feat(map): generate path tiles from terrain colors

src/world/paths/usePathTileData.ts

@@ -0,0 +1,68 @@
+import { useMemo } from "react";
+import { useTerrainSurfaceData } from "@/hooks/world/useTerrainSurfaceData";
+import type { Vector3Tuple } from "@/types/three/three";
+import { sampleTerrainSurfaceAtXZFromRaycast } from "@/utils/world/terrainSurfaceSampler";
+import type { MapAssetInstance } from "@/world/map-instancing/useMapInstancingData";
+import {
+  PATH_TILE_MAX_COUNT,
+  PATH_SURFACE_KEY,
+  PATH_TILE_ROTATION,
+  PATH_TILE_SAMPLE_STEP,
+  PATH_TILE_SCALE,
+} from "@/world/paths/pathConfig";
+
+function createSampleCenters(min: number, max: number, step: number): number[] {
+  const start = Math.ceil(min / step) * step + step * 0.5;
+  const centers: number[] = [];
+
+  for (let value = start; value <= max; value += step) {
+    centers.push(value);
+  }
+
+  return centers;
+}
+
+export function usePathTileData(): MapAssetInstance[] {
+  const terrainSurfaceData = useTerrainSurfaceData();
+
+  return useMemo(() => {
+    if (!terrainSurfaceData) return [];
+
+    const instances: MapAssetInstance[] = [];
+    const xCenters = createSampleCenters(
+      terrainSurfaceData.bounds.minX,
+      terrainSurfaceData.bounds.maxX,
+      PATH_TILE_SAMPLE_STEP,
+    );
+    const zCenters = createSampleCenters(
+      terrainSurfaceData.bounds.minZ,
+      terrainSurfaceData.bounds.maxZ,
+      PATH_TILE_SAMPLE_STEP,
+    );
+    const raycastY = terrainSurfaceData.bounds.maxY + 10;
+
+    for (const x of xCenters) {
+      for (const z of zCenters) {
+        if (instances.length >= PATH_TILE_MAX_COUNT) return instances;
+
+        const sample = sampleTerrainSurfaceAtXZFromRaycast(
+          terrainSurfaceData.imageData,
+          terrainSurfaceData.raycastTarget,
+          x,
+          z,
+          raycastY,
+        );
+
+        if (sample?.key !== PATH_SURFACE_KEY) continue;
+
+        instances.push({
+          position: [x, 0, z],
+          rotation: [...PATH_TILE_ROTATION] as Vector3Tuple,
+          scale: [...PATH_TILE_SCALE] as Vector3Tuple,
+        });
+      }
+    }
+
+    return instances;
+  }, [terrainSurfaceData]);
+}