Replicating a 2D dynamic array

转自：https://forums.unrealengine.com/community/community-content-tools-and-tutorials/105-saxonrahs-tutorial-thread-random-maze-generation-solving/page2?47-SaxonRahs-Tutorial-Thread-Random-Maze-Generation-amp-Solving=&viewfull=1

I made my own USTRUCT system for having a multi-dimensional UPROPERTY() friendly dynamic array version of your maze data structure.

Here's that code for you and others to enjoy!

USTRUCT()
struct FMazeGridRow
{
    GENERATED_USTRUCT_BODY()

    UPROPERTY()
    TArray<AStaticMeshActor*> Columns;
    
    void AddNewColumn()
    {
        Columns.Add(NULL);
    }
    //default properties
    FMazeGridRow()
    {
        
    }
};

USTRUCT()
struct FMazeGrid
{
    GENERATED_USTRUCT_BODY()

    UPROPERTY()
    TArray<FMazeGridRow> Rows;
    
    void AddNewRow()
    {
        Rows.Add(FMazeGridRow());
    }
    
    void AddUninitialized(const int32 RowCount, const int32 ColCount)
    {
        //Add Rows
        for(int32 v = 0; v < RowCount; v++)
        {
            AddNewRow();
        }
        
        //Add Columns
        for(int32 v = 0; v < RowCount; v++)
        {
            for(int32 b = 0; b < ColCount; b++)
            {
                Rows[v].AddNewColumn();
            }
        }
    }
    
    void Clear()
    {
        if(Rows.Num() <= 0) return;
        //~~~~~~~~~~~~~~~
        
        //Destroy any walls
        const int32 RowTotal = Rows.Num();
        const int32 ColTotal = Rows[0].Columns.Num();
        
        for(int32 v = 0; v < RowTotal; v++)
        {
            for(int32 b = 0; b < ColTotal; b++)
            {
                if(Rows[v].Columns[b] && Rows[v].Columns[b]->IsValidLowLevel() )
                {
                    Rows[v].Columns[b]->Destroy();
                }
            }
        }
        
        //Empty
        for(int32 v = 0; v < Rows.Num(); v++)
        {
            Rows[v].Columns.Empty();
        }
        Rows.Empty();
    }
    //default properties
    FMazeGrid()
    {
        
    }
};

//Now you have dynamic array benefits and also UPROPERTY()!
UPROPERTY()
FMazeGrid JoyMazeGrid;

//Init Maze
JoyMazeGrid.Clear();
JoyMazeGrid.AddUninitialized(tileX, tileY);
    
//Sample usage
//JoyMazeGrid.Rows[x].Columns[y] = SpawnBP<AStaticMeshActor>(GetWorld(), ...

Summary

The final result of all of this is that you have

1. dynamic array benefits (easily change the maze size and regenerate during runtime)

2. global access to the MazeGrid Actors, even from other classes

3. GC protection from the UPROPERTY() (if not using actors/objects for some reason)

4. And yet the syntax for 2D array using UPROPERTY() and TArray is still clean and clear and precise

JoyMazeGrid.Rows[x].Columns[y]

Enjoy!

Rama