Moonlight gate

1asset carnival_arch "Moonlight gate" complexity=6
2// the carnival's entrance: two striped towers on stone feet with onion domes and fluttering
3// pennants, a curved marquee board between them carrying a crescent moon and a star, a run of
4// marquee bulbs along its top edge, and a scalloped banner swag underneath
5let W = 4.0
6let TH = 4.6..4.9
7let stA = cherry:2|cobalt|grape|teal
8let stB = cream:3|white
9let trim = navy:2|plum
10let metal = brass:3|copper
11let bulbA = glow:3|sunflower
12let bulbB = pink:2|tangerine
13let flagC = sunflower:2|pink|aqua|lime
14 
15// the towers
16cyl foot at=(W, 0, 0) mirror h=.5 r=.62 sq=4 round=.08 color=trim segs=16
17cyl tower on=foot at=(0, .5, 0) h=TH-.5 r=.46 stripes=[stA stB] panels=8 color=stA segs=24
18torus band x2 on=tower at=(0, (TH-.5)*.5, 0) row=(0, (TH-.5)*.45, 0) R=.47 r=.07 color=metal segs=28 sides=6
19lathe dome on=tower at=(0, TH-.5, 0) h=1.3 r=.6 prof=[0:.85 .3:1 .65:.55 .9:.15 1:.05] stripes=[stB stA] panels=8 color=stB segs=24 rings=12
20ball dbulb x8 on=tower ring at=(.5, TH-.5, 0) r=.09 color=bulbA ink=glow segs=8 rings=5
21cyl spike on=dome at=(0, 1.22, 0) h=.7 r=.035 color=metal segs=6
22ball knob on=spike at=end r=.07 color=metal segs=8 rings=5
23slab pennant on=spike at=(0, .66, 0) pts=[0,0 .75,-.15 0,-.32] t=.04 round=.012 color=flagC edge=stB joint
24 
25// the marquee board: a gentle arch across the top
26slab board at=(0, TH-1.25, 0) pts=[-3.9,0 3.9,0 3.9,.75 3.0,1.08 1.8,1.32 0,1.42 -1.8,1.32 -3.0,1.08 -3.9,.75] t=.24 round=.06 color=trim edge=stA
27slab face on=board at=(0, .14, .14) pts=[-3.3,0 3.3,0 3.3,.5 2.5,.78 1.4,.95 0,1.02 -1.4,.95 -2.5,.78 -3.3,.5] t=.04 round=.015 color=stB
28torus moon on=face at=(-.32, .52, .06) rot=(90, 0, 60) R=.3 r=.085 arc=230 color=bulbA ink=glow segs=24 sides=8
29slab star on=face at=(.32, .52, .03) pts=[0,.3 .07,.1 .28,.09 .12,-.03 .18,-.25 0,-.12 -.18,-.25 -.12,-.03 -.28,.09 -.07,.1] t=.06 round=.02 color=bulbA ink=glow
30ball dot x6 on=face at=(-2.2, .32, .03) row=(.18, 0, 0) r=.05 color=stA segs=6 rings=4
31ball dot2 x6 on=face at=(1.3, .32, .03) row=(.18, 0, 0) r=.05 color=stA segs=6 rings=4
32 
33// marquee bulbs along the top edge (a parabola through the board's arch)
34ball mbulb x17 on=board at=(-3.7 + 7.4*t, .8 + .66*(1 - (-3.7 + 7.4*t)*(-3.7 + 7.4*t)/13.7), .12) r=.1 color=sel(i - 2*floor(i/2), bulbA, bulbB) ink=glow segs=8 rings=5
35 
36// the swag of scallops under the board
37ball swag x12 on=board at=(0, -.02, .12) row=(.64, 0, 0) r=(.33, .2, .06) color=sel(i - 2*floor(i/2), stA, stB) segs=10 rings=6
38 
39anim pennant ry sin amp=22 hz=1.2 twin=.4
40