I'm looking for something as similar as possible to ShaderToy, with one extra feature: the ability to load custom images to use as textures.

For those unfamiliar with ShaderToy, it's a web-based editor for GLSL fragment shaders. Your shaders are rendered on a 2D plane (not full 3D models), which is perfect for my purposes, as I want to use this for testing out shaders for 2D games. ShaderToy also has a nice bonus in that it allows you to share your shaders and see others' shaders.

ShaderToy itself has worked great for me in experimenting with shaders, but the lack of ability to load custom textures is limiting. I'd really like to try my hand at writing shaders that use normal maps, for example, but I can't reasonably do that without being able to load the normal maps as textures.

I don't have any strong preference for shader languages, but I'm guessing virtually all such web apps will use GLSL due to the existence of WebGL. Though I'd be more interested in using Cg shaders in the unlikely case that such a web app exists.

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    Does this help? My lack of knowledge of this kind of product means I can't help more than this alternativeto.net/software/shadertoy
    – CalvT
    Oct 9, 2015 at 19:54
  • @CalvT Thanks for the recommendation. The web apps there are nice, but it looks like they don't support custom textures, either. Checking out the desktop app now (FX Composer), which looks quite a bit more advanced but could be useful. Oct 9, 2015 at 21:06

1 Answer 1


The GSN Composer is a free online node-based visual programming environment that allows creating custom image shaders using WebGL/GLSL fragment shaders. The examples on the ImageShader documentation page show how to use our own images as input textures:


[1]: https://i.stack.imgur.com/eQSqs.png

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