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

444 lines
18 KiB
C++

// Copyright 2009-2021 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
// TODO:
// - adjust parallel build thresholds
// - openNodesBasedOnExtend should consider max extended size
#pragma once
#include "heuristic_binning.h"
#include "heuristic_spatial.h"
/* stop opening of all bref.geomIDs are the same */
#define EQUAL_GEOMID_STOP_CRITERIA 1
/* 10% spatial extend threshold */
#define MAX_EXTEND_THRESHOLD 0.1f
/* maximum is 8 children */
#define MAX_OPENED_CHILD_NODES 8
/* open until all build refs are below threshold size in one step */
#define USE_LOOP_OPENING 0
namespace embree
{
namespace isa
{
/*! Performs standard object binning */
template<typename NodeOpenerFunc, typename PrimRef, size_t OBJECT_BINS>
struct HeuristicArrayOpenMergeSAH
{
typedef BinSplit<OBJECT_BINS> Split;
typedef BinInfoT<OBJECT_BINS,PrimRef,BBox3fa> Binner;
static const size_t PARALLEL_THRESHOLD = 1024;
static const size_t PARALLEL_FIND_BLOCK_SIZE = 512;
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 = 128;
__forceinline HeuristicArrayOpenMergeSAH ()
: prims0(nullptr) {}
/*! remember prim array */
__forceinline HeuristicArrayOpenMergeSAH (const NodeOpenerFunc& nodeOpenerFunc, PrimRef* prims0, size_t max_open_size)
: prims0(prims0), nodeOpenerFunc(nodeOpenerFunc), max_open_size(max_open_size)
{
assert(max_open_size <= MAX_OPENED_CHILD_NODES);
}
struct OpenHeuristic
{
__forceinline OpenHeuristic( const PrimInfoExtRange& pinfo )
{
const Vec3fa diag = pinfo.geomBounds.size();
dim = maxDim(diag);
assert(diag[dim] > 0.0f);
inv_max_extend = 1.0f / diag[dim];
}
__forceinline bool operator () ( PrimRef& prim ) const {
return !prim.node.isLeaf() && prim.bounds().size()[dim] * inv_max_extend > MAX_EXTEND_THRESHOLD;
}
private:
size_t dim;
float inv_max_extend;
};
/*! compute extended ranges */
__forceinline 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 */
__forceinline 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);
}
}
/* estimates the extra space required when opening, and checks if all primitives are from same geometry */
__noinline std::pair<size_t,bool> getProperties(const PrimInfoExtRange& set)
{
const OpenHeuristic heuristic(set);
const unsigned int geomID = prims0[set.begin()].geomID();
auto body = [&] (const range<size_t>& r) -> std::pair<size_t,bool> {
bool commonGeomID = true;
size_t opens = 0;
for (size_t i=r.begin(); i<r.end(); i++) {
commonGeomID &= prims0[i].geomID() == geomID;
if (heuristic(prims0[i]))
opens += prims0[i].node.getN()-1; // coarse approximation
}
return std::pair<size_t,bool>(opens,commonGeomID);
};
auto reduction = [&] (const std::pair<size_t,bool>& b0, const std::pair<size_t,bool>& b1) -> std::pair<size_t,bool> {
return std::pair<size_t,bool>(b0.first+b1.first,b0.second && b1.second);
};
return parallel_reduce(set.begin(),set.end(),PARALLEL_FIND_BLOCK_SIZE,PARALLEL_THRESHOLD,std::pair<size_t,bool>(0,true),body,reduction);
}
// FIXME: should consider maximum available extended size
__noinline void openNodesBasedOnExtend(PrimInfoExtRange& set)
{
const OpenHeuristic heuristic(set);
const size_t ext_range_start = set.end();
if (false && set.size() < PARALLEL_THRESHOLD)
{
size_t extra_elements = 0;
for (size_t i=set.begin(); i<set.end(); i++)
{
if (heuristic(prims0[i]))
{
PrimRef tmp[MAX_OPENED_CHILD_NODES];
const size_t n = nodeOpenerFunc(prims0[i],tmp);
assert(extra_elements + n-1 <= set.ext_range_size());
for (size_t j=0; j<n; j++)
set.extend_center2(tmp[j]);
prims0[i] = tmp[0];
for (size_t j=1; j<n; j++)
prims0[ext_range_start+extra_elements+j-1] = tmp[j];
extra_elements += n-1;
}
}
set._end += extra_elements;
}
else
{
std::atomic<size_t> ext_elements;
ext_elements.store(0);
PrimInfo info = parallel_reduce( set.begin(), set.end(), CREATE_SPLITS_STEP_SIZE, PrimInfo(empty), [&](const range<size_t>& r) -> PrimInfo {
PrimInfo info(empty);
for (size_t i=r.begin(); i<r.end(); i++)
if (heuristic(prims0[i]))
{
PrimRef tmp[MAX_OPENED_CHILD_NODES];
const size_t n = nodeOpenerFunc(prims0[i],tmp);
const size_t ID = ext_elements.fetch_add(n-1);
assert(ID + n-1 <= set.ext_range_size());
for (size_t j=0; j<n; j++)
info.extend_center2(tmp[j]);
prims0[i] = tmp[0];
for (size_t j=1; j<n; j++)
prims0[ext_range_start+ID+j-1] = tmp[j];
}
return info;
}, [] (const PrimInfo& a, const PrimInfo& b) { return PrimInfo::merge(a,b); });
set.centBounds.extend(info.centBounds);
assert(ext_elements.load() <= set.ext_range_size());
set._end += ext_elements.load();
}
}
__noinline void openNodesBasedOnExtendLoop(PrimInfoExtRange& set, const size_t est_new_elements)
{
const OpenHeuristic heuristic(set);
size_t next_iteration_extra_elements = est_new_elements;
while (next_iteration_extra_elements <= set.ext_range_size())
{
next_iteration_extra_elements = 0;
size_t extra_elements = 0;
const size_t ext_range_start = set.end();
for (size_t i=set.begin(); i<set.end(); i++)
{
if (heuristic(prims0[i]))
{
PrimRef tmp[MAX_OPENED_CHILD_NODES];
const size_t n = nodeOpenerFunc(prims0[i],tmp);
assert(extra_elements + n-1 <= set.ext_range_size());
for (size_t j=0;j<n;j++)
set.extend_center2(tmp[j]);
prims0[i] = tmp[0];
for (size_t j=1;j<n;j++)
prims0[ext_range_start+extra_elements+j-1] = tmp[j];
extra_elements += n-1;
for (size_t j=0; j<n; j++)
if (heuristic(tmp[j]))
next_iteration_extra_elements += tmp[j].node.getN()-1; // coarse approximation
}
}
assert( extra_elements <= set.ext_range_size());
set._end += extra_elements;
for (size_t i=set.begin();i<set.end();i++)
assert(prims0[i].numPrimitives() > 0);
if (unlikely(next_iteration_extra_elements == 0)) break;
}
}
__noinline const Split find(PrimInfoExtRange& set, const size_t logBlockSize)
{
/* single element */
if (set.size() <= 1)
return Split();
/* disable opening if there is no overlap */
const size_t D = 4;
if (unlikely(set.has_ext_range() && set.size() <= D))
{
bool disjoint = true;
for (size_t j=set.begin(); j<set.end()-1; j++) {
for (size_t i=set.begin()+1; i<set.end(); i++) {
if (conjoint(prims0[j].bounds(),prims0[i].bounds())) {
disjoint = false; break;
}
}
}
if (disjoint) set.set_ext_range(set.end()); /* disables opening */
}
std::pair<size_t,bool> p(0,false);
/* disable opening when all primitives are from same geometry */
if (unlikely(set.has_ext_range()))
{
p = getProperties(set);
#if EQUAL_GEOMID_STOP_CRITERIA == 1
if (p.second) set.set_ext_range(set.end()); /* disable opening */
#endif
}
/* open nodes when we have sufficient space available */
if (unlikely(set.has_ext_range()))
{
#if USE_LOOP_OPENING == 1
openNodesBasedOnExtendLoop(set,p.first);
#else
if (p.first <= set.ext_range_size())
openNodesBasedOnExtend(set);
#endif
/* disable opening when unsufficient space for opening a node available */
if (set.ext_range_size() < max_open_size-1)
set.set_ext_range(set.end()); /* disable opening */
}
/* find best split */
return object_find(set,logBlockSize);
}
/*! finds the best object split */
__forceinline const Split object_find(const PrimInfoExtRange& set,const size_t logBlockSize)
{
if (set.size() < PARALLEL_THRESHOLD) return sequential_object_find(set,logBlockSize);
else return parallel_object_find (set,logBlockSize);
}
/*! finds the best object split */
__noinline const Split sequential_object_find(const PrimInfoExtRange& set, const size_t logBlockSize)
{
Binner binner(empty);
const BinMapping<OBJECT_BINS> mapping(set.centBounds);
binner.bin(prims0,set.begin(),set.end(),mapping);
return binner.best(mapping,logBlockSize);
}
/*! finds the best split */
__noinline const Split parallel_object_find(const PrimInfoExtRange& set, const size_t logBlockSize)
{
Binner binner(empty);
const BinMapping<OBJECT_BINS> mapping(set.centBounds);
const BinMapping<OBJECT_BINS>& _mapping = mapping; // CLANG 3.4 parser bug workaround
auto body = [&] (const range<size_t>& r) -> Binner {
Binner binner(empty); binner.bin(prims0+r.begin(),r.size(),_mapping); return binner;
};
auto reduction = [&] (const Binner& b0, const Binner& b1) -> Binner {
Binner r = b0; r.merge(b1,_mapping.size()); return r;
};
binner = parallel_reduce(set.begin(),set.end(),PARALLEL_FIND_BLOCK_SIZE,binner,body,reduction);
return binner.best(mapping,logBlockSize);
}
/*! array partitioning */
__noinline 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);
splitFallback(set,lset,rset);
return;
}
std::pair<size_t,size_t> ext_weights(0,0);
/* object split */
if (likely(set.size() < PARALLEL_THRESHOLD))
ext_weights = sequential_object_split(split,set,lset,rset);
else
ext_weights = parallel_object_split(split,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 Split& 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 vint4 vSplitPos(splitPos);
const vbool4 vSplitMask( (int)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); });
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>(local_left.size(),local_right.size());
}
/*! array partitioning */
__noinline std::pair<size_t,size_t> parallel_object_split(const Split& 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 vint4 vSplitPos(splitPos);
const vbool4 vSplitMask( (int)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); },
[] (PrimInfo& pinfo0,const PrimInfo& pinfo1) { pinfo0.merge(pinfo1); },
PARALLEL_PARTITION_BLOCK_SIZE);
new (&lset) PrimInfoExtRange(begin,center,center,left);
new (&rset) PrimInfoExtRange(center,end,end,right);
assert(area(lset.geomBounds) >= 0.0f);
assert(area(rset.geomBounds) >= 0.0f);
return std::pair<size_t,size_t>(left.size(),right.size());
}
void deterministic_order(const extended_range<size_t>& set)
{
/* required as parallel partition destroys original primitive order */
std::sort(&prims0[set.begin()],&prims0[set.end()]);
}
__forceinline 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]);
const size_t lweight = left.end;
PrimInfo right(empty);
for (size_t i=center; i<end; i++)
right.add_center2(prims0[i]);
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 NodeOpenerFunc& nodeOpenerFunc;
size_t max_open_size;
};
}
}