kicad/3d-viewer/3d_rendering/raytracing/accelerators/bvh_packet_traversal.cpp

280 lines
8.3 KiB
C++

/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
* Copyright (C) 2015-2016 Mario Luzeiro <mrluzeiro@ua.pt>
* Copyright (C) 2015-2020 KiCad Developers, see AUTHORS.txt for contributors.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
/**
* @file bvh_packet_traversal.cpp
* @brief This file implements packet traversal over the BVH PBRT implementation.
*/
#include "bvh_pbrt.h"
#define BVH_RANGED_TRAVERSAL
//#define BVH_PARTITION_TRAVERSAL
#define MAX_TODOS 64
struct StackNode
{
int cell;
unsigned int ia; // Index to the first alive ray
};
static inline unsigned int getFirstHit( const RAYPACKET& aRayPacket, const BBOX_3D& aBBox,
unsigned int ia, HITINFO_PACKET* aHitInfoPacket )
{
float hitT;
if( aBBox.Intersect( aRayPacket.m_ray[ia], &hitT )
&& ( hitT < aHitInfoPacket[ia].m_HitInfo.m_tHit ) )
return ia;
if( !aRayPacket.m_Frustum.Intersect( aBBox ) )
return RAYPACKET_RAYS_PER_PACKET;
for( unsigned int i = ia + 1; i < RAYPACKET_RAYS_PER_PACKET; ++i )
{
if( aBBox.Intersect( aRayPacket.m_ray[i], &hitT )
&& ( hitT < aHitInfoPacket[i].m_HitInfo.m_tHit ) )
return i;
}
return RAYPACKET_RAYS_PER_PACKET;
}
#ifdef BVH_RANGED_TRAVERSAL
static inline unsigned int getLastHit( const RAYPACKET& aRayPacket, const BBOX_3D& aBBox,
unsigned int ia, HITINFO_PACKET* aHitInfoPacket )
{
for( unsigned int ie = (RAYPACKET_RAYS_PER_PACKET - 1); ie > ia; --ie )
{
float hitT;
if( aBBox.Intersect( aRayPacket.m_ray[ie], &hitT )
&& ( hitT < aHitInfoPacket[ie].m_HitInfo.m_tHit ) )
return ie + 1;
}
return ia + 1;
}
// "Large Ray Packets for Real-time Whitted Ray Tracing"
// http://cseweb.ucsd.edu/~ravir/whitted.pdf
// Ranged Traversal
bool BVH_PBRT::Intersect( const RAYPACKET& aRayPacket, HITINFO_PACKET* aHitInfoPacket ) const
{
if( m_nodes == nullptr )
return false;
if( &m_nodes[0] == nullptr )
return false;
bool anyHit = false;
int todoOffset = 0, nodeNum = 0;
StackNode todo[MAX_TODOS];
unsigned int ia = 0;
while( true )
{
const LinearBVHNode *curCell = &m_nodes[nodeNum];
ia = getFirstHit( aRayPacket, curCell->bounds, ia, aHitInfoPacket );
if( ia < RAYPACKET_RAYS_PER_PACKET )
{
if( curCell->nPrimitives == 0 )
{
StackNode& node = todo[todoOffset++];
node.cell = curCell->secondChildOffset;
node.ia = ia;
nodeNum = nodeNum + 1;
continue;
}
else
{
const unsigned int ie = getLastHit( aRayPacket, curCell->bounds, ia,
aHitInfoPacket );
for( int j = 0; j < curCell->nPrimitives; ++j )
{
const OBJECT_3D* obj = m_primitives[curCell->primitivesOffset + j];
if( aRayPacket.m_Frustum.Intersect( obj->GetBBox() ) )
{
for( unsigned int i = ia; i < ie; ++i )
{
const bool hit = obj->Intersect( aRayPacket.m_ray[i],
aHitInfoPacket[i].m_HitInfo );
if( hit )
{
anyHit |= hit;
aHitInfoPacket[i].m_hitresult |= hit;
aHitInfoPacket[i].m_HitInfo.m_acc_node_info = nodeNum;
}
}
}
}
}
}
if( todoOffset == 0 )
break;
const StackNode& node = todo[--todoOffset];
nodeNum = node.cell;
ia = node.ia;
}
return anyHit;
}
#endif
// "Ray Tracing Deformable Scenes Using Dynamic Bounding Volume Hierarchies"
// http://www.cs.cmu.edu/afs/cs/academic/class/15869-f11/www/readings/wald07_packetbvh.pdf
#ifdef BVH_PARTITION_TRAVERSAL
static inline unsigned int getLastHit( const RAYPACKET& aRayPacket, const BBOX_3D& aBBox,
unsigned int ia, const unsigned int* aRayIndex,
HITINFO_PACKET* aHitInfoPacket )
{
for( unsigned int ie = (RAYPACKET_RAYS_PER_PACKET - 1); ie > ia; --ie )
{
float hitT;
if( aBBox.Intersect( aRayPacket.m_ray[ aRayIndex[ie] ], &hitT )
&& ( hitT < aHitInfoPacket[ aRayIndex[ie] ].m_HitInfo.m_tHit ) )
return ie + 1;
}
return ia + 1;
}
static inline unsigned int partRays( const RAYPACKET& aRayPacket, const BBOX_3D& aBBox,
unsigned int ia, unsigned int* aRayIndex,
HITINFO_PACKET* aHitInfoPacket )
{
if( !aRayPacket.m_Frustum.Intersect( aBBox ) )
return RAYPACKET_RAYS_PER_PACKET;
unsigned int ie = 0;
for( unsigned int i = 0; i < ia; ++i )
{
float hitT;
if( aBBox.Intersect( aRayPacket.m_ray[ aRayIndex[i] ], &hitT )
&& ( hitT < aHitInfoPacket[ aRayIndex[i] ].m_HitInfo.m_tHit ) )
std::swap( aRayIndex[ie++], aRayIndex[i] );
}
return ie;
}
bool BVH_PBRT::Intersect( const RAYPACKET& aRayPacket, HITINFO_PACKET* aHitInfoPacket ) const
{
bool anyHit = false;
int todoOffset = 0, nodeNum = 0;
StackNode todo[MAX_TODOS];
unsigned int I[RAYPACKET_RAYS_PER_PACKET];
memcpy( I, m_I, RAYPACKET_RAYS_PER_PACKET * sizeof( unsigned int ) );
unsigned int ia = 0;
while( true )
{
const LinearBVHNode *curCell = &m_nodes[nodeNum];
ia = partRays( aRayPacket, curCell->bounds, ia, I, aHitInfoPacket );
if( ia < RAYPACKET_RAYS_PER_PACKET )
{
if( curCell->nPrimitives == 0 )
{
StackNode& node = todo[todoOffset++];
node.cell = curCell->secondChildOffset;
node.ia = ia;
nodeNum = nodeNum + 1;
continue;
}
else
{
unsigned int ie = getLastHit( aRayPacket, curCell->bounds, ia, I,
aHitInfoPacket );
for( int j = 0; j < curCell->nPrimitives; ++j )
{
const OBJECT_3D* obj = m_primitives[curCell->primitivesOffset + j];
if( aRayPacket.m_Frustum.Intersect( obj->GetBBox() ) )
{
for( unsigned int i = 0; i < ie; ++i )
{
unsigned int idx = I[i];
bool hit = obj->Intersect( aRayPacket.m_ray[idx],
aHitInfoPacket[idx].m_HitInfo );
if( hit )
{
anyHit |= hit;
aHitInfoPacket[idx].m_hitresult |= hit;
aHitInfoPacket[idx].m_HitInfo.m_acc_node_info = nodeNum;
}
}
}
}
}
}
if( todoOffset == 0 )
break;
const StackNode& node = todo[--todoOffset];
nodeNum = node.cell;
ia = node.ia;
}
return anyHit;
}
#endif