Phaser shape recognition

This class provides some utilities for shape and stroke recognition using Phaser 3.
Can be used to process image data and feed neural networks.
Try demo here: https://jjcapellan.github.io/phaser-shape-recognition/

Table of contents

• Installation
  • Browser
  • From NPM
• Usage
• Methods
  • makeMatrix
  • test
• License

Installation

Browser

There are two alternatives:

• Point a script tag to the CDN link:

<script src="https://cdn.jsdelivr.net/gh/jjcapellan/phaser-shape-recognition/dist/phaser-shape-recognition.umd.js">

• Download the file phaser-shape-recognition.umd.js to your proyect folder and add a reference in your html:

<script src="localPath/phaser-shape-recognition.umd.js">

Then you can access the class by the global ShapeRec:

// In your create function ...
const shapeRec = new ShapeRec(this); 

From NPM

npm install phaser-shape-recognition

Then you can acces the class as:

• CommonJS module

const ShapeRec = require('phaser-shape-recognition');
 
// In your create function ...
const shapeRec = new ShapeRec(this); 

• ES6 module

import ShapeRec from 'phaser-shape-recognition';
 
// In your create function ...
const shapeRec = new ShapeRec(this); 

Usage

Example (Image vs Points comparison):

// In create function ...
const shapeRec = new ShapeRec(this);
 
// Makes an array of 10x10 of booleans from the image.
const imageMatrix = shapeRec.makeMatrix('textureKey', 'textureFrame', 10);
 
// Hardcoded array of points
const points =[{x: 2, y: 4}, {x: 4, y: 14}, { ... } ...];
 
// Makes an array of 10x10 of booleans from the points array
const pointsMatrix = shapeRec.makeMatrix(points, null, 10)
 
// Test the similitude between the image and the shape represented in the points array
// shapeRec.test() returns a number between 0 and 1. 1 means the two shapes are identical and 0 the opposite.
let similitude = shapeRec.test(imageMatrix, pointsMatrix);

Important:

• About images: makeMatrix() only use the alpha values, so the image should have transparent background.
• test() only can compare matrix of the same size. Ex: you can't compare 10x10 vs 12x12.

Methods

makeMatrix(source, frame, resolution)

Transforms an array of raw points or an image into a "normalized" array of booleans (matrix)
Params:

• source { string | Point[]} Can be the string key of a texture or an array of points (Ex: [{x: 2, y:2}, {x:3, y:5}, ...])
• frame { (string | number) } String or index of the texture frame. Not used if source is an array.
• [resolution = 10] { number } Size of the matrix. High values reduce false positives and increase false negatives in shape recognition. With low values the opposite occurs.

Returns:

• { boolean[][] } Matrix of booleans. Each cell of the matrix represents one sector of the image. If in that sector exists some positive alpha then its value will be "true".

test(matrix1, matrix2, checkNeighbors)

Compares two matrix of same size:

• matrix1[i][j] == matrix2[i][j] ---> HIT
• matrix1[i][j] != matrix2[i][j] ---> FAIL
  Params:
• matrix1 { boolean[][] } Matrix of first shape
• matrix2 { boolean[][] } Matrix of second shape
• checkNeighbors { boolean } Fail is not added if there are some neighbor cell with "true"

Returns:

• { number } Number between 0 and 1: hits / (hits + fails)

License

This code is released under MIT LICENSE.