TGFPA is simple texture generation tool, designed for fast prototyping.
Crate new shader file (File > New...), open in text editor of your choise and start editing. TGFPA support hot-reloading, so all your changes will be immediatly visible (keep in mind, that currently variable values aren't saved between compilation - that is very high on priority list).
Shader file have to be valid GLSL program, with main function having signature: void mainImage( out vec4 fragColor, in vec2 fragCoord ) (the same as Shadertoy).
TGFPA creates specific UI controls for all uniform variables (the ones with greyish tint are stripped by compiler). What controls are used can be altered with custom attributes: DRAG(), Range(min, max), Color() (only for vec3 and vec4).
TGFPA uses custom, #include-like system for adding libraries to shaders. Library file have to be inside shader/lib directory. To include library use LIB(<library-name>), keep in mind that it literally pastes library file on top of shader file, so all name collisions can occur.
Currently only building with Visual Studio is supported. To build run a x64 Developer Command Prompt (alternatively you can have vcvarsall in your PATH) and then run build.bat script. To build release version run the script with release parameter.
Linux builds will be (hopefully) supported in the future.