TerrainHoleStroke

Remarks

The parallel of TerrainStroke, and a separate type because a hole is not a delta. The seven sculpt tools write signed offsets into an edit layer, so their record is the layer's values either side; holes are one bit on TerrainHoles, which lives on the terrain rather than on a layer and has no alpha, no stack and no composite. Trying to record one in a TerrainStroke would be recording the wrong container's contents and restoring them onto ground the tool never touched.

⚠ The before image is taken lazily and never re-taken, exactly as Extend does it: a drag crossing the same ground forty times records it once, holding the bit it had before the first crossing. Re-recording would make undo restore the middle of the stroke.

Fields and properties (3)

• public TerrainRect Rect

  Everything the stroke has touched.

• public int RecordedSamples

  How many samples the record holds.

• public bool IsEmpty

  Whether anything has been recorded.

Methods (4)

• public TerrainHoleStroke(Terrain terrain)

  Begins recording.

• public TerrainRect Record(in TerrainBrush brush, in BrushStamp stamp)

  Records the bits a stamp is about to change, and says which samples those are.

• public TerrainRect Undo()

  Puts the mask back the way it was.

• public IReadOnlyDictionary<long, bool> Capture()

  Captures what the stroke left, so it can be redone.

Used by (2)

• TerrainEditVixen.Editor.Terrain
• TerrainHoleCommandVixen.Editor.Terrain