Skip to content
Grid Building Docs

GBGeometryMath

Summary

Section titled “Summary”

Geometry & collision math utilities for the grid building addon.

Provides compact, well-documented helper functions used across the addon for tile/polygon overlap and collision tasks. Main responsibilities include: - Computing polygon vs polygon intersection areas (uses Godot Geometry2D). - Producing tile polygons for square and isometric tiles and testing polygon overlaps against tiles (area-based and optimized native collision checks). - Converting various Shape2D types to polygon approximations for geometry processing (Rectangle, Circle, Capsule, ConvexPolygon, fallback to rect). - Utility helpers: axis-aligned rectangle detection and polygon bounding rect.

:::note[Note] TILE SHAPE ENFORCEMENT: All functions use TileSet.TileShape enum values.

Use: TileSet.TILE_SHAPE_SQUARE, TileSet.TILE_SHAPE_ISOMETRIC, TileSet.TILE_SHAPE_HALF_OFFSET_SQUARE

Do NOT use: integers (0, 1, 2) or strings (“square”, “isometric”, etc.) :::

Methods

Section titled “Methods”
static func _is_axis_aligned_rectangle( polygon: PackedVector2Array ) -> bool

Returns true if the polygon is an axis-aligned rectangle (all edges horizontal or vertical).

polygon: PackedVector2Array - Polygon to check.

Returns: bool - True if axis-aligned rectangle.

static func get_polygon_bounds( polygon: PackedVector2Array ) -> Rect2

Returns the bounding rectangle of a polygon.

polygon: PackedVector2Array - The polygon points.

Returns: Rect2 - Bounding rectangle of the polygon.

static func convert_shape_to_polygon( shape: Shape2D, transform: Transform2D ) -> PackedVector2Array

Converts a Shape2D to a polygon for consistent processing.

shape: Shape2D - The shape to convert.

transform: Transform2D - Transform to apply to the shape.

Returns: PackedVector2Array - Polygon representation of the shape.

static func intersection_polygon_area( points: PackedVector2Array ) -> float

Calculates the area of a polygon defined by a PackedVector2Array. Used to determine the area of intersection between two polygons (e.g., tile and collision shape). Returns 0.0 if the input does not form a valid polygon (fewer than 3 points). This is used in overlap checks to ensure that only true area overlaps (not just edge or point contacts) are counted.

static func is_exact_polygon_match( poly_a: PackedVector2Array, poly_b: PackedVector2Array ) -> bool

Checks if two polygons are exactly the same (vertex by vertex)

static func exact_polygon_area( poly: PackedVector2Array ) -> float

Returns area for exact polygon match

Source

Section titled “Source”

addons/grid_building/utils/gb_geometry_math.gd

This API reference is automatically generated from the plugin source code. For implementation examples and usage guides, see the guides section.