Scenes

You have a few different options, to generate a new scene programmatically.

The first is to generate a empty Scene like this:

YourApp.h

#include <HighLo.h>

class YourApp : public highlo::HLApplication
{
public:

    YourApp()
        : highlo::HLApplication()
    {
    }

    void OnInitialize() override
    {
        // This creates a new scene which is completely empty 
        m_Scene = Scene::CreateEmpty();
    }

    void OnUpdate(highlo::Timestep timestep) override;
    void OnShutdown() override;
    void OnEvent(highlo::Event &e) override;
    void OnUIRender(highlo::Timestep timestep) override;
    void OnResize(uint32 width, uint32 height) override;

private:

    Ref<Scene> m_Scene = nullptr;
};

The other option is to provide the scene name in the Create function like this:

YourApp.h

#include <HighLo.h>

class YourApp : public highlo::HLApplication
{
public:

    YourApp()
        : highlo::HLApplication()
    {
    }

    void OnInitialize() override
    {
        m_Scene = Scene::Create("Your first scene name");
    }

    void OnUpdate(highlo::Timestep timestep) override;
    void OnShutdown() override;
    void OnEvent(highlo::Event &e) override;
    void OnUIRender(highlo::Timestep timestep) override;
    void OnResize(uint32 width, uint32 height) override;

private:

    Ref<Scene> m_Scene = nullptr;
};

Updating a scene

To update a scene you have to keep track of your current scene state yourself. For that purpose you can create a custom SceneState Enum, that contains your States you wish to have. To be able to render something onto the screen, you have to create an instance of the SceneRenderer as well. The scene takes the renderer and renders its contents into the RenderPasses owned by the SceneRenderer. A complete example is shown below:

YourApp.h

#include <HighLo.h>

enum class SceneState
{
    Play  = 0,
    Pause = 1,
};

class YourApp : public highlo::HLApplication
{
public:

    YourApp()
        : highlo::HLApplication()
    {
    }

    void OnInitialize() override
    {
        m_Scene = Scene::Create("Your first scene name");
        m_ViewportRenderer = Ref<SceneRenderer>::Create(m_Scene);
    }

    void OnUpdate(highlo::Timestep timestep) override
    {
        switch (m_SceneState)
        {
            case SceneState::Play:
            {
                // Update scene entities
                m_Scene->UpdateScene(timestep);

                // Render scene content
                m_Scene->OnUpdateRuntime(m_ViewportRenderer, timestep);
                break;
            }

            case SceneState::Pause:
            {
                // Render last scene content without updating any transforms or attributes
                m_Scene->OnUpdateRuntime(m_ViewportRenderer, timestep);
                break;
            }
        }

        SceneRenderer::WaitForThreads();
    }

    void OnShutdown() override;
    void OnEvent(highlo::Event &e) override;
    void OnUIRender(highlo::Timestep timestep) override;

    void OnResize(uint32 width, uint32 height) override
    {
        m_ViewportRenderer->SetViewportSize(width, height);
    }

private:

    Ref<Scene> m_Scene = nullptr;
    Ref<SceneRenderer> m_ViewportRenderer = nullptr;
    SceneState m_SceneState = SceneState::Play;
};

Receiving events on a scene

To receive events on your scene you just have to forward the event object into your scene instance.

YourApp.h

#include <HighLo.h>

class YourApp : public highlo::HLApplication
{
public:

    YourApp()
        : highlo::HLApplication()
    {
    }

    void OnInitialize() override
    {
        m_Scene = Scene::Create("Your first scene name");
    }

    void OnUpdate(highlo::Timestep timestep) override;
    void OnShutdown() override;
    
    void OnEvent(highlo::Event &e) override
    {
        m_Scene->OnEvent(e);
    }

    void OnUIRender(highlo::Timestep timestep) override;
    void OnResize(uint32 width, uint32 height) override;

private:

    Ref<Scene> m_Scene = nullptr;
};