ITerrainTileSource

Remarks

The seam that decides whether this streams from disk or only into the atlas. TerrainStreamer is about which tiles a frame pays for; where their bytes are read from is this, and the two are separable because the residency service already is — LoadAsync is asynchronous precisely so that a source backed by a file does not stall the frame.

⚠ TerrainTileSource is the in-memory one and it is not a disk cache. A terrain the editor is sculpting is entirely in host memory by definition — it has an edit stack — so streaming it saves the upload and nothing else. That is still the expensive half: a 128×128-tile terrain is sixteen thousand block copies on its first frame, and a source's radius turns that into a few dozen. A file-backed source is what makes the host bytes optional too, and it needs a tile-addressable file, which TerrainStore's v1 layout is not.

Fields and properties (2)

• int TileSamples

  How many samples a tile is across, which fixes the page size.

• (int X, int Z) TileCounts

  How many tiles there are along each axis.

Methods (3)

• void Prepare()

  Brings whatever ReadAsync reads up to date, on the caller's thread.

• int RevisionOf(int tileX, int tileZ)

  What a tile's bytes are at, as a number that changes whenever they change.

• ValueTask<int> ReadAsync(int tileX, int tileZ, Memory<byte> destination, CancellationToken cancellation)

  Reads one tile's whole mip chain, packed level after level.

Used by (4)

• GatedSourceVixen.Rendering.Terrain.Tests
• TerrainStreamerVixen.Rendering.Terrain
• TerrainTilePagesVixen.Rendering.Terrain
• TerrainTileSourceVixen.Rendering.Terrain