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a4378546e5
#fyi ryan.schmidt #preflight 62c75d608558075f425ea868 [CL 20994952 by David Lesage in ue5-main branch]
76 lines
2.5 KiB
C++
76 lines
2.5 KiB
C++
// Copyright Epic Games, Inc. All Rights Reserved.
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#pragma once
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#include "MathUtil.h"
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#include "VectorTypes.h"
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namespace UE
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{
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namespace Geometry
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{
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class FDynamicMesh3;
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/**
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* FMeshResolveTJunctions splits edges to create matching vertices at T-Junctions in the mesh.
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* T-Junctions are edge configurations where a border vertex lies on an opposing border edge.
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* This frequently occurs in (eg) CAD meshes where the tessellator had bugs or simply did not
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* bother to ensure that tessellations match on adjacent spline patches.
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*
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* The simplest case would be, one side has two collinear edges [A,B] and [B,C],
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* and the other side has edge [F,G] such that F/A and G/C are coincident.
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* The implementation works by adding a matching vertex to [F,G], via an edge split
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* at the projected location of B, to create a new vertex X that could be welded with B.
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*
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* F A F A
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* So basically it | | | |
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* turns this | B into this one X B
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* configuration | | | |
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* G C G C
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*
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* If everything is within-tolerance, then after resolving all the T-Junctions,
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* a FMergeCoincidentMeshEdges would successfully weld the new set of border
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* edges back together (note: caller must do this, FMeshResolveTJunctions only splits, it does not weld!)
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*
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* Caller can provide a subset of edges via BoundaryEdges, otherwise all boundary edges
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* in Mesh will be used.
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*
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* Current implementation is O(N*M) in the number of boundary edges (N) and boundary vertices (M).
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* Could be improved with a spatial data structure.
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*/
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class DYNAMICMESH_API FMeshResolveTJunctions
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{
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public:
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/** default tolerance is float ZeroTolerance */
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static const double DEFAULT_TOLERANCE; // = FMathf::ZeroTolerance;
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/** The mesh that we are modifying */
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FDynamicMesh3* Mesh;
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/** Subset of mesh boundary edges (otherwise all boundary edges are processed) */
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TSet<int32> BoundaryEdges;
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/** Distance threshold used for various checks (eg is vertex on edge, end endpoint tolerance, etc) */
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double DistanceTolerance = DEFAULT_TOLERANCE;
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/** Number of edges that were split to resolve T-junctions */
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int32 NumSplitEdges = 0;
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public:
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FMeshResolveTJunctions(FDynamicMesh3* MeshIn) : Mesh(MeshIn)
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{
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}
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/**
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* Run the resolve operation and modify .Mesh
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* @return true if the algorithm succeeds
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*/
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bool Apply();
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};
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} // end namespace UE::Geometry
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} // end namespace UE
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