double dist = e.distanceTo(x, y, z) / r;
double sp = level.getSeenPercent(center, e.bb);
double pow = (1 - dist) * sp;
e.hurt(DamageSource.explosion, (int) ((pow * pow + pow) / 2 * 8 * r + 1));


    public float getSeenPercent(Vec3 center, AABB bb) {
        double xs = 1.0 / ((bb.x1 - bb.x0) * 2 + 1);
        double ys = 1.0 / ((bb.y1 - bb.y0) * 2 + 1);
        double zs = 1.0 / ((bb.z1 - bb.z0) * 2 + 1);
        int hits = 0;
        int count = 0;
        for (float xx = 0; xx <= 1; xx += xs)
            for (float yy = 0; yy <= 1; yy += ys)
                for (float zz = 0; zz <= 1; zz += zs) {
                    double x = bb.x0 + (bb.x1 - bb.x0) * xx;
                    double y = bb.y0 + (bb.y1 - bb.y0) * yy;
                    double z = bb.z0 + (bb.z1 - bb.z0) * zz;
                    if (clip(Vec3.getPool().allocate(x, y, z), center) == null) hits++;
                    count++;
                }

        return hits / (float) count;
    }