src/hooks/three/useTerrainHeight.ts

@@ -1,12 +1,16 @@
 import { useMemo } from "react";
 import { useGLTF } from "@react-three/drei";
 import * as THREE from "three";
+import { TERRAIN_MODEL_PATH } from "@/data/world/terrainConfig";
 import type { Vector3Tuple } from "@/types/three/three";
+import { getMapNodesByName } from "@/utils/map/loadMapSceneData";
 
-const TERRAIN_MODEL_PATH = "/models/terrain/model.gltf";
 const RAYCAST_Y = 500;
 const RAYCAST_FAR = 1000;
 const DOWN = new THREE.Vector3(0, -1, 0);
+const DEFAULT_TERRAIN_POSITION: Vector3Tuple = [0, 0, 0];
+const DEFAULT_TERRAIN_ROTATION: Vector3Tuple = [0, 0, 0];
+const DEFAULT_TERRAIN_SCALE: Vector3Tuple = [1, 1, 1];
 
 interface TerrainHeightSampler {
   getHeight: (x: number, z: number) => number | null;
@@ -14,8 +18,17 @@ interface TerrainHeightSampler {
 
 function createTerrainHeightSampler(
   scene: THREE.Object3D,
+  position: Vector3Tuple,
+  rotation: Vector3Tuple,
+  scale: Vector3Tuple,
 ): TerrainHeightSampler {
   const meshes: THREE.Mesh[] = [];
+  const terrainMatrix = new THREE.Matrix4().compose(
+    new THREE.Vector3(...position),
+    new THREE.Quaternion().setFromEuler(new THREE.Euler(...rotation)),
+    new THREE.Vector3(...scale),
+  );
+  const inverseTerrainMatrix = terrainMatrix.clone().invert();
   const raycaster = new THREE.Raycaster(
     new THREE.Vector3(),
     DOWN,
@@ -32,17 +45,29 @@ function createTerrainHeightSampler(
 
   return {
     getHeight: (x, z) => {
-      raycaster.set(new THREE.Vector3(x, RAYCAST_Y, z), DOWN);
+      const localOrigin = new THREE.Vector3(x, RAYCAST_Y, z).applyMatrix4(
+        inverseTerrainMatrix,
+      );
+      const localDirection =
+        DOWN.clone().transformDirection(inverseTerrainMatrix);
+      raycaster.set(localOrigin, localDirection);
       const hit = raycaster.intersectObjects(meshes, false)[0];
-      return hit?.point.y ?? null;
+      return hit?.point.applyMatrix4(terrainMatrix).y ?? null;
     },
   };
 }
 
 export function useTerrainHeightSampler(): TerrainHeightSampler {
   const { scene } = useGLTF(TERRAIN_MODEL_PATH);
+  const terrainNode = getMapNodesByName("terrain")[0];
+  const position = terrainNode?.position ?? DEFAULT_TERRAIN_POSITION;
+  const rotation = terrainNode?.rotation ?? DEFAULT_TERRAIN_ROTATION;
+  const scale = terrainNode?.scale ?? DEFAULT_TERRAIN_SCALE;
 
-  return useMemo(() => createTerrainHeightSampler(scene), [scene]);
+  return useMemo(
+    () => createTerrainHeightSampler(scene, position, rotation, scale),
+    [position, rotation, scale, scene],
+  );
 }
 
 export function useTerrainSnappedPosition(

src/world/GameMap.tsx

@@ -118,6 +118,7 @@ export function GameMap({
   const [collisionMapNodes, setCollisionMapNodes] = useState<LoadedMapNode[]>(
     [],
   );
+  const [terrainNode, setTerrainNode] = useState<MapNode | null>(null);
   const [mapLoaded, setMapLoaded] = useState(false);
   const [settledMapNodeCount, setSettledMapNodeCount] = useState(0);
   const mapReady = mapLoaded && settledMapNodeCount >= renderMapNodes.length;
@@ -133,6 +134,7 @@ export function GameMap({
     (currentStep: string) => {
       setRenderMapNodes([]);
       setCollisionMapNodes([]);
+      setTerrainNode(null);
       setMapLoaded(true);
       settledMapNodesRef.current.clear();
       setSettledMapNodeCount(0);
@@ -187,6 +189,7 @@ export function GameMap({
             const modelUrl = sceneData.models.get(node.name);
             return { node, modelUrl: modelUrl ?? null };
           });
+        const loadedTerrainNode = loadedCollisionNodes[0]?.node ?? null;
         const missingModelCount = loadedMapNodes.filter(
           (mapNode) => mapNode.modelUrl === null,
         ).length;
@@ -203,6 +206,7 @@ export function GameMap({
 
         setRenderMapNodes(loadedMapNodes);
         setCollisionMapNodes(loadedCollisionNodes);
+        setTerrainNode(loadedTerrainNode);
         setMapLoaded(true);
         settledMapNodesRef.current.clear();
         setSettledMapNodeCount(0);
@@ -265,7 +269,15 @@ export function GameMap({
       <CloudSystem />
       <VegetationSystem />
       {isMapModelVisible("terrain", { groups, models }) ? (
-        <TerrainModel />
+        terrainNode ? (
+          <TerrainModel
+            position={terrainNode.position}
+            rotation={terrainNode.rotation}
+            scale={terrainNode.scale}
+          />
+        ) : (
+          <TerrainModel />
+        )
       ) : null}
       <GameMapCollision
         buildOctree={buildOctree}