shadertoy-export v0.0.1
shadertoy-export
A small utility for exporting ShaderToy demos to large (print-ready) PNG images. On my MacBookPro, this can export up to 10,000x10,000 px images.
It only features a small set of shaders (those set to Public + API) and doesn't support cube maps, video inputs, etc.
This tool is experimental and not complete. If you want to help maintain it, let me know.
Some examples:

A 2880x1800 wallpaper from this shader.

Install
Install the tool globally with npm.
npm install shadertoy-export -gCommand-Line Usage
More docs to follow.
Basic usage, writes the first frame to process.stdout as PNG.
shadertoy-export shader.frag [opts] > image.pngYou can use --api or -a to grab from the ShaderToy API, which loads demos that are saved as Public + API. For this, you need to specify a demo ID like XslGRr, or a URL like https://www.shadertoy.com/view/XslGRr. Example:
shadertoy-export XslGRr --api > image.pngYou can use --output or -o instead of writing to stdout, and --size to render a different resolution. You can use --wait to wait N milliseconds before rendering a frame.
shadertoy-export XslGRr --api --output output/1.png --size 1080,768 --wait 1500interactive mode
You can also enter interactive (GUI) mode with the --frame or -f option. This opens a window which accepts mouse input, and you can hit Cmd + S or Ctrl + S at any point to save the image to your output path.
shadertoy-export -f --api --size=512,256 -o images/1.png XslGRr
You can also specify a --scale or -S option to reduce the interactive resolution (does not affect output). For example, --scale=0.5 will draw the scene at half resolution.
License
MIT, see LICENSE.md for details.