The library¶

lusine's library is a set of kernels: small laws written once in Trait, which a game calls by name, such as lusine.laws.drag. They are grouped into layers by what they are about. Each kernel's page shows its Trait source first, then checks what it computes.

Camera¶

Moving a game's camera: following a target, orbiting it, looking and walking in the first person.

Display¶

Turning a value into a colour to show: a grey level, a heat ramp.

Error¶

The seeded error: random draws that are the same on every run, from a seed, a step, a stream's name and an index.

Events¶

Noticing things between steps: the step a state turns on, and how much two intervals overlap.

Finance¶

Markets and money: returns and volatility, bonds and yields, options and their sensitivities, matching orders and a factor model's fair value.

Integrator¶

Moving bodies through time, a step at a time: velocity Verlet, semi-implicit Euler, contacts, impacts, rolling and turning.

Kinematics¶

Orientation: turning a vector into or out of a body's frame, and a rolling ball's spin.

Laws¶

Physical laws: gravity and drag, buoyancy, diffusion, elasticity, erosion, pressure, spin and lift, and the standard atmosphere.

Light¶

Light across a lattice: a directional beam and point sources, with the shadows what stands between casts.

Motion¶

Movement on a lattice by propose and grant: each item asks to move, and each place goes to one.

Movement by propose and grant

Properties¶

A material's properties derived from the library's tables: densities and mixtures, the speed of sound, optics, heat flow, and kinetic energy.

Radiation¶

A black body's light: Planck's law, the power it radiates, and where its spectrum peaks.

Rays¶

The rays a source or a direction casts across a lattice, the cells each passes through.

Render¶

Drawing a scene by tracing rays: a camera's rays, what they hit, how surfaces shade, shadows, the sky, haze, surface noise and tone mapping.

Sky¶

The sky over a world: the sun, the moon and the stars, sidereal time, and gravity at a height.

Sound¶

Sound: a sound field across a lattice and a loudness meter.

Space¶

Finding the items near each other: every pair within a radius.

The neighbours within a radius

Statistics¶

Summaries over a table: the weighted mean.

Stochastic¶

Chance and spread for a step of any length, from what holds over a period.