BABYLON-STEERING

Intro

A steering behaviors library for Babylon.js for moving entities in the x/z plane. The library was born thanks to these tutorials and the library three-steer.

The following behavious are supported:

Seek, Seek with Arrive and Attract (Seek with intensity)
Flee
Arrive
Pursue
Evade
Interpose
Wander
Collision Avoidance
Follow Path
Follow Leader
Queue
Cohesion, separation and alignment (Flocking)
Hide
Apply general force

Steering Entities can:

look at a specific target with the .lookAt() method
look where they are going with the .lookWhereGoing() method

How to setup

Include babylon-steering library:

import SteeringVehicle from 'babylon-steering';

Create a Babylon.js 3D scene with a mesh and simply instantiate a Steering Entity linked to this mesh (passing the engine to have the engine.getDeltaTime() and move the entities accordingly ):

const redSphere = new SteeringVehicle(my_mesh, engine, options);

/*
    options can be:

    options.maxSpeed || 0.2;
    options.mass || 1;

    // ARRIVAL
    options.arrivalThreshold || 100;

    // AVOID
    options.avoidDistance || 120;
    options.radius || 100;

    // WANDER
    options.wanderDistance || 10;
    options.wanderAngle || 10;
    options.wanderRadius || 5;
    options.wanderRange || 20;

    // QUEUE
    options.inSightDistance || 200;
    options.tooCloseDistance || 60;
*/

Add the behavior/s to the steering entity and the update method inside main render/animation loop:

scene.executeWhenReady(function () {
        engine.runRenderLoop(function () {

            my_mesh
                .seekWithArrive(greenTarget, 50)
                .hasInConeOfView(arrayOfEnemies)
                .avoid(obstacleIstances)
                .applyForce(new BABYLON.Vector3(1, 0, 0.75))    // For istance can be WIND...
                .lookWhereGoing(true);

            my_mesh.animate();  // Update the Steering Vehicle

            scene.render();
        });
});

Combine behaviours

It is possible to combine many simultaneous steering forces by passing the following parameters to the .animate() function according to the four methods described in this bog post:

priority for Priority Arbitration
weighted for Weighted Blending,
probability for 'Prioritised Dithering'
truncated for 'Weighted Prioritised Truncated Sum'

scene.executeWhenReady(function () {
        engine.runRenderLoop(function () {

            blueSphere
                .seek(greenBox, 50, { weigth: 1.7, priority: 1, probability: 0.6 })
                .flee(redSphere, 160, { weigth: 0.5, priority: 5, probability: 0.6 })
                .lookTarget(redSphere) // or .lookWhereGoing(true)
                .avoid(obstacleIstances, { weigth: 1, weigth: 0.8, probability: 0.6 });

            blueSphere.animate('blend');  // 'blend' 'priority' 'probability'  'truncated' 
            
            obstacleIstances.forEach(e => {
                    e.animate();
            });

            scene.render();
        });
});

Demo

# 1) istall dependencies
npm install
# 2) run the development server serving static demo pages at localhost:4000
npm start

# only demo page for seek, flee, avoid and hide are available....

Bugs

wander, avoid and flock are still work in progress!
Let me know!

Built With

ES6 Javascript, microbundle, Babylon.js

License

This project is licensed under the ISC License.

LorenzoCorbella74 / babylon-steering