Struct LightRig 

pub struct LightRig {
    pub lights: [Light; 3],
    pub ambient: (i32, i32, i32),
}

A rig of up to 3 directional lights – the maximum the PSX GTE supports natively.

Fields

lights: [Light; 3]

Three light slots; unused slots should be Light::OFF.

ambient: (i32, i32, i32)

Ambient term added before material multiply. Q3.12 per channel in an i32 (GTE’s BK register is 20-bit signed).

Implementations

impl LightRig

pub const OFF: Self

Empty rig: no lights, black ambient.

pub const fn new(lights: [Light; 3], ambient: (i32, i32, i32)) -> Self

Build a rig from 3 lights + an ambient term.

pub fn load(&self)

Pack this rig into the GTE’s control registers:

• LLM ← rows are light directions
• LCM ← columns are light RGB contributions
• BK ← ambient

Call once per object (or once per frame if lights are in a universal frame). Any subsequent NCCS / NCS / NCDS reads these.

pub fn for_object(&self, rotation: &Mat3I16) -> LightRig

Return a new rig with every light’s direction rotated into the frame in which rotation is the object’s local → world transform. I.e., if you pass the same Mat3I16 you pass to scene::load_rotation for RTPS, the returned rig is in object-local space – correct for feeding LLM when lighting mesh vertices that are themselves in local space.

Math: world_vert = R × local_vert, so local = R⁻¹ × world, and since R is a rotation, R⁻¹ = Rᵀ. We compute local_dir = Rᵀ × world_dir component-wise.

pub fn rotated(&self, rotation: &Mat3I16) -> LightRig

Return a new rig with every light’s direction rotated by rotation (direct R × dir, not the transpose).

Used to animate world-space lights over time – e.g. an orbiting key light. Compose this BEFORE [for_object] so the per-object transpose applies on top of the animation.

Trait Implementations

impl Clone for LightRig

fn clone(&self) -> LightRig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LightRig

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

Formats the value using the given formatter.

impl Copy for LightRig