Matchbox is an interactive development tool that allows you to run generic OpenGL Shading Language (GLSL) shader code, to add specific functionality, or create custom effects. GLSL is a high-level shading language that is part of the OpenGL specification.
Because of the nature of GLSL fragment shaders, Matchbox works well on image processing effects. You can however, create simulated 3D effects using a number of image processing techniques, such as a Z-depth pass, for example.
The Matchbox node populates the user interface dynamically, based on the parameters required by the shader.
Re-purposing of existing effects is easy, since Matchbox shaders use simple generic GLSL fragment shader code, with no required customization. Included are a number of useful examples and presets, that can be used as is, or serve as starting points for you to develop your own tools.
Matchbox shaders can also be used as timeline transitions. Smoke also includes some Matchbox transition presets. See: Using Matchbox as a Transition. The Matchbox XML schema contains tags to identify if the shader is designed as a Timeline FX or a Transition. The tags ShaderType and SoftwareVersion are added automatically to the XML by the shader_builder script.
Matchbox can be accessed from multiple places:
Timeline, then use ConnectFX (see Creating ConnectFX).
Timeline, then add Timeline FX from the Effects ribbon (see Adding Timeline FX).
The Modular Keyer, then select a node from the Node bin.