Enum LightType 

pub enum LightType {
    Directional,
    Point,
    Spot,
}

Describes the kind of light source being represented.

Direction convention

Every direction a Light carries is measured toward the light source, with one deliberate exception:

• LightType::Directional: direction points from the surface toward the light (sourceward), so a surface is lit when dot(normal, direction) > 0.
• LightType::Point: the direction is derived from position - surface_point at shading time and is also sourceward; the light stores no direction of its own.
• LightType::Spot: direction points outward along the cone axis, away from the lamp, i.e. the way the light travels. The surface→light vector used for shading is its negation. This is the opposite sense from the other two kinds, so a spot light’s cone axis and a spot light’s shading direction are not the same vector.

Variants

Directional

An infinitely distant directional light (e.g. sunlight).

The direction field carries the unit vector pointing from the shaded surface toward the light source, matching the convention of LightType::Point.

Point

A positional point light with inverse-square falloff.

The light radiates in every direction; the surface→light vector is computed from position at shading time.

Spot

A positional spotlight with a cone defined by a unit direction and a half-angle whose cosine is stored in the light’s spot_cos field.

The direction field is the cone axis pointing outward from the lamp, in the direction the beam travels — the opposite sense to the shading direction derived from position.

Trait Implementations

impl Clone for LightType

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for LightType

impl Debug for LightType

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for LightType

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for LightType

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for LightType