TextureAtlas class Assets and loading

A uniform grid texture atlas: one or more equally sized PBR maps packed as columns x rows square tiles, with an optional gutter of padding texels around each tile so mip sampling does not bleed across tile edges.

The atlas does the UV bookkeeping for tiled content (voxel block faces, sprite sheets, terrain tiles). Resolve a tile's atlas-space UV box with tileBounds, or map a within-tile coordinate with tileUv; a mesh writes those UVs into its texture coordinates so a single material and draw call covers every tile.

Maps follow the glTF metallic-roughness convention (baseColor, metallicRoughness with metallic in B and roughness in G, normal, occlusion); toMaterial wires them into a PhysicallyBasedMaterial.

This is a CPU-side atlas (one packed texture). Once Flutter GPU gains 2D array textures, a tile becomes an array layer and this padding/inset dance is no longer needed; see the texture-array work tracked upstream.

Constructors

TextureAtlas({required int columns, required int rows, required int tileSize, int padding = 0, Texture2D? baseColor, Texture2D? metallicRoughness, Texture2D? normal, Texture2D? occlusion})
Creates an atlas of columns x rows tiles, each tileSize texels square, separated by padding texels of gutter. The PBR maps are optional so the UV math can be used (and unit tested) on its own.

Properties

baseColor → Texture2D?
Packed PBR maps, all sharing the same grid layout. Any may be null.
final
columns → int
Tile grid dimensions.
final
hashCode → int
The hash code for this object.
no setterinherited
height → int
no setter
metallicRoughness → Texture2D?
final
normal → Texture2D?
final
occlusion → Texture2D?
final
padding → int
Gutter of (typically edge-replicated) texels around each tile, in texels.
final
rows → int
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
tileCount → int
Total number of tiles.
no setter
tileSize → int
Edge length of a tile's content area, in texels.
final
width → int
Atlas dimensions in texels (including the padding gutters).
no setter

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
tileBounds(int index) → Vector4
The atlas-space UV box of tile index's content area as (minU, minV, maxU, maxV), inset past the padding gutter so sampling stays inside the tile. Tiles are row-major with a top-left origin.
tileUv(int index, double u, double v) → Vector2
Maps a within-tile coordinate (u, v, each in [0, 1] with (0, 0) at the tile's top-left) to an atlas UV for tile index.
toMaterial() → PhysicallyBasedMaterial
Builds a PhysicallyBasedMaterial bound to this atlas's maps. The factors are left at their identity defaults so the textures drive the result; the caller picks alpha mode, vertex-color weight, and so on.
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited