1.y[i] = p1.y; v1.z[i] = p1.z;
v2.x[i] = p2.x; v2.y[i] = p2.y; v2.z[i] = p2.z;
}
Triangle4v::store_nt(accel,Triangle4v(v0,v1,v2,vgeomID,vprimID,vmask));
}
void BVH4BuilderFast::createTriangle1vLeaf(const BVH4BuilderFast* This, BuildRecord& current, Allocator& leafAlloc, size_t threadID)
{
size_t items = current.items();
size_t start = current.begin;
assert(items<=4);
/* allocate leaf node */
Triangle1v* accel = (Triangle1v*) leafAlloc.malloc(items*sizeof(Triangle1v));
*(NodeRef*)current.parentNode = This->bvh->encodeLeaf((char*)accel,items);
for (size_t i=0; i<items; i++)
{
const size_t geomID = This->prims[start+i].geomID();
const size_t primID = This->prims[start+i].primID();
const TriangleMesh* __restrict__ const mesh = This->scene->getTriangleMesh(geomID);
const TriangleMesh::Triangle& tri = mesh->triangle(primID);
const ssef v0 = select(0x7,(ssef)mesh->vertex(tri.v[0]),zero);
const ssef v1 = select(0x7,(ssef)mesh->vertex(tri.v[1]),zero);
const ssef v2 = select(0x7,(ssef)mesh->vertex(tri.v[2]),zero);
const ssef e1 = v0 - v1;
const ssef e2 = v2 - v0;
const ssef normal = cross(e1,e2);
store4f_nt(&accel[i].v0,cast(insert<3>(cast(v0),primID)));
store4f_nt(&accel[i].v1,cast(insert<3>(cast(v1),geomID)));
store4f_nt(&accel[i].v2,cast(insert<3>(cast(v2),mesh->mask)));
}
}
__forceinline void BVH4BuilderTopLevel::recurse(size_t depth, BuildRecord& current, const size_t mode, const size_t threadID, const size_t numThreads)
{
if (mode == BUILD_TOP_LEVEL) {
g_state->global_workStack.push_nolock(current);
}
else if (current.items() > THRESHOLD_FOR_SUBTREE_RECURSION) {
if (!g_state->thread_workStack[threadID].push(current))
recurseSAH(depth,current,RECURSE,threadID,numThreads);
}
else
recurseSAH(depth,current,RECURSE,threadID,numThreads);
}
__forceinline void BVH4BuilderFast::recurse(BuildRecord& current, Allocator& nodeAlloc, Allocator& leafAlloc, const size_t mode, const size_t threadID, const size_t numThreads)
{
if (mode == BUILD_TOP_LEVEL) {
g_state->workStack.push_nolock(current);
}
else if (mode == RECURSE_PARALLEL && current.items() > THRESHOLD_FOR_SUBTREE_RECURSION) {
if (!g_state->threadStack[threadID].push(current))
recurseSAH(current,nodeAlloc,leafAlloc,RECURSE_SEQUENTIAL,threadID,numThreads);
}
else
recurseSAH(current,nodeAlloc,leafAlloc,mode,threadID,numThreads);
}
void BVH4BuilderFast::createLeaf(BuildRecord& current, Allocator& nodeAlloc, Allocator& leafAlloc, size_t threadIndex, size_t threadCount)
{
#if defined(DEBUG)
if (current.depth > BVH4::maxBuildDepthLeaf)
throw std::runtime_error("ERROR: depth limit reached");
#endif
/* create leaf for few primitives */
if (current.items() <= QBVH_BUILDER_LEAF_ITEM_THRESHOLD) {
createSmallLeaf(this,current,leafAlloc,threadIndex);
return;
}
/* first split level */
BuildRecord record0, record1;
split_fallback(prims,current,record0,record1);
/* second split level */
BuildRecord children[4];
split_fallback(prims,record0,children[0],children[1]);
split_fallback(prims,record1,children[2],children[3]);
/* allocate node */
Node* node = (Node*) nodeAlloc.malloc(sizeof(Node)); node->clear();
*(NodeRef*)current.parentNode = bvh->encodeNode(node);
/* recurse into each child */
for (size_t i=0; i<4; i++)
{
node->set(i,children[i].bounds.geometry);
children[i].parentNode = (size_t)&node->child(i);
children[i].depth = current.depth+1;
createLeaf(children[i],nodeAlloc,leafAlloc,threadIndex,threadCount);
}
BVH4::compact(node); // move empty nodes to the end
}
void BVH4BuilderFast::build_parallel(size_t threadIndex, size_t threadCount, size_t taskIndex, size_t taskCount, TaskScheduler::Event* event)
{
/* wait for all threads to enter */
g_state->barrier.wait(threadIndex,threadCount);
/* start measurement */
double t0 = 0.0f;
if (g_verbose >= 2) t0 = getSeconds();
/* all worker threads enter tasking system */
if (threadIndex != 0) {
g_state->scheduler.dispatchTaskMainLoop(threadIndex,threadCount);
return;
}
/* calculate list of primrefs */
global_bounds.reset();
g_state->scheduler.dispatchTask( task_computePrimRefs, this, threadIndex, threadCount );
bvh->bounds = global_bounds.geometry;
/* initialize node and leaf allocator */
nodeAllocator.reset();
primAllocator.reset();
__aligned(64) Allocator nodeAlloc(nodeAllocator);
__aligned(64) Allocator leafAlloc(primAllocator);
/* create initial build record */
BuildRecord br;
br.init(global_bounds,0,numPrimitives);
br.depth = 1;
br.parentNode = (size_t)&bvh->root;
/* initialize thread-local work stacks */
for (size_t i=0; i<threadCount; i++)
g_state->threadStack[i].reset();
/* push initial build record to global work stack */
g_state->workStack.reset();
g_state->workStack.push_nolock(br);
/* work in multithreaded toplevel mode until sufficient subtasks got generated */
while (g_state->workStack.size() < 4*threadCount && g_state->workStack.size()+BVH4::N <= SIZE_WORK_STACK)
{
BuildRecord br;
/* pop largest item for better load balancing */
if (!g_state->workStack.pop_nolock_largest(br))
break;
/* guarantees to create no leaves in this stage */
if (br.items() <= QBVH_BUILDER_LEAF_ITEM_THRESHOLD)
break;
recurseSAH(br,nodeAlloc,leafAlloc,BUILD_TOP_LEVEL,threadIndex,threadCount);
}
/* now process all created subtasks on multiple threads */
g_state->scheduler.dispatchTask(task_buildSubTrees, this, threadIndex, threadCount );
/* release all threads again */
g_state->scheduler.releaseThreads(threadCount);
/* stop measurement */
if (g_verbose >= 2) dt = getSeconds()-t0;
}
