Sky Atmosphere

This is the default method 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.

It creates an HDR sky texture that physically simulates the properties of the atmosphere. Additionally, it uses a Directional Light to control the atmosphere light dispersion, as well as the light intensity and color.

SunComponent

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

Changing the Directional Light's rotation allows you to change the visual atmosphere, simulating effects like sunset, sunrise, or daylight:

This component has no properties; its only purpose is to mark a Directional Light as the Sun source.

Note

Only the first light with a SunComponent will be used.

AtmosphereController component

This component is responsible for controlling the physical properties of the atmosphere and rendering the sky dome texture.

Property	Default	Description
RayleighScattering	5.5, 13, 22.4	Rayleigh scattering coefficient for 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 the adjustment of the Sun color.
SunIntensity	22.0	The Sun's 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 allow you to simulate the 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 the Environment menu entry:

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

From Code

Here is a small code snippet to create the two 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);
}