Overlay Definition

Ground overlays: the paths, water and floors drawn on top of the terrain’s base colour.

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OverlayDefinition.Create

function TOverlayDefinition.Create(id: Integer; const data: TByteArray): TOverlayDefinition; static;

Decodes a ground overlay - the paths, water and floors drawn on top of the underlying terrain colour.

An overlay is drawn from whichever it has: a secondary colour, a texture, or its own colour. Both colours are converted to HSL here so the map renderer can pack them into a palette index without redoing the conversion per tile.

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TOverlayDefinitionArray.IndexOf

function TOverlayDefinitionArray.IndexOf(id: Integer): Integer;

The position of id in the array, or -1 if there is no such overlay.

Overlay definitions are stored one per id with no gaps, so an id is its own index; this exists to keep that assumption in one place.