https://github.com/semibran/tetromino

model tetrominos using minimal data structures
https://github.com/semibran/tetromino

game tetris tetromino

Last synced: about 2 months ago
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model tetrominos using minimal data structures

• Host: GitHub
• URL: https://github.com/semibran/tetromino
• Owner: semibran
• License: mit
• Created: 2017-02-07T06:24:40.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2017-06-27T06:58:36.000Z (over 7 years ago)
• Last Synced: 2024-10-20T13:16:20.723Z (2 months ago)
• Topics: game, tetris, tetromino
• Language: JavaScript
• Homepage:
• Size: 24.4 KB
• Stars: 8
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • License: license

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README

        
# tetromino

![The seven tetrominos](img/tetrominos.png)

Model [tetrominos](https://en.wikipedia.org/wiki/Tetromino) using minimal data structures, especially for use in Tetris clones.

```js

var tetromino = {

  type: 'L',

  position: [3, 0],

  rotation: 0

}

```

## usage

[![NPM](https://nodei.co/npm/tetromino.png?mini)](https://www.npmjs.com/package/tetromino)

```js

const { types, states, blocks } = require('tetromino')

```

### `blocks(tetromino)`

A tetromino can be represented as an object with the three fields `type`, `rotation`, and `position`. From this information, we can easily infer the location of each of the four cells that the tetromino occupies.

```js

> blocks(tetromino)

[ [ 3, 1 ], [ 4, 1 ], [ 5, 1 ], [ 5, 0 ] ]

```

### `type`

The `type` of a tetromino is a single character denoting its unique name. The image at the top of this page lists the tetrominos in the order `[I, J, L, O, S, T, Z]` - in fact, this particular array is exposed as `types`:

```js

> types

[ 'I', 'J', 'L', 'O', 'S', 'T', 'Z' ]

```

A common use case for this array is choosing a random tetromino to spawn.

```js

> types[Math.floor(Math.random() * types.length)]

'S'

```

### `position`

The `position` of a tetromino is a two-dimensional vector of the form `[x, y]`. Since the center point of each tetromino will vary, `position` is relative to the top-left point of the 4x4 region containing the piece.

![S tetromino demonstrating position](img/position.png)

### `rotation`

A tetromino's `rotation` is a zero-based index corresponding to a "rotation state" found in `states`. Most tetrominos have 4 rotation states, with the `O` piece being the exception. It only has one state and therefore cannot rotate.

```js

> states.T.length

4

> states.O.length

1

```

![J tetromino demonstrating rotation](img/rotation.gif)

### `states[type][rotation]`

The `states` object details the locations of each cell of a tetromino with a given type and rotation in compliance with the [SRS](http://tetris.wikia.com/wiki/SRS). It is used internally in the `blocks` function mentioned above.

Use `states` by specifying both [a tetromino type](#type) and [a rotation index](#rotation).

```js

> states.J[0]

[ [ 0, 1 ], [ 1, 1 ], [ 2, 1 ], [ 2, 0 ] ]

```

## see also

- [`semibran/vector`](https://github.com/semibran/vector): move tetrominos with `add(tetromino.position, delta)`

- [`semibran/wrap-around`](https://github.com/semibran/wrap-around): manage rotation indexes inline

## license

[MIT](https://opensource.org/licenses/MIT) © [Brandon Semilla](https://git.io/semibran)