SphericalHarmonics.EvaluateDirectionalLight Method

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Evaluates a directional light and returns spectral spherical harmonic (SH) data.

Overload List

public static void EvaluateDirectionalLight(int, Vector3, float, float, float, GraphicsStream, GraphicsStream, GraphicsStream);
public static void EvaluateDirectionalLight(int, Vector3, float, float, float, float[], float[], float[]);

Remarks

Evaluates a directional light and returns spectral SH data. The output vector is computed so that if the intensity ratio R/G/B is equal to 1, the resulting exit radiance of a point directly under the light on a diffuse object with an albedo of 1 would be 1.0. This will compute three spectral samples; redOutput will be returned, while greenOutput and blueOutput may be returned.

On the sphere with unit radius as shown, direction can be specified simply with theta, the angle about the z-axis in the right-handed direction, and phi, the angle from z.

Spherical coordinates

The following equations show the relationship between Cartesian (x, y, z) and spherical (theta, phi) coordinates on the unit sphere. The angle theta varies over the range of 0 to 2 pi, while phi varies from 0 to pi.

Spherical coordinates equations

Exceptions
InvalidCallException The method call is invalid. For example, a method's parameter might contain an invalid value.

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