Editing Verlet integration (section)

=== Algorithmic representation ===
Since '''velocity Verlet''' is a generally useful algorithm in 3D applications, a solution written in C++ could look like below. This type of position integration will significantly increase accuracy in 3D simulations and games when compared with the regular Euler method.<syntaxhighlight lang="c++" line="1">
struct Body
{
    Vec3d pos { 0.0, 0.0, 0.0 };
    Vec3d vel { 2.0, 0.0, 0.0 }; // 2 m/s along x-axis
    Vec3d acc { 0.0, 0.0, 0.0 }; // no acceleration at first
    double mass = 1.0; // 1kg

    /**
     * Updates pos and vel using "Velocity Verlet" integration
     * @param dt DeltaTime / time step [eg: 0.01]
     */
    void update(double dt)
    {
        Vec3d new_pos = pos + vel*dt + acc*(dt*dt*0.5);
        Vec3d new_acc = apply_forces();
        Vec3d new_vel = vel + (acc+new_acc)*(dt*0.5);
        pos = new_pos;
        vel = new_vel;
        acc = new_acc;
    }

    /**
     * To apply velocity to your objects, calculate the required Force vector instead
     * and apply the accumulated forces here.
     */
    Vec3d apply_forces() const
    {
        Vec3d new_acc = Vec3d{0.0, 0.0, -9.81 }; // 9.81 m/s² down in the z-axis
        // Apply any other forces here...
        // NOTE: Avoid depending on `vel` because Velocity Verlet assumes acceleration depends on position.
        return new_acc;
    }
};
</syntaxhighlight>