Added current moon/sun positions to the MapScreen

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/OrbitalPos.kt

@@ -63,10 +63,8 @@ data class OrbitalPos(
         val sinBeta = sin(beta)
         for (azimuth in 0..720) {
             val rads = azimuth * DEG2RAD
-            val sinRads = sin(rads)
-            val cosRads = cos(rads)
-            val lat = asin(sinLat * cosBeta + cosLat * sinBeta * cosRads)
-            val lon = longitude + atan2(sinRads * sinBeta * cosLat, cosBeta - sinLat * sin(lat))
+            val lat = asin(sinLat * cosBeta + cosLat * sinBeta * cos(rads))
+            val lon = longitude + atan2(sin(rads) * sinBeta * cosLat, cosBeta - sinLat * sin(lat))
             rangeCirclePoints.add(GeoPos(lat * RAD2DEG, lon * RAD2DEG))
         }
         return rangeCirclePoints

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapScreen.kt

@@ -83,7 +83,10 @@ private const val OVERLAY_STATION = 0
 private const val OVERLAY_TRACK = 1
 private const val OVERLAY_FOOTPRINT = 2
 private const val OVERLAY_POSITIONS = 3
-private const val OVERLAY_COUNT = 4
+private const val OVERLAY_TERMINATOR = 4
+private const val OVERLAY_SUN = 5
+private const val OVERLAY_MOON = 6
+private const val OVERLAY_COUNT = 7
 
 private val minLat = MapView.getTileSystem().minLatitude
 private val maxLat = MapView.getTileSystem().maxLatitude
@@ -106,6 +109,14 @@ private val textPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
     setShadowLayer(3f, 3f, 3f, Color.BLACK)
 }
 private val iconCache = LruCache<String, Drawable>(128)
+private val sunIconPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+    colorFilter =
+        android.graphics.PorterDuffColorFilter("#FFE082".toColorInt(), android.graphics.PorterDuff.Mode.SRC_IN)
+}
+private val moonIconPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+    colorFilter =
+        android.graphics.PorterDuffColorFilter("#E0E0E0".toColorInt(), android.graphics.PorterDuff.Mode.SRC_IN)
+}
 
 @Composable
 fun MapDestination() {
@@ -152,6 +163,9 @@ private fun MapScreen(uiState: MapState, onAction: (MapAction) -> Unit, mapView:
                     uiState.track?.let { setSatelliteTrack(it, view) }
                     uiState.footprint?.let { setFootprint(it, view) }
                     uiState.positions?.let { setPositions(it, view) { item -> onAction(MapAction.SelectItem(item)) } }
+                    setTerminator(uiState.sunLatDeg, uiState.sunLonDeg, view)
+                    setSubSolarPoint(uiState.sunLatDeg, uiState.sunLonDeg, view)
+                    setMoonPosition(uiState.moonLatDeg, uiState.moonLonDeg, view)
                     view.invalidate()
                 }
                 uiState.mapData?.let { mapData ->
@@ -280,8 +294,6 @@ private fun setPositions(
             lastMapView = mapView
             markerPool.clear()
             iconCache.evictAll()
-            footprintPolyline = null
-            footprintPoints = null
         }
         // Reuse the existing FolderOverlay — creating a new one and replacing it
         // causes osmdroid to detach shared Marker objects, making them invisible.
@@ -365,14 +377,12 @@ private var footprintPoints: ArrayList<GeoPoint>? = null
 private fun setFootprint(orbitalPos: OrbitalPos, mapView: MapView) {
     try {
         val rangeCircle = orbitalPos.getRangeCircle()
-        // Lazily initialize the reusable point list and polyline
         var pts = footprintPoints
         if (pts == null || pts.size != rangeCircle.size) {
             pts = ArrayList(rangeCircle.size)
             for (gp in rangeCircle) pts.add(GeoPoint(gp.latitude, gp.longitude))
             footprintPoints = pts
         } else {
-            // Update coordinates in-place — zero allocations
             for (i in rangeCircle.indices) {
                 pts[i].latitude = rangeCircle[i].latitude
                 pts[i].longitude = rangeCircle[i].longitude
@@ -388,6 +398,83 @@ private fun setFootprint(orbitalPos: OrbitalPos, mapView: MapView) {
         println(e)
     }
 }
+
+/**
+ * Update the NightOverlay with the current sub-solar position.
+ * The overlay is created once and kept in OVERLAY_TERMINATOR; only its
+ * sunLatDeg/sunLonDeg fields are updated each tick so osmdroid redraws it.
+ */
+private fun setTerminator(sunLatDeg: Double, sunLonDeg: Double, mapView: MapView) {
+    try {
+        val overlay = mapView.overlays[OVERLAY_TERMINATOR]
+        if (overlay is NightOverlay) {
+            overlay.sunLatDeg = sunLatDeg
+            overlay.sunLonDeg = sunLonDeg
+        } else {
+            mapView.overlays[OVERLAY_TERMINATOR] = NightOverlay().apply {
+                this.sunLatDeg = sunLatDeg
+                this.sunLonDeg = sunLonDeg
+            }
+        }
+    } catch (e: Exception) {
+        println(e)
+    }
+}
+
+/** Place an ic_sun icon marker at the sub-solar point. */
+private fun setSubSolarPoint(sunLatDeg: Double, sunLonDeg: Double, mapView: MapView) {
+    try {
+        val overlay = mapView.overlays[OVERLAY_SUN]
+        val sunPos = GeoPoint(sunLatDeg, sunLonDeg)
+        if (overlay is Marker) {
+            overlay.position = sunPos
+        } else {
+            val iconSize = 48
+            val bmp = createBitmap(iconSize, iconSize)
+            ContextCompat.getDrawable(mapView.context, R.drawable.ic_sun)?.apply {
+                setBounds(0, 0, iconSize, iconSize)
+                colorFilter = sunIconPaint.colorFilter
+                draw(Canvas(bmp))
+            }
+            mapView.overlays[OVERLAY_SUN] = Marker(mapView).apply {
+                setInfoWindow(null)
+                setAnchor(Marker.ANCHOR_CENTER, Marker.ANCHOR_CENTER)
+                icon = bmp.toDrawable(mapView.context.resources)
+                position = sunPos
+            }
+        }
+    } catch (e: Exception) {
+        println(e)
+    }
+}
+
+/** Place an ic_moon icon marker at the sub-lunar point. */
+private fun setMoonPosition(moonLatDeg: Double, moonLonDeg: Double, mapView: MapView) {
+    try {
+        val overlay = mapView.overlays[OVERLAY_MOON]
+        val moonPos = GeoPoint(moonLatDeg, moonLonDeg)
+        if (overlay is Marker) {
+            overlay.position = moonPos
+        } else {
+            val iconSize = 48
+            val bmp = createBitmap(iconSize, iconSize)
+            val c = Canvas(bmp)
+            ContextCompat.getDrawable(mapView.context, R.drawable.ic_moon)?.apply {
+                setBounds(0, 0, iconSize, iconSize)
+                colorFilter = moonIconPaint.colorFilter
+                draw(c)
+            }
+            mapView.overlays[OVERLAY_MOON] = Marker(mapView).apply {
+                setInfoWindow(null)
+                setAnchor(Marker.ANCHOR_CENTER, Marker.ANCHOR_CENTER)
+                icon = bmp.toDrawable(mapView.context.resources)
+                position = moonPos
+            }
+        }
+    } catch (e: Exception) {
+        println(e)
+    }
+}
 // endregion
 
 // region MapView lifecycle

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapState.kt

@@ -30,7 +30,11 @@ data class MapState(
     val orbitalPass: OrbitalPass,
     val track: List<List<GeoPos>>? = null,
     val footprint: OrbitalPos? = null,
-    val positions: Map<OrbitalObject, GeoPos>? = null
+    val positions: Map<OrbitalObject, GeoPos>? = null,
+    val sunLatDeg: Double = 0.0,
+    val sunLonDeg: Double = 0.0,
+    val moonLatDeg: Double = 0.0,
+    val moonLonDeg: Double = 0.0
 )
 
 sealed interface MapAction {

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapViewModel.kt

@@ -22,6 +22,7 @@ import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewModelScope
 import androidx.lifecycle.viewmodel.initializer
 import androidx.lifecycle.viewmodel.viewModelFactory
+import com.rtbishop.look4sat.core.domain.predict.CelestialComputer
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.OrbitalObject
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
@@ -177,10 +178,12 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
             }
         }
 
-        // 2. Derive footprint and info data from the already-computed selected position
+        // 2. Derive footprint, info data, sun and moon position from already-computed state
         val satPos = selectedSatPos ?: satelliteRepo.getPosition(selected, pos, date.time)
         val footprint = satPos
         val mapData = buildMapData(selected, satPos, date)
+        val sunPos = CelestialComputer.getSunPosition(stationPos, date.time)
+        val moonPos = CelestialComputer.getMoonPosition(stationPos, date.time)
 
         // 3. Single atomic state update — one recomposition per cycle
         _uiState.update {
@@ -188,7 +191,11 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
                 positions = positionsMap,
                 footprint = footprint,
                 mapData = mapData.first,
-                orbitalPass = mapData.second
+                orbitalPass = mapData.second,
+                sunLatDeg = sunPos.latitude,
+                sunLonDeg = sunPos.longitude,
+                moonLatDeg = moonPos.declination, // sub-lunar latitude = declination
+                moonLonDeg = if (moonPos.gha <= 180.0) -moonPos.gha else 360.0 - moonPos.gha
             )
         }
     }

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/NightOverlay.kt

@@ -0,0 +1,152 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.feature.map
+
+import android.graphics.Canvas
+import android.graphics.Color
+import android.graphics.Paint
+import android.graphics.RectF
+import org.osmdroid.views.MapView
+import org.osmdroid.views.overlay.Overlay
+import kotlin.math.cos
+import kotlin.math.sin
+
+/**
+ * Custom osmdroid overlay that shades the night side of the globe.
+ *
+ * Works entirely in screen-pixel space: for each vertical strip on screen it
+ * asks osmdroid for the geographic coordinate, then tests whether that point is
+ * in the night half-sphere relative to the sub-solar point.  Because the
+ * computation happens during draw() the result is always correct regardless
+ * of zoom level or map scroll position — no polygon winding issues possible.
+ *
+ * A point (latRad, lonRad) is in night when the angle to the sub-solar point
+ * exceeds 90°, i.e. the dot product of the two unit vectors is negative:
+ *   dot = sin(lat)*sin(sunLat) + cos(lat)*cos(sunLat)*cos(lon - sunLon) < 0
+ *
+ * Performance: we sample one column per [stepPx] pixels (default 4) and draw
+ * filled vertical rectangles.  On a 1080-wide screen this means ~270 trig
+ * evaluations per row, which is imperceptible.
+ */
+class NightOverlay : Overlay() {
+
+    /** Sub-solar latitude in degrees. */
+    var sunLatDeg: Double = 0.0
+
+    /** Sub-solar longitude in degrees. */
+    var sunLonDeg: Double = 0.0
+
+    private val nightPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+        style = Paint.Style.FILL
+        color = Color.argb(75, 0, 0, 0)
+    }
+
+    private val rect = RectF()
+
+    override fun draw(canvas: Canvas, mapView: MapView, shadow: Boolean) {
+        if (shadow) return
+
+        val proj = mapView.projection
+        val sunLatRad = Math.toRadians(sunLatDeg)
+        val sunLonRad = Math.toRadians(sunLonDeg)
+        val sinSunLat = sin(sunLatRad)
+        val cosSunLat = cos(sunLatRad)
+
+        val w = mapView.width
+        val h = mapView.height
+        val stepPx = 4 // sample every N pixels — balance quality vs CPU
+
+        // We scan column by column. For each column we determine the longitude,
+        // then find the latitude range that is in night and shade it.
+        // Since longitude is constant along a vertical strip and the day/night
+        // boundary at a given longitude is at most two latitudes, we can do a
+        // scan-line fill efficiently.
+
+        var x = 0
+        while (x < w) {
+            // Get the geographic coordinate at the top and bottom of this column.
+            val geoTop = proj.fromPixels(x, 0) ?: run { x += stepPx; continue }
+            val geoBot = proj.fromPixels(x, h - 1) ?: run { x += stepPx; continue }
+
+            val lonRad = Math.toRadians(geoTop.longitude)
+            val cosLonDiff = cos(lonRad - sunLonRad)
+
+            // Top pixel geographic lat
+            val latTopRad = Math.toRadians(geoTop.latitude)
+            // Bottom pixel geographic lat (osmdroid: y=0 is top of screen, higher y = lower lat)
+            val latBotRad = Math.toRadians(geoBot.latitude)
+
+            // dot(sunVec, pointVec) < 0 → night
+            // dot = sin(lat)*sinSunLat + cos(lat)*cosSunLat*cosLonDiff
+            val dotTop = sin(latTopRad) * sinSunLat + cos(latTopRad) * cosSunLat * cosLonDiff
+            val dotBot = sin(latBotRad) * sinSunLat + cos(latBotRad) * cosSunLat * cosLonDiff
+
+            when {
+                dotTop < 0 && dotBot < 0 -> {
+                    // Entire column is night — shade from top to bottom
+                    rect.set(x.toFloat(), 0f, (x + stepPx).toFloat(), h.toFloat())
+                    canvas.drawRect(rect, nightPaint)
+                }
+
+                dotTop >= 0 && dotBot >= 0 -> {
+                    // Entire column is day — nothing to draw
+                }
+
+                else -> {
+                    // Terminator crosses this column — find the crossing pixel by binary search
+                    val crossY = findCrossingY(proj, x, 0, h - 1, sinSunLat, cosSunLat, cosLonDiff)
+                    if (dotTop < 0) {
+                        // Night at top, day at bottom
+                        rect.set(x.toFloat(), 0f, (x + stepPx).toFloat(), crossY.toFloat())
+                        canvas.drawRect(rect, nightPaint)
+                    } else {
+                        // Day at top, night at bottom
+                        rect.set(x.toFloat(), crossY.toFloat(), (x + stepPx).toFloat(), h.toFloat())
+                        canvas.drawRect(rect, nightPaint)
+                    }
+                }
+            }
+            x += stepPx
+        }
+    }
+
+    /**
+     * Binary-search for the pixel row where the day/night boundary crosses column [x].
+     * [yTop] is in day, [yBot] is in night (or vice versa).
+     */
+    private fun findCrossingY(
+        proj: org.osmdroid.views.Projection,
+        x: Int,
+        yTop: Int,
+        yBot: Int,
+        sinSunLat: Double,
+        cosSunLat: Double,
+        cosLonDiff: Double
+    ): Int {
+        var lo = yTop
+        var hi = yBot
+        while (hi - lo > 1) {
+            val mid = (lo + hi) / 2
+            val geo = proj.fromPixels(x, mid) ?: return mid
+            val latRad = Math.toRadians(geo.latitude)
+            val dot = sin(latRad) * sinSunLat + cos(latRad) * cosSunLat * cosLonDiff
+            if (dot < 0) hi = mid else lo = mid
+        }
+        return (lo + hi) / 2
+    }
+}