Tutorial Creating basic shapes

Hello everyone! I've lately been working on a worldedit plugin, and noticed there have been a lot of questions about how to make shapes properly, and settings those for example to a given block. This tutorial is to clear that up for you. This tutorial is also aimed to make the process as mathematically easy as possible, and efficient, due to the scanning in for example a sphere not processing the same block additional times.

This tutorial is made for people who already know at least a decent amount of PocketMine API.

Now, let's start shall we? Let's begin by making the most basic shape: A cube.

Spoiler: Creating a cube

We first start by introducing a new function. There are a couple required things to make a cube. In our case, this is a center Vector3, and a radius.

PHP:

public function createCube(Position $center, float $radius) {
  for($x = $center->x - $radius; $x <= $center->x + $radius; $x++) {
    for($y = $center->y - $radius; $y <= $center->y + $radius; $y++) {
      for($z = $center->z - $radius; $z <= $center->z + $radius; $z++) {
        $center->getLevel()->setBlock(new Vector3($x, $y, $z), Block::get(Block::STONE), false, false); // Set block update to false to decrease lag with big areas.
      }
    }
  }
}


Now that we know how to make a cube, it is time to move on to the sphere. A sphere is the shape most coders have problems with. Spheres can be made using a lot of math, but there is a way easier way to do it without a big amount of math knowledge.

Spoiler: Creating a sphere

PHP:

public function createSphere(Position $center, float $radius) {
  $radiusSquared = $radius * $radius;
  for($x = $center->x - $radius; $x <= $center->x + $radius; $x++) {
    $xsquared = ($center->x - $x) * ($center->x - $x);
    for($y = $center->y - $radius; $y <= $center->y + $radius; $y++) {
      $ysquared = ($center->y - $y) * ($center->y - $y);
      for($z = $center->z - $radius; $z <= $center->z + $radius; $z++) {
        $zsquared = ($center->z = $z) * ($center->z - $z);
        if($xsquared + $ysquared + $zsquared < $radiusSquared) {
          $center->getLevel()->setBlock(new Vector3($x, $y, $z), Block::get(Block::STONE), false, false);
        }
      }
    }
  }
}


The code to make a sphere may look quite complicated at first, but if you look at it a couple times, you should slowly start to understand what it does. As soon as you understand how the sphere works, we can continue to the cylinder. Creating a cylinder is basically a combination between the creating of a cube, and the creating of a sphere.

Spoiler: Creating a cylinder

PHP:

// A cylinder is super similar to a sphere. Just change one for loop, and you're set!
public function createCylinder(Position $center, float $radius) {
  $radiusSquared = $radius * $radius;
  for($x = $center->x - $radius; $x <= $center->x + $radius; $x++) {
    $xsquared = ($center->x - $x) * ($center->x - $x);
    for($y = $center->y - $radius; $y <= $center->y + $radius; $y++) {
      for($z = $center->z - $radius; $z <= $center->z + $radius; $z++) {
        $zsquared = ($center->z = $z) * ($center->z - $z);
        if($xsquared + $zsquared < $radiusSquared) {
          $center->getLevel()->setBlock(new Vector3($x, $y, $z), Block::get(Block::STONE), false, false);
        }
      }
    }
  }
}


I made this in the hope that it'll be helpful, so please make sure to tell me if something is wrong or doesn't work, or if you need more help. I hope this tutorial helped some of you!

This method CAN be used for particles too. To make a good looking sphere though, you would have to replace for example $x++ with $x += 0.05 for a higher density.

Please note that setting blocks on this way is not very efficient when setting a huge amount of blocks. This tutorial is mainly for the part of showing how to do it, and could, when not handled with care, freeze the server.

 

Using setBlockIdAt, is pretty fast. I don't know what the cons are tho.

 

That's the only thing I didn't look into for optimizing. Thanks for the suggestion

 

wat.
that makes me get more confusion... TOO MANY MATHS! (I don't understand a single thing of it) (Whats an SPhere?)

 

The math required is honestly really little. Just try to visualize what you're doing with the code. Once you get that, it's really easy to understand

 

Don't use a 'for' loop in the completed WE plug, setting large amounts of blocks would cause the Main thread to be "frozen" for too long.

 

True. I'll add a warning. What do you suggest otherwise next to setting it in a repeating task or an async?

My world edit plugin doesn't allow to set big amounts of blocks anyways. It limits a radius bigger than 10.

 

In my WE plug (not public) I used one of the tasks shown here: http://blog.falkirks.com/setting-huge-areas-of-blocks/ the tick separated would work allowing the server to respond to players in-between block sets.

 

If you replace $i++ with ++$i you can save some time as pre incrementing doesn't make a copy of the var. Idk how much time you can actually save with that though, but your's is the farthest in optimization already.

Except for... (I could be wrong), setBlock outside a for loop might be better.

PHP:

public function createCube(Vector3 $center, float $radius) {
  $blockdata = [];
  for($x = $center->x - $radius; $x <= $center->x + $radius; $x++) {
    for($y = $center->y - $radius; $y <= $center->y + $radius; $y++) {
      for($z = $center->z - $radius; $z <= $center->z + $radius; $z++) {
        $blockdata[] = [$x, $y, $z];
      }
    }
  }
  foreach($blockdata as $coord) {
    //I think Location and Position have getLevel(), not sure about Vector3 having one.
    $center->getLevel()->setBlockIdAt($coord[0], $coord[1], $coord[2], Block::get(Block::STONE)); //no updates are sent.
  }
}


Nice work btw xd

 

Lol this thread was never meant to be a subject of optimizing block placement. It was just to show people how to make basic shapes. Of course there's ways to optimize it, but I leave that to the others.

 

How long does it take to create sphere with radius = 30?

 

With the basic setBlock method in the main thread, not that fast for sure.

 

Also this code http://pastebin.com/Lta2E2U0 is work's too
And it create sphere with radius = 30 for 1-2 sec

 

Call to undefined method pocketmine\math\Vector3::getLevel() @Sandertv

 

Call to undefined method pocketmine\math\Vector3::getLevel() @Sandertv

nope

 

I made this with $center as Position object in my head, for example a block. A basic Vector3 won't work, you'll have to make at least a new Position object for it, or get the block at that location.

 

How to make getBlock() as Position object?