godot/thirdparty/embree/kernels/bvh/bvh_traverser_stream.h

150 lines
4.6 KiB
C++

// Copyright 2009-2021 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include "bvh.h"
#include "../common/ray.h"
#include "../common/stack_item.h"
namespace embree
{
namespace isa
{
template<int N, int types>
class BVHNNodeTraverserStreamHitCoherent
{
typedef BVHN<N> BVH;
typedef typename BVH::NodeRef NodeRef;
typedef typename BVH::BaseNode BaseNode;
public:
template<class T>
static __forceinline void traverseClosestHit(NodeRef& cur,
size_t& m_trav_active,
const vbool<N>& vmask,
const vfloat<N>& tNear,
const T* const tMask,
StackItemMaskCoherent*& stackPtr)
{
const NodeRef parent = cur;
size_t mask = movemask(vmask);
assert(mask != 0);
const BaseNode* node = cur.baseNode();
/*! one child is hit, continue with that child */
const size_t r0 = bscf(mask);
assert(r0 < 8);
cur = node->child(r0);
BVHN<N>::prefetch(cur,types);
m_trav_active = tMask[r0];
assert(cur != BVH::emptyNode);
if (unlikely(mask == 0)) return;
const unsigned int* const tNear_i = (unsigned int*)&tNear;
/*! two children are hit, push far child, and continue with closer child */
NodeRef c0 = cur;
unsigned int d0 = tNear_i[r0];
const size_t r1 = bscf(mask);
assert(r1 < 8);
NodeRef c1 = node->child(r1);
BVHN<N>::prefetch(c1,types);
unsigned int d1 = tNear_i[r1];
assert(c0 != BVH::emptyNode);
assert(c1 != BVH::emptyNode);
if (likely(mask == 0)) {
if (d0 < d1) {
assert(tNear[r1] >= 0.0f);
stackPtr->mask = tMask[r1];
stackPtr->parent = parent;
stackPtr->child = c1;
stackPtr++;
cur = c0;
m_trav_active = tMask[r0];
return;
}
else {
assert(tNear[r0] >= 0.0f);
stackPtr->mask = tMask[r0];
stackPtr->parent = parent;
stackPtr->child = c0;
stackPtr++;
cur = c1;
m_trav_active = tMask[r1];
return;
}
}
/*! slow path for more than two hits */
size_t hits = movemask(vmask);
const vint<N> dist_i = select(vmask, (asInt(tNear) & 0xfffffff8) | vint<N>(step), 0);
const vint<N> dist_i_sorted = usort_descending(dist_i);
const vint<N> sorted_index = dist_i_sorted & 7;
size_t i = 0;
for (;;)
{
const unsigned int index = sorted_index[i];
assert(index < 8);
cur = node->child(index);
m_trav_active = tMask[index];
assert(m_trav_active);
BVHN<N>::prefetch(cur,types);
bscf(hits);
if (unlikely(hits==0)) break;
i++;
assert(cur != BVH::emptyNode);
assert(tNear[index] >= 0.0f);
stackPtr->mask = m_trav_active;
stackPtr->parent = parent;
stackPtr->child = cur;
stackPtr++;
}
}
template<class T>
static __forceinline void traverseAnyHit(NodeRef& cur,
size_t& m_trav_active,
const vbool<N>& vmask,
const T* const tMask,
StackItemMaskCoherent*& stackPtr)
{
const NodeRef parent = cur;
size_t mask = movemask(vmask);
assert(mask != 0);
const BaseNode* node = cur.baseNode();
/*! one child is hit, continue with that child */
size_t r = bscf(mask);
cur = node->child(r);
BVHN<N>::prefetch(cur,types);
m_trav_active = tMask[r];
/* simple in order sequence */
assert(cur != BVH::emptyNode);
if (likely(mask == 0)) return;
stackPtr->mask = m_trav_active;
stackPtr->parent = parent;
stackPtr->child = cur;
stackPtr++;
for (; ;)
{
r = bscf(mask);
cur = node->child(r);
BVHN<N>::prefetch(cur,types);
m_trav_active = tMask[r];
assert(cur != BVH::emptyNode);
if (likely(mask == 0)) return;
stackPtr->mask = m_trav_active;
stackPtr->parent = parent;
stackPtr->child = cur;
stackPtr++;
}
}
};
}
}