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description Core base classes for the picker system.
icon arrow-down-from-arc

Picker

Overview

This is the foundational infrastructure for PCGEx pickers, which are used to select indices from collections (like points in a dataset). Pickers convert values into index selections, supporting both discrete (exact indices) and normalized (relative 0-1 values) modes. The base configuration provides common settings for index interpretation, truncation, and safety handling.

Base Configuration

All picker types inherit these common settings from FPCGExPickerConfigBase:

Common Picker Settings

Treat As Normalized bool

Determines how picker values are interpreted.

  • False (default): Values are treated as discrete indices (0, 1, 2, 3...). A value of 5 means "select index 5."
  • True: Values are treated as normalized relative positions (0.0 to 1.0). A value of 0.5 means "select the item at 50% through the collection."

Default: false

⚡ PCG Overridable

Truncate Mode EPCGExTruncateMode

When using normalized values, determines how fractional positions are converted to discrete indices.

Option Description
Round Rounds to nearest index (0.4 → 0, 0.6 → 1)
Ceil Rounds up (0.1 → 1, 0.9 → 1)
Floor Rounds down (0.1 → 0, 0.9 → 0)

Default: Round

📋 Visible when Treat As Normalized is enabled

⚡ PCG Overridable

Safety EPCGExIndexSafety

Determines how to handle out-of-bounds index picks (indices less than 0 or greater than the collection size).

Option Description
Ignore Skip invalid indices silently
Clamp Clamp to valid range (negative → 0, too large → max)
Wrap Wrap around using modulo (treats collection as circular)
Tile Ping-pong/mirror at boundaries

Default: Ignore

⚡ PCG Overridable

Factory Types

The picker system uses a factory pattern:

  • UPCGExPickerFactoryData: Base factory class that stores and processes picks
    • Maintains DiscretePicks array for index-based selections
    • Maintains RelativePicks array for normalized selections
    • Provides AddPicks() method to populate pick sets
  • UPCGExPickerFactoryProviderSettings: Base provider class that creates picker factories
    • Outputs to the Picker pin
    • Derived classes implement specific picker behaviors

Picker Categories

Pickers are used throughout PCGEx for index-based selection tasks:

  • Attribute Set Pickers: Select indices based on attribute values
  • Constant Pickers: Use fixed values for picks
  • Range Pickers: Generate picks within specified ranges

Each picker type extends these base classes and adds specific functionality while inheriting the common configuration settings above.

Usage Pattern

Picker Provider Node
      ↓
Creates Factory (UPCGExPickerFactoryData)
      ↓
Processes Input (attributes, constants, etc.)
      ↓
Generates Picks (discrete or normalized)
      ↓
Output: Set of indices for selection

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