#/***********************************************************
#    3dgraph.rb -- 3次元グラフ
#***********************************************************/
require "plotter.rb"

Xmin = -1; Ymin = -1; Zmin = -1   # 座標の下限 
Xmax =  1; Ymax =  1; Zmax =  1   # 座標の上限 

def func(x,  z)             # 描く関数 (例) 
    r2 = x * x + z * z
    return Math::exp(-r2) * Math::cos(10 * Math::sqrt(r2))
end

lowerhorizon = []; upperhorizon = []

gr_on
for i in 0..240
    lowerhorizon[i] =  1e30;  # 正の無限大 
    upperhorizon[i] = -1e30;  # 負の無限大 
end
for iz in 0..20
    z = Zmin + (Zmax - Zmin) / 20.0 * iz
    ok1 = 0
    for ix in 0..200
        x = Xmin + (Xmax - Xmin) / 200.0 * ix
        i = ix + 2 * (20 - iz);  # 0..240 
        y = 30 * (func(x, z) - Ymin) / (Ymax - Ymin).to_f + 5 * iz; # 0..130 
        ok = 0
        if (y < lowerhorizon[i]) 
            lowerhorizon[i] = y;  ok = 1
        end
        if (y > upperhorizon[i]) 
            upperhorizon[i] = y;  ok = 1
        end
        if ((ok == 1) && (ok1 == 1)); draw(i, y); else; move(i, y); end
        ok1 = ok
    end
end
gr_off

exit 0