箱角撞地后弹得过高：接触冲量还要计算转动有效质量

v_contact = v + omega * perp(r)
vn = dot(v_contact, n)

Δv = j * inverseMass * n
Δomega = j * inverseInertia * cross(r,n)
Δvn = j * [inverseMass + inverseInertia * cross(r,n)^2]
k = inverseMass + inverseInertia * cross(r,n)^2
j = -(1+e) * vn / k

public readonly record struct V2(double X, double Y)
{
    public static V2 operator +(V2 a, V2 b) => new(a.X+b.X, a.Y+b.Y);
    public static V2 operator *(V2 a, double s) => new(a.X*s, a.Y*s);
    public double Dot(V2 b) => X*b.X+Y*b.Y;
    public double Cross(V2 b) => X*b.Y-Y*b.X;
    public V2 Perp => new(-Y, X);
    public bool Finite => double.IsFinite(X) && double.IsFinite(Y);
}

public readonly record struct Body(V2 Velocity, double Omega,
    double InverseMass, double InverseInertia);
public readonly record struct Hit(Body State, double Impulse);

public static class ContactImpulse
{
    public static double NormalSpeed(Body b, V2 r, V2 n) =>
        (b.Velocity + r.Perp*b.Omega).Dot(n);

    public static Hit Solve(Body b, V2 r, V2 n, double restitution)
    {
        if (!b.Velocity.Finite || !r.Finite || !n.Finite ||
            !double.IsFinite(b.Omega) || !double.IsFinite(b.InverseMass) ||
            !double.IsFinite(b.InverseInertia) || b.InverseMass < 0 ||
            b.InverseInertia < 0 || !double.IsFinite(restitution) ||
            restitution < 0 || restitution > 1 || Math.Abs(n.Dot(n)-1) > 1e-10)
            throw new ArgumentException("Invalid contact input");
        double lever = r.Cross(n);
        double k = b.InverseMass + b.InverseInertia*lever*lever;
        double vn = NormalSpeed(b, r, n);
        if (!double.IsFinite(k) || !double.IsFinite(vn))
            throw new ArgumentException("Contact arithmetic overflow");
        if (vn >= 0 || k == 0) return new(b, 0);
        double j = -(1+restitution)*vn/k;
        var next = b with {
            Velocity = b.Velocity + n*(j*b.InverseMass),
            Omega = b.Omega + j*b.InverseInertia*lever
        };
        if (!double.IsFinite(j) || !next.Velocity.Finite || !double.IsFinite(next.Omega))
            throw new ArgumentException("Impulse arithmetic overflow");
        return new(next, j);
    }
}

cd "$WORK_DIR"
dotnet build .tmp/daily-labs/2026-11-03-2000/ContactLab.csproj -c Release --no-restore
dotnet run --project .tmp/daily-labs/2026-11-03-2000/ContactLab.csproj -c Release --no-build

build: exit=0, warnings=0, errors=0
run: exit=0, passed=26, failed=0, skipped=0
elapsed_ms=44.1176
edge: j=1.5, vy=-2.25, omega=2.25, contact_vn=0
center: j=6, vy=0, omega=0
wrong: j=6, vy=0, omega=9, contact_vn=9
energy: before=9, after=6.75, wrong=27
samples=10000, random_failures=0
max_normal_speed_error=5.329070518200751e-15
max_rotated_frame_impulse_error=2.1316282072803006e-14
max_energy_increase=0