Colored box

[ztef]

I draw a BOX using Builder, it works. How to draw a solid red one ?

I am trying to use GeomInfo with color, and colors attributes without success. Any Idea ?

[robertosfield]

The vsgbuilder example has code paths that set up colours:

https://github.com/vsg-dev/vsgExamples/blob/master/examples/utils/vsgbuilder/vsgbuilder.cpp

If you can't spot the problem in your own code please post it so we can review it and see if we can spot the problem.

[ztef]

First, Thank you for your support, Following is the issue :

Here is a minimal code for drawing a red Cube :

#include <vsg/all.h>
#include

/*

VulkanSceneGraph Minimal Example : Draw a RED Cube.

*/

int main(int argc, char** argv)
{

auto windowTraits = vsg::WindowTraits::create();
windowTraits->windowTitle = "RED CUBE";


// Use a Builder
auto builder = vsg::Builder::create();



// Geometry and State variables 
vsg::GeometryInfo geomInfo;

    geomInfo.dx.set(1.0f, 0.0f, 0.0f);
    geomInfo.dy.set(0.0f, 1.0f, 0.0f);
    geomInfo.dz.set(0.0f, 0.0f, 1.0f);

vsg::StateInfo stateInfo;

    bool floatColors = true;
    stateInfo.wireframe = false;
    stateInfo.lighting = true;
    stateInfo.two_sided = false;


// Create the scene
auto scene = vsg::Switch::create();

        vsg::dvec3 centre = {0.0, 0.0, 0.0};
        double radius = 1.0;

        radius = vsg::length(geomInfo.dx + geomInfo.dy + geomInfo.dz);

        stateInfo.instance_positions_vec3 = true;

        auto positions = vsg::vec3Array::create(1);
        geomInfo.positions = positions;
    
        auto colors = vsg::vec4Array::create(1);
  
        for (auto& c : *(colors))
        {          
            c.set(1.0f,0.0f,0.0f,1.0f);
        }

        geomInfo.colors = colors;
    
        scene->addChild(true, builder->createBox(geomInfo, stateInfo));
       
        



// create the viewer and assign window(s) to it
auto viewer = vsg::Viewer::create();

auto window = vsg::Window::create(windowTraits);
if (!window)
{
    std::cout << "Could not create windows." << std::endl;
    return 1;
}

viewer->addWindow(window);

vsg::ref_ptr<vsg::LookAt> lookAt;


// set up the camera
lookAt = vsg::LookAt::create(centre + vsg::dvec3(0.0, -radius * 3.5, 0.0), centre, vsg::dvec3(0.0, 0.0, 1.0));

double nearFarRatio = 0.001;
auto perspective = vsg::Perspective::create(30.0, static_cast<double>(window->extent2D().width) / static_cast<double>(window->extent2D().height), nearFarRatio * radius, radius * 10.0);

auto camera = vsg::Camera::create(perspective, lookAt, vsg::ViewportState::create(window->extent2D()));


// add close handler to respond the close window button and pressing escape
viewer->addEventHandler(vsg::CloseHandler::create(viewer));

viewer->addEventHandler(vsg::Trackball::create(camera));



// OPTION 1 :    Creating a commandGraph directly...it WORKS (Draws a red Cube)

    //auto commandGraph = vsg::createCommandGraphForView(window, camera, scene);
    //viewer->assignRecordAndSubmitTaskAndPresentation({commandGraph});


// OPTION 2 :     Creating a view, then a renderGRaph   (Doesnt Work :      Draws a BLACK CUBE)

     auto view = vsg::View::create(camera, scene);

     auto renderGraph = vsg::RenderGraph::create(window);
    renderGraph->addChild(view);

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

    viewer->assignRecordAndSubmitTaskAndPresentation({commandGraph});






viewer->compile();



// rendering main loop
while (viewer->advanceToNextFrame() )
{
    // pass any events into EventHandlers assigned to the Viewer
    viewer->handleEvents();

    viewer->update();

    viewer->recordAndSubmit();

    viewer->present();      
}

return 0;

}

[ztef]

As you can see : (if uncomment the OPTION 1) :

auto commandGraph = vsg::createCommandGraphForView(window, camera, scene);
viewer->assignRecordAndSubmitTaskAndPresentation({commandGraph});

using the scene amd the camera to create a commandGRaph, it works fine and draw a red Box perfectly.

But the following (creating a view and a rendergraph first, the scene appears to loose any color related parameters and only draw a BLACK Cube :

auto view = vsg::View::create(camera, scene);

 auto renderGraph = vsg::RenderGraph::create(window);
renderGraph->addChild(view);

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

viewer->assignRecordAndSubmitTaskAndPresentation({commandGraph});

[ztef]

[ztef]

it is a bug ? or I am missing something ?

[ztef]

The reason I need the scene, is because the application i am trying to code is a scene selector, where each scene can handle their own world(camera, perspective etc...)

[robertosfield]

Hi Esteban,

I think the most likely reason for the black cube is that has been created with lighting on so needs a light source to illuminate it, and the vsg::createCommandGraphForView(window, camera, scene) convenience function assigns this to the vsg::View for you, but when you create the vsg::View by yourself it's in it's default state without any cameras assigned.

The vsg::createCommandGraphForView() calls vsg::createRenderGraphForView() function which has the assignment of the Light:

https://github.com/vsg-dev/VulkanSceneGraph/blob/master/src/vsg/app/RenderGraph.cpp#L187

Assigning one or more vsg::Light to View or elsewhere in your scene graph will illuminate the scene.

Robert.

[ztef]

Hi Robert,

You are a genius !! it works !! Thank you very much !!

By the way, what a wonderful project, congratulations.