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Collision Physics

Orbs collide elastically, transferring momentum and potentially triggering eliminations.

Collision Detection​

Two orbs collide when their centers are closer than the sum of their radii:

fn check_collision(orb_a: &Orb, orb_b: &Orb) -> bool {
    let distance = (orb_a.position - orb_b.position).length();
    let min_distance = orb_a.radius + orb_b.radius;

    distance < min_distance
}

Collision Resolution​

When orbs collide, velocities are exchanged along the collision axis:

fn resolve_collision(orb_a: &mut Orb, orb_b: &mut Orb, restitution: f32) {
    // Collision normal
    let normal = (orb_b.position - orb_a.position).normalize();

    // Relative velocity along normal
    let relative_velocity = orb_a.velocity - orb_b.velocity;
    let velocity_along_normal = relative_velocity.dot(normal);

    // Only resolve if approaching
    if velocity_along_normal > 0.0 {
        return;
    }

    // Calculate impulse (equal mass assumed)
    let impulse = -velocity_along_normal * restitution;

    // Apply impulse
    orb_a.velocity += normal * impulse;
    orb_b.velocity -= normal * impulse;

    // Separate overlapping orbs
    separate_orbs(orb_a, orb_b);
}

Configuration​

ParameterDescriptionCurrent Value
orbRestitutionEnergy transfer coefficient1.008

Restitution Effects​

ValueEffect
< 1.0Energy lost (dampening)
= 1.0Energy preserved
> 1.0Energy added (accelerating)

Current config (1.008) adds very slight energy, creating gradually faster gameplay.

Collision Events​

Collisions can trigger:

Tether Breaking​

If an orb is moving fast enough and hits a tether, the tether breaks.

Shockwaves​

High-impact collisions emit shockwaves that can cut nearby tethers.

Eliminations​

When all of a player's tethers are broken, they're eliminated.

Orb Properties​

PropertyValueDescription
radius12pxCollision hitbox
baseSpeed4.0Initial velocity
colors6Visual distinction

Next Steps​