fix(environment): preserve grass blade colors

docs/technical/editor.md

@@ -52,7 +52,7 @@ src/
 
 ## Responsibilities
 
-`src/pages/editor/page.tsx` is the route-level composition component. It owns route-specific state such as selected object, hovered object, transform mode, selection lock, player-mode toggle, cinematic preview requests, and editor scene loading state.
+`src/pages/editor/page.tsx` is the route-level composition component. It owns route-specific state such as primary selected object, selected object indexes, hovered object, transform mode, selection lock, player-mode toggle, cinematic preview requests, and editor scene loading state.
 
 `src/hooks/editor/useEditorSceneData.ts` loads the default map data and handles folder uploads.
 
@@ -60,7 +60,7 @@ src/
 
 `src/components/editor/scene/EditorScene.tsx` composes the editor canvas scene, camera controls, lights, keyboard shortcuts, and `EditorMap`.
 
-`src/components/editor/scene/EditorMap.tsx` renders map nodes, fallback cubes, selection highlighting, and transform controls.
+`src/components/editor/scene/EditorMap.tsx` renders map nodes, fallback cubes, selection highlighting, and transform controls. For multi-selection, it attaches `TransformControls` to a temporary group centered on the selected nodes, then decomposes the group delta back into each selected node transform.
 
 `src/components/editor/EditorControls.tsx` renders the HTML control panel outside the canvas. The panel is organized into top-level `details` groups: `Editor`, `Cinematics`, `Dialogues`, and `SRT`.
 
@@ -115,11 +115,12 @@ If `model.glb` and `model.gltf` are both missing, the editor renders a fallback
 4. If `/map.json` is missing, the page displays a folder-upload flow.
 5. `EditorSceneLoadingTracker` uses drei `useProgress()` to update the fullscreen editor loading overlay while models load.
 6. `EditorScene` renders the grid, lights, camera controls, and map nodes inside `Suspense`.
-7. `EditorControls` exposes transform mode, terrain snap, terrain-selection lock, add/delete node, precise scale inputs, history actions, camera focus/reset, export, save, JSON preview, selection lock, and the cinematic/dialogue/SRT editors.
+7. `EditorControls` exposes transform mode, terrain snap, terrain-selection lock, add/delete node, precise scale inputs, history actions, camera focus/reset, export, save, JSON preview, selection lock, multi-selection status, and the cinematic/dialogue/SRT editors.
 
 ## Controls
 
 - Click: select a node.
+- `Shift` + right click: add or remove a node from the multi-selection.
 - `Esc`: clear selection.
 - Click empty space: clear selection.
 - Selection lock button: prevent object clicks, empty-space clicks, and `Esc` from changing the current selection.
@@ -128,6 +129,7 @@ If `model.glb` and `model.gltf` are both missing, the editor renders a fallback
 - `R`: rotate mode.
 - `S`: scale mode.
 - Snap terrain on move: enabled by default and applied while translating an object.
+- Multi-selection transforms use a temporary centered group and write the resulting position, rotation, and scale back to every selected map node.
 - Lock terrain: enabled by default so terrain remains visible but ignores selection clicks.
 - Camera action: centers on the selected object or resets to the editor home view.
 - Add node: creates a fallback cube under `blocking` using the requested model folder name.

docs/user/editor.md

@@ -45,14 +45,15 @@ Only the `Editor` group is open by default. Open the other groups when you need
 
 1. Open `/editor` in the local app.
 2. Click an object in the scene to select it.
-3. Choose a transform mode: translate, rotate, or scale.
-4. Drag the transform gizmo in the 3D view.
-5. Keep `Snap terrain on move` enabled when placing objects on the terrain.
-6. Use `Center on object` or `Reset camera` from the `View` section when navigating large maps.
-7. Adjust scale numerically from the `Selection` section if the gizmo is not precise enough.
-8. Check the JSON inspector if you need exact values.
-9. Use undo or redo if the transform is not correct.
-10. Export the JSON or save it to the dev server.
+3. Use `Shift + right click` on other objects to add or remove them from the current multi-selection.
+4. Choose a transform mode: translate, rotate, or scale.
+5. Drag the transform gizmo in the 3D view. With multiple objects selected, the gizmo transforms the selected group and writes each object transform back to `map.json`.
+6. Keep `Snap terrain on move` enabled when placing objects on the terrain.
+7. Use `Center on object` or `Reset camera` from the `View` section when navigating large maps.
+8. Adjust scale numerically from the `Selection` section if the gizmo is not precise enough.
+9. Check the JSON inspector if you need exact values.
+10. Use undo or redo if the transform is not correct.
+11. Export the JSON or save it to the dev server.
 
 ## Adding And Deleting Nodes
 
@@ -70,6 +71,7 @@ Use the trash button in `Selection` to delete the selected node from the map tre
 | Action               | Input                      |
 | -------------------- | -------------------------- |
 | Select object        | Click object               |
+| Toggle multi-select  | `Shift` + right click      |
 | Deselect             | `Esc` or click empty space |
 | Lock selection       | `Lock` button in Selection |
 | Clear selection      | `X` button in Selection    |
@@ -87,6 +89,8 @@ Use the trash button in `Selection` to delete the selected node from the map tre
 The `Selection` section shows the selected object name and its index in `public/map.json`.
 
 - Click an object to select it.
+- Use `Shift + right click` on objects to add or remove them from a multi-selection.
+- When several objects are selected, the gizmo appears on the selection group and applies translate, rotate, or scale to each selected node.
 - Click empty space or press `Esc` to clear the selection.
 - Use the `X` button to clear the selection explicitly.
 - Use the `Lock` button to protect the current selection while editing.

src/components/editor/EditorControls.tsx

@@ -29,6 +29,7 @@ interface EditorControlsProps {
   transformMode: TransformMode;
   onTransformModeChange: (mode: TransformMode) => void;
   selectedNodeIndex: number | null;
+  selectedNodeIndexes: number[];
   mapNodes: MapNode[];
   nodesCount: number;
   selectedNodeName: string | null;
@@ -66,6 +67,7 @@ const TRANSFORM_OPTIONS = [
 
 const EDITOR_SHORTCUTS = [
   ["Click", "Select object"],
+  ["Shift + Right click", "Toggle multi-selection"],
   ["T / R / S", "Transform mode"],
   ["Ctrl Z / Y", "Undo / redo"],
   ["Esc", "Deselect"],
@@ -103,6 +105,7 @@ export function EditorControls({
   transformMode,
   onTransformModeChange,
   selectedNodeIndex,
+  selectedNodeIndexes,
   mapNodes,
   nodesCount,
   selectedNodeName,
@@ -135,6 +138,7 @@ export function EditorControls({
   const jsonPreview = getJsonPreview(mapNodes, selectedNodeIndex);
   const selectedNode =
     selectedNodeIndex !== null ? mapNodes[selectedNodeIndex] : null;
+  const selectionCount = selectedNodeIndexes.length;
   const transformValues = getTransformValues(selectedNode ?? null);
 
   return (
@@ -240,10 +244,14 @@ export function EditorControls({
                 <Box size={17} aria-hidden="true" />
                 <div>
                   <strong>
-                    {selectedNodeName || `Node ${selectedNodeIndex + 1}`}
+                    {selectionCount > 1
+                      ? `${selectionCount} selected nodes`
+                      : selectedNodeName || `Node ${selectedNodeIndex + 1}`}
                   </strong>
                   <span>
-                    Index {selectedNodeIndex + 1} of {nodesCount}
+                    {selectionCount > 1
+                      ? `Primary index ${selectedNodeIndex + 1} of ${nodesCount}`
+                      : `Index ${selectedNodeIndex + 1} of ${nodesCount}`}
                   </span>
                 </div>
                 <div className="editor-selected-actions">

src/components/editor/scene/EditorMap.tsx

@@ -1,4 +1,4 @@
-import { useRef, useEffect, useState } from "react";
+import { useCallback, useEffect, useLayoutEffect, useRef } from "react";
 import { Grid, TransformControls } from "@react-three/drei";
 import type { ThreeEvent } from "@react-three/fiber";
 import * as THREE from "three";
@@ -16,7 +16,9 @@ import {
 interface EditorMapProps {
   sceneData: SceneData;
   selectedNodeIndex: number | null;
+  selectedNodeIndexes: number[];
   onSelectNode: (index: number | null) => void;
+  onToggleNodeSelection: (index: number) => void;
   isSelectionLocked: boolean;
   hoveredNodeIndex: number | null;
   onHoverNode: (index: number | null) => void;
@@ -37,16 +39,31 @@ interface EditorNodeCommonProps {
   isHovered: boolean;
   objectsMapRef: EditorNodeObjectRef;
   onSelectNode: (index: number | null) => void;
+  onToggleNodeSelection: (index: number) => void;
   isSelectionLocked: boolean;
   onHoverNode: (index: number | null) => void;
 }
 
 interface EditorNodePointerHandlers {
   onClick: (event: ThreeEvent<MouseEvent>) => void;
+  onContextMenu: (event: ThreeEvent<MouseEvent>) => void;
   onPointerEnter: (event: ThreeEvent<PointerEvent>) => void;
   onPointerLeave: (event: ThreeEvent<PointerEvent>) => void;
 }
 
+interface TransformSnapshot {
+  groupMatrix: THREE.Matrix4;
+  objects: Map<number, THREE.Matrix4>;
+}
+
+const TEMP_BOX = new THREE.Box3();
+const TEMP_CENTER = new THREE.Vector3();
+const TEMP_DELTA_MATRIX = new THREE.Matrix4();
+const TEMP_INVERSE_GROUP_MATRIX = new THREE.Matrix4();
+const TEMP_POSITION = new THREE.Vector3();
+const TEMP_QUATERNION = new THREE.Quaternion();
+const TEMP_SCALE = new THREE.Vector3();
+
 function applyNodeTransform(object: THREE.Object3D, node: MapNode): void {
   object.position.set(...node.position);
   object.rotation.set(...node.rotation);
@@ -118,6 +135,7 @@ function getNodeHighlightColor(
 function createEditorNodePointerHandlers(
   index: number,
   onSelectNode: (index: number | null) => void,
+  onToggleNodeSelection: (index: number) => void,
   isSelectionLocked: boolean,
   onHoverNode: (index: number | null) => void,
 ): EditorNodePointerHandlers {
@@ -127,6 +145,12 @@ function createEditorNodePointerHandlers(
       if (isSelectionLocked) return;
       onSelectNode(index);
     },
+    onContextMenu: (event) => {
+      event.stopPropagation();
+      event.nativeEvent.preventDefault();
+      if (!event.nativeEvent.shiftKey || isSelectionLocked) return;
+      onToggleNodeSelection(index);
+    },
     onPointerEnter: (event) => {
       event.stopPropagation();
       onHoverNode(index);
@@ -141,7 +165,9 @@ function createEditorNodePointerHandlers(
 export function EditorMap({
   sceneData,
   selectedNodeIndex,
+  selectedNodeIndexes,
   onSelectNode,
+  onToggleNodeSelection,
   isSelectionLocked,
   hoveredNodeIndex,
   onHoverNode,
@@ -153,18 +179,110 @@ export function EditorMap({
   onNodeTransform,
 }: EditorMapProps): React.JSX.Element {
   const objectsMapRef = useRef<Map<number, THREE.Object3D>>(new Map());
+  const transformGroupRef = useRef<THREE.Group>(null);
+  const transformSnapshotRef = useRef<TransformSnapshot | null>(null);
   const terrainHeight = useTerrainHeightSampler();
 
-  const handleTransformMouseDown = () => {
-    onTransformStart();
-  };
+  const selectedIndexSet = new Set(selectedNodeIndexes);
+  const isMultiSelection = selectedNodeIndexes.length > 1;
 
-  const handleTransformMouseUp = () => {
-    syncSelectedObjectTransform();
-    onTransformEnd();
-  };
+  const getTransformObject = useCallback(() => {
+    if (isMultiSelection) {
+      return transformGroupRef.current;
+    }
+
+    if (selectedNodeIndex !== null) {
+      return objectsMapRef.current.get(selectedNodeIndex) ?? null;
+    }
+
+    return null;
+  }, [isMultiSelection, selectedNodeIndex]);
+
+  const prepareTransformGroup = useCallback(() => {
+    if (!isMultiSelection || !transformGroupRef.current) return;
+
+    const selectedObjects = selectedNodeIndexes
+      .map((index) => objectsMapRef.current.get(index))
+      .filter((object): object is THREE.Object3D => Boolean(object));
+
+    if (selectedObjects.length === 0) return;
+
+    TEMP_BOX.makeEmpty();
+    for (const object of selectedObjects) {
+      object.updateWorldMatrix(true, false);
+      TEMP_BOX.expandByPoint(object.getWorldPosition(TEMP_CENTER));
+    }
+
+    TEMP_BOX.getCenter(TEMP_CENTER);
+    transformGroupRef.current.position.copy(TEMP_CENTER);
+    transformGroupRef.current.rotation.set(0, 0, 0);
+    transformGroupRef.current.scale.set(1, 1, 1);
+    transformGroupRef.current.updateMatrixWorld(true);
+  }, [isMultiSelection, selectedNodeIndexes]);
+
+  const createTransformSnapshot = useCallback((): TransformSnapshot | null => {
+    const transformGroup = transformGroupRef.current;
+
+    if (!isMultiSelection || !transformGroup) return null;
+
+    const objects = new Map<number, THREE.Matrix4>();
+    for (const index of selectedNodeIndexes) {
+      const object = objectsMapRef.current.get(index);
+      if (!object) continue;
+
+      object.updateMatrixWorld(true);
+      objects.set(index, object.matrix.clone());
+    }
+
+    transformGroup.updateMatrixWorld(true);
+    return {
+      groupMatrix: transformGroup.matrix.clone(),
+      objects,
+    };
+  }, [isMultiSelection, selectedNodeIndexes]);
 
   const syncSelectedObjectTransform = () => {
+    if (isMultiSelection) {
+      const transformGroup = transformGroupRef.current;
+      const snapshot = transformSnapshotRef.current;
+      if (!transformGroup || !snapshot) return;
+
+      transformGroup.updateMatrix();
+      TEMP_INVERSE_GROUP_MATRIX.copy(snapshot.groupMatrix).invert();
+      TEMP_DELTA_MATRIX.multiplyMatrices(
+        transformGroup.matrix,
+        TEMP_INVERSE_GROUP_MATRIX,
+      );
+
+      for (const [index, startMatrix] of snapshot.objects) {
+        const obj = objectsMapRef.current.get(index);
+        const node = sceneData.mapNodes[index];
+        if (!obj || !node) continue;
+
+        const nextMatrix = TEMP_DELTA_MATRIX.clone().multiply(startMatrix);
+        nextMatrix.decompose(TEMP_POSITION, TEMP_QUATERNION, TEMP_SCALE);
+        obj.position.copy(TEMP_POSITION);
+        obj.quaternion.copy(TEMP_QUATERNION);
+        obj.scale.copy(TEMP_SCALE);
+
+        const terrainY = snapToTerrain
+          ? terrainHeight.getHeight(obj.position.x, obj.position.z)
+          : null;
+        if (terrainY !== null && transformMode === "translate") {
+          obj.position.y = terrainY;
+        }
+
+        onNodeTransform(index, {
+          ...node,
+          position: [obj.position.x, obj.position.y, obj.position.z],
+          rotation: [obj.rotation.x, obj.rotation.y, obj.rotation.z],
+          scale: [obj.scale.x, obj.scale.y, obj.scale.z],
+        });
+      }
+
+      return;
+    }
+
     if (selectedNodeIndex !== null) {
       const obj = objectsMapRef.current.get(selectedNodeIndex);
       if (!obj) return;
@@ -194,25 +312,30 @@ export function EditorMap({
     }
   };
 
-  const [selectedObject, setSelectedObject] = useState<THREE.Object3D | null>(
-    null,
-  );
+  const handleTransformMouseDown = () => {
+    prepareTransformGroup();
+    transformSnapshotRef.current = createTransformSnapshot();
+    onTransformStart();
+  };
+
+  const handleTransformMouseUp = () => {
+    syncSelectedObjectTransform();
+    transformSnapshotRef.current = null;
+    prepareTransformGroup();
+    onTransformEnd();
+  };
+
   const terrainNode = getTerrainMapNode(sceneData.mapNodes);
   const terrainNodeIndex = terrainNode
     ? sceneData.mapNodes.indexOf(terrainNode)
     : -1;
-  const selectedNode =
-    selectedNodeIndex !== null ? sceneData.mapNodes[selectedNodeIndex] : null;
-  const selectedModelName = selectedNode?.name ?? null;
+  useLayoutEffect(() => {
+    prepareTransformGroup();
+  }, [prepareTransformGroup]);
 
-  useEffect(() => {
-    if (selectedNodeIndex !== null) {
-      const obj = objectsMapRef.current.get(selectedNodeIndex);
-      setSelectedObject(obj || null);
-    } else {
-      setSelectedObject(null);
-    }
-  }, [selectedNodeIndex]);
+  // TransformControls needs the current Three object; editor refs are managed outside React rendering.
+  // eslint-disable-next-line react-hooks/refs
+  const selectedObject = getTransformObject();
 
   return (
     <>
@@ -236,11 +359,12 @@ export function EditorMap({
           <EditorTerrainNode
             index={terrainNodeIndex}
             node={terrainNode}
-            isSelected={selectedNodeIndex === terrainNodeIndex}
+            isSelected={selectedIndexSet.has(terrainNodeIndex)}
             isHovered={hoveredNodeIndex === terrainNodeIndex}
             lockTerrainSelection={lockTerrainSelection}
             objectsMapRef={objectsMapRef}
             onSelectNode={onSelectNode}
+            onToggleNodeSelection={onToggleNodeSelection}
             isSelectionLocked={isSelectionLocked}
             onHoverNode={onHoverNode}
           />
@@ -250,10 +374,6 @@ export function EditorMap({
             return null;
           }
 
-          if (selectedModelName && node.name !== selectedModelName) {
-            return null;
-          }
-
           const modelUrl = sceneData.models.get(node.name);
 
           if (modelUrl) {
@@ -263,10 +383,11 @@ export function EditorMap({
                 index={index}
                 node={node}
                 modelUrl={modelUrl}
-                isSelected={selectedNodeIndex === index}
+                isSelected={selectedIndexSet.has(index)}
                 isHovered={hoveredNodeIndex === index}
                 objectsMapRef={objectsMapRef}
                 onSelectNode={onSelectNode}
+                onToggleNodeSelection={onToggleNodeSelection}
                 isSelectionLocked={isSelectionLocked}
                 onHoverNode={onHoverNode}
               />
@@ -277,10 +398,11 @@ export function EditorMap({
                 key={index}
                 index={index}
                 node={node}
-                isSelected={selectedNodeIndex === index}
+                isSelected={selectedIndexSet.has(index)}
                 isHovered={hoveredNodeIndex === index}
                 objectsMapRef={objectsMapRef}
                 onSelectNode={onSelectNode}
+                onToggleNodeSelection={onToggleNodeSelection}
                 isSelectionLocked={isSelectionLocked}
                 onHoverNode={onHoverNode}
               />
@@ -289,6 +411,8 @@ export function EditorMap({
         })}
       </group>
 
+      <group ref={transformGroupRef} />
+
       {selectedObject && (
         <TransformControls
           object={selectedObject}
@@ -310,6 +434,7 @@ function EditorModelNode({
   isHovered,
   objectsMapRef,
   onSelectNode,
+  onToggleNodeSelection,
   isSelectionLocked,
   onHoverNode,
 }: EditorNodeCommonProps & {
@@ -329,6 +454,7 @@ function EditorModelNode({
   const pointerHandlers = createEditorNodePointerHandlers(
     index,
     onSelectNode,
+    onToggleNodeSelection,
     isSelectionLocked,
     onHoverNode,
   );
@@ -403,6 +529,7 @@ function EditorTerrainNode({
   lockTerrainSelection,
   objectsMapRef,
   onSelectNode,
+  onToggleNodeSelection,
   isSelectionLocked,
   onHoverNode,
 }: EditorNodeCommonProps & { lockTerrainSelection: boolean }) {
@@ -410,6 +537,7 @@ function EditorTerrainNode({
   const pointerHandlers = createEditorNodePointerHandlers(
     index,
     onSelectNode,
+    onToggleNodeSelection,
     isSelectionLocked,
     onHoverNode,
   );
@@ -435,6 +563,7 @@ function EditorFallbackNode({
   isHovered,
   objectsMapRef,
   onSelectNode,
+  onToggleNodeSelection,
   isSelectionLocked,
   onHoverNode,
 }: EditorNodeCommonProps) {
@@ -442,6 +571,7 @@ function EditorFallbackNode({
   const pointerHandlers = createEditorNodePointerHandlers(
     index,
     onSelectNode,
+    onToggleNodeSelection,
     isSelectionLocked,
     onHoverNode,
   );

src/components/editor/scene/EditorScene.tsx

@@ -5,7 +5,6 @@ import gsap from "gsap";
 import * as THREE from "three";
 import type { OrbitControls as OrbitControlsImpl } from "three-stdlib";
 import { EditorMap } from "@/components/editor/scene/EditorMap";
-import { TerrainModel } from "@/components/three/world/TerrainModel";
 import { FlyController } from "@/controls/editor/FlyController";
 import type { CinematicDefinition } from "@/types/cinematics/cinematics";
 import type { MapNode, TransformMode, SceneData } from "@/types/editor/editor";
@@ -21,7 +20,9 @@ export interface EditorCinematicPreviewRequest {
 interface EditorSceneProps {
   sceneData: SceneData;
   selectedNodeIndex: number | null;
+  selectedNodeIndexes: number[];
   onSelectNode: (index: number | null) => void;
+  onToggleNodeSelection: (index: number) => void;
   isSelectionLocked: boolean;
   hoveredNodeIndex: number | null;
   onHoverNode: (index: number | null) => void;
@@ -44,7 +45,9 @@ interface EditorSceneProps {
 export function EditorScene({
   sceneData,
   selectedNodeIndex,
+  selectedNodeIndexes,
   onSelectNode,
+  onToggleNodeSelection,
   isSelectionLocked,
   hoveredNodeIndex,
   onHoverNode,
@@ -209,7 +212,9 @@ export function EditorScene({
       <EditorMap
         sceneData={sceneData}
         selectedNodeIndex={selectedNodeIndex}
+        selectedNodeIndexes={selectedNodeIndexes}
         onSelectNode={onSelectNode}
+        onToggleNodeSelection={onToggleNodeSelection}
         isSelectionLocked={isSelectionLocked}
         hoveredNodeIndex={hoveredNodeIndex}
         onHoverNode={onHoverNode}
@@ -221,8 +226,6 @@ export function EditorScene({
         onNodeTransform={onNodeTransform}
       />
 
-      <TerrainModel />
-
       <ambientLight intensity={0.6} />
       <directionalLight position={[10, 20, 10]} intensity={1.5} castShadow />
       <directionalLight position={[-10, 10, -10]} intensity={0.5} />

src/pages/editor/page.tsx

@@ -313,6 +313,7 @@ export function EditorPage(): React.JSX.Element {
   const [selectedNodeIndex, setSelectedNodeIndex] = useState<number | null>(
     null,
   );
+  const [selectedNodeIndexes, setSelectedNodeIndexes] = useState<number[]>([]);
   const [hoveredNodeIndex, setHoveredNodeIndex] = useState<number | null>(null);
   const [transformMode, setTransformMode] =
     useState<TransformMode>("translate");
@@ -370,13 +371,31 @@ export function EditorPage(): React.JSX.Element {
 
   const handleSelectNode = useCallback((index: number | null) => {
     setSelectedNodeIndex(index);
+    setSelectedNodeIndexes(index === null ? [] : [index]);
     if (index !== null) {
       setCameraViewMode("object");
     }
   }, []);
 
+  const handleToggleNodeSelection = useCallback((index: number) => {
+    setSelectedNodeIndexes((currentIndexes) => {
+      const isSelected = currentIndexes.includes(index);
+      const nextIndexes = isSelected
+        ? currentIndexes.filter((item) => item !== index)
+        : [...currentIndexes, index];
+
+      setSelectedNodeIndex(nextIndexes.at(-1) ?? null);
+      if (nextIndexes.length > 0) {
+        setCameraViewMode("object");
+      }
+
+      return nextIndexes;
+    });
+  }, []);
+
   const handleClearSelection = useCallback(() => {
     setSelectedNodeIndex(null);
+    setSelectedNodeIndexes([]);
   }, []);
 
   const handleSelectionLockToggle = useCallback(() => {
@@ -401,7 +420,21 @@ export function EditorPage(): React.JSX.Element {
         if (currentIndex === null) return null;
 
         const selectedNode = sceneData?.mapNodes[currentIndex];
-        return selectedNode?.name === "terrain" ? null : currentIndex;
+        if (selectedNode?.name === "terrain") {
+          setSelectedNodeIndexes((indexes) =>
+            indexes.filter(
+              (index) => sceneData?.mapNodes[index]?.name !== "terrain",
+            ),
+          );
+          return null;
+        }
+
+        setSelectedNodeIndexes((indexes) =>
+          indexes.filter(
+            (index) => sceneData?.mapNodes[index]?.name !== "terrain",
+          ),
+        );
+        return currentIndex;
       });
     },
     [sceneData],
@@ -544,12 +577,14 @@ export function EditorPage(): React.JSX.Element {
         const newNode = createNewMapNode(newNodeName);
         const mapNodes = [...prev.mapNodes, removeEditorMetadata(newNode)];
         setSelectedNodeIndex(mapNodes.length - 1);
+        setSelectedNodeIndexes([mapNodes.length - 1]);
         return { ...prev, mapNodes };
       }
 
       const mapTree = addTreeNode(prev.mapTree, createNewMapNode(newNodeName));
       const nextSceneData = updateSceneDataTree(prev, mapTree);
       setSelectedNodeIndex(nextSceneData.mapNodes.length - 1);
+      setSelectedNodeIndexes([nextSceneData.mapNodes.length - 1]);
       return nextSceneData;
     });
   }, [newNodeName, setSceneData]);
@@ -563,6 +598,7 @@ export function EditorPage(): React.JSX.Element {
       if (!currentNode) return prev;
       if (!prev.mapTree || !currentNode.sourcePath) {
         setSelectedNodeIndex(null);
+        setSelectedNodeIndexes([]);
         return {
           ...prev,
           mapNodes: prev.mapNodes.filter(
@@ -576,6 +612,7 @@ export function EditorPage(): React.JSX.Element {
         currentNode.sourcePath,
       );
       setSelectedNodeIndex(null);
+      setSelectedNodeIndexes([]);
       return updateSceneDataTree(prev, mapTree);
     });
   }, [selectedNodeIndex, setSceneData]);
@@ -660,7 +697,9 @@ export function EditorPage(): React.JSX.Element {
           <EditorScene
             sceneData={sceneData!}
             selectedNodeIndex={selectedNodeIndex}
+            selectedNodeIndexes={selectedNodeIndexes}
             onSelectNode={handleSelectNode}
+            onToggleNodeSelection={handleToggleNodeSelection}
             isSelectionLocked={isSelectionLocked}
             hoveredNodeIndex={hoveredNodeIndex}
             onHoverNode={handleHoverNode}
@@ -689,6 +728,7 @@ export function EditorPage(): React.JSX.Element {
           transformMode={transformMode}
           onTransformModeChange={handleTransformModeChange}
           selectedNodeIndex={selectedNodeIndex}
+          selectedNodeIndexes={selectedNodeIndexes}
           mapNodes={sceneData.mapNodes}
           nodesCount={sceneData.mapNodes.length}
           selectedNodeName={

src/utils/map/mapRuntimeClassification.ts

@@ -30,6 +30,10 @@ export function isRuntimeSingleMapNode(node: MapNode): boolean {
   );
 }
 
+export function isRuntimeCollisionMapNode(node: MapNode): boolean {
+  return node.name === "terrain" || isRuntimeSingleMapNode(node);
+}
+
 export function isEditorVisibleMapNode(node: MapNode): boolean {
   return !isRuntimeStructureMapNode(node.name) && node.type !== "Mesh";
 }

src/world/GameMap.tsx

@@ -31,6 +31,7 @@ import { logger } from "@/utils/core/Logger";
 import { loadMapSceneData } from "@/utils/map/loadMapSceneData";
 import {
   getTerrainMapNode,
+  isRuntimeCollisionMapNode,
   isRuntimeSingleMapNode,
 } from "@/utils/map/mapRuntimeClassification";
 import { logModelLoadError } from "@/utils/three/modelLoadLogger";
@@ -178,7 +179,7 @@ export function GameMap({
           return { node, modelUrl: modelUrl ?? null };
         });
         const loadedCollisionNodes = sceneData.mapNodes
-          .filter((node) => node.name === "terrain")
+          .filter(isRuntimeCollisionMapNode)
           .map((node) => {
             const modelUrl = sceneData.models.get(node.name);
             return { node, modelUrl: modelUrl ?? null };

src/world/GameMapCollision.tsx

@@ -4,6 +4,7 @@ import {
   Suspense,
   useCallback,
   useEffect,
+  useMemo,
   useRef,
   useState,
 } from "react";
@@ -11,6 +12,11 @@ import * as THREE from "three";
 import { useClonedObject } from "@/hooks/three/useClonedObject";
 import { useLoggedGLTF } from "@/hooks/three/useLoggedGLTF";
 import { useOctreeGraphNode } from "@/hooks/three/useOctreeGraphNode";
+import {
+  getObjectBottomOffset,
+  normalizeMapScale,
+  useTerrainHeightSampler,
+} from "@/hooks/three/useTerrainHeight";
 import { WorldBoundsCollision } from "@/world/collision/WorldBoundsCollision";
 import type { MapNode } from "@/types/editor/editor";
 import type { OctreeReadyHandler } from "@/types/three/three";
@@ -27,6 +33,8 @@ interface ResolvedGameMapCollisionNode {
   modelUrl: string;
 }
 
+type TerrainHeightSampler = ReturnType<typeof useTerrainHeightSampler>;
+
 interface GameMapCollisionProps {
   buildOctree?: boolean;
   mapReady: boolean;
@@ -47,8 +55,6 @@ interface CollisionErrorBoundaryState {
   hasError: boolean;
 }
 
-const MAP_COLLISION_NODE_NAMES = new Set(["terrain"]);
-
 class CollisionErrorBoundary extends Component<
   CollisionErrorBoundaryProps,
   CollisionErrorBoundaryState
@@ -88,9 +94,7 @@ class CollisionErrorBoundary extends Component<
 function isCollisionNode(
   mapNode: GameMapCollisionNode,
 ): mapNode is ResolvedGameMapCollisionNode {
-  return (
-    mapNode.modelUrl !== null && MAP_COLLISION_NODE_NAMES.has(mapNode.node.name)
-  );
+  return mapNode.modelUrl !== null;
 }
 
 export function GameMapCollision({
@@ -105,6 +109,7 @@ export function GameMapCollision({
   const settledCollisionNodesRef = useRef(new Set<number>());
   const loadedNotifiedRef = useRef(false);
   const [settledCollisionNodeCount, setSettledCollisionNodeCount] = useState(0);
+  const terrainHeight = useTerrainHeightSampler();
   const collisionNodes = nodes.filter(isCollisionNode);
   const collisionReady =
     mapReady && settledCollisionNodeCount >= collisionNodes.length;
@@ -188,6 +193,7 @@ export function GameMapCollision({
                   node={mapNode.node}
                   modelUrl={mapNode.modelUrl}
                   onLoaded={() => handleCollisionNodeSettled(index)}
+                  terrainHeight={terrainHeight}
                 />
               </Suspense>
             </CollisionErrorBoundary>
@@ -201,19 +207,30 @@ function CollisionModelInstance({
   node,
   modelUrl,
   onLoaded,
+  terrainHeight,
 }: {
   node: MapNode;
   modelUrl: string;
   onLoaded: () => void;
+  terrainHeight: TerrainHeightSampler;
 }): React.JSX.Element {
   const { position, rotation, scale } = node;
+  const normalizedScale = normalizeMapScale(scale);
   const { scene } = useLoggedGLTF(modelUrl, {
     scope: "GameMapCollision.ModelInstance",
     position,
     rotation,
-    scale,
+    scale: normalizedScale,
   });
   const sceneInstance = useClonedObject(scene);
+  const collisionPosition = useMemo(() => {
+    if (node.name === "terrain") return position;
+
+    const [x, y, z] = position;
+    const height = terrainHeight.getHeight(x, z);
+    const bottomOffset = getObjectBottomOffset(sceneInstance, normalizedScale);
+    return [x, height !== null ? height + bottomOffset : y, z] as const;
+  }, [node.name, normalizedScale, position, sceneInstance, terrainHeight]);
 
   useEffect(() => {
     onLoaded();
@@ -222,9 +239,9 @@ function CollisionModelInstance({
   return (
     <primitive
       object={sceneInstance}
-      position={position}
+      position={collisionPosition}
       rotation={rotation}
-      scale={scale}
+      scale={normalizedScale}
     />
   );
 }

src/world/grass/GrassPatch.tsx

@@ -1,32 +1,22 @@
 import { useEffect, useMemo, useRef } from "react";
-import { useFrame } from "@react-three/fiber";
+import { useTexture } from "@react-three/drei";
+import { useFrame, useThree } from "@react-three/fiber";
 import * as THREE from "three";
-import { TERRAIN_SURFACE_PROJECTION } from "@/data/world/terrainConfig";
-import { useTerrainHeightSampler } from "@/hooks/three/useTerrainHeight";
 import { useWind } from "@/hooks/world/useWind";
-import type { TerrainSurfaceData } from "@/types/world/terrainSurface";
-import { sampleTerrainSurfaceAtXZ } from "@/utils/world/terrainSurfaceSampler";
 import {
-  getGrassTipColor,
+  GRASS_BASE_COLOR,
+  GRASS_COLORS,
   GRASS_CONFIG,
-  GRASS_SURFACE_KEYS,
 } from "@/world/grass/grassConfig";
 import {
   grassFragmentShader,
   grassVertexShader,
 } from "@/world/grass/grassShaders";
+import type { TerrainGrassSampler } from "@/world/grass/useTerrainGrassSampler";
 
 interface GrassPatchProps {
-  chunkX: number;
-  chunkZ: number;
   density: number;
-  terrainSurfaceData: TerrainSurfaceData;
-}
-
-interface GrassBladeVertexData {
-  color: number[];
-  heightFactor: number;
-  position: number[];
+  terrainSampler: TerrainGrassSampler;
 }
 
 function random01(seed: number): number {
@@ -34,216 +24,200 @@ function random01(seed: number): number {
   return value - Math.floor(value);
 }
 
-function lerp(min: number, max: number, ratio: number): number {
-  return min + (max - min) * ratio;
+function pushVector(target: number[], value: THREE.Vector3): void {
+  target.push(value.x, value.y, value.z);
 }
 
-function createGrassMaterial(): THREE.ShaderMaterial {
-  return new THREE.ShaderMaterial({
-    side: THREE.DoubleSide,
-    vertexColors: true,
-    vertexShader: grassVertexShader,
-    fragmentShader: grassFragmentShader,
-    uniforms: {
-      uTime: { value: 0 },
-      uWindDirection: { value: 0 },
-      uWindSpeed: { value: 0 },
-      uWindStrength: { value: 0 },
-      uWindNoiseScale: { value: GRASS_CONFIG.windNoiseScale },
-      uBendStrength: { value: GRASS_CONFIG.windBendStrength },
-    },
-  });
+function pushColor(target: number[], value: THREE.Color): void {
+  target.push(value.r, value.g, value.b);
 }
 
-function addGrassBlade(
-  positions: number[],
-  colors: number[],
-  bladeBases: number[],
-  heightFactors: number[],
-  windPhases: number[],
-  basePosition: THREE.Vector3,
-  yaw: number,
-  width: number,
-  height: number,
-  baseColor: THREE.Color,
-  tipColor: THREE.Color,
-  windPhase: number,
-): void {
-  const rightX = Math.cos(yaw) * width * 0.5;
-  const rightZ = Math.sin(yaw) * width * 0.5;
-  const leanX = Math.cos(yaw + Math.PI * 0.5) * width * 0.22;
-  const leanZ = Math.sin(yaw + Math.PI * 0.5) * width * 0.22;
-  const vertexData: GrassBladeVertexData[] = [
-    {
-      position: [
-        basePosition.x - rightX,
-        basePosition.y,
-        basePosition.z - rightZ,
-      ],
-      color: [baseColor.r, baseColor.g, baseColor.b],
-      heightFactor: 0,
-    },
-    {
-      position: [
-        basePosition.x + rightX,
-        basePosition.y,
-        basePosition.z + rightZ,
-      ],
-      color: [baseColor.r, baseColor.g, baseColor.b],
-      heightFactor: 0,
-    },
-    {
-      position: [
-        basePosition.x + leanX,
-        basePosition.y + height,
-        basePosition.z + leanZ,
-      ],
-      color: [tipColor.r, tipColor.g, tipColor.b],
-      heightFactor: 1,
-    },
-  ];
-
-  for (const vertex of vertexData) {
-    positions.push(...vertex.position);
-    colors.push(...vertex.color);
-    bladeBases.push(basePosition.x, basePosition.y, basePosition.z);
-    heightFactors.push(vertex.heightFactor);
-    windPhases.push(windPhase);
-  }
-}
-
-function createGrassGeometry(
-  chunkX: number,
-  chunkZ: number,
-  density: number,
-  terrainSurfaceData: TerrainSurfaceData,
-  getHeight: (x: number, z: number) => number | null,
-): THREE.BufferGeometry | null {
+function createGrassGeometry(density: number): THREE.BufferGeometry {
   const positions: number[] = [];
   const colors: number[] = [];
-  const bladeBases: number[] = [];
-  const heightFactors: number[] = [];
-  const windPhases: number[] = [];
-  const baseColor = new THREE.Color(GRASS_CONFIG.baseColor);
-  const startX = chunkX * GRASS_CONFIG.chunkSize;
-  const startZ = chunkZ * GRASS_CONFIG.chunkSize;
-  const endX = startX + GRASS_CONFIG.chunkSize;
-  const endZ = startZ + GRASS_CONFIG.chunkSize;
-  const bladeBudget = Math.round(GRASS_CONFIG.maxBladesPerChunk * density);
-  let bladeCount = 0;
+  const uvs: number[] = [];
+  const bladeOrigins: number[] = [];
+  const yaws: number[] = [];
+  const bladeCount = Math.round(GRASS_CONFIG.bladeCount * density);
+  const halfPatchSize = GRASS_CONFIG.patchSize * 0.5;
 
-  for (let x = startX; x < endX; x += GRASS_CONFIG.sampleStep) {
-    for (let z = startZ; z < endZ; z += GRASS_CONFIG.sampleStep) {
-      for (
-        let bladeIndex = 0;
-        bladeIndex < GRASS_CONFIG.bladesPerCell;
-        bladeIndex++
-      ) {
-        if (bladeCount >= bladeBudget) break;
+  for (let index = 0; index < bladeCount; index++) {
+    const seed = index * 997;
+    const origin = new THREE.Vector3(
+      random01(seed + 1) * GRASS_CONFIG.patchSize - halfPatchSize,
+      0,
+      random01(seed + 2) * GRASS_CONFIG.patchSize - halfPatchSize,
+    );
+    const yawAngle = random01(seed + 3) * Math.PI * 2;
+    const yaw = new THREE.Vector3(Math.sin(yawAngle), 0, -Math.cos(yawAngle));
+    const colorIndex = Math.floor(random01(seed + 4) * GRASS_COLORS.length);
+    const color = new THREE.Color(GRASS_COLORS[colorIndex] ?? GRASS_COLORS[0]);
+    const markerColors = [
+      new THREE.Color(0.1, 0, 0),
+      new THREE.Color(0, 0, 0.1),
+      new THREE.Color(1, 1, 1),
+    ] as const;
+    const uv = new THREE.Vector2(
+      origin.x / GRASS_CONFIG.patchSize + 0.5,
+      origin.z / GRASS_CONFIG.patchSize + 0.5,
+    );
 
-        const seed =
-          (chunkX + 101) * 92821 +
-          (chunkZ + 103) * 68917 +
-          Math.round(x * 13) * 193 +
-          Math.round(z * 17) * 389 +
-          bladeIndex * 997;
-        if (random01(seed) > density) continue;
-
-        const sampleX = x + (random01(seed + 1) - 0.5) * GRASS_CONFIG.jitter;
-        const sampleZ = z + (random01(seed + 2) - 0.5) * GRASS_CONFIG.jitter;
-        const sample = sampleTerrainSurfaceAtXZ(
-          terrainSurfaceData.imageData,
-          sampleX,
-          sampleZ,
-          terrainSurfaceData.bounds,
-          TERRAIN_SURFACE_PROJECTION,
-        );
-
-        if (!sample.key || !GRASS_SURFACE_KEYS.has(sample.key as never))
-          continue;
-
-        const height = getHeight(sampleX, sampleZ);
-        if (height === null) continue;
-
-        const heightRatio = random01(seed + 3);
-        const widthRatio = random01(seed + 4);
-        const tipColor = new THREE.Color(getGrassTipColor(sample.key));
-        const basePosition = new THREE.Vector3(
-          sampleX,
-          height + GRASS_CONFIG.surfaceOffset,
-          sampleZ,
-        );
-
-        addGrassBlade(
-          positions,
-          colors,
-          bladeBases,
-          heightFactors,
-          windPhases,
-          basePosition,
-          random01(seed + 5) * Math.PI * 2,
-          GRASS_CONFIG.bladeWidth * lerp(0.75, 1.25, widthRatio),
-          lerp(
-            GRASS_CONFIG.minBladeHeight,
-            GRASS_CONFIG.maxBladeHeight,
-            heightRatio,
-          ),
-          baseColor,
-          tipColor,
-          random01(seed + 6) * Math.PI * 2,
-        );
-        bladeCount += 1;
-      }
+    for (let vertexIndex = 0; vertexIndex < 3; vertexIndex++) {
+      pushVector(positions, origin);
+      pushColor(colors, markerColors[vertexIndex] ?? markerColors[2]);
+      pushVector(bladeOrigins, origin);
+      pushVector(yaws, yaw);
+      pushColor(colors, color);
+      uvs.push(uv.x, uv.y);
     }
   }
 
-  if (bladeCount === 0) return null;
-
   const geometry = new THREE.BufferGeometry();
+  const markerColorValues: number[] = [];
+  const bladeColorValues: number[] = [];
+
+  for (let index = 0; index < colors.length; index += 6) {
+    markerColorValues.push(
+      colors[index] ?? 0,
+      colors[index + 1] ?? 0,
+      colors[index + 2] ?? 0,
+    );
+    bladeColorValues.push(
+      colors[index + 3] ?? 0,
+      colors[index + 4] ?? 0,
+      colors[index + 5] ?? 0,
+    );
+  }
+
   geometry.setAttribute(
     "position",
     new THREE.Float32BufferAttribute(positions, 3),
   );
-  geometry.setAttribute("color", new THREE.Float32BufferAttribute(colors, 3));
   geometry.setAttribute(
-    "aBladeBase",
-    new THREE.Float32BufferAttribute(bladeBases, 3),
+    "color",
+    new THREE.Float32BufferAttribute(markerColorValues, 3),
   );
   geometry.setAttribute(
-    "aHeightFactor",
-    new THREE.Float32BufferAttribute(heightFactors, 1),
+    "aBladeColor",
+    new THREE.Float32BufferAttribute(bladeColorValues, 3),
   );
+  geometry.setAttribute("uv", new THREE.Float32BufferAttribute(uvs, 2));
   geometry.setAttribute(
-    "aWindPhase",
-    new THREE.Float32BufferAttribute(windPhases, 1),
+    "aBladeOrigin",
+    new THREE.Float32BufferAttribute(bladeOrigins, 3),
   );
+  geometry.setAttribute("aYaw", new THREE.Float32BufferAttribute(yaws, 3));
   geometry.computeVertexNormals();
   geometry.computeBoundingSphere();
 
   return geometry;
 }
 
+function createGrassMaterial(
+  terrainSampler: TerrainGrassSampler,
+  noiseTexture: THREE.Texture,
+  grassTexture: THREE.Texture,
+): THREE.ShaderMaterial {
+  return new THREE.ShaderMaterial({
+    vertexShader: grassVertexShader,
+    fragmentShader: grassFragmentShader,
+    vertexColors: true,
+    side: THREE.DoubleSide,
+    uniforms: {
+      uTime: { value: 0 },
+      uNoiseTexture: { value: noiseTexture },
+      uDiffuseMap: { value: grassTexture },
+      uHeightMap: { value: terrainSampler.heightTexture },
+      uPlayerPosition: { value: new THREE.Vector3() },
+      uBaseBladeColor: { value: new THREE.Color(GRASS_BASE_COLOR) },
+      uBoundingBoxMin: {
+        value: new THREE.Vector3(
+          terrainSampler.bounds.minX,
+          terrainSampler.minHeight,
+          terrainSampler.bounds.minZ,
+        ),
+      },
+      uBoundingBoxMax: {
+        value: new THREE.Vector3(
+          terrainSampler.bounds.maxX,
+          terrainSampler.maxHeight,
+          terrainSampler.bounds.maxZ,
+        ),
+      },
+      uPatchSize: { value: GRASS_CONFIG.patchSize },
+      uBladeWidth: { value: GRASS_CONFIG.bladeWidth },
+      uWindDirection: { value: 0 },
+      uWindSpeed: { value: 0 },
+      uWindNoiseScale: { value: GRASS_CONFIG.windNoiseScale },
+      uWindStrength: { value: GRASS_CONFIG.windStrength },
+      uBaldPatchModifier: { value: GRASS_CONFIG.baldPatchModifier },
+      uFalloffSharpness: { value: GRASS_CONFIG.falloffSharpness },
+      uHeightNoiseFrequency: { value: GRASS_CONFIG.heightNoiseFrequency },
+      uHeightNoiseAmplitude: { value: GRASS_CONFIG.heightNoiseAmplitude },
+      uClumpFrequency: { value: GRASS_CONFIG.clumpFrequency },
+      uClumpThreshold: { value: GRASS_CONFIG.clumpThreshold },
+      uClumpSoftness: { value: GRASS_CONFIG.clumpSoftness },
+      uZoneFrequency: { value: GRASS_CONFIG.zoneFrequency },
+      uNoGrassZoneThreshold: { value: GRASS_CONFIG.noGrassZoneThreshold },
+      uSparseZoneThreshold: { value: GRASS_CONFIG.sparseZoneThreshold },
+      uMediumZoneThreshold: { value: GRASS_CONFIG.mediumZoneThreshold },
+      uZoneSoftness: { value: GRASS_CONFIG.zoneSoftness },
+      uNoGrassZoneHeight: { value: GRASS_CONFIG.noGrassZoneHeight },
+      uSparseZoneHeight: { value: GRASS_CONFIG.sparseZoneHeight },
+      uMediumZoneHeight: { value: GRASS_CONFIG.mediumZoneHeight },
+      uTallZoneHeight: { value: GRASS_CONFIG.tallZoneHeight },
+      uNoGrassZoneDensity: { value: GRASS_CONFIG.noGrassZoneDensity },
+      uSparseZoneDensity: { value: GRASS_CONFIG.sparseZoneDensity },
+      uMediumZoneDensity: { value: GRASS_CONFIG.mediumZoneDensity },
+      uTallZoneDensity: { value: GRASS_CONFIG.tallZoneDensity },
+      uMaxBendAngle: { value: GRASS_CONFIG.maxBendAngle },
+      uMaxBladeHeight: { value: GRASS_CONFIG.maxBladeHeight },
+      uRandomHeightAmount: { value: GRASS_CONFIG.randomHeightAmount },
+      uSurfaceOffset: { value: GRASS_CONFIG.surfaceOffset },
+    },
+  });
+}
+
 export function GrassPatch({
-  chunkX,
-  chunkZ,
   density,
-  terrainSurfaceData,
-}: GrassPatchProps): React.JSX.Element | null {
-  const terrainHeight = useTerrainHeightSampler();
+  terrainSampler,
+}: GrassPatchProps): React.JSX.Element {
+  const camera = useThree((state) => state.camera);
   const wind = useWind();
+  const [noiseTexture, grassTexture] = useTexture([
+    "/textures/grass/noise.png",
+    "/textures/grass/grass.jpg",
+  ]) as [THREE.Texture, THREE.Texture];
+  const grassTextures = useMemo(() => {
+    const noise = noiseTexture.clone();
+    const grass = grassTexture.clone();
+
+    noise.wrapS = noise.wrapT = THREE.RepeatWrapping;
+    grass.wrapS = grass.wrapT = THREE.MirroredRepeatWrapping;
+    noise.needsUpdate = true;
+    grass.needsUpdate = true;
+
+    return { grass, noise };
+  }, [grassTexture, noiseTexture]);
   const materialRef = useRef<THREE.ShaderMaterial | null>(null);
-  const geometry = useMemo(
+  const geometry = useMemo(() => createGrassGeometry(density), [density]);
+
+  useEffect(() => {
+    return () => {
+      grassTextures.grass.dispose();
+      grassTextures.noise.dispose();
+    };
+  }, [grassTextures]);
+
+  const material = useMemo(
     () =>
-      createGrassGeometry(
-        chunkX,
-        chunkZ,
-        density,
-        terrainSurfaceData,
-        terrainHeight.getHeight,
+      createGrassMaterial(
+        terrainSampler,
+        grassTextures.noise,
+        grassTextures.grass,
       ),
-    [chunkX, chunkZ, density, terrainHeight.getHeight, terrainSurfaceData],
+    [grassTextures, terrainSampler],
   );
-  const material = useMemo(() => createGrassMaterial(), []);
 
   useEffect(() => {
     materialRef.current = material;
@@ -255,7 +229,7 @@ export function GrassPatch({
 
   useEffect(() => {
     return () => {
-      geometry?.dispose();
+      geometry.dispose();
     };
   }, [geometry]);
 
@@ -265,16 +239,16 @@ export function GrassPatch({
 
     const uniforms = currentMaterial.uniforms;
     if (uniforms.uTime) uniforms.uTime.value = clock.elapsedTime;
+    if (uniforms.uPlayerPosition) {
+      uniforms.uPlayerPosition.value.copy(camera.position);
+    }
     if (uniforms.uWindDirection) uniforms.uWindDirection.value = wind.direction;
     if (uniforms.uWindSpeed) uniforms.uWindSpeed.value = wind.speed;
-    if (uniforms.uWindStrength) uniforms.uWindStrength.value = wind.strength;
     if (uniforms.uWindNoiseScale) {
       uniforms.uWindNoiseScale.value =
         GRASS_CONFIG.windNoiseScale * wind.noiseScale;
     }
   });
 
-  if (!geometry) return null;
-
-  return <mesh geometry={geometry} material={material} frustumCulled />;
+  return <mesh geometry={geometry} material={material} frustumCulled={false} />;
 }

src/world/grass/GrassSystem.tsx

@@ -1,147 +1,25 @@
-import { Suspense, useCallback, useMemo, useRef, useState } from "react";
-import { useFrame, useThree } from "@react-three/fiber";
-import { useSceneMode } from "@/hooks/debug/useSceneMode";
-import { useTerrainSurfaceData } from "@/hooks/world/useTerrainSurfaceData";
+import { Suspense } from "react";
 import {
   useDynamicGrass,
   useGrassDensity,
 } from "@/hooks/world/useGraphicsSettings";
-import type { TerrainSurfaceBounds } from "@/types/world/terrainSurface";
 import { GRASS_CONFIG } from "@/world/grass/grassConfig";
 import { GrassPatch } from "@/world/grass/GrassPatch";
-
-interface GrassChunk {
-  centerX: number;
-  centerZ: number;
-  key: string;
-  x: number;
-  z: number;
-}
-
-function getChunkRange(min: number, max: number): number[] {
-  const start = Math.floor(min / GRASS_CONFIG.chunkSize);
-  const end = Math.floor(max / GRASS_CONFIG.chunkSize);
-  const chunks: number[] = [];
-
-  for (let value = start; value <= end; value++) {
-    chunks.push(value);
-  }
-
-  return chunks;
-}
-
-function createGrassChunks(bounds: TerrainSurfaceBounds): GrassChunk[] {
-  const chunks: GrassChunk[] = [];
-  const xChunks = getChunkRange(bounds.minX, bounds.maxX);
-  const zChunks = getChunkRange(bounds.minZ, bounds.maxZ);
-
-  for (const x of xChunks) {
-    for (const z of zChunks) {
-      chunks.push({
-        centerX: x * GRASS_CONFIG.chunkSize + GRASS_CONFIG.chunkSize * 0.5,
-        centerZ: z * GRASS_CONFIG.chunkSize + GRASS_CONFIG.chunkSize * 0.5,
-        key: `${x}:${z}`,
-        x,
-        z,
-      });
-    }
-  }
-
-  return chunks;
-}
+import { useTerrainGrassSampler } from "@/world/grass/useTerrainGrassSampler";
 
 export function GrassSystem(): React.JSX.Element | null {
-  const camera = useThree((state) => state.camera);
-  const terrainSurfaceData = useTerrainSurfaceData();
-  const sceneMode = useSceneMode();
+  const terrainSampler = useTerrainGrassSampler();
   const dynamicGrass = useDynamicGrass();
   const grassDensity = useGrassDensity();
-  const lastUpdateRef = useRef(-GRASS_CONFIG.updateInterval);
-  const [activeChunkKeys, setActiveChunkKeys] = useState<Set<string>>(
-    () => new Set(),
-  );
   const density = Math.max(0, grassDensity);
-  const chunks = useMemo(
-    () =>
-      terrainSurfaceData ? createGrassChunks(terrainSurfaceData.bounds) : [],
-    [terrainSurfaceData],
-  );
-  const streamingEnabled = sceneMode === "game";
 
-  const updateActiveChunks = useCallback(() => {
-    const nextKeys = new Set<string>();
-
-    for (const chunk of chunks) {
-      const distance = Math.hypot(
-        chunk.centerX - camera.position.x,
-        chunk.centerZ - camera.position.z,
-      );
-      const wasActive = activeChunkKeys.has(chunk.key);
-      const radius = wasActive
-        ? GRASS_CONFIG.unloadRadius
-        : GRASS_CONFIG.loadRadius;
-
-      if (distance <= radius) {
-        nextKeys.add(chunk.key);
-      }
-    }
-
-    if (
-      nextKeys.size === activeChunkKeys.size &&
-      [...nextKeys].every((key) => activeChunkKeys.has(key))
-    ) {
-      return;
-    }
-
-    setActiveChunkKeys(nextKeys);
-  }, [activeChunkKeys, camera, chunks]);
-
-  useFrame(({ clock }) => {
-    if (!streamingEnabled) return;
-
-    const now = clock.elapsedTime * 1000;
-    if (now - lastUpdateRef.current < GRASS_CONFIG.updateInterval) return;
-    lastUpdateRef.current = now;
-
-    updateActiveChunks();
-  });
-
-  if (
-    !GRASS_CONFIG.enabled ||
-    !dynamicGrass ||
-    density <= 0 ||
-    !terrainSurfaceData
-  ) {
+  if (!GRASS_CONFIG.enabled || !dynamicGrass || density <= 0) {
     return null;
   }
 
-  const visibleChunks = streamingEnabled
-    ? chunks.filter((chunk) => {
-        if (activeChunkKeys.size > 0) {
-          return activeChunkKeys.has(chunk.key);
-        }
-
-        return (
-          Math.hypot(
-            chunk.centerX - camera.position.x,
-            chunk.centerZ - camera.position.z,
-          ) <= GRASS_CONFIG.loadRadius
-        );
-      })
-    : chunks;
-
   return (
-    <group name="grass-system">
-      {visibleChunks.map((chunk) => (
-        <Suspense key={chunk.key} fallback={null}>
-          <GrassPatch
-            chunkX={chunk.x}
-            chunkZ={chunk.z}
-            density={density}
-            terrainSurfaceData={terrainSurfaceData}
-          />
-        </Suspense>
-      ))}
-    </group>
+    <Suspense fallback={null}>
+      <GrassPatch density={density} terrainSampler={terrainSampler} />
+    </Suspense>
   );
 }

src/world/grass/grassConfig.ts

@@ -1,33 +1,36 @@
-import { TERRAIN_COLORS } from "@/data/world/terrainConfig";
-
 export const GRASS_CONFIG = {
   enabled: true,
-  chunkSize: 20,
-  loadRadius: 30,
-  unloadRadius: 34,
-  updateInterval: 250,
-  sampleStep: 1.15,
-  jitter: 0.42,
-  bladesPerCell: 2,
-  maxBladesPerChunk: 720,
-  bladeWidth: 0.12,
-  minBladeHeight: 0.42,
-  maxBladeHeight: 0.82,
-  surfaceOffset: 0.06,
-  baseColor: "#1f3512",
-  windBendStrength: 0.42,
-  windNoiseScale: 0.09,
+  patchSize: 30,
+  bladeCount: 32000,
+  bladeWidth: 0.08,
+  maxBladeHeight: 0.56,
+  randomHeightAmount: 0.25,
+  surfaceOffset: 0.025,
+  heightTextureSize: 128,
+  windNoiseScale: 0.9,
+  windStrength: 0.35,
+  baldPatchModifier: 1.1,
+  falloffSharpness: 0.35,
+  heightNoiseFrequency: 9,
+  heightNoiseAmplitude: 1,
+  clumpFrequency: 2.6,
+  clumpThreshold: 0.18,
+  clumpSoftness: 0.45,
+  zoneFrequency: 0.035,
+  noGrassZoneThreshold: 0.2,
+  sparseZoneThreshold: 0.4,
+  mediumZoneThreshold: 0.65,
+  zoneSoftness: 0.08,
+  noGrassZoneHeight: 0,
+  sparseZoneHeight: 0.08,
+  mediumZoneHeight: 0.45,
+  tallZoneHeight: 1,
+  noGrassZoneDensity: 0,
+  sparseZoneDensity: 0.08,
+  mediumZoneDensity: 0.72,
+  tallZoneDensity: 1,
+  maxBendAngle: 14,
 } as const;
 
-export const GRASS_SURFACE_KEYS = new Set([
-  "grass1",
-  "grass2",
-  "grass3",
-] as const);
-
-export function getGrassTipColor(surfaceKey: string | null): string {
-  if (surfaceKey === "grass1") return TERRAIN_COLORS.grass1.grassTipColor;
-  if (surfaceKey === "grass2") return TERRAIN_COLORS.grass2.grassTipColor;
-  if (surfaceKey === "grass3") return TERRAIN_COLORS.grass3.grassTipColor;
-  return TERRAIN_COLORS.grass1.grassTipColor;
-}
+export const GRASS_COLORS = ["#84C66B", "#67B058", "#A3CA5B"] as const;
+export const GRASS_BASE_COLOR = "#1A3A1A" as const;

src/world/grass/grassShaders.ts

@@ -1,40 +1,167 @@
 export const grassVertexShader = /* glsl */ `
-  attribute vec3 aColor;
-  attribute vec3 aBladeBase;
-  attribute float aHeightFactor;
-  attribute float aWindPhase;
+  attribute vec3 aYaw;
+  attribute vec3 aBladeOrigin;
+  attribute vec3 aBladeColor;
 
   varying vec3 vColor;
 
   uniform float uTime;
+  uniform vec3 uPlayerPosition;
+  uniform vec3 uBaseBladeColor;
+  uniform sampler2D uHeightMap;
+  uniform sampler2D uDiffuseMap;
+  uniform sampler2D uNoiseTexture;
+  uniform vec3 uBoundingBoxMin;
+  uniform vec3 uBoundingBoxMax;
+  uniform float uPatchSize;
+  uniform float uBladeWidth;
   uniform float uWindDirection;
   uniform float uWindSpeed;
-  uniform float uWindStrength;
   uniform float uWindNoiseScale;
-  uniform float uBendStrength;
+  uniform float uWindStrength;
+  uniform float uBaldPatchModifier;
+  uniform float uFalloffSharpness;
+  uniform float uHeightNoiseFrequency;
+  uniform float uHeightNoiseAmplitude;
+  uniform float uClumpFrequency;
+  uniform float uClumpThreshold;
+  uniform float uClumpSoftness;
+  uniform float uZoneFrequency;
+  uniform float uNoGrassZoneThreshold;
+  uniform float uSparseZoneThreshold;
+  uniform float uMediumZoneThreshold;
+  uniform float uZoneSoftness;
+  uniform float uNoGrassZoneHeight;
+  uniform float uSparseZoneHeight;
+  uniform float uMediumZoneHeight;
+  uniform float uTallZoneHeight;
+  uniform float uNoGrassZoneDensity;
+  uniform float uSparseZoneDensity;
+  uniform float uMediumZoneDensity;
+  uniform float uTallZoneDensity;
+  uniform float uMaxBendAngle;
+  uniform float uMaxBladeHeight;
+  uniform float uRandomHeightAmount;
+  uniform float uSurfaceOffset;
+
+  float random(vec2 st) {
+    return fract(sin(dot(st.xy, vec2(12.9898, 78.233))) * 43758.5453123);
+  }
+
+  mat3 rotate3d(in vec3 axis, const in float angle) {
+    axis = normalize(axis);
+    float s = sin(angle);
+    float c = cos(angle);
+    float oc = 1.0 - c;
+    return mat3(
+      oc * axis.x * axis.x + c, oc * axis.x * axis.y - axis.z * s, oc * axis.z * axis.x + axis.y * s,
+      oc * axis.x * axis.y + axis.z * s, oc * axis.y * axis.y + c, oc * axis.y * axis.z - axis.x * s,
+      oc * axis.z * axis.x - axis.y * s, oc * axis.y * axis.z + axis.x * s, oc * axis.z * axis.z + c
+    );
+  }
+
+  float mapValue(float value, float inMin, float inMax, float outMin, float outMax) {
+    return mix(outMin, outMax, (value - inMin) / (inMax - inMin));
+  }
 
   void main() {
     vec3 transformed = position;
-    float topFactor = aHeightFactor * aHeightFactor;
-    vec2 windDirection = normalize(vec2(cos(uWindDirection), sin(uWindDirection)));
+    vec3 origin = aBladeOrigin;
+    float halfPatchSize = uPatchSize * 0.5;
 
-    float primaryWind = sin(
-      uTime * max(uWindSpeed, 0.05) +
-      aWindPhase +
-      aBladeBase.x * uWindNoiseScale +
-      aBladeBase.z * uWindNoiseScale
+    origin.x = mod(origin.x - uPlayerPosition.x + halfPatchSize, uPatchSize) - halfPatchSize;
+    origin.z = mod(origin.z - uPlayerPosition.z + halfPatchSize, uPatchSize) - halfPatchSize;
+
+    vec3 worldPos = vec3(uPlayerPosition.x + origin.x, 0.0, uPlayerPosition.z + origin.z);
+    transformed.x = worldPos.x;
+    transformed.z = worldPos.z;
+
+    vec2 terrainUv = vec2(
+      mapValue(worldPos.x, uBoundingBoxMin.x, uBoundingBoxMax.x, 0.0, 1.0),
+      mapValue(worldPos.z, uBoundingBoxMin.z, uBoundingBoxMax.z, 0.0, 1.0)
     );
-    float secondaryWind = sin(
-      uTime * max(uWindSpeed, 0.05) * 1.73 +
-      aWindPhase * 0.71 +
-      aBladeBase.x * uWindNoiseScale * 0.53 -
-      aBladeBase.z * uWindNoiseScale * 0.89
-    ) * 0.35;
+    terrainUv = clamp(terrainUv, 0.0, 1.0);
 
-    float bend = (primaryWind + secondaryWind) * uWindStrength * uBendStrength * topFactor;
-    transformed.xz += windDirection * bend;
+    float terrainHeightRatio = texture2D(uHeightMap, terrainUv).r;
+    float terrainHeight = mix(uBoundingBoxMin.y, uBoundingBoxMax.y, terrainHeightRatio);
+    transformed.y = terrainHeight + uSurfaceOffset;
+
+    vec3 heightNoise = texture2D(uNoiseTexture, terrainUv.yx * vec2(uHeightNoiseFrequency)).rgb;
+    float heightNoiseAverage = (heightNoise.r + heightNoise.g + heightNoise.b) / 3.0;
+    vec2 clumpUv = (worldPos.xz / uPatchSize) * uClumpFrequency;
+    float clumpNoise = texture2D(uNoiseTexture, clumpUv).r;
+    float clumpMask = smoothstep(uClumpThreshold, uClumpThreshold + uClumpSoftness, clumpNoise);
+    float zoneNoise = texture2D(uNoiseTexture, worldPos.xz * uZoneFrequency).r;
+    float noGrassZone = 1.0 - smoothstep(uNoGrassZoneThreshold, uNoGrassZoneThreshold + uZoneSoftness, zoneNoise);
+    float sparseZone =
+      smoothstep(uNoGrassZoneThreshold, uNoGrassZoneThreshold + uZoneSoftness, zoneNoise) *
+      (1.0 - smoothstep(uSparseZoneThreshold, uSparseZoneThreshold + uZoneSoftness, zoneNoise));
+    float mediumZone =
+      smoothstep(uSparseZoneThreshold, uSparseZoneThreshold + uZoneSoftness, zoneNoise) *
+      (1.0 - smoothstep(uMediumZoneThreshold, uMediumZoneThreshold + uZoneSoftness, zoneNoise));
+    float tallZone = smoothstep(uMediumZoneThreshold, uMediumZoneThreshold + uZoneSoftness, zoneNoise);
+    float zoneHeight =
+      noGrassZone * uNoGrassZoneHeight +
+      sparseZone * uSparseZoneHeight +
+      mediumZone * uMediumZoneHeight +
+      tallZone * uTallZoneHeight;
+    float zoneDensity =
+      noGrassZone * uNoGrassZoneDensity +
+      sparseZone * uSparseZoneDensity +
+      mediumZone * uMediumZoneDensity +
+      tallZone * uTallZoneDensity;
+    float bladeVisibility = step(random(worldPos.xz), zoneDensity);
+    float heightModifier = uMaxBladeHeight * mix(0.35, 1.0, heightNoiseAverage) * uHeightNoiseAmplitude;
+    heightModifier += random(terrainUv) * (uRandomHeightAmount * 0.1);
+    heightModifier = clamp(heightModifier, 0.0, uMaxBladeHeight);
+    heightModifier *= zoneHeight * bladeVisibility;
+
+    float edgeDistanceX = abs(origin.x) / halfPatchSize;
+    float edgeDistanceZ = abs(origin.z) / halfPatchSize;
+    float edgeFactor = 1.0 - max(edgeDistanceX, edgeDistanceZ);
+    edgeFactor = pow(clamp(edgeFactor, 0.0, 1.0), uFalloffSharpness);
+
+    float baldPatchOffset = heightNoise.r * (uBaldPatchModifier * (1.0 - edgeFactor));
+    heightModifier -= baldPatchOffset;
+    heightModifier = max(heightModifier, 0.0);
+
+    float edgeFade =
+      smoothstep(uBoundingBoxMin.x, uBoundingBoxMin.x + 2.0, worldPos.x) *
+      smoothstep(uBoundingBoxMax.x, uBoundingBoxMax.x - 2.0, worldPos.x) *
+      smoothstep(uBoundingBoxMin.z, uBoundingBoxMin.z + 2.0, worldPos.z) *
+      smoothstep(uBoundingBoxMax.z, uBoundingBoxMax.z - 2.0, worldPos.z);
+    heightModifier *= edgeFade * mix(0.45, 1.0, clumpMask);
+
+    float sideFactor = (color.r == 0.1) ? 1.0 : (color.b == 0.1) ? -1.0 : 0.0;
+    float tipFactor = color.g;
+    float width = smoothstep(0.02, uMaxBladeHeight * 0.85, heightModifier) * uBladeWidth * bladeVisibility;
+    transformed += aYaw * (width / 2.0) * sideFactor;
+
+    vColor = mix(uBaseBladeColor, aBladeColor, tipFactor);
+
+    float distanceFromCenter = length(origin.xz) / halfPatchSize;
+    float innerCircleFactor = clamp(smoothstep(0.0, 0.5, distanceFromCenter), 0.0, 1.0);
+    heightModifier *= mix(0.25, 1.0, innerCircleFactor);
+
+    float noiseScale = uWindNoiseScale * 0.1;
+    vec2 noiseUV = vec2(origin.x * noiseScale, origin.z * noiseScale);
+    mat2 rotation = mat2(
+      cos(uWindDirection), -sin(uWindDirection),
+      sin(uWindDirection), cos(uWindDirection)
+    );
+    vec2 rotatedNoiseUV = rotation * noiseUV + uTime * vec2(uWindSpeed);
+    vec3 windNoise = texture2D(uNoiseTexture, rotatedNoiseUV).rgb;
+
+    vec3 axis = vec3(windNoise.g, 0.0, windNoise.b);
+    float angle = radians(mapValue(windNoise.g + windNoise.b, 0.0, 2.0, -uMaxBendAngle, uMaxBendAngle)) * tipFactor * uWindStrength;
+    mat3 rotationMatrix = rotate3d(axis, angle);
+
+    vec3 basePosition = vec3(transformed.x, transformed.y - heightModifier, transformed.z);
+    vec3 relativePosition = transformed - basePosition;
+    relativePosition = rotationMatrix * relativePosition;
+    transformed = basePosition + relativePosition;
+    transformed.y += heightModifier * tipFactor;
 
-    vColor = aColor;
     gl_Position = projectionMatrix * modelViewMatrix * vec4(transformed, 1.0);
   }
 `;

src/world/grass/useTerrainGrassSampler.ts

@@ -0,0 +1,192 @@
+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 { TerrainSurfaceBounds } from "@/types/world/terrainSurface";
+import type { Vector3Tuple } from "@/types/three/three";
+import { getMapNodesByName } from "@/utils/map/loadMapSceneData";
+import { GRASS_CONFIG } from "@/world/grass/grassConfig";
+
+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];
+
+export interface TerrainGrassSample {
+  normal: THREE.Vector3;
+  position: THREE.Vector3;
+}
+
+export interface TerrainGrassSampler {
+  bounds: TerrainSurfaceBounds;
+  heightTexture: THREE.DataTexture;
+  maxHeight: number;
+  minHeight: number;
+  sample: (x: number, z: number) => TerrainGrassSample | null;
+}
+
+function createFallbackBounds(): TerrainSurfaceBounds {
+  return {
+    minX: -120,
+    maxX: 120,
+    minZ: -120,
+    maxZ: 120,
+  };
+}
+
+function createTerrainMatrix(
+  position: Vector3Tuple,
+  rotation: Vector3Tuple,
+  scale: Vector3Tuple,
+): THREE.Matrix4 {
+  return new THREE.Matrix4().compose(
+    new THREE.Vector3(...position),
+    new THREE.Quaternion().setFromEuler(new THREE.Euler(...rotation)),
+    new THREE.Vector3(...scale),
+  );
+}
+
+function createTerrainGrassSampler(
+  scene: THREE.Object3D,
+  position: Vector3Tuple,
+  rotation: Vector3Tuple,
+  scale: Vector3Tuple,
+): TerrainGrassSampler {
+  const meshes: THREE.Mesh[] = [];
+  const terrainMatrix = createTerrainMatrix(position, rotation, scale);
+  const inverseTerrainMatrix = terrainMatrix.clone().invert();
+  const normalMatrix = new THREE.Matrix3().getNormalMatrix(terrainMatrix);
+  const raycaster = new THREE.Raycaster(
+    new THREE.Vector3(),
+    DOWN,
+    0,
+    RAYCAST_FAR,
+  );
+
+  scene.updateMatrixWorld(true);
+  scene.traverse((child) => {
+    if (child instanceof THREE.Mesh) {
+      meshes.push(child);
+    }
+  });
+
+  const terrainBounds = new THREE.Box3().setFromObject(scene);
+  if (!terrainBounds.isEmpty()) {
+    terrainBounds.applyMatrix4(terrainMatrix);
+  }
+
+  const bounds = terrainBounds.isEmpty()
+    ? createFallbackBounds()
+    : {
+        minX: terrainBounds.min.x,
+        maxX: terrainBounds.max.x,
+        minZ: terrainBounds.min.z,
+        maxZ: terrainBounds.max.z,
+      };
+
+  const sample = (x: number, z: number): TerrainGrassSample | null => {
+    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];
+    if (!hit) return null;
+
+    const normal = hit.face?.normal
+      .clone()
+      .transformDirection(hit.object.matrixWorld)
+      .applyMatrix3(normalMatrix)
+      .normalize();
+
+    return {
+      position: hit.point.clone().applyMatrix4(terrainMatrix),
+      normal: normal ?? new THREE.Vector3(0, 1, 0),
+    };
+  };
+
+  const { heightTexture, maxHeight, minHeight } = createTerrainHeightTexture(
+    bounds,
+    sample,
+  );
+
+  return {
+    bounds,
+    heightTexture,
+    maxHeight,
+    minHeight,
+    sample,
+  };
+}
+
+function createTerrainHeightTexture(
+  bounds: TerrainSurfaceBounds,
+  sample: (x: number, z: number) => TerrainGrassSample | null,
+): { heightTexture: THREE.DataTexture; maxHeight: number; minHeight: number } {
+  const size = GRASS_CONFIG.heightTextureSize;
+  const heights = new Float32Array(size * size);
+  let minHeight = Number.POSITIVE_INFINITY;
+  let maxHeight = Number.NEGATIVE_INFINITY;
+
+  for (let zIndex = 0; zIndex < size; zIndex++) {
+    for (let xIndex = 0; xIndex < size; xIndex++) {
+      const xRatio = size <= 1 ? 0 : xIndex / (size - 1);
+      const zRatio = size <= 1 ? 0 : zIndex / (size - 1);
+      const x = bounds.minX + (bounds.maxX - bounds.minX) * xRatio;
+      const z = bounds.minZ + (bounds.maxZ - bounds.minZ) * zRatio;
+      const terrainSample = sample(x, z);
+      const height = terrainSample?.position.y ?? 0;
+      const index = zIndex * size + xIndex;
+
+      heights[index] = height;
+      minHeight = Math.min(minHeight, height);
+      maxHeight = Math.max(maxHeight, height);
+    }
+  }
+
+  if (!Number.isFinite(minHeight) || !Number.isFinite(maxHeight)) {
+    minHeight = 0;
+    maxHeight = 1;
+  }
+
+  const range = Math.max(maxHeight - minHeight, 0.0001);
+  const data = new Uint8Array(size * size);
+
+  for (let index = 0; index < heights.length; index++) {
+    data[index] = Math.round(
+      (((heights[index] ?? minHeight) - minHeight) / range) * 255,
+    );
+  }
+
+  const heightTexture = new THREE.DataTexture(
+    data,
+    size,
+    size,
+    THREE.RedFormat,
+    THREE.UnsignedByteType,
+  );
+  heightTexture.magFilter = THREE.LinearFilter;
+  heightTexture.minFilter = THREE.LinearFilter;
+  heightTexture.wrapS = THREE.ClampToEdgeWrapping;
+  heightTexture.wrapT = THREE.ClampToEdgeWrapping;
+  heightTexture.needsUpdate = true;
+
+  return { heightTexture, maxHeight, minHeight };
+}
+
+export function useTerrainGrassSampler(): TerrainGrassSampler {
+  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(
+    () => createTerrainGrassSampler(scene, position, rotation, scale),
+    [position, rotation, scale, scene],
+  );
+}

src/world/player/PlayerController.tsx

@@ -26,6 +26,7 @@ import {
   PLAYER_XZ_DAMPING_FACTOR,
 } from "@/data/player/playerConfig";
 import { useRepairMovementLocked } from "@/hooks/gameplay/useRepairMovementLocked";
+import { useTerrainHeightSampler } from "@/hooks/three/useTerrainHeight";
 import { InteractionManager } from "@/managers/InteractionManager";
 import { useGameStore } from "@/managers/stores/useGameStore";
 import { useSettingsStore } from "@/managers/stores/useSettingsStore";
@@ -47,6 +48,10 @@ const DEFAULT_KEYS: Keys = {
   jump: false,
 };
 
+const PLAYER_COLLISION_ITERATIONS = 3;
+const PLAYER_FLOOR_NORMAL_MIN = 0.15;
+const PLAYER_GROUND_SNAP_DISTANCE = 0.22;
+
 interface PlayerControllerProps {
   octree: Octree | null;
   spawnPosition: Vector3Tuple;
@@ -113,12 +118,17 @@ function setMovementKey(keys: Keys, key: string, pressed: boolean): boolean {
   }
 }
 
+function getCapsuleFootY(capsule: Capsule): number {
+  return capsule.start.y - capsule.radius;
+}
+
 export function PlayerController({
   octree,
   spawnPosition,
 }: PlayerControllerProps): null {
   const camera = useThree((state) => state.camera);
   const movementLocked = useRepairMovementLocked();
+  const terrainHeight = useTerrainHeightSampler();
   const movementLockedRef = useRef(movementLocked);
   const keys = useRef<Keys>({ ...DEFAULT_KEYS });
   const velocity = useRef(new THREE.Vector3());
@@ -300,17 +310,26 @@ export function PlayerController({
     capsule.current.translate(_translateVec);
 
     if (octree) {
-      const result = octree.capsuleIntersect(capsule.current);
       onFloor.current = false;
 
-      if (result) {
-        onFloor.current = result.normal.y > 0;
+      for (let index = 0; index < PLAYER_COLLISION_ITERATIONS; index++) {
+        const result = octree.capsuleIntersect(capsule.current);
+        if (!result) break;
 
-        if (!onFloor.current) {
-          const vn = result.normal.dot(velocity.current);
-          velocity.current.addScaledVector(result.normal, -vn);
-        } else {
+        const isFloorCollision = result.normal.y > PLAYER_FLOOR_NORMAL_MIN;
+        onFloor.current ||= isFloorCollision;
+        const normalVelocity = result.normal.dot(velocity.current);
+
+        if (!isFloorCollision && normalVelocity < 0) {
+          velocity.current.addScaledVector(result.normal, -normalVelocity);
+        }
+
+        if (isFloorCollision) {
           velocity.current.y = Math.max(0, velocity.current.y);
+          capsule.current.translate(
+            _collisionCorrection.set(0, result.depth / result.normal.y, 0),
+          );
+          continue;
         }
 
         capsule.current.translate(
@@ -319,6 +338,22 @@ export function PlayerController({
       }
     }
 
+    const groundHeight = terrainHeight.getHeight(
+      capsule.current.end.x,
+      capsule.current.end.z,
+    );
+    if (groundHeight !== null && velocity.current.y <= 0) {
+      const groundOffset = getCapsuleFootY(capsule.current) - groundHeight;
+
+      if (groundOffset <= PLAYER_GROUND_SNAP_DISTANCE) {
+        capsule.current.translate(
+          _collisionCorrection.set(0, -groundOffset, 0),
+        );
+        velocity.current.y = 0;
+        onFloor.current = true;
+      }
+    }
+
     camera.position.copy(capsule.current.end);
   });