Files
UnrealEngine/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Private/Operations/OffsetMeshRegion.cpp
2025-05-18 13:04:45 +08:00

1109 lines
37 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#include "Operations/OffsetMeshRegion.h"
#include "Algo/Reverse.h"
#include "DynamicMesh/MeshNormals.h"
#include "DynamicMeshEditor.h"
#include "Parameterization/DynamicMeshUVEditor.h"
#include "Selections/MeshVertexSelection.h"
#include "DynamicMesh/DynamicMeshChangeTracker.h"
#include "Selections/MeshConnectedComponents.h"
#include "Operations/ExtrudeMesh.h"
#include "EdgeLoop.h"
#include "DynamicSubmesh3.h"
#include "Selections/QuadGridPatch.h"
#include "Operations/PolyEditingUVUtil.h"
#include "Operations/PolyEditingEdgeUtil.h"
#include "Operations/QuadGridPatchUtil.h"
#include "Operations/PolyModeling/PolyModelingMaterialUtil.h"
using namespace UE::Geometry;
FOffsetMeshRegion::FOffsetMeshRegion(FDynamicMesh3* mesh) : Mesh(mesh)
{
}
bool FOffsetMeshRegion::Apply()
{
FMeshConnectedComponents RegionComponents(Mesh);
RegionComponents.FindConnectedTriangles(Triangles);
bool bAllOK = true;
OffsetRegions.SetNum(RegionComponents.Num());
for (int k = 0; k < RegionComponents.Num(); ++k)
{
FOffsetInfo& Region = OffsetRegions[k];
Region.OffsetTids = MoveTemp(RegionComponents.Components[k].Indices);
if (bOffsetFullComponentsAsSolids)
{
TArray<int32> AllTriangles;
FMeshConnectedComponents::GrowToConnectedTriangles(Mesh, Region.OffsetTids, AllTriangles);
Region.bIsSolid = AllTriangles.Num() == Region.OffsetTids.Num();
}
bool bRegionOK = ApplyOffset(Region);
bAllOK = bAllOK && bRegionOK;
}
return bAllOK;
}
namespace OffsetMeshRegionLocals
{
typedef TPair<int32, TPair<int8, int8>> TriVertPair;
/**
* @return true if mesh edges are parallel or either is degenerate (the degenerate tolerance is quite large though, 0.0001).
*/
bool EdgesAreParallel(FDynamicMesh3* Mesh, int32 Eid1, int32 Eid2)
{
FIndex2i Vids1 = Mesh->GetEdgeV(Eid1);
FIndex2i Vids2 = Mesh->GetEdgeV(Eid2);
FVector3d Vec1 = Mesh->GetVertex(Vids1.A) - Mesh->GetVertex(Vids1.B);
FVector3d Vec2 = Mesh->GetVertex(Vids2.A) - Mesh->GetVertex(Vids2.B);
if (!Vec1.Normalize(KINDA_SMALL_NUMBER) || !Vec2.Normalize(KINDA_SMALL_NUMBER))
{
// A degenerate edge is parallel enough for our purposes
return true;
}
return FMath::Abs(Vec1.Dot(Vec2)) >= 1 - KINDA_SMALL_NUMBER;
}
/**
* Assuming GroupIDs is a list of integer IDs for a contiguous "loop", ie last
* element is adjacent to first element, this function returns the index of the first
* value in the first non-broken contiguous span of duplicate values. IE if the array
* is [0,0,0,1,1,2,2] it will return "0" but if it were [0,0,1,1,2,2,0] it would return "2",
* ie the inde of the first "1". The purpose is to allow iterating through the array
* in the order [1,1,2,2,0,0,0], ie the "0" values are not split across the N-1/0 transition
*/
static int32 FindLoopShiftFromGroupIDs(const TArray<int32>& GroupIDs)
{
int32 N = GroupIDs.Num();
if (GroupIDs[0] != GroupIDs[N - 1])
{
return 0;
}
for (int32 k = 0; k < N-1; ++k)
{
if (GroupIDs[k] != GroupIDs[k + 1])
{
return k+1;
}
}
return 0; // all values are the same, no shift
}
/**
* Cycle/Shift the values in the Values array to the left ShiftNum times.
* Uses a temporary array internally.
*/
template<typename ValueType>
static void LeftShiftArray(TArray<ValueType>& Values, int ShiftNum)
{
if (ShiftNum == 0 ) return;
int32 N = Values.Num();
// there is probably some clever way to do this w/o a temporary array...
TArray<ValueType> Tmp;
Tmp.SetNum(N);
for (int32 k = 0; k < N; ++k)
{
Tmp[k] = Values[(ShiftNum+k)%N];
}
Values = MoveTemp(Tmp);
}
struct FStitchConfigOptions
{
int NumSubdivisions = 0;
double UVScaleFactor = 1.0;
bool bGroupPerSubdivision = true;
bool bUVIslandPerGroup = true;
double CreaseAngleThreshold = 180.0;
int SetMaterialID = 0;
bool bInferMaterialID = false;
};
/**
* Stitch pairs of border loops of Mesh defined by LoopPairs.
*
*/
static bool StitchRegionBorderLoopPairs_Version1(
FDynamicMesh3& Mesh,
const TArray<FDynamicMeshEditor::FLoopPairSet>& LoopPairs,
const TArray<TArray<int32>>& LoopsPerEdgeNewGroupIDs,
const TArray<TArray<FMeshTriOrderedEdgeID>>& InnerTriOrderedEdgeLoops,
FStitchConfigOptions StitchConfig,
TArray<bool>& bLoopOK,
TArray<TArray<int32>>& PerLoopTrianglesOut,
TArray<TArray<int32>>& PerLoopGroupsOut )
{
FDynamicMeshEditor Editor(&Mesh);
bool bAllSuccess = true;
int NumInitialLoops = LoopPairs.Num();
PerLoopTrianglesOut.SetNum(NumInitialLoops);
PerLoopGroupsOut.SetNum(NumInitialLoops);
bLoopOK.Init(false, NumInitialLoops);
for (int32 LoopIndex = 0; LoopIndex < LoopPairs.Num(); ++LoopIndex)
{
// note we are assuming here that the loops are aligned w/ a group transition
const TArray<int32>& OuterLoopV = LoopPairs[LoopIndex].OuterVertices;
const TArray<int32>& InnerLoopV = LoopPairs[LoopIndex].InnerVertices;
const TArray<FMeshTriOrderedEdgeID>& InnerTriOrderedEdgeLoop = InnerTriOrderedEdgeLoops[LoopIndex];
int32 NV = OuterLoopV.Num();
// populate list of Material IDs attached to inner loop
TArray<int32> MaterialIDs;
FDynamicMeshMaterialAttribute* MaterialIDAttrib = (Mesh.HasAttributes() && Mesh.Attributes()->HasMaterialID()) ?
Mesh.Attributes()->GetMaterialID() : nullptr;
if ( MaterialIDAttrib && StitchConfig.bInferMaterialID )
{
UE::Geometry::ComputeMaterialIDsForVertexPath(Mesh, InnerLoopV, true, MaterialIDs, StitchConfig.SetMaterialID);
}
else if ( MaterialIDAttrib )
{
MaterialIDs.Init(StitchConfig.SetMaterialID, NV);
}
// LoopStack is the set of NumSubdivisions+1 loops that will be stitched,
// where the "last" loop is the Outer loop. The "first" Inner loop is not
// included in LoopStack, it has special handling below
TArray<TArray<int32>> LoopStack;
LoopStack.SetNum(StitchConfig.NumSubdivisions+1);
LoopStack[StitchConfig.NumSubdivisions] = OuterLoopV;
int LastTemp = LoopStack[StitchConfig.NumSubdivisions][0];
// build interior loops if there are any
for ( int32 StackIdx = 0; StackIdx < StitchConfig.NumSubdivisions; ++StackIdx )
{
LoopStack[StackIdx].Reserve(NV);
double t = (double)(StackIdx+1) / (double)(StitchConfig.NumSubdivisions+1);
for ( int32 k = 0; k < NV; ++k )
{
FVector3d A = Mesh.GetVertex(InnerLoopV[k]);
FVector3d B = Mesh.GetVertex(OuterLoopV[k]);
FVector3d StackPos = Lerp(A, B, t);
LoopStack[StackIdx].Add( Mesh.AppendVertex(StackPos) );
}
LastTemp = LoopStack[StackIdx][0];
}
// build the first strip from the Inner loop to the next loop
FDynamicMeshEditResult StitchResult;
TArray<int32> InnerVertexLoop, TempEdgeLoop;
UE::Geometry::ConvertTriOrderedEdgeLoopToLoop(Mesh, InnerTriOrderedEdgeLoop, InnerVertexLoop, &TempEdgeLoop);
bLoopOK[LoopIndex] = Editor.StitchVertexLoopsMinimal(InnerVertexLoop, LoopStack[0], StitchResult);
if (!bLoopOK[LoopIndex])
{
bAllSuccess = false;
continue;
}
FQuadGridPatch QuadPatch;
TArray<int32> TempSpan = LoopStack[0]; // annoying to have to make a copy like this...need to perserve for LoopStack[k-1] below though
TempSpan.Add(LoopStack[0][0]);
QuadPatch.InitializeFromQuadStrip(Mesh, StitchResult.NewQuads, TempSpan);
QuadPatch.ReverseRows(); // need LoopStack[0] to be the second span but it's currently the first one...
// incrementally stitch intermediate strips and accumulate into the Quad Patch
for ( int32 k = 1; k <= StitchConfig.NumSubdivisions; ++k )
{
FDynamicMeshEditResult StripResult;
bLoopOK[LoopIndex] = Editor.StitchVertexLoopsMinimal(LoopStack[k-1], LoopStack[k], StripResult);
FQuadGridPatch NextQuadStrip;
TempSpan = LoopStack[k-1]; // must preserve LoopStack arrays currently
TempSpan.Add(LoopStack[k-1][0]);
NextQuadStrip.InitializeFromQuadStrip(Mesh, StripResult.NewQuads, TempSpan);
QuadPatch.AppendQuadPatchRows(MoveTemp(NextQuadStrip), true);
}
QuadPatch.ReverseRows(); // for an extrude/offset this makes sense, quads will "start" at the transition from base loop
// set group IDs on patch, propagating up the subdivisions columns
const TArray<int32>& PerEdgeNewGroupIDs = LoopsPerEdgeNewGroupIDs[LoopIndex]; // is it always guaranteed to be the same length??
QuadPatch.ForEachQuad( [&](int32 QuadRow, int32 QuadCol, FIndex2i QuadTris)
{
int32 GroupID = PerEdgeNewGroupIDs[QuadCol];
Mesh.SetTriangleGroup(QuadTris.A, GroupID);
Mesh.SetTriangleGroup(QuadTris.B, GroupID);
if (MaterialIDAttrib)
{
MaterialIDAttrib->SetValue(QuadTris.A, MaterialIDs[QuadCol]);
MaterialIDAttrib->SetValue(QuadTris.B, MaterialIDs[QuadCol]);
}
});
// split quad patch by group ID into a set of quad patches
bool bSplitDueToCrease = false;
TArray<FQuadGridPatch> GroupStrips;
QuadPatch.SplitColumnsByPredicate(
[&](int32 ColumnIdx, int32 NextColumnIdx) {
if (PerEdgeNewGroupIDs[ColumnIdx] != PerEdgeNewGroupIDs[NextColumnIdx])
{
return true;
}
else if (QuadPatch.GetQuadOpeningAngleDeg(Mesh, NextColumnIdx, NextColumnIdx+1, 0) > StitchConfig.CreaseAngleThreshold)
{
bSplitDueToCrease = true;
return true;
}
return false;
},
GroupStrips);
// compute normals and UVs for each group-quad-patch
if (Mesh.HasAttributes())
{
for (FQuadGridPatch& GroupPatch : GroupStrips)
{
UE::Geometry::ComputeNormalsForQuadPatch(Mesh, GroupPatch);
if ( StitchConfig.bUVIslandPerGroup )
{
UE::Geometry::ComputeUVIslandForQuadPatch(Mesh, GroupPatch, StitchConfig.UVScaleFactor);
}
}
}
// if not per-group UV islands, do it for the entire strip)
if (StitchConfig.bUVIslandPerGroup == false)
{
UE::Geometry::ComputeUVIslandForQuadPatch(Mesh, QuadPatch, StitchConfig.UVScaleFactor);
}
// if we split groups due to a crease, we need to reassign groups in row 0
if (bSplitDueToCrease)
{
for (FQuadGridPatch& GroupPatch : GroupStrips)
{
int32 NewPatchGroup = Mesh.AllocateTriangleGroup();
GroupPatch.ForEachQuad([&](int32 Row, int32 Col, FIndex2i QuadTris)
{
Mesh.SetTriangleGroup(QuadTris.A, NewPatchGroup);
Mesh.SetTriangleGroup(QuadTris.B, NewPatchGroup);
});
}
}
// Assign a new group to each row of group-quad-patch
if ( StitchConfig.bGroupPerSubdivision )
{
for (FQuadGridPatch& GroupPatch : GroupStrips)
{
int32 NumQuadRows = GroupPatch.NumVertexRowsV-1;
TArray<int32> RowGroups;
RowGroups.SetNum(NumQuadRows);
// if we split at a crease we need to reassign first column too...
for ( int32 k =1; k < NumQuadRows; ++k )
{
RowGroups[k] = Mesh.AllocateTriangleGroup();
}
GroupPatch.ForEachQuad([&](int32 Row, int32 Col, FIndex2i QuadTris)
{
if ( Row > 0 )
{
Mesh.SetTriangleGroup(QuadTris.A, RowGroups[Row]);
Mesh.SetTriangleGroup(QuadTris.B, RowGroups[Row]);
}
});
}
}
// save the stitch triangles set and associated group IDs
QuadPatch.GetAllTriangles(PerLoopTrianglesOut[LoopIndex]);
for (int32 tid : PerLoopTrianglesOut[LoopIndex])
{
PerLoopGroupsOut[LoopIndex].AddUnique( Mesh.GetTriangleGroup(tid) );
}
}
return bAllSuccess;
}
static void SetStitchStripNormalsUVs_Legacy(
FDynamicMesh3& Mesh,
FDynamicMeshEditor& Editor,
FDynamicMeshEditResult& StitchResult,
const TArray<int32>& OuterLoopV,
double UVScaleFactor )
{
int NumNewQuads = StitchResult.NewQuads.Num();
double AccumUVTranslation = 0;
FFrame3d FirstProjectFrame;
FVector3d FrameUp;
for (int k = 0; k < NumNewQuads; k++)
{
FVector3f Normal = Editor.ComputeAndSetQuadNormal(StitchResult.NewQuads[k], true);
// align axis 0 of projection frame to first edge, then for further edges,
// rotate around 'up' axis to keep normal aligned and frame horizontal
FFrame3d ProjectFrame;
if (k == 0)
{
FVector3d FirstEdge = Mesh.GetVertex(OuterLoopV[1]) - Mesh.GetVertex(OuterLoopV[0]);
Normalize(FirstEdge);
FirstProjectFrame = FFrame3d(FVector3d::Zero(), (FVector3d)Normal);
FirstProjectFrame.ConstrainedAlignAxis(0, FirstEdge, (FVector3d)Normal);
FrameUp = FirstProjectFrame.GetAxis(1);
ProjectFrame = FirstProjectFrame;
}
else
{
ProjectFrame = FirstProjectFrame;
ProjectFrame.ConstrainedAlignAxis(2, (FVector3d)Normal, FrameUp);
}
if (k > 0)
{
AccumUVTranslation += Distance(Mesh.GetVertex(OuterLoopV[k]), Mesh.GetVertex(OuterLoopV[k-1]));
}
// translate horizontally such that vertical spans are adjacent in UV space (so textures tile/wrap properly)
double TranslateU = UVScaleFactor * AccumUVTranslation;
Editor.SetQuadUVsFromProjection(StitchResult.NewQuads[k], ProjectFrame, (float)UVScaleFactor, FVector2f((float)TranslateU, 0));
}
}
static bool StitchRegionBorderLoopPairs_Legacy(
FDynamicMesh3& Mesh,
const TArray<FDynamicMeshEditor::FLoopPairSet>& LoopPairs,
const TArray<TArray<int32>>& LoopsPerEdgeNewGroupIDs,
const TArray<TArray<TriVertPair>> OffsetStitchSides,
double UVScaleFactor,
TArray<bool>& bLoopOK,
TArray<TArray<int32>>& PerLoopTrianglesOut,
TArray<TArray<int32>>& PerLoopGroupsOut )
{
FDynamicMeshEditor Editor(&Mesh);
bool bAllSuccess = true;
int NumInitialLoops = LoopPairs.Num();
PerLoopTrianglesOut.SetNum(NumInitialLoops);
PerLoopGroupsOut.SetNum(NumInitialLoops);
bLoopOK.Init(false, NumInitialLoops);
for (int32 LoopIndex = 0; LoopIndex < LoopPairs.Num(); ++LoopIndex)
{
const FDynamicMeshEditor::FLoopPairSet& LoopPair = LoopPairs[LoopIndex];
const TArray<int32>& EdgeGroups = LoopsPerEdgeNewGroupIDs[LoopIndex];
const TArray<int32>& BaseLoopV = LoopPair.OuterVertices;
const TArray<int32>& OffsetLoopV = LoopPair.InnerVertices;
const TArray<TriVertPair>& OffsetLoopTriVertPairs = OffsetStitchSides[LoopIndex];
// stitch the loops
FDynamicMeshEditResult StitchResult;
bLoopOK[LoopIndex] = Editor.StitchVertexLoopToTriVidPairSequence(OffsetLoopTriVertPairs, LoopPair.OuterVertices, StitchResult);
if (!bLoopOK[LoopIndex])
{
bAllSuccess = false;
continue;
}
// set the groups of the new quad strip created by the stitching
int NumNewQuads = StitchResult.NewQuads.Num();
TArray<int32> NewGroupsInLoop;
const TArray<int32>& PerEdgeNewGroupIDs = LoopsPerEdgeNewGroupIDs[LoopIndex]; // is it always guaranteed to be the same length??
for (int32 k = 0; k < NumNewQuads; k++)
{
Mesh.SetTriangleGroup(StitchResult.NewQuads[k].A, PerEdgeNewGroupIDs[k]);
Mesh.SetTriangleGroup(StitchResult.NewQuads[k].B, PerEdgeNewGroupIDs[k]);
NewGroupsInLoop.AddUnique(PerEdgeNewGroupIDs[k]);
}
// save the stitch triangles set and associated group IDs
StitchResult.GetAllTriangles(PerLoopTrianglesOut[LoopIndex]);
PerLoopGroupsOut[LoopIndex] = MoveTemp(NewGroupsInLoop);
// for each polygon we created in stitch, set UVs and normals
if (Mesh.HasAttributes())
{
SetStitchStripNormalsUVs_Legacy(Mesh, Editor, StitchResult, BaseLoopV, UVScaleFactor);
}
}
return bAllSuccess;
}
template<typename ListType>
FVector3d GetAngleWeightedAverageNormal(const FDynamicMesh3& Mesh, int32 VertexID, const ListType& TriangleList)
{
FVector3d ExtrusionVector = FVector3d::Zero();
// Get angle-weighted normalized average vector
for (int32 TriangleID : Mesh.VtxTrianglesItr(VertexID))
{
if (TriangleList.Contains(TriangleID))
{
FIndex3i Triangle = Mesh.GetTriangle(TriangleID);
double Angle = Mesh.GetTriInternalAngleR(TriangleID, Triangle.IndexOf(VertexID));
ExtrusionVector += Angle * Mesh.GetTriNormal(TriangleID);
}
}
ExtrusionVector.Normalize();
return ExtrusionVector;
}
template<typename ListType>
FVector3d GetAngleWeightedAdjustedNormal(const FDynamicMesh3& Mesh, int32 VertexID, const ListType& TriangleList,
double MaxAdjustmentScale)
{
FVector3d InitialExtrusionVector = GetAngleWeightedAverageNormal<ListType>(Mesh, VertexID, TriangleList);
// Perform an angle-weighted adjustment of the vector length. For each triangle normal, the
// length needs to be multiplied by 1/cos(theta) to place the vertex in the plane that it
// would be in if the face was moved a unit along triangle normal (where theta is angle of
// triangle normal to the current extrusion vector).
double AngleSum = 0;
double Adjustment = 0;
double InvertedMaxScale = FMath::Max(FMathd::ZeroTolerance, 1.0 / MaxAdjustmentScale);
for (int32 TriangleID : Mesh.VtxTrianglesItr(VertexID))
{
if (TriangleList.Contains(TriangleID))
{
FIndex3i Triangle = Mesh.GetTriangle(TriangleID);
double Angle = Mesh.GetTriInternalAngleR(TriangleID, Triangle.IndexOf(VertexID));
double CosTheta = Mesh.GetTriNormal(TriangleID).Dot(InitialExtrusionVector);
if (CosTheta <= InvertedMaxScale)
{
CosTheta = InvertedMaxScale;
}
Adjustment += Angle / CosTheta;
// For the average at the end
AngleSum += Angle;
}
}
Adjustment /= AngleSum;
return InitialExtrusionVector * Adjustment;
}
} // end namespace OffsetMeshRegionLocals
bool FOffsetMeshRegion::ApplyOffset(FOffsetInfo& Region)
{
if (UseVersion == EVersion::Legacy)
{
return ApplyOffset_Legacy(Region);
}
else // Version1, Current
{
return ApplyOffset_Version1(Region);
}
}
bool FOffsetMeshRegion::ApplyOffset_Version1(FOffsetInfo& Region)
{
const TArray<int32>& RegionTriangles = Region.OffsetTids;
// Split any bowties in the offset region. An extrusion of a bowtie creates a nonmanifold edge which is not permitted
FDynamicMeshEditor TmpEditor(Mesh);
FDynamicMeshEditResult IgnoreResult;
TmpEditor.SplitBowtiesAtTriangles(RegionTriangles, IgnoreResult);
TMap<int32, int32> OffsetGroupMap;
// Remap GroupIDs in offset region
if (Mesh->HasTriangleGroups())
{
for (int32 TriangleID : RegionTriangles)
{
int32 CurGroupID = Mesh->GetTriangleGroup(TriangleID);
int32 NewGroupID = CurGroupID;
int32* FoundNewGroupID = OffsetGroupMap.Find(CurGroupID);
if (FoundNewGroupID == nullptr)
{
NewGroupID = Mesh->AllocateTriangleGroup();
OffsetGroupMap.Add(CurGroupID, NewGroupID);
Region.OffsetGroups.Add(NewGroupID);
}
else
{
NewGroupID = *FoundNewGroupID;
}
Mesh->SetTriangleGroup(TriangleID, NewGroupID);
}
}
FMeshRegionBoundaryLoops InitialLoops(Mesh, RegionTriangles, false);
bool bOK = InitialLoops.Compute();
if (bOK == false)
{
return false;
}
AllModifiedAndNewTriangles.Append(RegionTriangles);
TSet<int32> TriangleSet(RegionTriangles);
// Before we start changing triangles, prepare by allocating group IDs that we'll use
// for the stitched sides (doing it before changes to the mesh allows user-provided
// LoopEdgesShouldHaveSameGroup functions to operate on the original mesh).
TArray<TArray<int32>> LoopsEdgeGroups;
TArray<int32> NewGroupIDs;
LoopsEdgeGroups.SetNum(InitialLoops.Loops.Num());
for (int32 i = 0; i < InitialLoops.Loops.Num(); ++i)
{
TArray<int32>& LoopEids = InitialLoops.Loops[i].Edges;
TArray<int32>& CurrentEdgeGroups = LoopsEdgeGroups[i];
UE::Geometry::ComputeNewGroupIDsAlongEdgeLoop(*Mesh, LoopEids, CurrentEdgeGroups, NewGroupIDs,
LoopEdgesShouldHaveSameGroup);
// if a group is split over the start/end of the loop, shift the loops to so that index 0 lies on a group transition,
// this will simplify later processing
int GroupShift = OffsetMeshRegionLocals::FindLoopShiftFromGroupIDs(CurrentEdgeGroups);
if (GroupShift != 0)
{
OffsetMeshRegionLocals::LeftShiftArray(InitialLoops.Loops[i].Vertices, GroupShift);
OffsetMeshRegionLocals::LeftShiftArray(InitialLoops.Loops[i].Edges, GroupShift);
OffsetMeshRegionLocals::LeftShiftArray(CurrentEdgeGroups, GroupShift);
}
}
FDynamicMeshEditor Editor(Mesh);
TArray<FDynamicMeshEditor::FLoopPairSet> LoopPairs;
FDynamicMeshEditResult DuplicateResult;
if (Region.bIsSolid)
{
// In the solid case, we want to duplicate the region so we can cap it.
FMeshIndexMappings IndexMap;
Editor.DuplicateTriangles(RegionTriangles, IndexMap, DuplicateResult);
AllModifiedAndNewTriangles.Append(DuplicateResult.NewTriangles);
// Populate LoopPairs
LoopPairs.SetNum(InitialLoops.Loops.Num());
for (int LoopIndex = 0; LoopIndex < InitialLoops.Loops.Num(); ++LoopIndex)
{
FEdgeLoop& BaseLoop = InitialLoops.Loops[LoopIndex];
FDynamicMeshEditor::FLoopPairSet& LoopPair = LoopPairs[LoopIndex];
// The original RegionTriangles are the ones that are offset, so InnerVertices/Edges
// should be the boundaries of those.
LoopPair.InnerVertices = BaseLoop.Vertices;
LoopPair.InnerEdges = BaseLoop.Edges;
// However depending on whether we extruded down or up, we may need to reverse
// the loops to get them to be stitched right side out.
if (!bIsPositiveOffset)
{
Algo::Reverse(LoopPair.InnerVertices);
// Reversing the edges is slightly different because the last edge is between the first
// and last vertex, and that needs to stay in the same place when vertices are reversed.
int32 LastEid = LoopPair.InnerEdges.Pop();
Algo::Reverse(LoopPair.InnerEdges);
LoopPair.InnerEdges.Add(LastEid);
int32 LastEdgeGroupID = LoopsEdgeGroups[LoopIndex].Pop();
Algo::Reverse(LoopsEdgeGroups[LoopIndex]);
LoopsEdgeGroups[LoopIndex].Add(LastEdgeGroupID);
}
// Now assemble the paired loop
for (int32 Vid : LoopPair.InnerVertices)
{
LoopPair.OuterVertices.Add(IndexMap.GetNewVertex(Vid));
}
FEdgeLoop::VertexLoopToEdgeLoop(Mesh, LoopPair.OuterVertices, LoopPair.OuterEdges);
}
}
else
{
bOK = Editor.DisconnectTriangles(TriangleSet, InitialLoops.Loops, LoopPairs, true /*bHandleBoundaryVertices*/);
}
if (bOK == false)
{
return false;
}
// Store the vid-independent offset loop before we break bowties
// NO LONGER NECESSARY
TArray<TArray<FMeshTriOrderedEdgeID>> OffsetTriOrderedEdgeLoops;
OffsetTriOrderedEdgeLoops.SetNum(LoopPairs.Num());
for (int32 i = 0; i < LoopPairs.Num(); ++i)
{
bOK = bOK && UE::Geometry::ConvertLoopToTriOrderedEdgeLoop(
*Mesh, LoopPairs[i].InnerVertices, LoopPairs[i].InnerEdges, OffsetTriOrderedEdgeLoops[i]);
}
if (bOK == false)
{
return false;
}
FMeshVertexSelection SelectionV(Mesh);
SelectionV.SelectTriangleVertices(RegionTriangles);
TArray<int32> SelectedVids = SelectionV.AsArray();
// If we need to, assemble the vertex vectors for us to use (before we actually start moving things)
TArray<FVector3d> VertexExtrudeVectors;
if (ExtrusionVectorType == EVertexExtrusionVectorType::SelectionTriNormalsAngleWeightedAverage
|| ExtrusionVectorType == EVertexExtrusionVectorType::SelectionTriNormalsAngleWeightedAdjusted)
{
VertexExtrudeVectors.SetNumUninitialized(SelectedVids.Num());
// Used to test which triangles are in selection
for (int32 i = 0; i < SelectedVids.Num(); ++i)
{
VertexExtrudeVectors[i] = ( ExtrusionVectorType == EVertexExtrusionVectorType::SelectionTriNormalsAngleWeightedAdjusted ) ?
OffsetMeshRegionLocals::GetAngleWeightedAdjustedNormal(*Mesh, SelectedVids[i], TriangleSet, MaxScaleForAdjustingTriNormalsOffset)
: OffsetMeshRegionLocals::GetAngleWeightedAverageNormal(*Mesh, SelectedVids[i], TriangleSet);
}
}
else if (ExtrusionVectorType == EVertexExtrusionVectorType::VertexNormal)
{
VertexExtrudeVectors.SetNumUninitialized(SelectedVids.Num());
for (int32 i = 0; i < SelectedVids.Num(); ++i)
{
VertexExtrudeVectors[i] = Mesh->HasVertexNormals() ?
(FVector3d)Mesh->GetVertexNormal(SelectedVids[i]) : FMeshNormals::ComputeVertexNormal(*Mesh, SelectedVids[i]);
}
}
// Perform the actual vertex displacement.
for (int32 i = 0; i < SelectedVids.Num(); ++i)
{
int32 VertexID = SelectedVids[i];
FVector3d OldPosition = Mesh->GetVertex(VertexID);
FVector3d ExtrusionVector = (ExtrusionVectorType == EVertexExtrusionVectorType::Zero) ? FVector3d::Zero() : VertexExtrudeVectors[i];
FVector3d NewPosition = OffsetPositionFunc(OldPosition, ExtrusionVector, VertexID);
Mesh->SetVertex(VertexID, NewPosition);
}
// Stitch the loops
OffsetMeshRegionLocals::FStitchConfigOptions StitchConfig;
StitchConfig.UVScaleFactor = this->UVScaleFactor;
StitchConfig.NumSubdivisions = this->NumSubdivisions;
StitchConfig.bGroupPerSubdivision = this->bGroupPerSubdivision;
StitchConfig.bUVIslandPerGroup = this->bUVIslandPerGroup;
StitchConfig.CreaseAngleThreshold = this->CreaseAngleThresholdDeg;
StitchConfig.SetMaterialID = this->SetMaterialID;
StitchConfig.bInferMaterialID = this->bInferMaterialID;
TArray<bool> bLoopSuccess;
bool bSuccess = OffsetMeshRegionLocals::StitchRegionBorderLoopPairs_Version1( *Mesh,
LoopPairs, LoopsEdgeGroups, OffsetTriOrderedEdgeLoops,
StitchConfig,
bLoopSuccess, Region.StitchTriangles, Region.StitchPolygonIDs);
int NumInitialLoops = LoopPairs.Num();
Region.BaseLoops.SetNum(NumInitialLoops);
Region.OffsetLoops.SetNum(NumInitialLoops);
for (int32 LoopIndex = 0; LoopIndex < NumInitialLoops; ++LoopIndex)
{
if (bLoopSuccess[LoopIndex])
{
Region.BaseLoops[LoopIndex].InitializeFromVertices(Mesh, LoopPairs[LoopIndex].OuterVertices);
Region.OffsetLoops[LoopIndex].InitializeFromVertices(Mesh, LoopPairs[LoopIndex].InnerVertices);
}
}
if (Region.bIsSolid)
{
if (bIsPositiveOffset)
{
// Flip the "bottom" of the region to face outwards
Editor.ReverseTriangleOrientations(DuplicateResult.NewTriangles, true);
}
else
{
Editor.ReverseTriangleOrientations(RegionTriangles, true);
}
}
if (bSingleGroupPerArea && Mesh->HasTriangleGroups() && Region.OffsetGroups.Num() > 1)
{
int32 NewGroupID = Region.OffsetGroups[0];
for (int32 TriangleID : RegionTriangles)
{
Mesh->SetTriangleGroup(TriangleID, NewGroupID);
}
Region.OffsetGroups.SetNum(1);
}
return bSuccess;
}
bool FOffsetMeshRegion::ApplyOffset_Legacy(FOffsetInfo& Region)
{
// Store offset groups
if (Mesh->HasTriangleGroups())
{
for (int32 Tid : Region.OffsetTids)
{
Region.OffsetGroups.AddUnique(Mesh->GetTriangleGroup(Tid));
}
}
FMeshRegionBoundaryLoops InitialLoops(Mesh, Region.OffsetTids, false);
bool bOK = InitialLoops.Compute();
if (bOK == false)
{
return false;
}
AllModifiedAndNewTriangles.Append(Region.OffsetTids);
// Before we start changing triangles, prepare by allocating group IDs that we'll use
// for the stitched sides (doing it before changes to the mesh allows user-provided
// LoopEdgesShouldHaveSameGroup functions to operate on the original mesh).
TArray<TArray<int32>> LoopsEdgeGroups;
TArray<int32> NewGroupIDs;
LoopsEdgeGroups.SetNum(InitialLoops.Loops.Num());
for (int32 i = 0; i < InitialLoops.Loops.Num(); ++i)
{
TArray<int32>& LoopEids = InitialLoops.Loops[i].Edges;
int32 NumEids = LoopEids.Num();
if (!ensure(NumEids > 2))
{
// Shouldn't actually happen because we're extruding triangles
continue;
}
TArray<int32>& CurrentEdgeGroups = LoopsEdgeGroups[i];
CurrentEdgeGroups.SetNumUninitialized(NumEids);
CurrentEdgeGroups[0] = Mesh->AllocateTriangleGroup();
NewGroupIDs.Add(CurrentEdgeGroups[0]);
// Propagate the group backwards first so we don't allocate an unnecessary group
// at the end and then have to fix it.
int32 LastDifferentGroupIndex = NumEids - 1;
while (LastDifferentGroupIndex > 0
&& LoopEdgesShouldHaveSameGroup(LoopEids[0], LoopEids[LastDifferentGroupIndex]))
{
CurrentEdgeGroups[LastDifferentGroupIndex] = CurrentEdgeGroups[0];
--LastDifferentGroupIndex;
}
// Now add new groups forward
for (int32 j = 1; j <= LastDifferentGroupIndex; ++j)
{
if (!LoopEdgesShouldHaveSameGroup(LoopEids[j], LoopEids[j - 1]))
{
CurrentEdgeGroups[j] = Mesh->AllocateTriangleGroup();
NewGroupIDs.Add(CurrentEdgeGroups[j]);
}
else
{
CurrentEdgeGroups[j] = CurrentEdgeGroups[j-1];
}
}
}
FDynamicMeshEditor Editor(Mesh);
TArray<FDynamicMeshEditor::FLoopPairSet> LoopPairs;
FDynamicMeshEditResult DuplicateResult;
if (Region.bIsSolid)
{
// In the solid case, we want to duplicate the region so we can cap it.
FMeshIndexMappings IndexMap;
Editor.DuplicateTriangles(Region.OffsetTids, IndexMap, DuplicateResult);
AllModifiedAndNewTriangles.Append(DuplicateResult.NewTriangles);
// Populate LoopPairs
LoopPairs.SetNum(InitialLoops.Loops.Num());
for (int LoopIndex = 0; LoopIndex < InitialLoops.Loops.Num(); ++LoopIndex)
{
FEdgeLoop& BaseLoop = InitialLoops.Loops[LoopIndex];
FDynamicMeshEditor::FLoopPairSet& LoopPair = LoopPairs[LoopIndex];
// The original OffsetTids are the ones that are offset, so InnerVertices/Edges
// should be the boundaries of those.
LoopPair.InnerVertices = BaseLoop.Vertices;
LoopPair.InnerEdges = BaseLoop.Edges;
// However depending on whether we extruded down or up, we may need to reverse
// the loops to get them to be stitched right side out.
if (!bIsPositiveOffset)
{
Algo::Reverse(LoopPair.InnerVertices);
// Reversing the edges is slightly different because the last edge is between the first
// and last vertex, and that needs to stay in the same place when vertices are reversed.
int32 LastEid = LoopPair.InnerEdges.Pop();
Algo::Reverse(LoopPair.InnerEdges);
LoopPair.InnerEdges.Add(LastEid);
int32 LastEdgeGroupID = LoopsEdgeGroups[LoopIndex].Pop();
Algo::Reverse(LoopsEdgeGroups[LoopIndex]);
LoopsEdgeGroups[LoopIndex].Add(LastEdgeGroupID);
}
// Now assemble the paired loop
for (int32 Vid : LoopPair.InnerVertices)
{
LoopPair.OuterVertices.Add(IndexMap.GetNewVertex(Vid));
}
FEdgeLoop::VertexLoopToEdgeLoop(Mesh, LoopPair.OuterVertices, LoopPair.OuterEdges);
}
}
else
{
// Disconnect the triangles. Note that this will recompute FMeshRegionBoundaryLoops internally,
// and so the output LoopPairs will generally correspond to InitialLoops for that reason,
// but there isn't a guarantee otherwise
bOK = Editor.DisconnectTriangles(Region.OffsetTids, LoopPairs, true /*bHandleBoundaryVertices*/);
}
if (bOK == false)
{
return false;
}
// Store the vid-independent offset loop before we break bowties
TArray<TArray<OffsetMeshRegionLocals::TriVertPair>> OffsetStitchSides;
OffsetStitchSides.SetNum(LoopPairs.Num());
for (int32 i = 0; i < LoopPairs.Num(); ++i)
{
bOK = bOK && FDynamicMeshEditor::ConvertLoopToTriVidPairSequence(*Mesh, LoopPairs[i].InnerVertices, LoopPairs[i].InnerEdges, OffsetStitchSides[i]);
}
if (bOK == false)
{
return false;
}
// Split bowties in the chosen region
FDynamicMeshEditResult Result;
Editor.SplitBowtiesAtTriangles(Region.OffsetTids, Result);
bool bSomeLoopsBroken = Result.NewVertices.Num() > 0;
// BUG: once we split bowties, there some of the existing LoopPairs may actually no longer be boundary loops.
// This occurs with an "interior" bowtie, where say a figure-8 shape that was two separate loops, becomes one loop.
// In this case things go downhill as OffsetTriOrderedEdgeLoops can no longer be converted back to a valid
// boundary loop (since it's not a loop anymore). The FDynamicMeshEditor::StitchVertexLoopsMinimal function called below
// does not actually check that the loop it is stitching is a boundary loop, it simply stitches edge pairs with quads,
// which means that the function will usually appear to succeed even though it may have created broken topology.
// If we broke bowties, the loops in the offset region have changed, and our OffsetLoops no longer
// match BaseLoops.
if (bSomeLoopsBroken)
{
// NOTE: Region.OffsetLoops is only used for output here, this does not affect the loops that
// will be stitched, it just needs to be computed before stitching
FMeshRegionBoundaryLoops UpdatedOffsetLoops(Mesh, Region.OffsetTids, false);
bOK = UpdatedOffsetLoops.Compute();
if (!bOK)
{
return false;
}
Region.OffsetLoops = UpdatedOffsetLoops.Loops;
}
FMeshVertexSelection SelectionV(Mesh);
SelectionV.SelectTriangleVertices(Region.OffsetTids);
TArray<int32> SelectedVids = SelectionV.AsArray();
// If we need to, assemble the vertex vectors for us to use (before we actually start moving things)
TArray<FVector3d> VertexExtrudeVectors;
if (ExtrusionVectorType == EVertexExtrusionVectorType::SelectionTriNormalsAngleWeightedAverage
|| ExtrusionVectorType == EVertexExtrusionVectorType::SelectionTriNormalsAngleWeightedAdjusted)
{
VertexExtrudeVectors.SetNumUninitialized(SelectedVids.Num());
// Used to test which triangles are in selection
TSet<int32> TriangleSet(Region.OffsetTids);
// Used to test which triangles are in selection
for (int32 i = 0; i < SelectedVids.Num(); ++i)
{
VertexExtrudeVectors[i] = ( ExtrusionVectorType == EVertexExtrusionVectorType::SelectionTriNormalsAngleWeightedAdjusted ) ?
OffsetMeshRegionLocals::GetAngleWeightedAdjustedNormal(*Mesh, SelectedVids[i], TriangleSet, MaxScaleForAdjustingTriNormalsOffset)
: OffsetMeshRegionLocals::GetAngleWeightedAverageNormal(*Mesh, SelectedVids[i], TriangleSet);
}
}
else if (ExtrusionVectorType == EVertexExtrusionVectorType::VertexNormal)
{
VertexExtrudeVectors.SetNumUninitialized(SelectedVids.Num());
for (int32 i = 0; i < SelectedVids.Num(); ++i)
{
int32 Vid = SelectedVids[i];
VertexExtrudeVectors[i] = Mesh->HasVertexNormals() ? (FVector3d)Mesh->GetVertexNormal(Vid) : FMeshNormals::ComputeVertexNormal(*Mesh, Vid);
}
}
// Perform the actual vertex displacement.
for (int32 i = 0; i < SelectedVids.Num(); ++i)
{
int32 Vid = SelectedVids[i];
FVector3d OldPosition = Mesh->GetVertex(Vid);
FVector3d ExtrusionVector = (ExtrusionVectorType == EVertexExtrusionVectorType::Zero) ? FVector3d::Zero() : VertexExtrudeVectors[i];
FVector3d NewPosition = OffsetPositionFunc(OldPosition, ExtrusionVector, Vid);
Mesh->SetVertex(Vid, NewPosition);
}
// Stitch the loops
bool bSuccess = true;
int NumInitialLoops = LoopPairs.Num();
Region.BaseLoops.SetNum(NumInitialLoops);
if (!bSomeLoopsBroken)
{
Region.OffsetLoops.SetNum(NumInitialLoops);
}
Region.StitchTriangles.SetNum(NumInitialLoops);
Region.StitchPolygonIDs.SetNum(NumInitialLoops);
for (int32 LoopIndex = 0; LoopIndex < LoopPairs.Num(); ++LoopIndex)
{
FDynamicMeshEditor::FLoopPairSet& LoopPair = LoopPairs[LoopIndex];
const TArray<int32>& EdgeGroups = LoopsEdgeGroups[LoopIndex];
TArray<int32>& BaseLoopV = LoopPair.OuterVertices;
TArray<int32>& OffsetLoopV = LoopPair.InnerVertices;
TArray<OffsetMeshRegionLocals::TriVertPair>& OffsetLoopTriVertPairs = OffsetStitchSides[LoopIndex];
// stitch the loops
FDynamicMeshEditResult StitchResult;
bool bStitchSuccess = Editor.StitchVertexLoopToTriVidPairSequence(OffsetLoopTriVertPairs, LoopPair.OuterVertices, StitchResult);
if (!bStitchSuccess)
{
bSuccess = false;
continue;
}
// set the groups of the new quads along the stitch
int NumNewQuads = StitchResult.NewQuads.Num();
for (int32 k = 0; k < NumNewQuads; k++)
{
Mesh->SetTriangleGroup(StitchResult.NewQuads[k].A, EdgeGroups[k]);
Mesh->SetTriangleGroup(StitchResult.NewQuads[k].B, EdgeGroups[k]);
}
// save the stitch triangles set and associated group IDs
StitchResult.GetAllTriangles(Region.StitchTriangles[LoopIndex]);
Region.StitchPolygonIDs[LoopIndex] = NewGroupIDs;
AllModifiedAndNewTriangles.Append(Region.StitchTriangles[LoopIndex]);
// for each polygon we created in stitch, set UVs and normals
if (Mesh->HasAttributes())
{
float AccumUVTranslation = 0;
FFrame3d FirstProjectFrame;
FVector3d FrameUp;
for (int k = 0; k < NumNewQuads; k++)
{
FVector3f Normal = Editor.ComputeAndSetQuadNormal(StitchResult.NewQuads[k], true);
// align axis 0 of projection frame to first edge, then for further edges,
// rotate around 'up' axis to keep normal aligned and frame horizontal
FFrame3d ProjectFrame;
if (k == 0)
{
FVector3d FirstEdge = Mesh->GetVertex(BaseLoopV[1]) - Mesh->GetVertex(BaseLoopV[0]);
Normalize(FirstEdge);
FirstProjectFrame = FFrame3d(FVector3d::Zero(), (FVector3d)Normal);
FirstProjectFrame.ConstrainedAlignAxis(0, FirstEdge, (FVector3d)Normal);
FrameUp = FirstProjectFrame.GetAxis(1);
ProjectFrame = FirstProjectFrame;
}
else
{
ProjectFrame = FirstProjectFrame;
ProjectFrame.ConstrainedAlignAxis(2, (FVector3d)Normal, FrameUp);
}
if (k > 0)
{
AccumUVTranslation += (float)Distance(Mesh->GetVertex(BaseLoopV[k]), Mesh->GetVertex(BaseLoopV[k - 1]));
}
// translate horizontally such that vertical spans are adjacent in UV space (so textures tile/wrap properly)
float TranslateU = UVScaleFactor * AccumUVTranslation;
Editor.SetQuadUVsFromProjection(StitchResult.NewQuads[k], ProjectFrame, UVScaleFactor, FVector2f(TranslateU, 0));
}
}
Region.BaseLoops[LoopIndex].InitializeFromVertices(Mesh, BaseLoopV);
if (!bSomeLoopsBroken)
{
Region.OffsetLoops[LoopIndex].InitializeFromVertices(Mesh, OffsetLoopV);
}
}
if (Region.bIsSolid)
{
if (bIsPositiveOffset)
{
// Flip the "bottom" of the region to face outwards
Editor.ReverseTriangleOrientations(DuplicateResult.NewTriangles, true);
}
else
{
Editor.ReverseTriangleOrientations(Region.OffsetTids, true);
}
}
return bSuccess;
}
bool FOffsetMeshRegion::EdgesSeparateSameGroupsAndAreColinearAtBorder(FDynamicMesh3* Mesh,
int32 Eid1, int32 Eid2, bool bCheckColinearityAtBorder)
{
if (!Mesh->IsEdge(Eid1) || !Mesh->IsEdge(Eid2))
{
return ensure(false);
}
FIndex2i Tris1 = Mesh->GetEdgeT(Eid1);
FIndex2i Groups1(Mesh->GetTriangleGroup(Tris1.A),
Tris1.B == IndexConstants::InvalidID ? IndexConstants::InvalidID : Mesh->GetTriangleGroup(Tris1.B));
FIndex2i Tris2 = Mesh->GetEdgeT(Eid2);
FIndex2i Groups2(Mesh->GetTriangleGroup(Tris2.A),
Tris2.B == IndexConstants::InvalidID ? IndexConstants::InvalidID : Mesh->GetTriangleGroup(Tris2.B));
if (bCheckColinearityAtBorder
&& Groups1.A == Groups2.A
&& Groups1.B == IndexConstants::InvalidID
&& Groups2.B == IndexConstants::InvalidID)
{
return OffsetMeshRegionLocals::EdgesAreParallel(Mesh, Eid1, Eid2);
}
else return (Groups1.A == Groups2.A && Groups1.B == Groups2.B)
|| (Groups1.A == Groups2.B && Groups1.B == Groups2.A);
}