@4bitlabs/crt-lite

@4bitlabs/crt-lite

A tiny, simple CRT-like webgl2-based canvas renderer for ImageData.

Before	After

Documentation

Full documentation for the library can be found here.

Getting Started

import { createCrtRenderer } from '@4bitlabs/crt-lite';

// Setup the canvas element to draw to.
const target = document.getElementById('target');
const { update } = createCrtRenderer(canvasEl);

// Get some image data
const source = document.getElementById('source');
const ctx = source.getContext('2d');
/* draw whatever you want */
const imgData = ctx.getImageData(0, 0, ctx.width, ctx.height);

//🪄🎩🐰
update(imgData);

Render Parameters

There are several tunable options when invoking the update function that can be used to adjust the monitor style.

Setting	Type	Description
Fx	number	Horizontal monitor curve/barrel distortion.
Fy	number	Vertical monitor curve/barrel distortion.
S	number	Monitor zoom.
hBlur	number	Fast GPU horizontal box-blur in pixels.
grain	number	Monitor grain. 0.0 = none/off, 1.0 = max.
vignette	number	CRT Vignetting. 0.0 = none/off, 1.0 = max.
scanLines	boolean	CGA/EGA monitor scan-line simulation.

import { createCrtRenderer, type CrtUpdateOptions } from '@4bitlabs/crt-lite';

const { update } = createCrtRenderer(canvasEl);

const crtOptions: CrtUpdateOptions = {
  Fx: -0.025,
  Fy: -0.035,
  S: 0.995,
  hBlur: 2.0,
  grain: 0.125,
  vignette: 1.0,
  scanLines: true,
};

update(imgData, crtOptions);

Setting Render Defaults

You can also set up a set of render defaults as the base for every render.

import { createCrtRenderer, type CrtUpdateOptions } from '@4bitlabs/crt-lite';

const renderDefaults: CrtUpdateOptions = {
  Fx: -0.025,
  Fy: -0.035,
  S: 0.995,
  hBlur: 2.0,
  grain: 0.125,
  vignette: 1.0,
  scanLines: true,
};

const { update } = createCrtRenderer(canvasEl, { renderDefaults });

// Render using the defaults…
update(imgData);

// Override and disable the grain for just this render.
update(imgData, { grain: 0.0 });