Scriptcraft – A Little Friendly Vandalism

For this week’s sample script, building on the ideas developed the week before, I decided to pander to the crowd a little and show a script called tagger.js which allows you to ‘spray’ a design, in a block type of your choice onto the environment. It can be downloaded from here.

Description: Graffiti near Moganshan Road in Shanghai. Photographer: Jakub Hałun. Artist: Unknown. Source: Wikimedia Commons

Defining Our Design

The script contains an array of strings used to defined our design. In the array each string represents a row. Each character in those strings represents a block. Spaces are treated as blanks, anything else is a part of our design. Take a look at this specification which represents a peace sign:

var tag = ["   ***   ",
           " ** * ** ",
           " *  *  * ",
           "*   *   *",
           "*  ***  *",
           "* * * * *",
           " *  *  * ",
           " ** * ** ",
           "   ***   "];

It may be a little hard to make out at first, because characters are much narrower than lines are tall and the whole thing is stretched. Comparing to this drawing should help:

Peace Sign

Peace sign design for tagger.js

I’ve used asterisks in my strings just because it fills the space, but any non-space character will work just as well.

Spraying Onto What’s Already There

The fun thing about tagger.js is that it places the design on whatever is already in the world. It’s not restricted to flat surfaces!

The script looks at the area the player is facing and moves forwards, within a sensible limit, until it encounters a solid block (not air). If it finds one, it changes the block to the requested type. These diagrams show the operation.

Tagger_before

Tagger_after

If no block is found within the search depth, as has happened several times in the diagram above, that part of the design is left out.

In Action

Below is a screenshot of tagger in action: a big stone sphere with a love heart, made of red wool, and a partial smiley, made of gold blocks, sprayed onto it (partial because I was too far away when I called the script and some blocks were beyond the default depth).

tagger

Not Only … But Also

The script also has a few other little interesting features. In common with many of the standard Scriptcraft functions, this one shows how to check for parameters being left out and how to provide default values when that happens. It also shows how to retrieve a part of an existing string, used here to get a single character at a time. Take a look at the script yourself to see how this happens.

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