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

445 lines
12 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#include "Sampling/MeshImageBakingCache.h"
using namespace UE::Geometry;
void FMeshImageBakingCache::SetDetailMesh(const FDynamicMesh3* Mesh, const FDynamicMeshAABBTree3* Spatial)
{
check(Mesh);
DetailMesh = Mesh;
check(Spatial);
DetailSpatial = Spatial;
InvalidateSamples();
InvalidateOccupancy();
}
void FMeshImageBakingCache::SetBakeTargetMesh(const FDynamicMesh3* Mesh)
{
check(Mesh);
TargetMesh = Mesh;
InvalidateSamples();
InvalidateOccupancy();
}
void FMeshImageBakingCache::SetDimensions(FImageDimensions DimensionsIn)
{
if (Dimensions != DimensionsIn)
{
Dimensions = DimensionsIn;
InvalidateSamples();
InvalidateOccupancy();
}
}
void FMeshImageBakingCache::SetGutterSize(int32 GutterSizeIn)
{
if (GutterSize != GutterSizeIn)
{
GutterSize = GutterSizeIn;
InvalidateOccupancy();
}
}
void FMeshImageBakingCache::SetUVLayer(int32 UVLayerIn)
{
if (UVLayer != UVLayerIn)
{
UVLayer = UVLayerIn;
InvalidateSamples();
InvalidateOccupancy();
}
}
void FMeshImageBakingCache::SetThickness(double ThicknessIn)
{
if (Thickness != ThicknessIn)
{
Thickness = ThicknessIn;
InvalidateSamples();
InvalidateOccupancy(); // do we need to do this?
}
}
void FMeshImageBakingCache::SetCorrespondenceStrategy(ECorrespondenceStrategy Strategy)
{
if (CorrespondenceStrategy != Strategy)
{
CorrespondenceStrategy = Strategy;
InvalidateSamples();
InvalidateOccupancy(); // do we need to do this?
}
}
const FDynamicMeshNormalOverlay* FMeshImageBakingCache::GetDetailNormals() const
{
check(DetailMesh && DetailMesh->HasAttributes());
return DetailMesh->Attributes()->PrimaryNormals();
}
const FDynamicMeshUVOverlay* FMeshImageBakingCache::GetBakeTargetUVs() const
{
check(TargetMesh && TargetMesh->HasAttributes() && UVLayer < TargetMesh->Attributes()->NumUVLayers());
return TargetMesh->Attributes()->GetUVLayer(UVLayer);
}
const FDynamicMeshNormalOverlay* FMeshImageBakingCache::GetBakeTargetNormals() const
{
check(TargetMesh && TargetMesh->HasAttributes());
return TargetMesh->Attributes()->PrimaryNormals();
}
const FImageOccupancyMap* FMeshImageBakingCache::GetOccupancyMap() const
{
check(IsCacheValid());
return OccupancyMap.Get();
}
void FMeshImageBakingCache::InvalidateSamples()
{
bSamplesValid = false;
}
void FMeshImageBakingCache::InvalidateOccupancy()
{
bOccupancyValid = false;
}
namespace UE
{
namespace Geometry
{
/**
* Find point on Detail mesh that corresponds to point on Base mesh.
* Strategy is:
* 1) cast a ray inwards along -Normal from BasePoint + Thickness*Normal
* 2) cast a ray outwards along Normal from BasePoint
* 3) cast a ray inwards along -Normal from BasePoint
* We take (1) preferentially, and then (2), and then (3)
*
* If all of those fail, if bFailToNearestPoint is true we fall back to nearest-point,
*
* If all the above fail, return false
*/
static bool GetDetailTrianglePoint_Raycast(
const FDynamicMesh3& DetailMesh,
const FDynamicMeshAABBTree3& DetailSpatial,
const FVector3d& BasePoint,
const FVector3d& BaseNormal,
int32& DetailTriangleOut,
FVector3d& DetailTriBaryCoords,
double Thickness,
bool bFailToNearestPoint
)
{
// TODO: should we check normals here? inverse normal should probably not be considered valid
// shoot rays forwards and backwards
FRay3d InwardRay = FRay3d(BasePoint + Thickness * BaseNormal, -BaseNormal);
FRay3d ForwardRay(BasePoint, BaseNormal);
FRay3d BackwardRay(BasePoint, -BaseNormal);
int32 ForwardHitTID = IndexConstants::InvalidID, InwardHitTID = IndexConstants::InvalidID, BackwardHitTID = IndexConstants::InvalidID;
double ForwardHitDist, InwardHitDist, BackwardHitDist;
IMeshSpatial::FQueryOptions Options;
Options.MaxDistance = Thickness;
bool bHitInward = DetailSpatial.FindNearestHitTriangle(InwardRay, InwardHitDist, InwardHitTID, Options);
bool bHitForward = DetailSpatial.FindNearestHitTriangle(ForwardRay, ForwardHitDist, ForwardHitTID, Options);
bool bHitBackward = DetailSpatial.FindNearestHitTriangle(BackwardRay, BackwardHitDist, BackwardHitTID, Options);
FRay3d HitRay;
int32 HitTID = IndexConstants::InvalidID;
double HitDist = TNumericLimits<double>::Max();
if (bHitInward)
{
HitRay = InwardRay;
HitTID = InwardHitTID;
HitDist = InwardHitDist;
}
else if (bHitForward)
{
HitRay = ForwardRay;
HitTID = ForwardHitTID;
HitDist = ForwardHitDist;
}
else if (bHitBackward)
{
HitRay = BackwardRay;
HitTID = BackwardHitTID;
HitDist = BackwardHitDist;
}
// if we did not find any hits, try nearest-point
if (DetailMesh.IsTriangle(HitTID) == false)
{
IMeshSpatial::FQueryOptions OnSurfQueryOptions;
OnSurfQueryOptions.MaxDistance = Thickness;
double NearDistSqr = 0;
int32 NearestTriID = DetailSpatial.FindNearestTriangle(BasePoint, NearDistSqr, OnSurfQueryOptions);
if (DetailMesh.IsTriangle(NearestTriID))
{
DetailTriangleOut = NearestTriID;
FDistPoint3Triangle3d DistQuery = TMeshQueries<FDynamicMesh3>::TriangleDistance(DetailMesh, NearestTriID, BasePoint);
DetailTriBaryCoords = DistQuery.TriangleBaryCoords;
return true;
}
}
// if we got a valid ray hit, use it
if (DetailMesh.IsTriangle(HitTID))
{
DetailTriangleOut = HitTID;
FIntrRay3Triangle3d IntrQuery = TMeshQueries<FDynamicMesh3>::TriangleIntersection(DetailMesh, HitTID, HitRay);
DetailTriBaryCoords = IntrQuery.TriangleBaryCoords;
return true;
}
// if we get this far, all rays missed or were too far, so use absolute nearest point regardless of distance
if (bFailToNearestPoint)
{
double NearDistSqr = 0;
int32 NearestTriID = DetailSpatial.FindNearestTriangle(BasePoint, NearDistSqr);
if (DetailMesh.IsTriangle(NearestTriID))
{
DetailTriangleOut = NearestTriID;
FDistPoint3Triangle3d DistQuery = TMeshQueries<FDynamicMesh3>::TriangleDistance(DetailMesh, NearestTriID, BasePoint);
DetailTriBaryCoords = DistQuery.TriangleBaryCoords;
return true;
}
}
return false;
}
/**
* Find point on Detail mesh that corresponds to point on Base mesh using minimum distance
*/
static bool GetDetailTrianglePoint_Nearest(
const FDynamicMesh3& DetailMesh,
const FDynamicMeshAABBTree3& DetailSpatial,
const FVector3d& BasePoint,
int32& DetailTriangleOut,
FVector3d& DetailTriBaryCoords)
{
double NearDistSqr = 0;
int32 NearestTriID = DetailSpatial.FindNearestTriangle(BasePoint, NearDistSqr);
if (DetailMesh.IsTriangle(NearestTriID))
{
DetailTriangleOut = NearestTriID;
FDistPoint3Triangle3d DistQuery = TMeshQueries<FDynamicMesh3>::TriangleDistance(DetailMesh, NearestTriID, BasePoint);
DetailTriBaryCoords = DistQuery.TriangleBaryCoords;
return true;
}
return false;
}
}
}
bool FMeshImageBakingCache::ValidateCache()
{
check(TargetMesh && DetailMesh && DetailSpatial);
check(Dimensions.GetWidth() > 0 && Dimensions.GetHeight() > 0);
const FDynamicMesh3* Mesh = TargetMesh;
const FDynamicMeshUVOverlay* UVOverlay = GetBakeTargetUVs();
const FDynamicMeshNormalOverlay* NormalOverlay = GetBakeTargetNormals();
// make UV-space version of mesh
if (bOccupancyValid == false)
{
FDynamicMesh3 FlatMesh(EMeshComponents::FaceGroups);
for (int32 tid : Mesh->TriangleIndicesItr())
{
if (UVOverlay->IsSetTriangle(tid))
{
FVector2f A, B, C;
UVOverlay->GetTriElements(tid, A, B, C);
int32 VertA = FlatMesh.AppendVertex(FVector3d(A.X, A.Y, 0));
int32 VertB = FlatMesh.AppendVertex(FVector3d(B.X, B.Y, 0));
int32 VertC = FlatMesh.AppendVertex(FVector3d(C.X, C.Y, 0));
int32 NewTriID = FlatMesh.AppendTriangle(VertA, VertB, VertC, tid);
}
}
// calculate occupancy map
OccupancyMap = MakeUnique<FImageOccupancyMap>();
OccupancyMap->GutterSize = GutterSize;
OccupancyMap->Initialize(Dimensions);
OccupancyMap->ComputeFromUVSpaceMesh(FlatMesh, [&](int32 TriangleID) { return FlatMesh.GetTriangleGroup(TriangleID); });
bOccupancyValid = true;
}
if (bSamplesValid == false)
{
ECorrespondenceStrategy UseStrategy = this->CorrespondenceStrategy;
if (UseStrategy == ECorrespondenceStrategy::Identity && ensure(DetailMesh == Mesh) == false)
{
// Identity strategy requires mesh to be the same. Could potentially have two copies, in which
// case this ensure is too conservative, but for now we will assume this
UseStrategy = ECorrespondenceStrategy::NearestPoint;
}
// this sampler finds the correspondence between base surface and detail surface
TMeshSurfaceUVSampler<FCorrespondenceSample> DetailMeshSampler;
DetailMeshSampler.Initialize(Mesh, UVOverlay, EMeshSurfaceSamplerQueryType::TriangleAndUV, FCorrespondenceSample(),
[Mesh, NormalOverlay, UseStrategy, this](const FMeshUVSampleInfo& SampleInfo, FCorrespondenceSample& ValueOut)
{
NormalOverlay->GetTriBaryInterpolate<double>(SampleInfo.TriangleIndex, &SampleInfo.BaryCoords.X, &ValueOut.BaseNormal.X);
Normalize(ValueOut.BaseNormal);
FVector3d RayDir = ValueOut.BaseNormal;
ValueOut.BaseSample = SampleInfo;
ValueOut.DetailTriID = FDynamicMesh3::InvalidID;
if (UseStrategy == ECorrespondenceStrategy::Identity)
{
ValueOut.DetailTriID = SampleInfo.TriangleIndex;
ValueOut.DetailBaryCoords = SampleInfo.BaryCoords;
}
else if (UseStrategy == ECorrespondenceStrategy::NearestPoint)
{
bool bFoundTri = GetDetailTrianglePoint_Nearest(*DetailMesh, *DetailSpatial, SampleInfo.SurfacePoint,
ValueOut.DetailTriID, ValueOut.DetailBaryCoords);
}
else // fall back to raycast strategy
{
double SampleThickness = this->GetThickness(); // could modulate w/ a map here...
// find detail mesh triangle point
bool bFoundTri = GetDetailTrianglePoint_Raycast(*DetailMesh, *DetailSpatial, SampleInfo.SurfacePoint, RayDir,
ValueOut.DetailTriID, ValueOut.DetailBaryCoords, SampleThickness,
(UseStrategy == ECorrespondenceStrategy::RaycastStandardThenNearest) );
}
});
SampleMap.Resize(Dimensions.GetWidth(), Dimensions.GetHeight());
// calculate interior texels
ParallelFor(Dimensions.GetHeight(), [this, &DetailMeshSampler](int32 ImgY)
{
if (CancelF())
{
return;
}
for (int32 ImgX = 0; ImgX < Dimensions.GetWidth(); ImgX++)
{
int64 LinearIdx = Dimensions.GetIndex(ImgX, ImgY);
if (OccupancyMap->IsInterior(LinearIdx) == false)
{
continue;
}
FVector2d UVPosition = (FVector2d)OccupancyMap->TexelQueryUV[LinearIdx];
int32 UVTriangleID = OccupancyMap->TexelQueryTriangle[LinearIdx];
FCorrespondenceSample Sample;
DetailMeshSampler.SampleUV(UVTriangleID, UVPosition, Sample);
SampleMap[LinearIdx] = Sample;
}
});
bSamplesValid = true;
}
return IsCacheValid();
}
void FMeshImageBakingCache::EvaluateSamples(
TFunctionRef<void(const FVector2i&, const FCorrespondenceSample&)> SampleFunction,
bool bParallel) const
{
check(IsCacheValid());
ParallelFor(Dimensions.GetHeight(), [this, &SampleFunction](int32 ImgY)
{
if (CancelF())
{
return;
}
for (int32 ImgX = 0; ImgX < Dimensions.GetWidth(); ImgX++)
{
int64 LinearIdx = Dimensions.GetIndex(ImgX, ImgY);
if (OccupancyMap->IsInterior(LinearIdx) == false)
{
continue;
}
FVector2i Coords(ImgX, ImgY);
const FCorrespondenceSample& Sample = SampleMap[LinearIdx];
SampleFunction(Coords, Sample);
}
}, !bParallel ? EParallelForFlags::ForceSingleThread : EParallelForFlags::None);
}
void FMeshImageBakingCache::FindSamplingHoles(
TFunctionRef<bool(const FVector2i&)> IsInvalidSampleFunction,
TArray<FVector2i>& HolePixelsOut,
bool bParallel) const
{
check(IsCacheValid());
FCriticalSection HoleLock;
ParallelFor(Dimensions.GetHeight(), [this, &IsInvalidSampleFunction, &HoleLock, &HolePixelsOut](int32 ImgY)
{
if (CancelF())
{
return;
}
for (int32 ImgX = 0; ImgX < Dimensions.GetWidth(); ImgX++)
{
int64 LinearIdx = Dimensions.GetIndex(ImgX, ImgY);
if (OccupancyMap->IsInterior(LinearIdx) == false)
{
continue;
}
FVector2i Coords(ImgX, ImgY);
const FCorrespondenceSample& Sample = SampleMap[LinearIdx];
if (IsInvalidSampleFunction(Coords))
{
HoleLock.Lock();
HolePixelsOut.Add(Coords);
HoleLock.Unlock();
}
}
}, !bParallel ? EParallelForFlags::ForceSingleThread : EParallelForFlags::None);
}