From 7886f4cfa06d22e72462e5ba0663b7c8ad756c36 Mon Sep 17 00:00:00 2001
From: Victor Giers <mail@victorgiers.com>
Date: Sun, 3 May 2026 13:22:41 +0200
Subject: [PATCH] Add unit tests for FoliageInstancedRenderer

---
 .../domain/foliage-instanced-renderer.test.ts | 178 ++++++++++++++++++
 1 file changed, 178 insertions(+)
 create mode 100644 tests/domain/foliage-instanced-renderer.test.ts

diff --git a/tests/domain/foliage-instanced-renderer.test.ts b/tests/domain/foliage-instanced-renderer.test.ts
new file mode 100644
index 00000000..b5992097
--- /dev/null
+++ b/tests/domain/foliage-instanced-renderer.test.ts
@@ -0,0 +1,178 @@
+import {
+  BoxGeometry,
+  Group,
+  Mesh,
+  MeshBasicMaterial,
+  PerspectiveCamera,
+  type Object3D
+} from "three";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+import {
+  createTerrain,
+  createTerrainFoliageMask
+} from "../../src/document/terrains";
+import { BUNDLED_FOLIAGE_PROTOTYPES } from "../../src/foliage/bundled-foliage-manifest";
+import { createFoliageLayer } from "../../src/foliage/foliage";
+
+const loaderState = vi.hoisted(() => ({
+  loadCalls: [] as string[]
+}));
+
+vi.mock("../../src/foliage/bundled-foliage-model-loader", () => ({
+  loadBundledFoliageModelTemplate: async (bundledPath: string) => {
+    loaderState.loadCalls.push(bundledPath);
+
+    const template = new Group();
+    template.add(
+      new Mesh(new BoxGeometry(1, 1, 1), new MeshBasicMaterial())
+    );
+
+    return template;
+  }
+}));
+
+import { FoliageInstancedRenderer } from "../../src/foliage/foliage-instanced-renderer";
+
+const TEST_TERRAIN_ID = "terrain-renderer";
+const TEST_LAYER_ID = "foliage-layer-renderer";
+
+function createCamera(position: { x: number; y: number; z: number }) {
+  const camera = new PerspectiveCamera(60, 1, 0.1, 500);
+
+  camera.position.set(position.x, position.y, position.z);
+  camera.lookAt(8, 0, 8);
+  camera.updateProjectionMatrix();
+  camera.updateMatrixWorld(true);
+
+  return camera;
+}
+
+function createRendererInput() {
+  const prototype = BUNDLED_FOLIAGE_PROTOTYPES[0]!;
+  const sampleCount = 17;
+  const terrain = createTerrain({
+    id: TEST_TERRAIN_ID,
+    position: { x: 0, y: 0, z: 0 },
+    sampleCountX: sampleCount,
+    sampleCountZ: sampleCount,
+    cellSize: 1,
+    heights: new Array<number>(sampleCount * sampleCount).fill(0),
+    foliageMasks: {
+      [TEST_LAYER_ID]: createTerrainFoliageMask({
+        layerId: TEST_LAYER_ID,
+        resolutionX: sampleCount,
+        resolutionZ: sampleCount,
+        values: new Array<number>(sampleCount * sampleCount).fill(1)
+      })
+    }
+  });
+  const layer = createFoliageLayer({
+    id: TEST_LAYER_ID,
+    name: "Renderer foliage layer",
+    prototypeIds: [prototype.id],
+    density: 3,
+    seed: 11
+  });
+
+  return {
+    terrains: {
+      [terrain.id]: terrain
+    },
+    foliageLayers: {
+      [layer.id]: layer
+    },
+    bundledFoliagePrototypes: {
+      [prototype.id]: prototype
+    },
+    quality: {
+      enabled: true,
+      densityMultiplier: 1,
+      maxDistanceMultiplier: 1,
+      shadows: "near" as const
+    }
+  };
+}
+
+function getInstancedMeshes(group: Group): Object3D[] {
+  const meshes: Object3D[] = [];
+
+  group.traverse((object) => {
+    const maybeInstancedMesh = object as Object3D & {
+      isInstancedMesh?: boolean;
+    };
+
+    if (maybeInstancedMesh.isInstancedMesh === true) {
+      meshes.push(object);
+    }
+  });
+
+  return meshes;
+}
+
+function getVisibleBatchKeys(group: Group): string[] {
+  const keys: string[] = [];
+
+  group.traverse((object) => {
+    if (object.type !== "Group" || object.visible !== true) {
+      return;
+    }
+
+    const batchKey = object.userData.foliageBatchKey;
+
+    if (typeof batchKey === "string") {
+      keys.push(batchKey);
+    }
+  });
+
+  return keys.sort();
+}
+
+describe("FoliageInstancedRenderer", () => {
+  beforeEach(() => {
+    loaderState.loadCalls.length = 0;
+  });
+
+  it("updates camera-dependent foliage LOD by visibility without rebuilding resources", async () => {
+    let rebuildCount = 0;
+    const rebuildWaiters: Array<() => void> = [];
+    const renderer = new FoliageInstancedRenderer({
+      onRebuilt: () => {
+        rebuildCount += 1;
+        rebuildWaiters.shift()?.();
+      }
+    });
+    const waitForRebuild = () =>
+      new Promise<void>((resolve) => {
+        rebuildWaiters.push(resolve);
+      });
+
+    const initialRebuild = waitForRebuild();
+    renderer.sync(createRendererInput());
+    renderer.updateView(createCamera({ x: 8, y: 8, z: 8 }));
+    await initialRebuild;
+
+    const activeBatchRoot = renderer.group.children[0];
+    const instancedMeshes = getInstancedMeshes(renderer.group);
+    const initialVisibleBatchKeys = getVisibleBatchKeys(renderer.group);
+    const initialLoadCallCount = loaderState.loadCalls.length;
+    const initialRebuildCount = rebuildCount;
+
+    expect(activeBatchRoot).toBeDefined();
+    expect(instancedMeshes.length).toBeGreaterThan(0);
+    expect(initialVisibleBatchKeys.some((key) => key.includes("|0|"))).toBe(
+      true
+    );
+
+    renderer.updateView(createCamera({ x: 68, y: 8, z: 8 }));
+    await Promise.resolve();
+
+    expect(renderer.group.children[0]).toBe(activeBatchRoot);
+    expect(getInstancedMeshes(renderer.group)).toEqual(instancedMeshes);
+    expect(loaderState.loadCalls).toHaveLength(initialLoadCallCount);
+    expect(rebuildCount).toBe(initialRebuildCount);
+    expect(getVisibleBatchKeys(renderer.group)).not.toEqual(
+      initialVisibleBatchKeys
+    );
+  });
+});