The Scene Window¶

To make it easier to create 3D applications ivf2 provides a specialised version of the GLFWWindow class called GLFWSceneWindow. This class manages the scene graph and provides a number of convenience functions for rendering and updating the scene. The GLFWSceneWindow class is a subclass of GLFWWindow and inherits all of its functionality.

Instead of maintaining your own scene instance nodes can be added in the onSetup() method using the add(...) method. There is also no need to implement the onRender() method as this is handled by the GLFWSceneWindow class. The onUpdate() method is still available for you to implement your own logic.

The class also supports rendering to a texture. This is useful for creating effects such as shadow mapping or post-processing, which is also supported by the class.

The class also automates the creation of UiWindow derived ImGui windows.

Creating a Scene Window¶

To create a scene window you need to create a subclass of GLFWSceneWindow and implement the onSetup() and onUpdate() methods. The onSetup() method is called once when the window is created and is used to set up the scene. The onUpdate() method is called every frame and is used to update the scene.

The example below shows how to create a simple scene window with a few shapes and a light source.

#include <iostream>
#include <memory>
#include <string>
#include <vector>

#include <ivf/gl.h>
#include <ivf/nodes.h>
#include <ivfui/ui.h>

using namespace ivf;
using namespace std;

class ExampleWindow : public GLFWSceneWindow {
private:

public:
    ExampleWindow(int width, int height, std::string title) : GLFWSceneWindow(width, height, title)
    {}

    static std::shared_ptr<ExampleWindow> create(int width, int height, std::string title)
    {
        return std::make_shared<ExampleWindow>(width, height, title);
    }

    int onSetup()
    {
        auto lightMgr = LightManager::create();

        auto pointLight1 = lightMgr->addPointLight();
        pointLight1->setEnabled(true);
        pointLight1->setDiffuseColor(glm::vec3(1.0, 1.0, 1.0));
        pointLight1->setSpecularColor(glm::vec3(1.0, 1.0, 1.0));
        pointLight1->setAttenuation(1.0, 0.0, 0.0);
        pointLight1->setPosition(glm::vec3(5.0, 5.0, 5.0));
        lightMgr->apply();

        auto axis = Axis::create();

        this->add(axis);

        for (auto i = 0; i < 500; i++)
        {
            double r = random(0.0, 9.0);

            TransformNodePtr node;

            if (r < 1.0)
                node = Cube::create();
            else if ((r >= 1) && (r < 2.0))
                node = Sphere::create(random(0.2, 1.0));
            else if ((r >= 2.0) && (r < 3.0))
                node = Box::create(glm::vec3(random(0.2, 2.0), random(0.2, 2.0), random(0.2, 2.0)));
            else if ((r >= 3.0) && (r < 4.0))
                node = RoundedBox::create(glm::vec3(random(0.2, 2.0), random(0.2, 2.0), random(0.2, 2.0)));
            else if ((r >= 4.0) && (r < 5.0))
                node = CappedCylinder::create(random(0.2, 1.0), random(0.2, 1.0));
            else if ((r >= 5.0) && (r < 6.0))
                node = Cylinder::create(random(0.2, 1.0), random(0.2, 1.0));
            else if ((r >= 6.0) && (r < 7.0))
                node = CappedCone::create(random(0.2, 1.0), random(0.2, 1.0));
            else if ((r >= 7.0) && (r < 8.0))
                node = Cone::create(random(0.2, 1.0), random(0.2, 1.0));
            else
                node = Dodecahedron::create(random(0.2, 1.0));

            auto material = Material::create();
            material->setDiffuseColor(glm::vec4(random(0.0, 1.0), random(0.0, 1.0), random(0.0, 1.0), 1.0));
            material->setAmbientColor(glm::vec4(0.1, 0.1, 0.1, 1.0));

            node->setPos(glm::vec3(random(-20.0, 20.0), random(-20.0, 20.0), random(-20.0, 20.0)));
            node->setMaterial(material);

            this->add(node);
        }

        return 0;
    }
};

typedef std::shared_ptr<ExampleWindow> ExampleWindowPtr;

int main()
{
    auto app = GLFWApplication::create();

    app->hint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    app->hint(GLFW_CONTEXT_VERSION_MINOR, 3);
    app->hint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    app->hint(GLFW_SAMPLES, 4);

    auto window = ExampleWindow::create(800, 800, "Example 2");
    window->maximize();

    app->addWindow(window);
    return app->loop();
}