From ca1d5b33109e2b6d317d4411fcd9375b680d7273 Mon Sep 17 00:00:00 2001
From: Mike van Riel <mike@ingewikkeld.net>
Date: Thu, 12 Dec 2024 12:21:02 +0100
Subject: [PATCH] Tweak zoomlevels to show a crispier image instead of using
 the calculations that match the 'official' zoom levels

---
 Assets/ATMDataController.cs                   | 35 +++++++++++++------
 Assets/Scenes/Main.unity                      |  2 ++
 .../CartesianTiles/ImageProjectionLayer.cs    | 12 ++++---
 3 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/Assets/ATMDataController.cs b/Assets/ATMDataController.cs
index 1be00c9d..ff04a3ac 100644
--- a/Assets/ATMDataController.cs
+++ b/Assets/ATMDataController.cs
@@ -14,6 +14,11 @@ public class ATMDataController : MonoBehaviour
         private const double equatorialCircumference = 2 * Mathf.PI * earthRadius;
         private const double log2x = 0.30102999566d;
 
+        [Tooltip("The zoomlevels are scaled exponentially across this height range, tweak to get better tiling visuals")]
+        [SerializeField] private float minHeightForZoomLevels = 200f;
+        [Tooltip("The zoomlevels are scaled exponentially across this height range, tweak to get better tiling visuals")]
+        [SerializeField] private float maxHeightForZoomLevels = 40_000_000f;
+
         private int currentYear;
         private int lastValidYear;
         public delegate void ATMDataHandler (int year);
@@ -100,6 +105,13 @@ public int RoundDownYearMaps(int inputYear)
             { 20, 23 }
         };
 
+        private Transform cameraTransform;
+
+        private void Awake()
+        {
+            cameraTransform = Camera.main.transform;
+        }
+
         public int GetTileSizeForZoomLevel(int zoomLevel)
         {
             return atmZoomTileSizes[zoomLevel];
@@ -115,18 +127,19 @@ public int GetTileSizeForZoomLevel(int zoomLevel)
 
         public int CalculateZoomLevel()
         {
-            Vector3 camPosition = Camera.main.transform.position;      
-            var unityCoordinate = new Coordinate(
-                CoordinateSystem.Unity,
-                camPosition.x,
-                camPosition.y,
-                camPosition.z
-            );
-            Coordinate coord = unityCoordinate.Convert(CoordinateSystem.WGS84);
-            double latitude = coord.northing;
-            double cosLatitude = Math.Cos(latitude * Mathf.Deg2Rad);
-            double zoomLevel = Math.Log(equatorialCircumference * cosLatitude / camPosition.y) / log2x;
+            Vector3 camPosition = cameraTransform.position;
+
             var currentYearZoomBounds = GetZoomBounds();
+
+            float minimumZoomLevel = atmZoomTileSizes.Keys.Min();
+            float maximumZoomLevel = atmZoomTileSizes.Keys.Max();
+            float currentHeight = camPosition.y;
+            
+            var zoomLevel = maximumZoomLevel
+                - (Mathf.Log(currentHeight / minHeightForZoomLevels) / Mathf.Log(maxHeightForZoomLevels / minHeightForZoomLevels))
+                * (maximumZoomLevel - minimumZoomLevel);
+            
+            // Clamp to the min and max of this specific zoom level.
             zoomLevel = Math.Clamp(zoomLevel, currentYearZoomBounds.minZoom, currentYearZoomBounds.maxZoom);
 
             return (int)zoomLevel;  
diff --git a/Assets/Scenes/Main.unity b/Assets/Scenes/Main.unity
index 0250aa18..d92eb4e4 100644
--- a/Assets/Scenes/Main.unity
+++ b/Assets/Scenes/Main.unity
@@ -1073,6 +1073,8 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: 18e1f17bb2b6bc34c892ceb40d510e4e, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
+  minHeightForZoomLevels: 100
+  maxHeightForZoomLevels: 10000
 --- !u!4 &1444587089
 Transform:
   m_ObjectHideFlags: 0
diff --git a/Assets/Scripts/CartesianTiles/ImageProjectionLayer.cs b/Assets/Scripts/CartesianTiles/ImageProjectionLayer.cs
index 9cf850d1..a84603a5 100644
--- a/Assets/Scripts/CartesianTiles/ImageProjectionLayer.cs
+++ b/Assets/Scripts/CartesianTiles/ImageProjectionLayer.cs
@@ -54,12 +54,16 @@ public override void HandleTile(TileChange tileChange, Action<TileChange> callba
                     tiles[tileKey].runningCoroutine = StartCoroutine(DownloadDataAndGenerateTexture(tileChange, callback));
                     break;
                 case TileAction.Upgrade:
-                    tiles[tileKey].unityLOD++;
-                    tiles[tileKey].runningCoroutine = StartCoroutine(DownloadDataAndGenerateTexture(tileChange, callback));
+                    if (tiles.ContainsKey(tileKey)) {
+                        tiles[tileKey].unityLOD++;
+                        tiles[tileKey].runningCoroutine = StartCoroutine(DownloadDataAndGenerateTexture(tileChange, callback));
+                    }
                     break;
                 case TileAction.Downgrade:
-                    tiles[tileKey].unityLOD--;
-                    tiles[tileKey].runningCoroutine = StartCoroutine(DownloadDataAndGenerateTexture(tileChange, callback));
+                    if (tiles.ContainsKey(tileKey)) {
+                        tiles[tileKey].unityLOD--;
+                        tiles[tileKey].runningCoroutine = StartCoroutine(DownloadDataAndGenerateTexture(tileChange, callback));
+                    }
                     break;
                 case TileAction.Remove:
                     InteruptRunningProcesses(tileKey);