pyvvisf

Python library for parsing and rendering ISF shaders. Pure Python on top of PyOpenGL and GLFW, no C++ to build, runs the same on Linux, macOS, and Windows.

I wrote it because I wanted an LLM to be able to validate, render, and inspect the GLSL it generates before claiming success. The existing reference is the C++ VVISF-GL, which works but is slow to iterate on and slow to install. pyvvisf reads the JSON5 metadata block, compiles the shader, runs the multi-pass render graph, and gives you back a buffer you can save as an image or hand back to the model with structured error messages when things break.

The API is small. with ISFRenderer(shader_source) as renderer: renderer.render(width, height). Inputs are typed via Pydantic and can be set at runtime with set_input(name, value). Full ISF 2.0 spec, including IMG_THIS_PIXEL, IMG_PIXEL, and IMG_SIZE.

Most of the code was written by AI. That’s the point: it’s a tool for an AI shader pipeline, dogfooded from the start.