WorldWind Kotlin/earth.worldwind.shape/PointMemo

PointMemo

Per-shape memo of the window-independent terms of a geographic to Cartesian conversion, reused across frames and rendering windows by point shapes (Placemark, Label).

Cached terms: the altitude-zero base point and the altitude direction (every projection is linear in altitude: cartesian(lat, lon, h) = base + normal * h), the global elevation model height and the geoid offset. All of them are identical for every window, so one memo per shape is correct in multi-window rendering. Terrain-clamped surface points are NOT memoized - the tessellated terrain differs per window and per LoD and is still resolved each frame.

Position and globe configuration changes are detected by value, so in-place position edits stay safe. Altitude mode handling mirrors RenderContext.geographicToCartesian (without the useEM flag, which point shapes do not use); the equivalence is pinned by PointMemoTest, which compares both paths for every altitude mode.

Constructors

PointMemo

constructor()

Types

Companion

object Companion

Functions

geographicToCartesian

fun geographicToCartesian(rc: RenderContext, position: Position, altitudeMode: AltitudeMode, result: Vec3): Vec3

Converts a geographic position to Cartesian coordinates according to an altitudeMode, exactly as RenderContext.geographicToCartesian does, reusing the memoized terms.

fun geographicToCartesian(rc: RenderContext, latitude: Angle, longitude: Angle, altitude: Double, altitudeMode: AltitudeMode, result: Vec3): Vec3

Converts a geographic location to Cartesian coordinates according to an altitudeMode, exactly as RenderContext.geographicToCartesian does, reusing the memoized terms.

geographicToCartesianNormal

fun geographicToCartesianNormal(rc: RenderContext, latitude: Angle, longitude: Angle, result: Vec3): Vec3

Provides the globe's Cartesian surface normal at a geographic location, reusing the memoized value.

invalidate

fun invalidate()

Forgets all cached terms, forcing recomputation on next use.