have fun

double getDistanceToLine(Vec3 normale, Vec3 punkt, double verschiebung){
    return abs((normale/normale.Length())*punkt-verschiebung);
}

Vec3 spiegelungUmNomrale(Vec3 V,Vec3 A){
    Vec3 result = V-2*((A*V)/(A*A))*A;
    return result;
}

Vec3 W1W2ORTHO((W1-W2).p[2],0,-(W1-W2).p[0]);
    if(getDistanceToLine(W1W2ORTHO,Vec3(posX_,0,posZ_),W1W2ORTHO/W1W2ORTHO.Length()*W1)<=0){
                //mouseSpeed=spiegelungUrsprungsgerade(getAngle2D((W1-W2).p[0],(W1-W2).p[2],1,0),mouseSpeed);
                mouseSpeed=spiegelungUmNomrale(mouseSpeed,W1W2ORTHO);
        }