Function transform

crawl-ref/source/transform.cc:2132–2174

* Attempts to transform the player into the specified form. * * If the player is already in that form, attempt to refresh its duration and * power. * * @param dur The duration of the transformation (0 if the * transformation should be permanent.) * @param which_trans The form which the player should become. * @param involuntary Checks for

 *                          Otherwise, false.
 */
bool transform(int dur, transformation which_trans, bool involuntary,
               bool using_talisman)
{
    // Zin's protection.
    if (have_passive(passive_t::resist_polymorph)
        && x_chance_in_y(you.piety(), piety_breakpoint(5))
        && which_trans != transformation::none)
    {
        simple_god_message(" protects your body from unnatural transformation!");
        return false;
    }

    if (!involuntary && crawl_state.is_god_acting())
        involuntary = true;

    if (!check_transform_into(which_trans, involuntary,
                                using_talisman ? you.active_talisman() : nullptr))
    {
        return false;
    }

    // If swapping to a different talisman of the same type, make sure to
    // activate properties of the new one.
    if (using_talisman && you.form == which_trans
        && is_artefact(*you.active_talisman()))
    {
        you.equipment.update();
        equip_artefact_effect(*you.active_talisman(), nullptr, false);

        return true;
    }

    // Vampire should shift into bat swarm without reverting to fully untransformed in the middle
    if (you.form != transformation::none
        && !(you.form == transformation::vampire && which_trans == transformation::bat_swarm))
    {
        untransform(true, !using_talisman, !using_talisman, which_trans);
    }

    _enter_form(dur, which_trans, using_talisman);

    return true;
}

/**
 * End the player's transformation and return them to having no