Class DistantLight

Namespace

Egami.Operations

Assembly

Egami.dll

A light infinitely far away, shining from one direction on every pixel, as SVG's feDistantLight. The direction toward the light is (cos Azimuth · cos Elevation, sin Azimuth · cos Elevation, sin Elevation) in the raster's coordinates (y down), which is the vector Skia's DistantLit factories take.

public sealed record DistantLight : Light, IEquatable<Light>, IEquatable<DistantLight>

Inheritance

object

Light

DistantLight

Implements

IEquatable<Light>

IEquatable<DistantLight>

Inherited Members

Light.Color

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Examples

// Three light sources, as SVG and Skia have them. Positions are pixels: x right, y down, z up out of the image.
Light sun = new DistantLight(azimuth: 225, elevation: 40);              // from the top left, 40° up
Light bulb = new PointLight(new Vector3(60, 20, 80)) { Color = new Rgba8(255, 240, 210, 255) };
Light spot = new SpotLight(new Vector3(0, 0, 150), target: new Vector3(120, 60, 0), exponent: 4, coneAngle: 30);

// Two ways a surface reflects: matte (N·L) or shiny (a highlight, (N·H)^shininess).
LightingModel matte = LightingModel.Diffuse(kd: 1.2f);
LightingModel shiny = LightingModel.Specular(ks: 1, shininess: 20);

using Raster<Rgba8> map = logo.Derive(ops => ops.Lighting(sun, matte), Ct);   // the light map, opaque
using Raster<Rgba8> glints = logo.Derive(ops => ops.Lighting(bulb, shiny), Ct); // alpha = brightest channel
using Raster<Rgba8> pool = logo.Derive(ops => ops.Lighting(spot, matte), Ct);

Constructors

DistantLight(float, float)

Initializes a new instance of the DistantLight class.

public DistantLight(float azimuth, float elevation)

Parameters

azimuth float

The direction of the light in the image plane, in degrees clockwise from the x axis (y points down), as SVG's azimuth.

elevation float

The angle of the light above the image plane, in degrees, from −90 to 90; 90 shines straight down.

Exceptions

ArgumentOutOfRangeException

azimuth is not finite, or elevation is not from −90 to 90.

Properties

Azimuth

Gets the direction of the light in the image plane, in degrees clockwise from the x axis (y points down).

public float Azimuth { get; init; }

Property Value

float

Exceptions

ArgumentOutOfRangeException

The value is not finite.

Elevation

Gets the angle of the light above the image plane, in degrees.

public float Elevation { get; init; }

Property Value

float

Exceptions

ArgumentOutOfRangeException

The value is not from −90 to 90.