Files
UnrealEngineUWP/Engine/Source/Developer/MeshSimplifier/Private/MeshSimplify.h
Jason Bestimt e7ed7cd3ff Unblock robomerge from Main
#RB:none

[CL 4604382 by Jason Bestimt in Dev-VR branch]
2018-11-28 15:05:11 -05:00

1601 lines
36 KiB
C++

// Copyright (C) 2009 Nine Realms, Inc
//
#pragma once
#include "CoreMinimal.h"
#define SIMP_CACHE 1
#include "MeshSimplifyElements.h"
#include "Quadric.h"
#include "Containers/HashTable.h"
#include "Containers/BinaryHeap.h"
//#include "Cache.h"
template< typename T, uint32 NumAttributes >
class TMeshSimplifier
{
typedef typename TSimpVert<T>::TriIterator TriIterator;
typedef TQuadricAttr< NumAttributes > QuadricType;
public:
TMeshSimplifier( const T* Verts, uint32 NumVerts, const uint32* Indexes, uint32 NumIndexes );
~TMeshSimplifier();
void SetAttributeWeights( const float* weights );
void SetBoundaryLocked();
void InitCosts();
float SimplifyMesh( float maxErrorLimit, int minTris, int minVerts = INT_MAX);
int GetNumVerts() const { return numVerts; }
int GetNumTris() const { return numTris; }
void OutputMesh( T* Verts, uint32* Indexes );
protected:
void LockVertFlags( uint32 flag );
void UnlockVertFlags( uint32 flag );
void LockTriFlags( uint32 flag );
void UnlockTriFlags( uint32 flag );
void GatherUpdates( TSimpVert<T>* v );
void GroupVerts();
void GroupEdges();
void InitVert( TSimpVert<T>* v );
QuadricType GetQuadric( TSimpVert<T>* v );
FQuadric GetEdgeQuadric( TSimpVert<T>* v );
// TODO move away from pointers and remove these functions
uint32 GetVertIndex( const TSimpVert<T>* vert ) const;
uint32 GetTriIndex( const TSimpTri<T>* tri ) const;
uint32 GetEdgeIndex( const TSimpEdge<T>* edge ) const;
uint32 HashPoint( const FVector& p ) const;
uint32 HashEdge( const TSimpVert<T>* u, const TSimpVert<T>* v ) const;
TSimpEdge<T>* FindEdge( const TSimpVert<T>* u, const TSimpVert<T>* v );
void RemoveEdge( TSimpEdge<T>* edge );
void ReplaceEdgeVert( const TSimpVert<T>* oldV, const TSimpVert<T>* otherV, TSimpVert<T>* newV );
void CollapseEdgeVert( const TSimpVert<T>* oldV, const TSimpVert<T>* otherV, TSimpVert<T>* newV );
float ComputeNewVerts( TSimpEdge<T>* edge, TArray< T, TInlineAllocator<16> >& newVerts );
float ComputeEdgeCollapseCost( TSimpEdge<T>* edge );
void Collapse( TSimpEdge<T>* edge );
void UpdateTris();
void UpdateVerts();
void UpdateEdges();
uint32 vertFlagLock;
uint32 triFlagLock;
float attributeWeights[ NumAttributes ];
TSimpVert<T>* sVerts;
TSimpTri<T>* sTris;
int numSVerts;
int numSTris;
int numVerts;
int numTris;
TArray< TSimpEdge<T> > edges;
FHashTable edgeHash;
FBinaryHeap<float> edgeHeap;
TArray< TSimpVert<T>* > updateVerts;
TArray< TSimpTri<T>* > updateTris;
TArray< TSimpEdge<T>* > updateEdges;
#if SIMP_CACHE
TBitArray<> VertQuadricsValid;
TArray< QuadricType > VertQuadrics;
TBitArray<> TriQuadricsValid;
TArray< QuadricType > TriQuadrics;
TBitArray<> EdgeQuadricsValid;
TArray< FQuadric > EdgeQuadrics;
#endif
};
//=============
// TMeshSimplifier
//=============
template< typename T, uint32 NumAttributes >
TMeshSimplifier<T, NumAttributes>::TMeshSimplifier( const T* Verts, uint32 NumVerts, const uint32* Indexes, uint32 NumIndexes )
: edgeHash( 1 << FMath::Min( 16u, FMath::FloorLog2( NumVerts ) ) )
{
vertFlagLock = 0;
triFlagLock = 0;
for( uint32 i = 0; i < NumAttributes; i++ )
{
attributeWeights[i] = 1.0f;
}
numSVerts = NumVerts;
numSTris = NumIndexes / 3;
this->numVerts = numSVerts;
this->numTris = numSTris;
sVerts = new TSimpVert<T>[ numSVerts ];
sTris = new TSimpTri<T>[ numSTris ];
#if SIMP_CACHE
VertQuadricsValid.Init( false, numSVerts );
VertQuadrics.SetNum( numSVerts );
TriQuadricsValid.Init( false, numSTris );
TriQuadrics.SetNum( numSTris );
EdgeQuadricsValid.Init( false, numSVerts );
EdgeQuadrics.SetNum( numSVerts );
#endif
for( int i = 0; i < numSVerts; i++ )
{
sVerts[i].vert = Verts[i];
}
for( int i = 0; i < numSTris; i++ )
{
for( int j = 0; j < 3; j++ )
{
sTris[i].verts[j] = &sVerts[ Indexes[3*i+j] ];
sTris[i].verts[j]->adjTris.Add( &sTris[i] );
}
}
GroupVerts();
int maxEdgeSize = FMath::Min( 3 * numSTris, 3 * numSVerts - 6 );
edges.Empty( maxEdgeSize );
for( int i = 0; i < numSVerts; i++ )
{
InitVert( &sVerts[i] );
}
// Guessed wrong on num edges. Array was resized so fix up pointers.
if( edges.Num() > maxEdgeSize )
{
for( int i = 0; i < edges.Num(); i++ )
{
TSimpEdge<T>& edge = edges[i];
edge.next = &edge;
edge.prev = &edge;
}
}
GroupEdges();
edgeHash.Resize( edges.Num() );
for( int i = 0; i < edges.Num(); i++ )
{
edgeHash.Add( HashEdge( edges[i].v0, edges[i].v1 ), i );
}
edgeHeap.Resize( edges.Num(), edges.Num() );
}
template< typename T, uint32 NumAttributes >
TMeshSimplifier<T, NumAttributes>::~TMeshSimplifier()
{
delete[] sVerts;
delete[] sTris;
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::SetAttributeWeights( const float* weights )
{
for( uint32 i = 0; i < NumAttributes; i++ )
{
attributeWeights[i] = weights[i];
}
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::SetBoundaryLocked()
{
TArray< TSimpVert<T>*, TInlineAllocator<64> > adjVerts;
for( int i = 0; i < numSVerts; i++ )
{
TSimpVert<T>* v0 = &sVerts[i];
check( v0->adjTris.Num() > 0 );
adjVerts.Reset();
v0->FindAdjacentVertsGroup( adjVerts );
for( TSimpVert<T>* v1 : adjVerts )
{
if( v0 < v1 )
{
LockTriFlags( SIMP_MARK1 );
// set if this edge is boundary
// find faces that share v0 and v1
v0->EnableAdjTriFlagsGroup( SIMP_MARK1 );
v1->DisableAdjTriFlagsGroup( SIMP_MARK1 );
int faceCount = 0;
TSimpVert<T>* vert = v0;
do
{
for( TriIterator j = vert->adjTris.Begin(); j != vert->adjTris.End(); ++j )
{
TSimpTri<T>* tri = *j;
faceCount += tri->TestFlags( SIMP_MARK1 ) ? 0 : 1;
}
vert = vert->next;
} while( vert != v0 );
v0->DisableAdjTriFlagsGroup( SIMP_MARK1 );
if( faceCount == 1 )
{
// only one face on this edge
v0->EnableFlagsGroup( SIMP_LOCKED );
v1->EnableFlagsGroup( SIMP_LOCKED );
}
UnlockTriFlags( SIMP_MARK1 );
}
}
}
}
// locking functions for nesting safety
template< typename T, uint32 NumAttributes >
FORCEINLINE void TMeshSimplifier<T, NumAttributes>::LockVertFlags( uint32 f )
{
checkSlow( ( vertFlagLock & f ) == 0 );
vertFlagLock |= f;
}
template< typename T, uint32 NumAttributes >
FORCEINLINE void TMeshSimplifier<T, NumAttributes>::UnlockVertFlags( uint32 f )
{
vertFlagLock &= ~f;
}
template< typename T, uint32 NumAttributes >
FORCEINLINE void TMeshSimplifier<T, NumAttributes>::LockTriFlags( uint32 f )
{
checkSlow( ( triFlagLock & f ) == 0 );
triFlagLock |= f;
}
template< typename T, uint32 NumAttributes >
FORCEINLINE void TMeshSimplifier<T, NumAttributes>::UnlockTriFlags( uint32 f )
{
triFlagLock &= ~f;
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::InitVert( TSimpVert<T>* v )
{
check( v->adjTris.Num() > 0 );
TArray< TSimpVert<T>*, TInlineAllocator<64> > adjVerts;
v->FindAdjacentVerts( adjVerts );
TSimpVert<T>* v0 = v;
for( TSimpVert<T>* v1 : adjVerts )
{
if( v0 < v1 )
{
check( v0->GetMaterialIndex() == v1->GetMaterialIndex() );
// add edge
edges.AddDefaulted();
TSimpEdge<T>& edge = edges.Last();
edge.v0 = v0;
edge.v1 = v1;
}
}
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::GroupVerts()
{
// group verts that share a point
FHashTable HashTable( 1 << FMath::Min( 16u, FMath::FloorLog2( numSVerts / 2 ) ), numSVerts );
for( int i = 0; i < numSVerts; i++ )
{
HashTable.Add( HashPoint( sVerts[i].GetPos() ), i );
}
for( int i = 0; i < numSVerts; i++ )
{
// already grouped
if( sVerts[i].next != &sVerts[i] )
{
continue;
}
// find any matching verts
uint32 hash = HashPoint( sVerts[i].GetPos() );
for( int j = HashTable.First( hash ); HashTable.IsValid(j); j = HashTable.Next(j) )
{
TSimpVert<T>* v1 = &sVerts[i];
TSimpVert<T>* v2 = &sVerts[j];
if( v1 == v2 )
continue;
// link
if( v1->GetPos() == v2->GetPos() )
{
checkSlow( v2->next == v2 );
checkSlow( v2->prev == v2 );
v2->next = v1->next;
v2->prev = v1;
v2->next->prev = v2;
v2->prev->next = v2;
}
}
}
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::GroupEdges()
{
FHashTable HashTable( 1 << FMath::Min( 16u, FMath::FloorLog2( edges.Num() / 2 ) ), edges.Num() );
for( int i = 0; i < edges.Num(); i++ )
{
uint32 Hash0 = HashPoint( edges[i].v0->GetPos() );
uint32 Hash1 = HashPoint( edges[i].v1->GetPos() );
uint32 Hash = Murmur32( { FMath::Min( Hash0, Hash1 ), FMath::Max( Hash0, Hash1 ) } );
HashTable.Add( Hash, i );
}
for( int i = 0; i < edges.Num(); i++ )
{
// already grouped
if( edges[i].next != &edges[i] )
{
continue;
}
// find any matching edges
uint32 Hash0 = HashPoint( edges[i].v0->GetPos() );
uint32 Hash1 = HashPoint( edges[i].v1->GetPos() );
uint32 Hash = Murmur32( { FMath::Min( Hash0, Hash1 ), FMath::Max( Hash0, Hash1 ) } );
for( uint32 j = HashTable.First( Hash ); HashTable.IsValid(j); j = HashTable.Next(j) )
{
TSimpEdge<T>* e1 = &edges[i];
TSimpEdge<T>* e2 = &edges[j];
if( e1 == e2 )
continue;
bool m1 = e1->v0->GetPos() == e2->v0->GetPos() &&
e1->v1->GetPos() == e2->v1->GetPos();
bool m2 = e1->v0->GetPos() == e2->v1->GetPos() &&
e1->v1->GetPos() == e2->v0->GetPos();
// backwards
if( m2 )
{
Swap( e2->v0, e2->v1 );
}
// link
if( m1 || m2 )
{
check( e2->next == e2 );
check( e2->prev == e2 );
e2->next = e1->next;
e2->prev = e1;
e2->next->prev = e2;
e2->prev->next = e2;
}
}
}
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::InitCosts()
{
for( int i = 0; i < edges.Num(); i++ )
{
float cost = ComputeEdgeCollapseCost( &edges[i] );
check( FMath::IsFinite( cost ) );
edgeHeap.Add( cost, i );
}
}
template< typename T, uint32 NumAttributes >
TQuadricAttr< NumAttributes > TMeshSimplifier<T, NumAttributes>::GetQuadric( TSimpVert<T>* v )
{
#if SIMP_CACHE
uint32 VertIndex = GetVertIndex( v );
if( VertQuadricsValid[ VertIndex ] )
{
return VertQuadrics[ VertIndex ];
}
#endif
QuadricType vertQuadric;
vertQuadric.Zero();
// sum tri quadrics
for( TriIterator i = v->adjTris.Begin(); i != v->adjTris.End(); ++i )
{
TSimpTri<T>* tri = *i;
#if SIMP_CACHE
uint32 TriIndex = GetTriIndex( tri );
if( TriQuadricsValid[ TriIndex ] )
{
vertQuadric += TriQuadrics[ TriIndex ];
}
else
{
QuadricType triQuadric(
tri->verts[0]->GetPos(), tri->verts[1]->GetPos(), tri->verts[2]->GetPos(),
tri->verts[0]->GetAttributes(), tri->verts[1]->GetAttributes(), tri->verts[2]->GetAttributes(),
attributeWeights );
vertQuadric += triQuadric;
TriQuadricsValid[ TriIndex ] = true;
TriQuadrics[ TriIndex ] = triQuadric;
}
#else
QuadricType triQuadric(
tri->verts[0]->GetPos(), tri->verts[1]->GetPos(), tri->verts[2]->GetPos(),
tri->verts[0]->GetAttributes(), tri->verts[1]->GetAttributes(), tri->verts[2]->GetAttributes(),
attributeWeights );
vertQuadric += triQuadric;
#endif
}
#if SIMP_CACHE
VertQuadricsValid[ VertIndex ] = true;
VertQuadrics[ VertIndex ] = vertQuadric;
#endif
return vertQuadric;
}
template< typename T, uint32 NumAttributes >
FQuadric TMeshSimplifier<T, NumAttributes>::GetEdgeQuadric( TSimpVert<T>* v )
{
#if SIMP_CACHE
uint32 VertIndex = GetVertIndex( v );
if( EdgeQuadricsValid[ VertIndex ] )
{
return EdgeQuadrics[ VertIndex ];
}
#endif
FQuadric vertQuadric;
vertQuadric.Zero();
TArray< TSimpVert<T>*, TInlineAllocator<64> > adjVerts;
v->FindAdjacentVerts( adjVerts );
LockTriFlags( SIMP_MARK1 );
v->EnableAdjTriFlags( SIMP_MARK1 );
for( TSimpVert<T>* vert : adjVerts )
{
TSimpTri<T>* face = NULL;
int faceCount = 0;
for( TriIterator j = vert->adjTris.Begin(); j != vert->adjTris.End(); ++j )
{
TSimpTri<T>* tri = *j;
if( tri->TestFlags( SIMP_MARK1 ) )
{
face = tri;
faceCount++;
}
}
if( faceCount == 1 )
{
// only one face on this edge
FQuadric edgeQuadric( v->GetPos(), vert->GetPos(), face->GetNormal(), 256.0f );
vertQuadric += edgeQuadric;
}
}
v->DisableAdjTriFlags( SIMP_MARK1 );
UnlockTriFlags( SIMP_MARK1 );
#if SIMP_CACHE
EdgeQuadricsValid[ VertIndex ] = true;
EdgeQuadrics[ VertIndex ] = vertQuadric;
#endif
return vertQuadric;
}
template< typename T, uint32 NumAttributes >
FORCEINLINE uint32 TMeshSimplifier<T, NumAttributes>::GetVertIndex( const TSimpVert<T>* vert ) const
{
ptrdiff_t Index = vert - &sVerts[0];
return (uint32)Index;
}
template< typename T, uint32 NumAttributes >
FORCEINLINE uint32 TMeshSimplifier<T, NumAttributes>::GetTriIndex( const TSimpTri<T>* tri ) const
{
ptrdiff_t Index = tri - &sTris[0];
return (uint32)Index;
}
template< typename T, uint32 NumAttributes >
FORCEINLINE uint32 TMeshSimplifier<T, NumAttributes>::GetEdgeIndex( const TSimpEdge<T>* edge ) const
{
ptrdiff_t Index = edge - &edges[0];
return (uint32)Index;
}
template< typename T, uint32 NumAttributes >
FORCEINLINE uint32 TMeshSimplifier<T, NumAttributes>::HashPoint( const FVector& p ) const
{
union { float f; uint32 i; } x;
union { float f; uint32 i; } y;
union { float f; uint32 i; } z;
x.f = p.X;
y.f = p.Y;
z.f = p.Z;
return Murmur32( { x.i, y.i, z.i } );
}
template< typename T, uint32 NumAttributes >
FORCEINLINE uint32 TMeshSimplifier<T, NumAttributes>::HashEdge( const TSimpVert<T>* u, const TSimpVert<T>* v ) const
{
uint32 ui = GetVertIndex( u );
uint32 vi = GetVertIndex( v );
// must be symmetrical
return Murmur32( { FMath::Min( ui, vi ), FMath::Max( ui, vi ) } );
}
template< typename T, uint32 NumAttributes >
TSimpEdge<T>* TMeshSimplifier<T, NumAttributes>::FindEdge( const TSimpVert<T>* u, const TSimpVert<T>* v )
{
uint32 hash = HashEdge( u, v );
for( uint32 i = edgeHash.First( hash ); edgeHash.IsValid(i); i = edgeHash.Next(i) )
{
if( ( edges[i].v0 == u && edges[i].v1 == v ) ||
( edges[i].v0 == v && edges[i].v1 == u ) )
{
return &edges[i];
}
}
return NULL;
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::RemoveEdge( TSimpEdge<T>* edge )
{
if( edge->TestFlags( SIMP_REMOVED ) )
{
checkSlow( edge->next == edge );
checkSlow( edge->prev == edge );
return;
}
uint32 hash = HashEdge( edge->v0, edge->v1 );
for( uint32 i = edgeHash.First( hash ); edgeHash.IsValid(i); i = edgeHash.Next(i) )
{
if( &edges[i] == edge )
{
edgeHash.Remove( hash, i );
edgeHeap.Remove( i );
break;
}
}
// remove edge
edge->EnableFlags( SIMP_REMOVED );
// ungroup edge
edge->prev->next = edge->next;
edge->next->prev = edge->prev;
edge->next = edge;
edge->prev = edge;
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::ReplaceEdgeVert( const TSimpVert<T>* oldV, const TSimpVert<T>* otherV, TSimpVert<T>* newV )
{
uint32 hash = HashEdge( oldV, otherV );
uint32 index;
for( index = edgeHash.First( hash ); edgeHash.IsValid( index ); index = edgeHash.Next( index ) )
{
if( ( edges[ index ].v0 == oldV && edges[ index ].v1 == otherV ) ||
( edges[ index ].v1 == oldV && edges[ index ].v0 == otherV ) )
break;
}
checkSlow( index != -1 );
TSimpEdge<T>* edge = &edges[ index ];
edgeHash.Remove( hash, index );
TSimpEdge<T>* ExistingEdge = FindEdge( newV, otherV );
if( ExistingEdge )
{
// Not entirely sure why this happens. I believe these are invalid edges from bridge tris.
RemoveEdge( ExistingEdge );
}
if( newV )
{
edgeHash.Add( HashEdge( newV, otherV ), index );
if( edge->v0 == oldV )
edge->v0 = newV;
else
edge->v1 = newV;
}
else
{
// remove edge
edge->EnableFlags( SIMP_REMOVED );
// ungroup old edge
edge->prev->next = edge->next;
edge->next->prev = edge->prev;
edge->next = edge;
edge->prev = edge;
edgeHeap.Remove( index );
}
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::CollapseEdgeVert( const TSimpVert<T>* oldV, const TSimpVert<T>* otherV, TSimpVert<T>* newV )
{
uint32 hash = HashEdge( oldV, otherV );
uint32 index;
for( index = edgeHash.First( hash ); edgeHash.IsValid( index ); index = edgeHash.Next( index ) )
{
if( ( edges[ index ].v0 == oldV && edges[ index ].v1 == otherV ) ||
( edges[ index ].v1 == oldV && edges[ index ].v0 == otherV ) )
break;
}
checkSlow( index != -1 );
TSimpEdge<T>* edge = &edges[ index ];
edgeHash.Remove( hash, index );
edgeHeap.Remove( index );
// remove edge
edge->EnableFlags( SIMP_REMOVED );
// ungroup old edge
edge->prev->next = edge->next;
edge->next->prev = edge->prev;
edge->next = edge;
edge->prev = edge;
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::GatherUpdates( TSimpVert<T>* v )
{
// Update all tris touching collapse edge.
for( TriIterator i = v->adjTris.Begin(); i != v->adjTris.End(); ++i )
{
updateTris.AddUnique( *i );
}
TArray< TSimpVert<T>*, TInlineAllocator<64> > adjVerts;
v->FindAdjacentVerts( adjVerts );
LockVertFlags( SIMP_MARK1 | SIMP_MARK2 );
// Update verts from tris adjacent to collapsed edge
for( int i = 0, Num = adjVerts.Num(); i < Num; i++ )
{
updateVerts.AddUnique( adjVerts[i] );
adjVerts[i]->EnableFlags( SIMP_MARK2 );
}
// update the costs of all edges connected to any face adjacent to v
for( int i = 0, Num = adjVerts.Num(); i < Num; i++ )
{
adjVerts[i]->EnableAdjVertFlags( SIMP_MARK1 );
for( TriIterator j = adjVerts[i]->adjTris.Begin(); j != adjVerts[i]->adjTris.End(); ++j )
{
TSimpTri<T>* tri = *j;
for( int k = 0; k < 3; k++ )
{
TSimpVert<T>* vert = tri->verts[k];
if( vert->TestFlags( SIMP_MARK1 ) && !vert->TestFlags( SIMP_MARK2 ) )
{
TSimpEdge<T>* edge = FindEdge( adjVerts[i], vert );
updateEdges.AddUnique( edge );
}
vert->DisableFlags( SIMP_MARK1 );
}
}
adjVerts[i]->DisableFlags( SIMP_MARK2 );
}
UnlockVertFlags( SIMP_MARK1 | SIMP_MARK2 );
}
template< typename T, uint32 NumAttributes >
float TMeshSimplifier<T, NumAttributes>::ComputeNewVerts( TSimpEdge<T>* edge, TArray< T, TInlineAllocator<16> >& newVerts )
{
TSimpEdge<T>* e;
TSimpVert<T>* v;
TArray< QuadricType, TInlineAllocator<16> > quadrics;
TQuadricAttrOptimizer< NumAttributes > optimizer;
LockVertFlags( SIMP_MARK1 );
edge->v0->EnableFlagsGroup( SIMP_MARK1 );
edge->v1->EnableFlagsGroup( SIMP_MARK1 );
// add edges
e = edge;
do {
checkSlow( e == FindEdge( e->v0, e->v1 ) );
checkSlow( e->v0->adjTris.Num() > 0 );
checkSlow( e->v1->adjTris.Num() > 0 );
checkSlow( e->v0->GetMaterialIndex() == e->v1->GetMaterialIndex() );
newVerts.Add( e->v0->vert );
QuadricType quadric;
quadric = GetQuadric( e->v0 );
quadric += GetQuadric( e->v1 );
quadrics.Add( quadric );
optimizer.AddQuadric( quadric );
e->v0->DisableFlags( SIMP_MARK1 );
e->v1->DisableFlags( SIMP_MARK1 );
e = e->next;
} while( e != edge );
// add remainder verts
v = edge->v0;
do {
if( v->TestFlags( SIMP_MARK1 ) )
{
newVerts.Add( v->vert );
QuadricType quadric;
quadric = GetQuadric( v );
quadrics.Add( quadric );
optimizer.AddQuadric( quadric );
v->DisableFlags( SIMP_MARK1 );
}
v = v->next;
} while( v != edge->v0 );
v = edge->v1;
do {
if( v->TestFlags( SIMP_MARK1 ) )
{
newVerts.Add( v->vert );
QuadricType quadric;
quadric = GetQuadric( v );
quadrics.Add( quadric );
optimizer.AddQuadric( quadric );
v->DisableFlags( SIMP_MARK1 );
}
v = v->next;
} while( v != edge->v1 );
UnlockVertFlags( SIMP_MARK1 );
check( quadrics.Num() <= 256 );
FQuadric edgeQuadric;
edgeQuadric.Zero();
v = edge->v0;
do {
edgeQuadric += GetEdgeQuadric( v );
v = v->next;
} while( v != edge->v0 );
v = edge->v1;
do {
edgeQuadric += GetEdgeQuadric( v );
v = v->next;
} while( v != edge->v1 );
optimizer.AddQuadric( edgeQuadric );
FVector newPos;
{
bool bLocked0 = edge->v0->TestFlags( SIMP_LOCKED );
bool bLocked1 = edge->v1->TestFlags( SIMP_LOCKED );
//checkSlow( !bLocked0 || !bLocked1 );
// find position
if( bLocked0 )
{
// v0 position
newPos = edge->v0->GetPos();
}
else if( bLocked1 )
{
// v1 position
newPos = edge->v1->GetPos();
}
else
{
// optimal position
bool valid = optimizer.Optimize( newPos );
if( !valid )
{
// Couldn't find optimal so choose middle
newPos = ( edge->v0->GetPos() + edge->v1->GetPos() ) * 0.5f;
}
}
}
float cost = 0.0f;
for( int i = 0; i < quadrics.Num(); i++ )
{
newVerts[i].GetPos() = newPos;
if( quadrics[i].a > 1e-8 )
{
// calculate vert attributes from the new position
quadrics[i].CalcAttributes( newVerts[i].GetPos(), newVerts[i].GetAttributes(), attributeWeights );
newVerts[i].Correct();
}
// sum cost of new verts
cost += quadrics[i].Evaluate( newVerts[i].GetPos(), newVerts[i].GetAttributes(), attributeWeights );
}
cost += edgeQuadric.Evaluate( newPos );
return cost;
}
template< typename T, uint32 NumAttributes >
float TMeshSimplifier<T, NumAttributes>::ComputeEdgeCollapseCost( TSimpEdge<T>* edge )
{
TArray< T, TInlineAllocator<16> > newVerts;
float cost = ComputeNewVerts( edge, newVerts );
const FVector& newPos = newVerts[0].GetPos();
// add penalties
// the below penalty code works with groups so no need to worry about remainder verts
TSimpVert<T>* u = edge->v0;
TSimpVert<T>* v = edge->v1;
TSimpVert<T>* vert;
float penalty = 0.0f;
{
const int degreeLimit = 24;
const float degreePenalty = 100.0f;
int degree = 0;
// u
vert = u;
do {
degree += vert->adjTris.Num();
vert = vert->next;
} while( vert != u );
// v
vert = v;
do {
degree += vert->adjTris.Num();
vert = vert->next;
} while( vert != v );
if( degree > degreeLimit )
penalty += degreePenalty * ( degree - degreeLimit );
}
{
// Penalty to prevent edge folding
const float invalidPenalty = 1000000.0f;
LockTriFlags( SIMP_MARK1 );
v->EnableAdjTriFlagsGroup( SIMP_MARK1 );
// u
vert = u;
do {
for( TriIterator i = vert->adjTris.Begin(); i != vert->adjTris.End(); ++i )
{
TSimpTri<T>* tri = *i;
if( !tri->TestFlags( SIMP_MARK1 ) )
penalty += tri->ReplaceVertexIsValid( vert, newPos ) ? 0.0f : invalidPenalty;
tri->DisableFlags( SIMP_MARK1 );
}
vert = vert->next;
} while( vert != u );
// v
vert = v;
do {
for( TriIterator i = vert->adjTris.Begin(); i != vert->adjTris.End(); ++i )
{
TSimpTri<T>* tri = *i;
if( tri->TestFlags( SIMP_MARK1 ) )
penalty += tri->ReplaceVertexIsValid( vert, newPos ) ? 0.0f : invalidPenalty;
tri->DisableFlags( SIMP_MARK1 );
}
vert = vert->next;
} while( vert != v );
UnlockTriFlags( SIMP_MARK1 );
}
return cost + penalty;
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::Collapse( TSimpEdge<T>* edge )
{
TSimpVert<T>* u = edge->v0;
TSimpVert<T>* v = edge->v1;
// Collapse the edge uv by moving vertex u onto v
checkSlow( u && v );
checkSlow( edge == FindEdge( u, v ) );
checkSlow( u->adjTris.Num() > 0 );
checkSlow( v->adjTris.Num() > 0 );
checkSlow( u->GetMaterialIndex() == v->GetMaterialIndex() );
if( u->TestFlags( SIMP_LOCKED ) )
v->EnableFlags( SIMP_LOCKED );
LockVertFlags( SIMP_MARK1 );
// update edges from u to v
u->EnableAdjVertFlags( SIMP_MARK1 );
v->DisableAdjVertFlags( SIMP_MARK1 );
if( u->TestFlags( SIMP_MARK1 ) )
{
// Invalid edge, results from collapsing a bridge tri
// There are no actual triangles connecting these verts
u->DisableAdjVertFlags( SIMP_MARK1 );
UnlockVertFlags( SIMP_MARK1 );
return;
}
for( TriIterator i = u->adjTris.Begin(); i != u->adjTris.End(); ++i )
{
TSimpTri<T>* tri = *i;
for( int j = 0; j < 3; j++ )
{
TSimpVert<T>* vert = tri->verts[j];
if( vert->TestFlags( SIMP_MARK1 ) )
{
ReplaceEdgeVert( u, vert, v );
vert->DisableFlags( SIMP_MARK1 );
}
}
}
// remove dead edges
u->EnableAdjVertFlags( SIMP_MARK1 );
u->DisableFlags( SIMP_MARK1 );
v->DisableFlags( SIMP_MARK1 );
for( TriIterator i = v->adjTris.Begin(); i != v->adjTris.End(); ++i )
{
TSimpTri<T>* tri = *i;
for( int j = 0; j < 3; j++ )
{
TSimpVert<T>* vert = tri->verts[j];
if( vert->TestFlags( SIMP_MARK1 ) )
{
ReplaceEdgeVert( u, vert, NULL );
vert->DisableFlags( SIMP_MARK1 );
}
}
}
u->DisableAdjVertFlags( SIMP_MARK1 );
// fixup triangles
for( TriIterator i = u->adjTris.Begin(); i != u->adjTris.End(); ++i )
{
TSimpTri<T>* tri = *i;
checkSlow( !tri->TestFlags( SIMP_REMOVED ) );
checkSlow( tri->HasVertex(u) );
if( tri->HasVertex(v) )
{
// delete triangles on edge uv
numTris--;
tri->EnableFlags( SIMP_REMOVED );
#if SIMP_CACHE
TriQuadricsValid[ GetTriIndex( tri ) ] = false;
#endif
// remove references to tri
for( int j = 0; j < 3; j++ )
{
TSimpVert<T>* vert = tri->verts[j];
checkSlow( !vert->TestFlags( SIMP_REMOVED ) );
if( vert != u )
{
vert->adjTris.Remove( tri );
#if 0
if( vert != v && vert->adjTris.Num() == 0 ) {
if( !vert->TestFlags( SIMP_REMOVED ) ) { // not sure why this happens
numVerts--;
vert->EnableFlags( SIMP_REMOVED );
}
ReplaceEdgeVert( v, vert, NULL );
}
#endif
}
}
}
else
{
// update triangles to have v instead of u
tri->ReplaceVertex( u, v );
v->adjTris.Add( tri );
}
}
#if SIMP_CACHE
// remove modified verts and tris from cache
v->EnableAdjVertFlags( SIMP_MARK1 );
for( TriIterator i = v->adjTris.Begin(); i != v->adjTris.End(); ++i )
{
TSimpTri<T>* tri = *i;
TriQuadricsValid[ GetTriIndex( tri ) ] = false;
for( int j = 0; j < 3; j++ )
{
TSimpVert<T>* vert = tri->verts[j];
if( vert->TestFlags( SIMP_MARK1 ) )
{
VertQuadricsValid[ GetVertIndex( vert ) ] = false;
vert->DisableFlags( SIMP_MARK1 );
}
}
}
#endif
UnlockVertFlags( SIMP_MARK1 );
u->adjTris.Clear(); // u has been removed
u->EnableFlags( SIMP_REMOVED );
numVerts--;
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::UpdateTris()
{
// remove degenerate triangles
// not sure why this happens
for( TSimpTri<T>* tri : updateTris )
{
if( tri->TestFlags( SIMP_REMOVED ) )
continue;
#if SIMP_CACHE
TriQuadricsValid[ GetTriIndex( tri ) ] = false;
#endif
const FVector& p0 = tri->verts[0]->GetPos();
const FVector& p1 = tri->verts[1]->GetPos();
const FVector& p2 = tri->verts[2]->GetPos();
const FVector n = ( p2 - p0 ) ^ ( p1 - p0 );
if( n.SizeSquared() == 0.0f )
{
numTris--;
tri->EnableFlags( SIMP_REMOVED );
// remove references to tri
for( int j = 0; j < 3; j++ )
{
TSimpVert<T>* vert = tri->verts[j];
vert->adjTris.Remove( tri );
// orphaned verts are removed below
}
}
}
updateTris.Reset();
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::UpdateVerts()
{
// remove orphaned verts
for( TSimpVert<T>* vert : updateVerts )
{
if( vert->TestFlags( SIMP_REMOVED ) )
continue;
#if SIMP_CACHE
VertQuadricsValid[ GetVertIndex( vert ) ] = false;
EdgeQuadricsValid[ GetVertIndex( vert ) ] = false;
#endif
if( vert->adjTris.Num() == 0 )
{
numVerts--;
vert->EnableFlags( SIMP_REMOVED );
// ungroup
vert->prev->next = vert->next;
vert->next->prev = vert->prev;
vert->next = vert;
vert->prev = vert;
}
}
updateVerts.Reset();
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::UpdateEdges()
{
uint32 NumEdges = updateEdges.Num();
// add all grouped edges
for( uint32 i = 0; i < NumEdges; i++ )
{
TSimpEdge<T>* edge = updateEdges[i];
if( edge->TestFlags( SIMP_REMOVED ) )
continue;
TSimpEdge<T>* e = edge;
do {
updateEdges.AddUnique(e);
e = e->next;
} while( e != edge );
}
// remove dead edges
for( uint32 i = 0, Num = updateEdges.Num(); i < Num; i++ )
{
TSimpEdge<T>* edge = updateEdges[i];
if( edge->TestFlags( SIMP_REMOVED ) )
continue;
if( edge->v0->TestFlags( SIMP_REMOVED ) ||
edge->v1->TestFlags( SIMP_REMOVED ) )
{
RemoveEdge( edge );
continue;
}
}
// Fix edge groups
{
FHashTable HashTable( 128, NumEdges );
// ungroup edges
for( uint32 i = 0, Num = updateEdges.Num(); i < Num; i++ )
{
TSimpEdge<T>* edge = updateEdges[i];
if( edge->TestFlags( SIMP_REMOVED ) )
continue;
edge->next = edge;
edge->prev = edge;
HashTable.Add( HashPoint( edge->v0->GetPos() ) ^ HashPoint( edge->v1->GetPos() ), i );
}
// regroup edges
for( uint32 i = 0, Num = updateEdges.Num(); i < Num; i++ )
{
TSimpEdge<T>* edge = updateEdges[i];
if( edge->TestFlags( SIMP_REMOVED ) )
continue;
// already grouped
if( edge->next != edge )
continue;
// find any matching edges
uint32 hash = HashPoint( edge->v0->GetPos() ) ^ HashPoint( edge->v1->GetPos() );
for( uint32 j = HashTable.First( hash ); HashTable.IsValid(j); j = HashTable.Next( j ) )
{
TSimpEdge<T>* e1 = updateEdges[i];
TSimpEdge<T>* e2 = updateEdges[j];
if( e1 == e2 )
continue;
bool m1 = e1->v0->GetPos() == e2->v0->GetPos() &&
e1->v1->GetPos() == e2->v1->GetPos();
bool m2 = e1->v0->GetPos() == e2->v1->GetPos() &&
e1->v1->GetPos() == e2->v0->GetPos();
// backwards
if( m2 )
Swap( e2->v0, e2->v1 );
// link
if( m1 || m2 )
{
checkSlow( e2->next == e2 );
checkSlow( e2->prev == e2 );
e2->next = e1->next;
e2->prev = e1;
e2->next->prev = e2;
e2->prev->next = e2;
}
}
}
}
// update edges
for( uint32 i = 0; i < NumEdges; i++ )
{
TSimpEdge<T>* edge = updateEdges[i];
if( edge->TestFlags( SIMP_REMOVED ) )
continue;
float cost = ComputeEdgeCollapseCost( edge );
TSimpEdge<T>* e = edge;
do {
uint32 EdgeIndex = GetEdgeIndex(e);
if( edgeHeap.IsPresent( EdgeIndex ) )
{
edgeHeap.Update( cost, EdgeIndex );
}
e = e->next;
} while( e != edge );
}
updateEdges.Reset();
}
template< typename T, uint32 NumAttributes >
float TMeshSimplifier<T, NumAttributes>::SimplifyMesh( float maxErrorLimit, int minTris, int minVerts )
{
TSimpVert<T>* v;
TSimpEdge<T>* e;
float maxError = 0.0f;
while( edgeHeap.Num() > 0 )
{
if( numTris <= minTris || numVerts <= minVerts )
break;
// get the next vertex to collapse
uint32 TopIndex = edgeHeap.Top();
float error = edgeHeap.GetKey( TopIndex );
if( error > maxErrorLimit )
{
break;
}
maxError = FMath::Max( maxError, error );
edgeHeap.Pop();
TSimpEdge<T>* top = &edges[ TopIndex ];
int numEdges = 0;
TSimpEdge<T>* edgeList[32];
TSimpEdge<T>* edge = top;
do {
edgeList[ numEdges++ ] = edge;
edge = edge->next;
} while( edge != top );
check(top);
// skip locked edges
bool locked = false;
for( int i = 0; i < numEdges; i++ )
{
edge = edgeList[i];
if( edge->v0->TestFlags( SIMP_LOCKED ) && edge->v1->TestFlags( SIMP_LOCKED ) )
{
locked = true;
}
}
if( locked )
continue;
v = top->v0;
do {
GatherUpdates( v );
v = v->next;
} while( v != top->v0 );
v = top->v1;
do {
GatherUpdates( v );
v = v->next;
} while( v != top->v1 );
#if 1
// remove edges with already removed verts
// not sure why this happens
for( int i = 0; i < numEdges; i++ )
{
if( edgeList[i]->v0->adjTris.Num() == 0 ||
edgeList[i]->v1->adjTris.Num() == 0 )
{
RemoveEdge( edgeList[i] );
edgeList[i] = NULL;
}
else
{
checkSlow( !edgeList[i]->TestFlags( SIMP_REMOVED ) );
}
}
if( top->v0->adjTris.Num() == 0 || top->v1->adjTris.Num() == 0 )
continue;
#endif
// move verts to new verts
{
edge = top;
TArray< T, TInlineAllocator<16> > newVerts;
ComputeNewVerts( edge, newVerts );
uint32 i = 0;
LockVertFlags( SIMP_MARK1 );
edge->v0->EnableFlagsGroup( SIMP_MARK1 );
edge->v1->EnableFlagsGroup( SIMP_MARK1 );
// edges
e = edge;
do {
checkSlow( e == FindEdge( e->v0, e->v1 ) );
checkSlow( e->v0->adjTris.Num() > 0 );
checkSlow( e->v1->adjTris.Num() > 0 );
checkSlow( e->v0->GetMaterialIndex() == e->v1->GetMaterialIndex() );
e->v1->vert = newVerts[ i++ ];
e->v0->DisableFlags( SIMP_MARK1 );
e->v1->DisableFlags( SIMP_MARK1 );
e = e->next;
} while( e != edge );
// remainder verts
v = edge->v0;
do {
if( v->TestFlags( SIMP_MARK1 ) )
{
v->vert = newVerts[ i++ ];
v->DisableFlags( SIMP_MARK1 );
}
v = v->next;
} while( v != edge->v0 );
v = edge->v1;
do {
if( v->TestFlags( SIMP_MARK1 ) ) {
v->vert = newVerts[ i++ ];
v->DisableFlags( SIMP_MARK1 );
}
v = v->next;
} while( v != edge->v1 );
UnlockVertFlags( SIMP_MARK1 );
}
// collapse all edges
for( int i = 0; i < numEdges; i++ )
{
edge = edgeList[i];
if( !edge )
continue;
if( edge->TestFlags( SIMP_REMOVED ) ) // wtf?
continue;
if( edge->v0->adjTris.Num() == 0 )
continue;
if( edge->v1->adjTris.Num() == 0 )
continue;
Collapse( edge );
RemoveEdge( edge );
}
// add v0 remainder verts to v1
{
// combine v0 and v1 groups
top->v0->next->prev = top->v1->prev;
top->v1->prev->next = top->v0->next;
top->v0->next = top->v1;
top->v1->prev = top->v0;
// ungroup removed verts
uint32 vertListNum = 0;
TSimpVert<T>* vertList[256];
v = top->v1;
do {
vertList[ vertListNum++ ] = v;
v = v->next;
} while( v != top->v1 );
check( vertListNum <= 256 );
for( uint32 i = 0; i < vertListNum; i++ )
{
v = vertList[i];
if( v->TestFlags( SIMP_REMOVED ) )
{
// ungroup
v->prev->next = v->next;
v->next->prev = v->prev;
v->next = v;
v->prev = v;
}
}
}
{
// spread locked flag to vert group
uint32 flags = 0;
v = top->v1;
do {
flags |= v->flags & SIMP_LOCKED;
v = v->next;
} while( v != top->v1 );
v = top->v1;
do {
v->flags |= flags;
v = v->next;
} while( v != top->v1 );
}
UpdateTris();
UpdateVerts();
UpdateEdges();
}
// remove degenerate triangles
// not sure why this happens
for( int i = 0; i < numSTris; i++ )
{
TSimpTri<T>* tri = &sTris[i];
if( tri->TestFlags( SIMP_REMOVED ) )
continue;
const FVector& p0 = tri->verts[0]->GetPos();
const FVector& p1 = tri->verts[1]->GetPos();
const FVector& p2 = tri->verts[2]->GetPos();
const FVector n = ( p2 - p0 ) ^ ( p1 - p0 );
if( n.SizeSquared() == 0.0f )
{
numTris--;
tri->EnableFlags( SIMP_REMOVED );
// remove references to tri
for( int j = 0; j < 3; j++ )
{
TSimpVert<T>* vert = tri->verts[j];
vert->adjTris.Remove( tri );
// orphaned verts are removed below
}
}
}
// remove orphaned verts
for( int i = 0; i < numSVerts; i++ )
{
TSimpVert<T>* vert = &sVerts[i];
if( vert->TestFlags( SIMP_REMOVED ) )
continue;
if( vert->adjTris.Num() == 0 )
{
numVerts--;
vert->EnableFlags( SIMP_REMOVED );
}
}
return maxError;
}
template< typename T, uint32 NumAttributes >
void TMeshSimplifier<T, NumAttributes>::OutputMesh( T* verts, uint32* indexes )
{
FHashTable HashTable( 4096, GetNumVerts() );
#if 1
int count = 0;
for( int i = 0; i < numSVerts; i++ )
count += sVerts[i].TestFlags( SIMP_REMOVED ) ? 0 : 1;
check( numVerts == count );
#endif
int numV = 0;
int numI = 0;
for( int i = 0; i < numSTris; i++ )
{
if( sTris[i].TestFlags( SIMP_REMOVED ) )
continue;
// TODO this is sloppy. There should be no duped verts. Alias by index.
for( int j = 0; j < 3; j++ )
{
TSimpVert<T>* vert = sTris[i].verts[j];
checkSlow( !vert->TestFlags( SIMP_REMOVED ) );
checkSlow( vert->adjTris.Num() != 0 );
const FVector& p = vert->GetPos();
uint32 hash = HashPoint( p );
uint32 f;
for( f = HashTable.First( hash ); HashTable.IsValid(f); f = HashTable.Next( f ) )
{
if( vert->vert == verts[f] )
break;
}
if( !HashTable.IsValid(f) )
{
HashTable.Add( hash, numV );
verts[ numV ] = vert->vert;
indexes[ numI++ ] = numV;
numV++;
}
else
{
indexes[ numI++ ] = f;
}
}
}
check( numV <= numVerts );
check( numI <= numTris * 3 );
numVerts = numV;
numTris = numI / 3;
}