Broken default light for multi-window setup

[PowerOfNames]

Hey.

So I got the following issue: In my application, it must be possible to independently create and add windows to the VSG. Then, durign runtime, it must also be possible to add/remove models from the per-window scene.

Separately, these features already work for me. But:
When I open window 1 (which is created together with a camera, a Group(node) as root, and a directional light as child to the root) and then window 2, models added afterwards during runtime are all placed in an unlit state.

Whereas, when I first open window 1, then add geometry, lighting works as expected. I then add another window and geometry to that, which also works.

Question: Do I need to take extra care of states when multiple windows are active, or have I found a bug?

[robertosfield]

The light(s) need to be each vsg::View, if each vsg::View shares the same subgraph that contains the light(s) then both View's should be lit.

Extra windows shouldn't in principle change things, but if the window is on a different graphics device then you may need multiple Vulkan logical vkDevices.

There are multiple examples that illustrate multiple views, windows, creating views and windows dynamically:

vsgwindows.cpp
vsgoverlay.cpp
vsgmultiviews.cpp
vsgcameras.cpp
vsgstateswitch.cpp
vsganaglyphicstereo.cpp

If you can't spot the error yourself then you might be best to just modify one of these examples to illustrate the problem you are seeing and then share those modifications. I suggest this as trying to debug program and data that only user has in front of them is very hard, often impossible as there are simple way too many unknowns.

[PowerOfNames]

Thanks!. I've been using the vsgdynamicwindowsexample as reference.

I have not implemented one vsg::View at all, so I will investigate there. Most of the examples seem to create just a window and then have one view, containing a headlight and a root (most of the time Group, sometimes StateGroup). I added all my own nodes to the root.

I create the first window like so:

`WINDOW_HANDLE CreateFirstWindow(double x, double y, double width, double height, const char* windowTitle)
{
auto window = CreateNewWindow(x, y, width, height, windowTitle);

//static cast only works when platform is windows
HWND hwndPtr = (HWND) * static_cast<vsgWin32::Win32_Window*>(window.get());
if (!hwndPtr)
	std::cout << "Failed to get native window handle!" << std::endl;


auto& root = vsg::Group::create();
auto directionalLight = vsg::DirectionalLight::create();
directionalLight->name = "directional";
directionalLight->color.set(1.0f, 1.0f, 1.0f);
directionalLight->intensity = 0.15f;
directionalLight->direction.set(0.0f, -1.0f, -1.0f);
root->addChild(directionalLight);
auto& windowData = WindowsData[hwndPtr] = EvaVSG::WindowHandle::create(root);

auto bounds = vsg::visit<vsg::ComputeBounds>(root).bounds;
vsg::dvec3 center = (bounds.min + bounds.max) * 0.5;
double radius = length(bounds.max - center);
auto lookAt = vsg::LookAt::create(
	vsg::dvec3(0.0, -5.0, 0.0),
	vsg::dvec3(0.0, 0.0, 0.0),
	vsg::dvec3(0.0, 0.0, 1.0)
);
auto perspective = vsg::Perspective::create(45.0, static_cast<double>(window->extent2D().width) / static_cast<double>(window->extent2D().height), 0.01, 1000.0);
auto camera = vsg::Camera::create(perspective, lookAt, vsg::ViewportState::create(window->extent2D()));

auto trackBall = vsg::Trackball::create(camera);

trackBall->addWindow(window);
Viewer->addEventHandler(trackBall);
Viewer->addEventHandler(vsg::CloseHandler::create(Viewer));

auto view = vsg::View::create(camera);
view->addChild(vsg::createHeadlight());
view->addChild(root);

auto renderGraph = vsg::RenderGraph::create(window, view);
renderGraph->clearValues[0].color = vsg::sRGB_to_linear(0.2f, 0.2f, 0.2f, 1.0f);

auto commandGraph = vsg::CommandGraph::create(window);
commandGraph->addChild(renderGraph);

Viewer->assignRecordAndSubmitTaskAndPresentation({ commandGraph });
Viewer->compile();

return hwndPtr;

}`

and every additional window using the code from the mentioned example (I start the render loop in another thread as soon as the first window was created and compiled)
The directional light added for testing is also completely ignored, but I might have a misconception about its usage.