tiramisu/light

Types

Light

opaque </>

Light types for illuminating the scene.

Different lights have different performance impacts and visual characteristics. Most games use a combination of ambient + directional for outdoor scenes, or ambient + point/spot for indoor scenes.

pub opaque type Light

LightError

</>

pub type LightError {
  NegativeIntensity(Float)
  OutOfBoundsColor(Int)
  NegativeDistance(Float)
  InvalidShadowResolution(Int)
  InvalidShadowBias(Float)
}

Constructors

```
NegativeIntensity(Float)
```
```
OutOfBoundsColor(Int)
```
```
NegativeDistance(Float)
```
```
InvalidShadowResolution(Int)
```
```
InvalidShadowBias(Float)
```

Values

ambient

</>

pub fn ambient(
  intensity intensity: Float,
  color color: Int,
) -> Result(Light, LightError)

directional

</>

pub fn directional(
  intensity intensity: Float,
  color color: Int,
) -> Result(Light, LightError)

hemisphere

</>

pub fn hemisphere(
  intensity intensity: Float,
  sky_color sky_color: Int,
  ground_color ground_color: Int,
) -> Result(Light, LightError)

point

</>

pub fn point(
  intensity intensity: Float,
  color color: Int,
  distance distance: Float,
) -> Result(Light, LightError)

spot

</>

pub fn spot(
  intensity intensity: Float,
  color color: Int,
  distance distance: Float,
  angle angle: Float,
  penumbra penumbra: Float,
) -> Result(Light, LightError)

with_shadow_bias

</>

pub fn with_shadow_bias(
  light: Light,
  bias: Float,
) -> Result(Light, LightError)

Set shadow bias to reduce shadow acne artifacts.

Typical values: 0.00001 to 0.001 (default: 0.0001). Increase if you see shadow artifacts (shadow acne). Decrease if shadows appear detached from objects.

Example

let assert Ok(sun) = light.directional(intensity: 1.0, color: 0xffffff)
  |> light.with_shadows(True)
  |> light.with_shadow_bias(0.0005)

with_shadow_resolution

</>

pub fn with_shadow_resolution(
  light: Light,
  resolution: Int,
) -> Result(Light, LightError)

Set shadow map resolution (in pixels).

Higher values produce sharper shadows but use more memory. Common values: 512, 1024 (default), 2048, 4096. Must be a power of 2.

Example

let assert Ok(sun) = light.directional(intensity: 1.0, color: 0xffffff)
  |> light.with_shadows(True)
  |> light.with_shadow_resolution(2048)

with_shadows

</>

pub fn with_shadows(light: Light, cast_shadow: Bool) -> Light

Enable shadow casting for a light.

Only directional, point, and spot lights can cast shadows. Ambient and hemisphere lights are ignored.

Example

let assert Ok(sun) = light.directional(intensity: 1.0, color: 0xffffff)
  |> light.with_shadows(True)