Update terrain layer material imports and dispose logic in ViewportHost

src/runtime-three/runtime-host.ts

@@ -129,6 +129,8 @@ import { createFogQualityMaterial } from "../rendering/fog-material";
 import { updatePlanarReflectionCamera } from "../rendering/planar-reflection";
 import {
   createTerrainLayerBlendMaterial,
+  createTerrainLayerColorBlendMaterial,
+  getTerrainLayerPreviewColor,
   getTerrainLayerTexture
 } from "../rendering/terrain-layer-material";
 import {

src/viewport-three/viewport-host.ts

@@ -9651,7 +9651,8 @@ export class ViewportHost {
         geometry.dispose();
       }
 
-      renderObjects.material.dispose();
+      renderObjects.detailMaterial.dispose();
+      renderObjects.distantMaterial.dispose();
 
       for (const material of renderObjects.debugMaterials) {
         material.dispose();