A problem with vsgcameras example

[varolomer]

Hello to the VSG Community,

I am a complete beginner in VSG and having a problem with the vsgExamples->examples->app->vsgcameras.

When I directly use the code provided in the example and run it, I always get the following result where the main view is always black and only one camera (despite we have 4 cameras in the loop) on the right bottom side is shown, of which the projection matrix is always wrong:

---

When I comment out the following loop where we add the render passes for our secondary cameras I can see our main view properly with the correct projection matrix:

    for (auto& [nodePath, camera] : scene_cameras)
    {
        // create a RenderGraph to add a secondary vsg::View on the top right part of the window.
        auto projectionMatrix = camera->projectionMatrix;
        auto viewMatrix = vsg::TrackingViewMatrix::create(nodePath);
        auto viewportState = vsg::ViewportState::create(x, y, secondary_width, secondary_height);

        auto secondary_camera = vsg::Camera::create(projectionMatrix, viewMatrix, viewportState);

        auto secondary_view = vsg::View::create(secondary_camera, scenegraph);
        auto secondary_RenderGraph = vsg::RenderGraph::create(window, secondary_view);
        secondary_RenderGraph->clearValues[0].color = { {1.0f, 1.0f, 1.0f, 1.0f} };

        commandGraph->addChild(secondary_RenderGraph);

        y += secondary_height + margin;
    }

---

I also removed the other three cameras in the example to see if it works with only one secondary camera but it did not work and I got the same result. Other than that I also tried to clear the depth buffer in the loop as shown in the multiviews example but it also did not work.

Any idea what I miss here? I would be very happy if you could point out to me a way to resolve the issue because later on I want to create an app where I will need to properly deal with many viewports with different manipulators, shared manipulators etc. (As I mentioned, I directly run the code from the official example with no edit.)

Many thanks to all VSG contributors and authors and also many thanks in advance for your help!

[robertosfield]

I have just tried vsgcameras on Linux (Kununtu 22.04 + Geforece 2060) and got the following correct result:

While on my new Windows machine with Intel iCore7, using it's integrated GPU:

While this isn't exactly the same error is seems to have similarities with the background not being cleared correctly.

I have run vsgcameras with -d to enable the Vulkan debug/validation layer but don't see any errors.

This could be a driver bug. What hardware and drivers are you using?

[varolomer]

Hello Robert, thank you for the quick reply.

I also turned on the validation layer but I also could not see any errors. Now, I tried it in my laptop and I got the result but with some artifacts around the teapot:

Laptop configuration:

• Windows11 Home
• 12th Gen Intel Core i7-12700H, 2.3GHZ
• Intel Iris XE Graphics

---

The situation in my PC is unfortunately still going on. The configuration:

• Windows10 Enterprise
• AMD Ryzen 7 2700X 8 Core
• NVIDIA GeForce GTX 1050Ti

I will update the drivers again and try to re-run the example.

[varolomer]

Unfortunately, the issue persists the same way after the graphics driver update. Thinking that having multiple monitors on my PC could cause the problem I tested it with one monitor as well but it also did not work.

[robertosfield]

It might be worth trying RenderDoc to see what might be happening.

I recall other users hitting upon hardware/driver combinations that have issues with situations like this, I don't recall the specifics though. I think there might be oddities in how some driver/hardware combinations handle frame buffers. I can't really help further at this point in time as I have other work to complete. Perhaps others can provide insights.

[AnyOldName3]

Just to add another datapoint, I get the correct output with a Radeon 7800 XT on Windows with AMD's proprietary driver, also with no validation errors.

[AnyOldName3]

Renderdoc is unhappy, though:

[AnyOldName3]

Hopefully this points someone in the right direction:

[timoore]

I'm sure this is the same problem as #898 . That issue was closed after the user updated their drivers and the problem went away.

At the time I speculated that it wasn't appropriate to have an attachment final layout of VK_IMAGE_LAYOUT_PRESENT_SRC_KHR if further rendering was going to be done in the attachment.

[varolomer]

Thank you, @robertosfield. I understand, and I wish you the best of luck with all!

@timoore @AnyOldName3 Thank you so much for the contribution, I will try to dive into the issue more and resolve it. If I can solve it out or find something useful I will share it here.