# meshToReadable

Promotes a render `Mesh` into a CPU-readable shape by ensuring its vertex buffer has `GPUBufferUsage.COPY_SRC`. Use it before inspection tools (wireframe, byte comparisons) that need to read vertex data.

## Import

```ts
import { meshToReadable } from "@vgpu/render/inspect";
```

## Signature

```ts
export function meshToReadable(mesh: Mesh, device: Device): Promise<Mesh>;
```

## Parameters

| Param | Type | Required | Default | Notes |
|---|---|---|---|---|
| mesh | Mesh | ✔ | — | Source mesh. Must come from `@vgpu/render` helpers or user code with a valid `vertexBuffer`. |
| device | Device | ✔ | — | Device that owns the target vertex buffer and command encoder used for the copy. |

**Returns:** `Promise<Mesh>` — resolves to the original mesh when it already has `copy_src` usage or to a frozen clone that shares all metadata but replaces `vertexBuffer` with a readable copy.

**Throws:** `VGPU-CORE-INVALID-USAGE` when the source vertex buffer exposes an invalid `GPUBuffer.usage` mask (non-finite); fix by creating the geometry through `geometry(gpu, ...)` or adding `copy_src` when constructing buffers manually.

## Examples

```ts
import { createMockAdapter } from "@vgpu/adapter-mock";
import { meshToReadable } from "@vgpu/render/inspect";
import { init, geometry } from "vgpu/mock";
import { box } from "vgpu/scene";

async function main(): Promise<void> {
  const adapter = createMockAdapter();
  const gpu = await init({ adapter });
  const geo = geometry(gpu, box({ size: 1 }));

  const readable = await meshToReadable(geo as never, gpu.device);
  const vertices = await readable.vertexBuffer.read(readable.vertexBuffer.options.size);
  console.log("Readable bytes", new Float32Array(vertices));
}

main().catch((error) => {
  console.error(error);
});
```

## Notes

- When the input already includes `copy_src`, the function returns the exact same object; equality checks remain stable.
- Newly created readable buffers add `copy_src` (and `copy_dst` if it was missing) without removing the original usage flags.
- Index buffers and mesh metadata (`vertexCount`, `attributes`, etc.) are preserved by reference; only the vertex buffer identity changes.
- Await `queue.onSubmittedWorkDone()` in environments that expose it to guarantee the copy finished before reading.
- **See also:** `meshToWireframe`, `wireframeMaterial`