godot/thirdparty/embree/kernels/builders/heuristic_spatial_array.h

547 lines
24 KiB
C++

// Copyright 2009-2021 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include "heuristic_binning.h"
#include "heuristic_spatial.h"
namespace embree
{
namespace isa
{
#if 0
#define SPATIAL_ASPLIT_OVERLAP_THRESHOLD 0.2f
#define SPATIAL_ASPLIT_SAH_THRESHOLD 0.95f
#define SPATIAL_ASPLIT_AREA_THRESHOLD 0.0f
#else
#define SPATIAL_ASPLIT_OVERLAP_THRESHOLD 0.1f
#define SPATIAL_ASPLIT_SAH_THRESHOLD 0.99f
#define SPATIAL_ASPLIT_AREA_THRESHOLD 0.000005f
#endif
struct PrimInfoExtRange : public CentGeomBBox3fa, public extended_range<size_t>
{
__forceinline PrimInfoExtRange() {
}
__forceinline PrimInfoExtRange(EmptyTy)
: CentGeomBBox3fa(EmptyTy()), extended_range<size_t>(0,0,0) {}
__forceinline PrimInfoExtRange(size_t begin, size_t end, size_t ext_end, const CentGeomBBox3fa& centGeomBounds)
: CentGeomBBox3fa(centGeomBounds), extended_range<size_t>(begin,end,ext_end) {}
__forceinline float leafSAH() const {
return expectedApproxHalfArea(geomBounds)*float(size());
}
__forceinline float leafSAH(size_t block_shift) const {
return expectedApproxHalfArea(geomBounds)*float((size()+(size_t(1)<<block_shift)-1) >> block_shift);
}
};
template<typename ObjectSplit, typename SpatialSplit>
struct Split2
{
__forceinline Split2 () {}
__forceinline Split2 (const Split2& other)
{
spatial = other.spatial;
sah = other.sah;
if (spatial) spatialSplit() = other.spatialSplit();
else objectSplit() = other.objectSplit();
}
__forceinline Split2& operator= (const Split2& other)
{
spatial = other.spatial;
sah = other.sah;
if (spatial) spatialSplit() = other.spatialSplit();
else objectSplit() = other.objectSplit();
return *this;
}
__forceinline ObjectSplit& objectSplit() { return *( ObjectSplit*)data; }
__forceinline const ObjectSplit& objectSplit() const { return *(const ObjectSplit*)data; }
__forceinline SpatialSplit& spatialSplit() { return *( SpatialSplit*)data; }
__forceinline const SpatialSplit& spatialSplit() const { return *(const SpatialSplit*)data; }
__forceinline Split2 (const ObjectSplit& objectSplit, float sah)
: spatial(false), sah(sah)
{
new (data) ObjectSplit(objectSplit);
}
__forceinline Split2 (const SpatialSplit& spatialSplit, float sah)
: spatial(true), sah(sah)
{
new (data) SpatialSplit(spatialSplit);
}
__forceinline float splitSAH() const {
return sah;
}
__forceinline bool valid() const {
return sah < float(inf);
}
public:
__aligned(64) char data[sizeof(ObjectSplit) > sizeof(SpatialSplit) ? sizeof(ObjectSplit) : sizeof(SpatialSplit)];
bool spatial;
float sah;
};
/*! Performs standard object binning */
template<typename PrimitiveSplitterFactory, typename PrimRef, size_t OBJECT_BINS, size_t SPATIAL_BINS>
struct HeuristicArraySpatialSAH
{
typedef BinSplit<OBJECT_BINS> ObjectSplit;
typedef BinInfoT<OBJECT_BINS,PrimRef,BBox3fa> ObjectBinner;
typedef SpatialBinSplit<SPATIAL_BINS> SpatialSplit;
typedef SpatialBinInfo<SPATIAL_BINS,PrimRef> SpatialBinner;
//typedef extended_range<size_t> Set;
typedef Split2<ObjectSplit,SpatialSplit> Split;
static const size_t PARALLEL_THRESHOLD = 3*1024;
static const size_t PARALLEL_FIND_BLOCK_SIZE = 1024;
static const size_t PARALLEL_PARTITION_BLOCK_SIZE = 128;
static const size_t MOVE_STEP_SIZE = 64;
static const size_t CREATE_SPLITS_STEP_SIZE = 64;
__forceinline HeuristicArraySpatialSAH ()
: prims0(nullptr) {}
/*! remember prim array */
__forceinline HeuristicArraySpatialSAH (const PrimitiveSplitterFactory& splitterFactory, PrimRef* prims0, const CentGeomBBox3fa& root_info)
: prims0(prims0), splitterFactory(splitterFactory), root_info(root_info) {}
/*! compute extended ranges */
__noinline void setExtentedRanges(const PrimInfoExtRange& set, PrimInfoExtRange& lset, PrimInfoExtRange& rset, const size_t lweight, const size_t rweight)
{
assert(set.ext_range_size() > 0);
const float left_factor = (float)lweight / (lweight + rweight);
const size_t ext_range_size = set.ext_range_size();
const size_t left_ext_range_size = min((size_t)(floorf(left_factor * ext_range_size)),ext_range_size);
const size_t right_ext_range_size = ext_range_size - left_ext_range_size;
lset.set_ext_range(lset.end() + left_ext_range_size);
rset.set_ext_range(rset.end() + right_ext_range_size);
}
/*! move ranges */
__noinline void moveExtentedRange(const PrimInfoExtRange& set, const PrimInfoExtRange& lset, PrimInfoExtRange& rset)
{
const size_t left_ext_range_size = lset.ext_range_size();
const size_t right_size = rset.size();
/* has the left child an extended range? */
if (left_ext_range_size > 0)
{
/* left extended range smaller than right range ? */
if (left_ext_range_size < right_size)
{
/* only move a small part of the beginning of the right range to the end */
parallel_for( rset.begin(), rset.begin()+left_ext_range_size, MOVE_STEP_SIZE, [&](const range<size_t>& r) {
for (size_t i=r.begin(); i<r.end(); i++)
prims0[i+right_size] = prims0[i];
});
}
else
{
/* no overlap, move entire right range to new location, can be made fully parallel */
parallel_for( rset.begin(), rset.end(), MOVE_STEP_SIZE, [&](const range<size_t>& r) {
for (size_t i=r.begin(); i<r.end(); i++)
prims0[i+left_ext_range_size] = prims0[i];
});
}
/* update right range */
assert(rset.ext_end() + left_ext_range_size == set.ext_end());
rset.move_right(left_ext_range_size);
}
}
/*! finds the best split */
const Split find(const PrimInfoExtRange& set, const size_t logBlockSize)
{
SplitInfo oinfo;
const ObjectSplit object_split = object_find(set,logBlockSize,oinfo);
const float object_split_sah = object_split.splitSAH();
if (unlikely(set.has_ext_range()))
{
const BBox3fa overlap = intersect(oinfo.leftBounds, oinfo.rightBounds);
/* do only spatial splits if the child bounds overlap */
if (safeArea(overlap) >= SPATIAL_ASPLIT_AREA_THRESHOLD*safeArea(root_info.geomBounds) &&
safeArea(overlap) >= SPATIAL_ASPLIT_OVERLAP_THRESHOLD*safeArea(set.geomBounds))
{
const SpatialSplit spatial_split = spatial_find(set, logBlockSize);
const float spatial_split_sah = spatial_split.splitSAH();
/* valid spatial split, better SAH and number of splits do not exceed extended range */
if (spatial_split_sah < SPATIAL_ASPLIT_SAH_THRESHOLD*object_split_sah &&
spatial_split.left + spatial_split.right - set.size() <= set.ext_range_size())
{
return Split(spatial_split,spatial_split_sah);
}
}
}
return Split(object_split,object_split_sah);
}
/*! finds the best object split */
__forceinline const ObjectSplit object_find(const PrimInfoExtRange& set, const size_t logBlockSize, SplitInfo &info)
{
if (set.size() < PARALLEL_THRESHOLD) return sequential_object_find(set,logBlockSize,info);
else return parallel_object_find (set,logBlockSize,info);
}
/*! finds the best object split */
__noinline const ObjectSplit sequential_object_find(const PrimInfoExtRange& set, const size_t logBlockSize, SplitInfo &info)
{
ObjectBinner binner(empty);
const BinMapping<OBJECT_BINS> mapping(set);
binner.bin(prims0,set.begin(),set.end(),mapping);
ObjectSplit s = binner.best(mapping,logBlockSize);
binner.getSplitInfo(mapping, s, info);
return s;
}
/*! finds the best split */
__noinline const ObjectSplit parallel_object_find(const PrimInfoExtRange& set, const size_t logBlockSize, SplitInfo &info)
{
ObjectBinner binner(empty);
const BinMapping<OBJECT_BINS> mapping(set);
const BinMapping<OBJECT_BINS>& _mapping = mapping; // CLANG 3.4 parser bug workaround
binner = parallel_reduce(set.begin(),set.end(),PARALLEL_FIND_BLOCK_SIZE,binner,
[&] (const range<size_t>& r) -> ObjectBinner { ObjectBinner binner(empty); binner.bin(prims0+r.begin(),r.size(),_mapping); return binner; },
[&] (const ObjectBinner& b0, const ObjectBinner& b1) -> ObjectBinner { ObjectBinner r = b0; r.merge(b1,_mapping.size()); return r; });
ObjectSplit s = binner.best(mapping,logBlockSize);
binner.getSplitInfo(mapping, s, info);
return s;
}
/*! finds the best spatial split */
__forceinline const SpatialSplit spatial_find(const PrimInfoExtRange& set, const size_t logBlockSize)
{
if (set.size() < PARALLEL_THRESHOLD) return sequential_spatial_find(set, logBlockSize);
else return parallel_spatial_find (set, logBlockSize);
}
/*! finds the best spatial split */
__noinline const SpatialSplit sequential_spatial_find(const PrimInfoExtRange& set, const size_t logBlockSize)
{
SpatialBinner binner(empty);
const SpatialBinMapping<SPATIAL_BINS> mapping(set);
binner.bin2(splitterFactory,prims0,set.begin(),set.end(),mapping);
/* todo: best spatial split not exeeding the extended range does not provide any benefit ?*/
return binner.best(mapping,logBlockSize); //,set.ext_size());
}
__noinline const SpatialSplit parallel_spatial_find(const PrimInfoExtRange& set, const size_t logBlockSize)
{
SpatialBinner binner(empty);
const SpatialBinMapping<SPATIAL_BINS> mapping(set);
const SpatialBinMapping<SPATIAL_BINS>& _mapping = mapping; // CLANG 3.4 parser bug workaround
binner = parallel_reduce(set.begin(),set.end(),PARALLEL_FIND_BLOCK_SIZE,binner,
[&] (const range<size_t>& r) -> SpatialBinner {
SpatialBinner binner(empty);
binner.bin2(splitterFactory,prims0,r.begin(),r.end(),_mapping);
return binner; },
[&] (const SpatialBinner& b0, const SpatialBinner& b1) -> SpatialBinner { return SpatialBinner::reduce(b0,b1); });
/* todo: best spatial split not exeeding the extended range does not provide any benefit ?*/
return binner.best(mapping,logBlockSize); //,set.ext_size());
}
/*! subdivides primitives based on a spatial split */
__noinline void create_spatial_splits(PrimInfoExtRange& set, const SpatialSplit& split, const SpatialBinMapping<SPATIAL_BINS> &mapping)
{
assert(set.has_ext_range());
const size_t max_ext_range_size = set.ext_range_size();
const size_t ext_range_start = set.end();
/* atomic counter for number of primref splits */
std::atomic<size_t> ext_elements;
ext_elements.store(0);
const float fpos = split.mapping.pos(split.pos,split.dim);
const unsigned int mask = 0xFFFFFFFF >> RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS;
parallel_for( set.begin(), set.end(), CREATE_SPLITS_STEP_SIZE, [&](const range<size_t>& r) {
for (size_t i=r.begin();i<r.end();i++)
{
const unsigned int splits = prims0[i].geomID() >> (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS);
if (likely(splits <= 1)) continue; /* todo: does this ever happen ? */
//int bin0 = split.mapping.bin(prims0[i].lower)[split.dim];
//int bin1 = split.mapping.bin(prims0[i].upper)[split.dim];
//if (unlikely(bin0 < split.pos && bin1 >= split.pos))
if (unlikely(prims0[i].lower[split.dim] < fpos && prims0[i].upper[split.dim] > fpos))
{
assert(splits > 1);
PrimRef left,right;
const auto splitter = splitterFactory(prims0[i]);
splitter(prims0[i],split.dim,fpos,left,right);
// no empty splits
if (unlikely(left.bounds().empty() || right.bounds().empty())) continue;
left.lower.u = (left.lower.u & mask) | ((splits-1) << (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS));
right.lower.u = (right.lower.u & mask) | ((splits-1) << (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS));
const size_t ID = ext_elements.fetch_add(1);
/* break if the number of subdivided elements are greater than the maximum allowed size */
if (unlikely(ID >= max_ext_range_size))
break;
/* only write within the correct bounds */
assert(ID < max_ext_range_size);
prims0[i] = left;
prims0[ext_range_start+ID] = right;
}
}
});
const size_t numExtElements = min(max_ext_range_size,ext_elements.load());
assert(set.end()+numExtElements<=set.ext_end());
set._end += numExtElements;
}
/*! array partitioning */
void split(const Split& split, const PrimInfoExtRange& set_i, PrimInfoExtRange& lset, PrimInfoExtRange& rset)
{
PrimInfoExtRange set = set_i;
/* valid split */
if (unlikely(!split.valid())) {
deterministic_order(set);
return splitFallback(set,lset,rset);
}
std::pair<size_t,size_t> ext_weights(0,0);
if (unlikely(split.spatial))
{
create_spatial_splits(set,split.spatialSplit(), split.spatialSplit().mapping);
/* spatial split */
if (likely(set.size() < PARALLEL_THRESHOLD))
ext_weights = sequential_spatial_split(split.spatialSplit(),set,lset,rset);
else
ext_weights = parallel_spatial_split(split.spatialSplit(),set,lset,rset);
}
else
{
/* object split */
if (likely(set.size() < PARALLEL_THRESHOLD))
ext_weights = sequential_object_split(split.objectSplit(),set,lset,rset);
else
ext_weights = parallel_object_split(split.objectSplit(),set,lset,rset);
}
/* if we have an extended range, set extended child ranges and move right split range */
if (unlikely(set.has_ext_range()))
{
setExtentedRanges(set,lset,rset,ext_weights.first,ext_weights.second);
moveExtentedRange(set,lset,rset);
}
}
/*! array partitioning */
std::pair<size_t,size_t> sequential_object_split(const ObjectSplit& split, const PrimInfoExtRange& set, PrimInfoExtRange& lset, PrimInfoExtRange& rset)
{
const size_t begin = set.begin();
const size_t end = set.end();
PrimInfo local_left(empty);
PrimInfo local_right(empty);
const unsigned int splitPos = split.pos;
const unsigned int splitDim = split.dim;
const unsigned int splitDimMask = (unsigned int)1 << splitDim;
const typename ObjectBinner::vint vSplitPos(splitPos);
const typename ObjectBinner::vbool vSplitMask(splitDimMask);
size_t center = serial_partitioning(prims0,
begin,end,local_left,local_right,
[&] (const PrimRef& ref) {
return split.mapping.bin_unsafe(ref,vSplitPos,vSplitMask);
},
[] (PrimInfo& pinfo,const PrimRef& ref) { pinfo.add_center2(ref,ref.lower.u >> (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS)); });
const size_t left_weight = local_left.end;
const size_t right_weight = local_right.end;
new (&lset) PrimInfoExtRange(begin,center,center,local_left);
new (&rset) PrimInfoExtRange(center,end,end,local_right);
assert(area(lset.geomBounds) >= 0.0f);
assert(area(rset.geomBounds) >= 0.0f);
return std::pair<size_t,size_t>(left_weight,right_weight);
}
/*! array partitioning */
__noinline std::pair<size_t,size_t> sequential_spatial_split(const SpatialSplit& split, const PrimInfoExtRange& set, PrimInfoExtRange& lset, PrimInfoExtRange& rset)
{
const size_t begin = set.begin();
const size_t end = set.end();
PrimInfo local_left(empty);
PrimInfo local_right(empty);
const unsigned int splitPos = split.pos;
const unsigned int splitDim = split.dim;
const unsigned int splitDimMask = (unsigned int)1 << splitDim;
/* init spatial mapping */
const SpatialBinMapping<SPATIAL_BINS> &mapping = split.mapping;
const vint4 vSplitPos(splitPos);
const vbool4 vSplitMask( (int)splitDimMask );
size_t center = serial_partitioning(prims0,
begin,end,local_left,local_right,
[&] (const PrimRef& ref) {
const Vec3fa c = ref.bounds().center();
return any(((vint4)mapping.bin(c) < vSplitPos) & vSplitMask);
},
[] (PrimInfo& pinfo,const PrimRef& ref) { pinfo.add_center2(ref,ref.lower.u >> (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS)); });
const size_t left_weight = local_left.end;
const size_t right_weight = local_right.end;
new (&lset) PrimInfoExtRange(begin,center,center,local_left);
new (&rset) PrimInfoExtRange(center,end,end,local_right);
assert(area(lset.geomBounds) >= 0.0f);
assert(area(rset.geomBounds) >= 0.0f);
return std::pair<size_t,size_t>(left_weight,right_weight);
}
/*! array partitioning */
__noinline std::pair<size_t,size_t> parallel_object_split(const ObjectSplit& split, const PrimInfoExtRange& set, PrimInfoExtRange& lset, PrimInfoExtRange& rset)
{
const size_t begin = set.begin();
const size_t end = set.end();
PrimInfo left(empty);
PrimInfo right(empty);
const unsigned int splitPos = split.pos;
const unsigned int splitDim = split.dim;
const unsigned int splitDimMask = (unsigned int)1 << splitDim;
const typename ObjectBinner::vint vSplitPos(splitPos);
const typename ObjectBinner::vbool vSplitMask(splitDimMask);
auto isLeft = [&] (const PrimRef &ref) { return split.mapping.bin_unsafe(ref,vSplitPos,vSplitMask); };
const size_t center = parallel_partitioning(
prims0,begin,end,EmptyTy(),left,right,isLeft,
[] (PrimInfo &pinfo,const PrimRef &ref) { pinfo.add_center2(ref,ref.lower.u >> (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS)); },
[] (PrimInfo &pinfo0,const PrimInfo &pinfo1) { pinfo0.merge(pinfo1); },
PARALLEL_PARTITION_BLOCK_SIZE);
const size_t left_weight = left.end;
const size_t right_weight = right.end;
left.begin = begin; left.end = center;
right.begin = center; right.end = end;
new (&lset) PrimInfoExtRange(begin,center,center,left);
new (&rset) PrimInfoExtRange(center,end,end,right);
assert(area(left.geomBounds) >= 0.0f);
assert(area(right.geomBounds) >= 0.0f);
return std::pair<size_t,size_t>(left_weight,right_weight);
}
/*! array partitioning */
__noinline std::pair<size_t,size_t> parallel_spatial_split(const SpatialSplit& split, const PrimInfoExtRange& set, PrimInfoExtRange& lset, PrimInfoExtRange& rset)
{
const size_t begin = set.begin();
const size_t end = set.end();
PrimInfo left(empty);
PrimInfo right(empty);
const unsigned int splitPos = split.pos;
const unsigned int splitDim = split.dim;
const unsigned int splitDimMask = (unsigned int)1 << splitDim;
/* init spatial mapping */
const SpatialBinMapping<SPATIAL_BINS>& mapping = split.mapping;
const vint4 vSplitPos(splitPos);
const vbool4 vSplitMask( (int)splitDimMask );
auto isLeft = [&] (const PrimRef &ref) {
const Vec3fa c = ref.bounds().center();
return any(((vint4)mapping.bin(c) < vSplitPos) & vSplitMask); };
const size_t center = parallel_partitioning(
prims0,begin,end,EmptyTy(),left,right,isLeft,
[] (PrimInfo &pinfo,const PrimRef &ref) { pinfo.add_center2(ref,ref.lower.u >> (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS)); },
[] (PrimInfo &pinfo0,const PrimInfo &pinfo1) { pinfo0.merge(pinfo1); },
PARALLEL_PARTITION_BLOCK_SIZE);
const size_t left_weight = left.end;
const size_t right_weight = right.end;
left.begin = begin; left.end = center;
right.begin = center; right.end = end;
new (&lset) PrimInfoExtRange(begin,center,center,left);
new (&rset) PrimInfoExtRange(center,end,end,right);
assert(area(left.geomBounds) >= 0.0f);
assert(area(right.geomBounds) >= 0.0f);
return std::pair<size_t,size_t>(left_weight,right_weight);
}
void deterministic_order(const PrimInfoExtRange& set)
{
/* required as parallel partition destroys original primitive order */
std::sort(&prims0[set.begin()],&prims0[set.end()]);
}
void splitFallback(const PrimInfoExtRange& set,
PrimInfoExtRange& lset,
PrimInfoExtRange& rset)
{
const size_t begin = set.begin();
const size_t end = set.end();
const size_t center = (begin + end)/2;
PrimInfo left(empty);
for (size_t i=begin; i<center; i++) {
left.add_center2(prims0[i],prims0[i].lower.u >> (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS));
}
const size_t lweight = left.end;
PrimInfo right(empty);
for (size_t i=center; i<end; i++) {
right.add_center2(prims0[i],prims0[i].lower.u >> (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS));
}
const size_t rweight = right.end;
new (&lset) PrimInfoExtRange(begin,center,center,left);
new (&rset) PrimInfoExtRange(center,end,end,right);
/* if we have an extended range */
if (set.has_ext_range()) {
setExtentedRanges(set,lset,rset,lweight,rweight);
moveExtentedRange(set,lset,rset);
}
}
private:
PrimRef* const prims0;
const PrimitiveSplitterFactory& splitterFactory;
const CentGeomBBox3fa& root_info;
};
}
}