To use this starfield generator in your own app, use starfield.js and its dependencies Star.js, hashFnv32a.js, and rrcache.js. starfield.js provides a function called getStars, which takes the following parameters:

1. worldOffsetX, the x position of the upper-left corner of the current viewport in the gameworld's coordinates.
2. worldOffsetY, the y position of the same.
3. worldWidth, the width of the current viewport in the gameworld's coordinates.
4. worldHeight, the height.

and returns an array of Star objects, which specify the positions of the stars in the gameworld's coordinates as well as their brightnesses, which range from 0 to 1.

The remaining files in the project handle rendering to the canvas, browser events, and fullscreen. You can leave them out if your project already handles those tasks.

Here's a write-up about how the starfield generator works:

http://mshang.ca/2014/10/20/starfield.html