fix(core): preserve instance buffer during resource gc

packages/core/src/RenderPipeline/InstanceBuffer.ts

@@ -39,6 +39,7 @@ export class InstanceBuffer {
       this._intView = new Int32Array(this._data);
       this.buffer?.destroy();
       this.buffer = new Buffer(this._engine, BufferBindFlag.ConstantBuffer, totalBytes, BufferUsage.Dynamic);
+      this.buffer.isGCIgnored = true;
     }
   }
 

tests/src/core/RenderPipeline/InstanceBuffer.test.ts

@@ -0,0 +1,25 @@
+import { WebGLEngine } from "@galacean/engine";
+import { afterEach, describe, expect, it } from "vitest";
+
+describe("InstanceBuffer", () => {
+  let engine: WebGLEngine | undefined;
+
+  afterEach(() => {
+    engine?.destroy();
+    engine = undefined;
+  });
+
+  it("keeps its engine-owned buffer alive across resource-manager garbage collection", async () => {
+    engine = await WebGLEngine.create({ canvas: document.createElement("canvas") });
+    const instanceBuffer = engine._batcherManager.instanceBuffer;
+    instanceBuffer.setLayout({ instanceFields: [], instanceMaxCount: 1, structSize: 16 });
+    const buffer = instanceBuffer.buffer;
+
+    engine.resourceManager.gc();
+
+    expect(buffer.destroyed).toBe(false);
+
+    engine._batcherManager.destroy();
+    expect(buffer.destroyed).toBe(true);
+  });
+});