Boids§

The Boids model was the first simulation to be implemented with the use of the krABMaga framework. It is a steering behaviour agent-based model for autonomous agents simulating the flocking behaviour of birds. The agent behaviour is derived by a linear combination of three independent rules:

• Avoidance
• Consistency
• Cohesion

There are currently two versions:

• The simulation without the visualization framework. Outputs the time elapsed for given a number of steps and number of agents (currently hardcoded), along with the step for seconds.
• The simulation with the visualization framework enabled (either natively or compiled to WebAssembly). It shows a graphical interface describing the flockers moving in the environment, casually grouping together and avoiding other flockers. The simulation never stops.

Implementation§

The structure of the main agent of this simulation, the Bird, is very simple:

#[derive(Clone, Copy)]
pub struct Bird {
    pub id: u32,
    pub pos: Real2D,
    pub last_d: Real2D,
}

Birds simply have a current and a previous location field, along with an ID to differentiate them.

The definition of the state is just as simple:

pub struct Flocker {
    pub step: u64,
    pub field1: Field2D<Bird>,
    pub initial_flockers: u32,
    pub dim: (f32, f32),
}

impl Flocker {
    pub fn new(dim: (f32, f32), initial_flockers: u32) -> Self {
        Flocker {
            step: 0,
            field1: Field2D::new(dim.0, dim.1, DISCRETIZATION, TOROIDAL),
            initial_flockers,
            dim,
        }
    }
}