Question

I’m creating a minecraft like voxel engine thing in xna, and have started about implementing “infinite” world but have ran into a few problems. One such problem is that the following line always seems to apply the oppisite (eg if the player moved X+ REGION_SIZE_X it would assign Direction.X_DECREASING instead of the expected Direction.X_INCREASING).

    Thread regionLoader;

    public void CheckPlayer()
    {
        Direction direction = Direction.MAX;

        float distancetraveledx = player.Origin.X - player.Position.X;
        float distancetraveledy = player.Origin.Y - player.Position.Y;
        float distancetraveledz = player.Origin.Z - player.Position.Z;

        if (distancetraveledx > Variables.REGION_SIZE_X)
        {
            direction = Direction.XIncreasing;
            player.Position = new Vector3(player.Origin.X, player.Position.Y, player.Position.Z);
        }
        else if (distancetraveledx < -Variables.REGION_SIZE_X)
        {
            direction = Direction.XDecreasing; 
            player.Position = new Vector3(player.Origin.X, player.Position.Y, player.Position.Z);
        }
        else if (distancetraveledz > Variables.REGION_SIZE_Z)
        {
            direction = Direction.ZIncreasing;
            player.Position = new Vector3(player.Position.X, player.Position.Y, player.Origin.Z);
        }
        else  if (distancetraveledz < -Variables.REGION_SIZE_Z)
        {
            direction = Direction.ZDecreasing;
            player.Position = new Vector3(player.Position.X, player.Position.Y, player.Origin.Z);
        }
        if (direction != Direction.MAX)
        {
            regionManager.direction = direction;

            regionLoader = new Thread(new ThreadStart(regionManager.ShiftRegions));
            regionLoader.Start();
        }
    }

So what this is doing is checking if the player has moved REGION_SIZE from it’s origin and if it has, reset the component of the position which has moved over that boundary.

This then calls the following function:

    public void ShiftRegions()
    {
        // Future and current arrays are to avoid moving elements twice (or maybe I am thinking about it in the wrong way...)
        future_regions = new Region[(int)Variables.RENDER_DISTANCE, (int)Variables.RENDER_DISTANCE, (int)Variables.RENDER_DISTANCE];

        for (short j = 0; j < future_regions.GetLength(0); j++)
        {
            for (short m = 0; m < future_regions.GetLength(1); m++)
            {
                for (short i = 0; i < future_regions.GetLength(2); i++)
                {
                    future_regions[j, m, i] = new Region(world, new Vector3i(new Vector3(j, m, i)));

                    switch (direction)
                    {
                            // This appears to work as XDecreasing
                        case Direction.XIncreasing:
                            // If it is not at the back
                            if (j != future_regions.GetLength(0) - 1)
                            {
                                // Make the regions look like they are scrolling backward
                                future_regions[j, m, i] = regions[j + 1, m, i];
                                future_regions[j, m, i].Index = new Vector3i((uint)j, (uint)m, (uint)i);
                                // In the next call the vertex buffer will be regenerated thus placing the "blocks" in the correct position
                                future_regions[j, m, i].Dirty = true;
                            }
                            // If it is the front most region to which the player is traveling ing
                            if (j == 0)
                            {
                                // New the region setting the Generated flags to false thus allowing it to be regenerated
                                future_regions[j, m, i] = new Region(world, new Vector3i(new Vector3(j, m, i)));
                            }
                            // If it is at the back of the regions
                            if (j == future_regions.GetLength(0) - 1)
                            {
                                //store region
                            }

                            break;
                        case Direction.XDecreasing:

                            break;
                    }
                }
            }
        }


        generator.build(ref future_regions);
        direction = Direction.MAX;

        this.regions = future_regions;
    }

This actually moves the regions which causes the scrolling effect and the new regions which appear at the front. Which doesn’t seem to work.

I was thinking istead of actually “moving” the regions i could just assign different offsets and move in the world matrix but when I do so i just get a blue screen…

Here is the rest of the code:

Generator class function:

    public virtual void build(ref Region[,,] regions)
    {


        for (short j = 0; j < regions.GetLength(0); j++)
        {
            for (short m = 0; m < regions.GetLength(1); m++)
            {
                for (short i = 0; i < regions.GetLength(2); i++)
                {
                    OutputBuffer.Add("Generating...");

                    if (regions[j, m, i].Generated == false)
                    {
                        regions[j, m, i].Dirty = true;
                        regions[j, m, i].Generated = true;

                        for (short x = 0; x < Variables.REGION_SIZE_X; x++)
                        {
                            for (short y = 0; y < Variables.REGION_SIZE_Y; y++)
                            {
                                for (short z = 0; z < Variables.REGION_SIZE_Z; z++)
                                {
                                    regions[j, m, i].Blocks[x, y, z] = new Block();

                                    Vector3i relativeBlock = new Vector3i(new Vector3(x + Variables.REGION_SIZE_X * j, y + Variables.REGION_SIZE_Y * m, z + Variables.REGION_SIZE_Z * i));

                                    if (x == 0 || x == 16 || x == 32 || z == 0 || z == 16 || z == 32 || y == 0 || y == 16 || y == 32)
                                    {
                                        regions[j, m, i].Blocks[x, y, z].BlockType = BlockType.dirt;
                                    }
                                    else
                                    {
                                        regions[j, m, i].Blocks[x, y, z].BlockType = BlockType.grass;

                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }

and the code that checks if the region’s buffers need to be rebuilt:

    public void Update(World world)
    {
        this.world = world;

        for (short j = 0; j < regions.GetLength(0); j++)
        {
            for (short m = 0; m < regions.GetLength(1); m++)
            {
                for (short i = 0; i < regions.GetLength(2); i++)
                {
                    if (regions[j, m, i].Dirty &&
                        regions[j, m, i].Generated)
                    {
                        regions[j, m, i].BuildVertexBuffers();
                    }
                }
            }
        }
    }

By the way, if Dirty is set to true this means that the buffers need to be regenerated.

Any ideas why this is not creating new regions at the front and why it is not scrolling properly?

EDIT: I was just thinking logically and that my idea with the changing the regions position in the array will not change it’s world position, and like I said above with transforming them to the correct positions instead of copying them – that seems like the most logical step. Well the thing is I may have to copy some to different places in the regions array because the array may become spaghetti in no time if you just transform them…

Thanks, Darestium

Answer 1

Just looking at this part

float distancetraveledx = player.Origin.X - player.Position.X;

You’re subtracting position from origin, you should probably reverse the order and do this

float distancetraveledx = player.Position.X - player.Origin.X;

For example, if the player has moved from (0, 0, 0) to (10, 0, 0), the player has moved 10 units in the X direction, but your ‘distancetraveledx’ would give you 0 – 10, or -10.

Unrelated to your question:
Your variables will be easier to use if you follow CamelCase, with the first letter lower or upper-case:

float distanceTraveledX = player.Position.X - player.Origin.X;

In C# the convention is to have class names with the first letter capitalized, and variables with the first letter lower-case, like such:

MyClass myClass;