YASE (Yet Another Shader Editor) is a WebGL-based shader editor designed to enable quick sketching of particle-based effects. YASE interprets your shader output as particle positions instead of pixel colors. Additionally, some predefined inputs such as a shadow map are provided.
In addition to being a web based tool, it has been adapted for use in a live performance setting.
A collection of shaders made with YASE can found on the GitHub project page.