nativeTexture() and rivePresentingTexture() not exported in native/platform/windows/rive_native_windows.cpp

Description

rive_native_windows.cpp does not export a function to retrieve the currently-presenting D3D11 swapchain texture from an opaque WindowsContextPLS* renderer. External consumers that need the rendered frame (e.g., for GPU compositing via DXGI shared handles) cannot access it because WindowsContextPLS is opaque and the swapchain uses 4-texture quad-buffering.

Current Exports (rive_native_windows.cpp)

EXPORT rive::Renderer* makeRenderer(WindowsContextPLS* pls);
EXPORT bool clear(WindowsContextPLS* pls, bool clear, uint32_t color);
EXPORT bool flush(WindowsContextPLS* pls, float devicePixelRatio);
EXPORT void riveFlushGpuCommands() {}    // no-op stub

There is no nativeTexture() equivalent to retrieve the presenting ID3D11Texture2D*.

Changes We Made
Added three exports to rive_native_windows.cpp (after flush() , around line 310):

EXPORT void *nativeTexture(WindowsContextPLS *pls) {
  if (pls == nullptr) {
    return nullptr;
  }
  FlutterWindowsSwapchain::PresentingTextureLock lock(pls->m_swapchain);
  const auto &tex = lock.texture();
  if (!tex || !tex->nativeTexture) {
    return nullptr;
  }
  return tex->nativeTexture.Get();
}

EXPORT void *rivePresentingTexture(void *rendererPtr) {
  return nativeTexture(static_cast<WindowsContextPLS *>(rendererPtr));
}

EXPORT void riveFlushGpuCommands() {}

Note:
nativeTexture accesses pls->m_swapchain, which is currently a private member. This required making m_swapchain accessible (via friend, accessor, or by making nativeTexture a member function).

Impact
Without this, external consumers must re-implement the function in a separate DLL, requiring access to internal types (FlutterWindowsSwapchain, PresentingTextureLock).

Environment

• Package: rive_native 0.1.2
• Platform: Windows (D3D11)
• File: native/platform/windows/rive_native_windows.cpp

Start in native/platform/windows/rive_native_windows.cpp and inspect FlutterWindowsSwapchain and PresentingTextureLock, especially how m_swapchain is accessed. Expose nativeTexture() and rivePresentingTexture() while preserving the null and missing-texture cases described, then build the Windows target and verify external consumers can retrieve the presenting texture.