Sky Atmosphere

This is the default way to create environment lighting in Evergine. When you create a new Scene in Evergine Studio, it will use this method to provide the environmental lighting.

They create a HDR sky texture that simulates physically the atmosphere properties. Additionally it will use a Directional Light to control the atmosphere light dispersion and light intensity and color.

SunComponent

This component is used to mark a DirectionalLight as the light source that will use the atmosphere controller. When you create a Evergine Scene, it will create a DirectionalLight with a SunComponent.

Changing the DirectionalLight rotation allows you to change the visual atmospheric, simulating effects like sunset, sunrise or daylight:

This component has no properties, and the only purpose is to mark a DirectionalLight as the Sun source.

Note

Only the first light with SunComponent will be used.

AtmosphereController component

This component is responsible to control the set the physical properties of the atmosphere and render the sky dome texture.

Property	Default	Description
RayleighScattering	5.5, 13, 22.4	Rayleigh scattering coefficient per each color channel wavelength (Red, Green and Blue).
RayleighScaleHeight	8000	Scale height for Rayleigh scattering measured in meters.
PlanetRadiusInKm	6371	Radius of the planet in Kilometers
AtmosphereRadiusInKm	6471	Radius of the atmosphere in Kilometers
MieScatteringCoefficient	21	Mie scattering coefficient.
MieScaleHeight	12000	Mie scattering scale height in meters
MiePreferredScattering	0.758	Mie preferred scattering direction.
ModifySunColor	true	This will force to
SunIntensity	22.0	The Sun intensity.
SunDiskEnabled	true	Indicates if the environment will create a sun disk.
SunDiskSize	0.02	The size of the sun disk in degrees

These properties allows you to simulate another atmospheres of other worlds, like Mars (atmosphere obtained from here):

Or you can simulate any exotic atmosphere:

Using Sky Atmosphere

In Evergine Studio

You can add two entities from Evergine Studio under Environment menu entry:

• Sun Light: This will create a Photometric Directional Light marked as a Sun light with the SunComponent
• Sky Atmospheric dome: Will create a Sphere mesh with the AtmosphereController component to create the atmosphere. This entity also has the "Skybox" tag.

From code

This is a small code snippet to create both entities needed to create a sky atmosphere:

protected override void CreateScene()
{
    // Create the sun light
    var sun = new Entity()
        .AddComponent(new Transform3D() { LocalRotation = new Vector3(-2, 0, 0) }) // Add some rotation to the light...
        .AddComponent(new PhotometricDirectionalLight())
        .AddComponent(new SunComponent());

    this.Managers.EntityManager.Add(sun);

    // Create the sphere sky dome
    var skyDome = new Entity()
        .AddComponent(new Transform3D())
        .AddComponent(new MaterialComponent())
        .AddComponent(new SphereMesh())
        .AddComponent(new MeshRenderer())
        .AddComponent(new AtmosphereController());

    this.Managers.EntityManager.Add(skyDome);
}