public static void GetSunlight(
	float altitude,
	float turbidity,
	Vector3D sunDirection,
	out Vector3F directSunlight,
	out Vector3F scatteredSunlight
)

Public Shared Sub GetSunlight ( 
	altitude As Single,
	turbidity As Single,
	sunDirection As Vector3D,
	<OutAttribute> ByRef directSunlight As Vector3F,
	<OutAttribute> ByRef scatteredSunlight As Vector3F
)

public:
static void GetSunlight(
	float altitude, 
	float turbidity, 
	Vector3D sunDirection, 
	[OutAttribute] Vector3F% directSunlight, 
	[OutAttribute] Vector3F% scatteredSunlight
)

static member GetSunlight : 
        altitude : float32 * 
        turbidity : float32 * 
        sunDirection : Vector3D * 
        directSunlight : Vector3F byref * 
        scatteredSunlight : Vector3F byref -> unit 

Parameters

altitude

Type: SystemSingle
The altitude (elevation) of the observer's position in meters above the mean sea level.

turbidity

Type: SystemSingle
The turbidity, which measures how polluted the air is. The values should be in the range [1.8, 20]. A turbidity of 2 describes a clear day whereas a turbidity of 20 represents thick haze. A commonly used value is 2.2.

sunDirection

Type: DigitalRune.Mathematics.AlgebraVector3D
The direction from the observer's position to the sun.

directSunlight

Type: DigitalRune.Mathematics.AlgebraVector3F
The direct sunlight illuminance in [lux].

scatteredSunlight

Type: DigitalRune.Mathematics.AlgebraVector3F
The scattered sunlight illuminance (= ambient light, indirect light or "skylight" contribution of the sun) in [lux].

The light values are computed for the earth using NASA data, experimental data and a physically-based model of the atmosphere.

All light values are computed for a cloudless sky. When the sky is cloudy, reduce the direct light and increase the scattered/ambient light. Additionally you will want to increase the ambient light at night to model light pollution.

Thread-Safety: This method is not thread-safe, i.e. it must not be called simultaneously from multiple threads.

Reference