distanceBetween(agentA, agentB, distanceFunction)

This function returns the distance between two agents, using a specific distance function. You can pass the current agent's state as one of the agents. The different distance functions are:

function behavior(state, context) {
const { neighborA, neighborB } = context.neighbors();
// Find the closest of 2 neighbors to you
const distanceToA = hstd.distanceBetween(state, neighborA);
const distanceToB = hstd.distanceBetween(state, neighborB);
state.closest = distanceToB > distanceToA ? "A" : "B";
// Check if neighbors are closer to each other than to you
const neighborDistance = hstd.distanceBetween(neighborA, neighborB);
const selfDistance = state.closest === "A" ? distanceToA : distanceToB;
state.closer_to_neighbors = selfDistance < neighborDistance;


This function returns the unit vector of the vec array. You can use it to normalize an agent's direction vector after it's modified.

function behavior(state, context) {
const dir = state.direction;
// Modify the direction by adding a vector [1, 2, 0]
dir[0] += 1;
dir[1] += 2;
// Turn it back into a unit vector
state.direction = hstd.normalizeVector(dir);

randomPosition(topology, z_plane)

This function returns a random integer position within the bounds of the topology. The Topology should be user-defined in globals.json (see Topology). By defaultz_plane is false and the returned position is in a 2D plane. Pass true to return a position in 3D space.

function behavior(state, context) {
// Move to a random position
const topology = context.globals().topology;
const new_pos = hstd.randomPosition(topology);
state.position = new_pos;