filterchain Reference

Module defined in lua/common/utils/filterchain.lua. Functional programming filter chain for signal processing - chains composable filter objects (smooth, interval, scale, digitize, etc.) into a processing pipeline.

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Exports

Functions

M.test()

Run built-in test/demo of the filter chain system.

Filter Types (via internal F table)

F.smooth(rate)

Smooth a value toward a target at a given rate per second.

F.interval(offsetTime, timeOn, timeOff)

Generate on/off intervals (blinking/pulsing).

F.scale(scaleVal)

Multiply value by a constant.

F.digitize(threshold)

Convert to 0/1 based on threshold (default 0.5).

F.floor()

Apply math.floor to value.

F.clamp(minval, maxval)

Clamp value between min and max (default 0–1).

F.examine(str, commonArgumentsCount)

Debug filter - logs all values passing through with a label.

• Parameters:
  • str - string - Debug label
  • commonArgumentsCount - number|nil - Number of common args to skip (default 0)

F.startdelay(startdelay)

Delay filter activation until the input has been high for a duration.

• Parameters:
  • startdelay - number - Required high-time in seconds before passing through

Factory Function (internal)

newFilterchain(filterlist, debug, commonFilterArguments, codeArgs)

Create a new filter chain from a list of filter specifications.

• Parameters:
  • filterlist - table - Array of filter definitions
  • debug - boolean - Enable debug output
  • commonFilterArguments - table - Shared arguments (e.g., {'dt'})
  • codeArgs - table - Additional code-level arguments

Internal Notes

• Proof-of-concept functional programming pattern by BeamNG
• F.plus and F.pushConstant exist in source but are commented out (experimental)
• Filters are objects with a :get(dt, value) method
• getGenerator creates filter instances from specification tables
• getVarByNameInScope resolves dotted variable names in nested tables
• Common filter argument is dt (delta time) passed to all filters