FindCollision UV

struct FVertexUVPair
{
    FVector2D UVs;
    FVector Position;
};

struct FSortVertexByDistance
{
    FSortVertexByDistance(const FVector& InSourceLocation)
        : SourceLocation(InSourceLocation)
    {

    }

    FVector SourceLocation;

    bool operator()(const FVertexUVPair A, const FVertexUVPair B) const
    {
        float DistanceA = FVector::DistSquared(SourceLocation, A.Position);
        float DistanceB = FVector::DistSquared(SourceLocation, B.Position);

        return DistanceA < DistanceB;
    }
};


bool USG_GameplayStatics::FindCollisionUVFromHit(const struct FHitResult& Hit, FVector2D& UV)
{
    if (UPrimitiveComponent* HitPrimComp = Hit.Component.Get())
    {
        TArray<FVertexUVPair> AllVertices;
        const FVector LocalHitPos = HitPrimComp->GetComponentToWorld().InverseTransformPosition(Hit.Location);

        if (USkeletalMeshComponent* SkelComp = Cast<USkeletalMeshComponent>(HitPrimComp))
        {
            if (FSkeletalMeshRenderData* RenderData = SkelComp->GetSkeletalMeshRenderData())
            {
                if (RenderData->LODRenderData.Num() > 0)
                {
                    for (uint32 i = 0; i < RenderData->LODRenderData[0].StaticVertexBuffers.StaticMeshVertexBuffer.GetNumVertices() ; ++i)
                    {
                        FVertexUVPair NewPair;
                        NewPair.Position = RenderData->LODRenderData[0].StaticVertexBuffers.PositionVertexBuffer.VertexPosition(i);
                        NewPair.UVs = RenderData->LODRenderData[0].StaticVertexBuffers.StaticMeshVertexBuffer.GetVertexUV(i, 0);
                        AllVertices.Emplace(NewPair);
                    }
                }
            }
        }
        else if(UBodySetup* BodySetup = HitPrimComp->GetBodySetup())
        {
            const int32 VertexCount = BodySetup->UVInfo.VertPositions.Num();
            for (int32 Index = 0; Index < VertexCount; Index++)
            {
                FVertexUVPair NewPair;
                NewPair.Position = BodySetup->UVInfo.VertPositions[Index];
                NewPair.UVs = BodySetup->UVInfo.VertUVs[0][Index];
                AllVertices.Emplace(NewPair);
            }
        }

        // Sort Shortest Vertex from LocalHitPos
        AllVertices.Sort(FSortVertexByDistance(LocalHitPos));

        if (AllVertices.Num() < 7)
        {
            return false;
        }

        // Get three vertex for computing barycentric coords
        FVector Pos0 = AllVertices[0].Position;
        FVector Pos1 = AllVertices[3].Position;
        FVector Pos2 = AllVertices[6].Position;

        FVector2D UV0 = AllVertices[0].UVs;
        FVector2D UV1 = AllVertices[3].UVs;
        FVector2D UV2 = AllVertices[6].UVs;

        // Transform hit location from world to local space.
        // Find barycentric coords
        FVector BaryCoords = FMath::ComputeBaryCentric2D(LocalHitPos, Pos0, Pos1, Pos2);
        // Use to blend UVs
        UV = (BaryCoords.X * UV0) + (BaryCoords.Y * UV1) + (BaryCoords.Z * UV2);

        return true;
    }

    return false;
}