! Example of 3d surface plot.
! Author: Francois Tonneau

include s3.gle
include palettes.gle

size 16 15

xrange -5 5
yrange -5 5
zrange -1 1

xaxisrange -6 6
yaxisrange -6 6

angles 35 25
persp 0.80

viewport 10 9

amove 3 3

set cap round join round

begin origin

! Draw plot panes.

set lwidth 0.03 color gray40 fill "#e0e0e0"
pane B
grid xB -3 3 3
grid yB -3 3 3
pane I
grid xI -3 3 3
grid zI -1 0 1
pane J
grid yJ -3 3 3
grid zJ -1 0 1

! Add axis labels.

set color black font ss hei 0.4
set just cr
label XB -3 0.5 "-3"
label XB  0 0.5   0
label XB  3 0.5 "+3"
set just cc
label YB -3 0.5 "-3"
label YB  0 0.5   0
label YB  3 0.5 "+3"
set just rc
label JX -1 0.3 "-1.0"
label JX  0 0.3 " 0.0"
label JX  1 0.3 "+1.0"

! Add axis titles.

set hei 0.5
label XB -0.2 1.7 "X"
label YB -0.1 1.7 "Y"
label JX  0.2 1.4 "Z"

! Proceed to plot.

sub hat x y
    return sin(sqrt(x*x + y*y))
end sub

sub fillpalette z
    return viridis((z + 1)/2)
end sub

sub linepalette z
    return "#222222"
end sub

set lwidth 0.02
s3funcsurf hat fillpalette linepalette 50 50

end origin