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Extents

Based on game build 714014 | Last updated: 2026-02-27

Overview​

This file contains standalone utility functions for computing spatial extents (axis-aligned bounding boxes) and minimum bounding radii for collections of nodes and polygonal shapes. It does not implement an Entity Component System (ECS) component; rather, it offers standalone helper functions used elsewhere in the map generation and layout systems to calculate spatial bounds. Functions here operate on plain Lua tables representing node data and polygon vertices, and update or return extent metadata including min/max coordinates, size, and radius.

Usage example​

local extents = ResetextentsForNodes(my_nodes)
print("Bounding box:", extents.xmin, extents.ymin, extents.xmax, extents.ymax)

local poly_extents = ResetextentsForPoly({
    {0, 0},
    {4, 0},
    {4, 3},
    {0, 3}
})
print("Polygon radius:", poly_extents.radius)

local radius, cx, cy = GetMinimumRadiusForNodes(my_nodes)

Dependencies & tags​

Components used: None identified.
Tags: None identified.

Properties​

No public properties are initialized in a component constructor, as this file defines only stateless utility functions.

Main functions​

UpdateextentsForNode(extents, node)​

  • Description: Expands the given extents bounding box to include the spatial footprint of node, assuming node.data.position is a 2D point and node.data.size is the half-size (axis-aligned square centered at position).
  • Parameters:
    • extents: Table with keys xmin, ymin, xmax, ymax. Modified in place.
    • node: Table expected to have node.data.position = {x, y} and node.data.size = number.
  • Returns: None (modifies extents in place).
  • Error states: Assumes node.data.position is indexable and node.data.size is numeric; undefined behavior if not.

ResetextentsForNodes(nodes)​

  • Description: Computes a new bounding box that tightly encloses all nodes in the list. Initializes with extreme initial values (xmin=1000000, xmax=-1000000, etc.) and iteratively expands via UpdateextentsForNode.
  • Parameters:
    • nodes: List (array-like table) of node tables with node.data.position and node.data.size.
  • Returns: Table with keys xmin, ymin, xmax, ymax.
  • Error states: Returns extreme initial values if nodes is empty.

GetMinimumRadiusForNodes(nodes)​

  • Description: Computes the radius of the smallest circle that encloses all node centers and their extents. Internally constructs a list of candidate points (center and points offset by +/-size along each axis) and delegates to a global getminimumradius function.
  • Parameters:
    • nodes: List of node tables with node.data.position and node.data.size.
  • Returns: Three values: radius (number), cx (center X), cy (center Y). (Exact definition of returned center depends on getminimumradius implementation, which is not provided.)
  • Error states: Returns nil or undefined values if nodes is empty or getminimumradius fails.

UpdateextentsForPoint(extents, point)​

  • Description: Expands the given extents bounding box to include a single 2D point (represented as a two-element table).
  • Parameters:
    • extents: Table with keys xmin, ymin, xmax, ymax. Modified in place.
    • point: Table {x, y} (indices 1 and 2) of numeric coordinates.
  • Returns: None (modifies extents in place).
  • Error states: Assumes point is indexable and numeric; undefined behavior otherwise.

ResetextentsForPoly(poly)​

  • Description: Computes a bounding box for a polygon defined by a list of vertices, and also calculates size and radius fields for convenience. Radius is defined as the larger of width and height.
  • Parameters:
    • poly: List of 2D points (each {x, y} or {point[1], point[2]}).
  • Returns: Table with keys:
    • xmin, ymin, xmax, ymax: bounding coordinates.
    • size: {x = width, y = height}.
    • radius: max(width, height).
  • Error states: Returns extreme initial values if poly is empty.

Events & listeners​

None. This file contains no event registration or emission logic.