Re-introducing sin_time_function

[ynedelec3]

Hi,
I've added the sin function (considering sin is in fact si(2 x pi x t / 10) to the time functions module.
I write the code below if it is useful and correct (it was added in master branch, up to date on June 08 2021) ... :

In io .hpp :
line 1469 and following

bool read(simulation& /*sim*/, time_func& dyn) noexcept
    {
        if (!(is >> temp_1))
            return false;

        if (std::strcmp(temp_1, "sin") == 0)         /* Nedelec */
            dyn.default_f = &sin_time_function;      /* Nedelec */
        else if (std::strcmp(temp_1, "square") == 0) /* Nedelec */
            dyn.default_f = &square_time_function;   /* Nedelec */
        else                                         /* Nedelec */
            dyn.default_f = &time_function;          /* Nedelec */

        return true;
    }

In node-editor.cpp :
line 2298 and following

static void
show_dynamics_inputs(editor& /*ed*/, time_func& dyn)
{
    const char* items[] = { "time", "square", "sin" }; /* Nedelec */
    ImGui::PushItemWidth(120.0f);
    int item_current = dyn.default_f == &time_function ? 0
                       : dyn.default_f == &square_time_function
                         ? 1
                         : 2; /* Nedelec */
    if (ImGui::Combo("function", &item_current, items, IM_ARRAYSIZE(items))) {
        dyn.default_f = item_current == 0   ? &time_function
                        : item_current == 1 ? &square_time_function
                                            : sin_time_function; /* Nedelec */
    }
    ImGui::PopItemWidth();
}

[quesnel]

Thank you. I merged your code in master branch.