2017

Using Shaders to Create Your Own Ef-
fects
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.
You can create your own Matchbox shaders to use in Smoke. You can also create preset looks for your shaders by exporting
settings into a shell directly from Smoke. Tools are provided to build and test your shaders, and a Shader Builder API Guide
is available to help you at
http://www.autodesk.com/shader_builder_api_guide .
TIP You can find many more shaders by visiting the community-driven shader repository at https://logik-matchbook.org/. You
can download free shaders created by fellow Smoke users, or share your own custom shaders with other users.
About Matchbox
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. By default, Matchbox has six physical inputs, but you are not limited to the amount of actual inputs
you can use in the effect, since you can use the same image for more than one input. You can also specify
colours as inputs, such as black or white; in this case, you may need to select User Defined in the Output
Resolution box in the Matchbox menu to be able to view the colour result.
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. If the loaded shader has any preset
starting points built into it (such as in the Duotone shader), you can find them in the Presets list in the
Shader tab of the Matchbox menu.
Matchbox shaders can also be used as timeline transitions. Smoke includes some Matchbox transition presets
(see
Using Matchbox as a Transition (page 996)). 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 (page 394)).
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