Add Normal in vertex. And add light in shader.

LandblockExtraction/AtlasMaker/TerrainInfo/SubTerrain.cs

@@ -0,0 +1,15 @@
+namespace LandblockExtraction.AtlasMaker;
+
+public class SubTerrain {
+    public int terrainIndex { get; set; }
+    public float minPitch { get; set; }
+    public float maxPitch { get; set; }
+    public SubTerrain(int terrainIndex, float minPitch, float maxPitch) {
+        this.terrainIndex = terrainIndex;
+        this.minPitch = minPitch;
+        this.maxPitch = maxPitch;
+    }
+    public bool MatchesPitch(float pitch) {
+        return pitch >= minPitch && pitch <= maxPitch;
+    }
+}

LandblockExtraction/AtlasMaker/TerrainInfo/Terrain.cs

@@ -0,0 +1,22 @@
+namespace LandblockExtraction.AtlasMaker;
+public class Terrain {
+    public int terrainIndex { get; set; }
+    public List<SubTerrain> subTerrains { get; set; }
+
+    public Terrain(int index) {
+        terrainIndex = index;
+        subTerrains = new List<SubTerrain>();
+    }
+    public void AddSubTerrain(SubTerrain sousTerrain) {
+        subTerrains.Add(sousTerrain);
+    }
+
+    public int DetermineSubTerrain(float pitch) {
+        foreach (var terrain in subTerrains) {
+            if (terrain.MatchesPitch(pitch)) {
+                return terrain.terrainIndex;
+            }
+        }
+        return terrainIndex;
+    }
+}