Minimal app for Windows Phone 8.1 (no XAML) : differences with desktop app

Question

I'm beginning the development of Windows Runtime applications in C++. I'm experienced on Win32/C++ development but this is a new world for me.

The following is a minimal, no-XAML app I've typed, collecting information from various sources (MSDN, DirectXTutorial.com, etc).

My question is: In Windows desktop, works well by displaying a blank window and receiving the PointerPressed Event. But in Windows Phone I only reach the app start logo and nothing happens.

What is the difference between two platforms for this minimal app? Do I require to create some DirectX or drawing surface in the case of the Windows Phone 8.1 platform?

I'm using WIndows 10 host plus Visual Studio 2015. Thanks.

#include "pch.h"

using namespace Windows::ApplicationModel;
using namespace Windows::ApplicationModel::Core;
using namespace Windows::ApplicationModel::Activation;
using namespace Windows::UI::Core;
using namespace Windows::Foundation;
using namespace Platform;

ref class dxAppView sealed : IFrameworkView
{
    bool _bActive;

public:
    virtual void Initialize(CoreApplicationView ^applicationView)
    {
        applicationView->Activated += ref new TypedEventHandler<CoreApplicationView ^, IActivatedEventArgs ^>(this, &dxAppView::OnActivated);
        CoreApplication::Suspending += ref new EventHandler<SuspendingEventArgs^>(this, &dxAppView::OnSuspending);
        CoreApplication::Resuming += ref new EventHandler<Object ^>(this, &dxAppView::OnResuming);

        _bActive = true;
    }

    virtual void SetWindow(CoreWindow ^window)
    {       
        window->PointerPressed += ref new TypedEventHandler<CoreWindow^, PointerEventArgs^>(this, &dxAppView::OnPointerPressed);
        window->Closed += ref new Windows::Foundation::TypedEventHandler<Windows::UI::Core::CoreWindow ^, Windows::UI::Core::CoreWindowEventArgs ^>(this, &dxAppView::OnClosed);
    }

    virtual void Load(String ^entryPoint) {}
    virtual void Run() 
    {
        CoreWindow^ wnd = CoreWindow::GetForCurrentThread();

        while (_bActive)
        {
            wnd->Dispatcher->ProcessEvents(CoreProcessEventsOption::ProcessAllIfPresent);
        }

    }

    virtual void Uninitialize() {}

    void OnActivated(CoreApplicationView ^sender, IActivatedEventArgs ^args)
    {
        CoreWindow^ wnd = CoreWindow::GetForCurrentThread();
        wnd->Activate();
    }

    void OnPointerPressed(CoreWindow ^sender, PointerEventArgs^  args)
    {
        Windows::UI::Popups::MessageDialog dlg(L"Hi From Windows Runtime app.");
        dlg.ShowAsync();
    }

    void OnSuspending(Platform::Object ^sender, Windows::ApplicationModel::SuspendingEventArgs ^args){}

    void OnResuming(Platform::Object ^sender, Platform::Object ^args){}

    void OnClosed(Windows::UI::Core::CoreWindow ^sender, Windows::UI::Core::CoreWindowEventArgs ^args)
    {
        _bActive = false;
    }
};

ref class dxAppFrameworkViewSource sealed : IFrameworkViewSource
{
public:
    virtual IFrameworkView^ CreateView()
    {
        return ref new dxAppView;
    }
};


[MTAThread]
int main(Array<String^>^ args)
{
    CoreApplication::Run(ref new dxAppFrameworkViewSource());
    return 0;
};

Answer 1

I've found it, seems that you can't do anything in Phone 8.1 without a DX swap chain active. So, the minimal no-XAML application involves the following additional code:

Create a Direct3D Device

(Variables prefixed with underscore are class members)

ComPtr<ID3D11DeviceContext> pDevCtx;
ComPtr<ID3D11Device>        pDev;
ComPtr<IDXGISwapChain>      pSwapChain;

D3D_FEATURE_LEVEL fLevel;

HRESULT hr = D3D11CreateDevice(
        nullptr,
        D3D_DRIVER_TYPE_HARDWARE,
        nullptr,
        0,
        nullptr,
        0,
        D3D11_SDK_VERSION,
        &pDev,
        &fLevel,
        &pDevCtx);

Create a swap chain

pDevCtx.As(&_pDevCtx);
pDev.As(&_pDevice);

ComPtr<IDXGIDevice1> pDXGIDev;
pDev.As(&pDXGIDev);

ComPtr<IDXGIAdapter> pDXGIAdapter;
pDXGIDev->GetAdapter(&pDXGIAdapter);

ComPtr<IDXGIFactory2> pDXGIFactory;
pDXGIAdapter->GetParent(__uuidof(IDXGIFactory2), &pDXGIFactory);

DXGI_SWAP_CHAIN_DESC1 swChDesc = { 0 };
swChDesc.BufferCount = 2;
swChDesc.SampleDesc.Count = 1;
swChDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
swChDesc.SampleDesc.Quality = 0;
swChDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
swChDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;

CoreWindow^ wnd  = CoreWindow::GetForCurrentThread();

pDXGIFactory->CreateSwapChainForCoreWindow(
    _pDevice.Get(),
    (IUnknown*) wnd,
    &swChDesc,
    nullptr,
    _pSwapChain.GetAddressOf());

Present (flip your buffers)

while (_bActive)
{
  wnd->Dispatcher->ProcessEvents(CoreProcessEventsOption::ProcessAllIfPresent);
  Render();
}

where Render() can be something like:

_pSwapChain->Present(1, NULL);