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 (
+  return mapNode.modelUrl !== null;
-    mapNode.modelUrl !== null && MAP_COLLISION_NODE_NAMES.has(mapNode.node.name)
-  );
 }
 
 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/player/PlayerController.tsx

@@ -47,6 +47,9 @@ const DEFAULT_KEYS: Keys = {
   jump: false,
 };
 
+const PLAYER_COLLISION_ITERATIONS = 3;
+const PLAYER_FLOOR_NORMAL_MIN = 0.5;
+
 interface PlayerControllerProps {
   octree: Octree | null;
   spawnPosition: Vector3Tuple;
@@ -300,16 +303,21 @@ export function PlayerController({
     capsule.current.translate(_translateVec);
 
     if (octree) {
-      const result = octree.capsuleIntersect(capsule.current);
       onFloor.current = false;
 
-      if (result) {
+      for (let index = 0; index < PLAYER_COLLISION_ITERATIONS; index++) {
-        onFloor.current = result.normal.y > 0;
+        const result = octree.capsuleIntersect(capsule.current);
+        if (!result) break;
 
-        if (!onFloor.current) {
+        const isFloorCollision = result.normal.y > PLAYER_FLOOR_NORMAL_MIN;
-          const vn = result.normal.dot(velocity.current);
+        onFloor.current ||= isFloorCollision;
-          velocity.current.addScaledVector(result.normal, -vn);
+        const normalVelocity = result.normal.dot(velocity.current);
-        } else {
+
+        if (!isFloorCollision && normalVelocity < 0) {
+          velocity.current.addScaledVector(result.normal, -normalVelocity);
+        }
+
+        if (isFloorCollision) {
           velocity.current.y = Math.max(0, velocity.current.y);
         }