Les saisons
Author: Daniel Mentrard

Un peu lourd à cause de la rotation de laTerre

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Animation manuelle

Earth

Vitesse

t = 541 (slider from 0 to 625, step 1)
or: 12.0 * t / 314.0
B: (60.0 * cos(t / 100.0), 30.0 * sin(t / 100.0))
a = Line(B, xAxis)
e = Line(B, yAxis)
b = 17.6 (slider from -5 to 50, step 0.1)
d = Circle(B, b)
A, C = Intersect(d, a)
f = Line(C, e)
D, E = Intersect(d, e)
g = Line(D, a)
F = Intersect(f, g)
I = Midpoint(F, B)
J = If(t < 157.0, Rotate[F, (4.0 * (6.0 - or))°, I], If[t < 314.0, Rotate[F, (-4.0 * (6.0 - or))°, I], If[t < 471.0, Rotate[F, (24.0 - 4.0 * (or - 12.0))°, I], Rotate[F, (4.0 * (or - 18.0))°, I]]])
M = Mirror(J, I)
L = Rotate(J, 90.0*°, I)
G = Midpoint(M, L)
i = Line(G, I)
p = Circle(G, b / 4.0)
O, P = Intersect(p, i)
R = Midpoint(P, G)
N = Midpoint(R, G)
c = Circle(B, 10.0)
M2 = (-52.34359317009517, 28.85302508163108)
K = Rotate(J, 270.0*°, I)
h = Mod(t, 12.0)
T1: "" + h
H = Midpoint(K, J)
k = Circle(I, G)
l = Line(O, xAxis)
n = Line(R, yAxis)
j = Line(I, yAxis)
m = Segment(O, N)
O' = Mirror(O, I)
N' = Mirror(N, I)
q = Segment(O', N')
r = Segment(N, N')
Q = (60, 0)
S = (-60, 3.67394039744206E-15)
T = (30.000000000000007, 25.980762113533157)
V = Mirror(T, xAxis)
U = Mirror(T, yAxis)
s = Conic(V, Q, T, U, S)
u = Vector(B, I)
c1 = Translate(s, u)
W = Point(c1)
a1 = Line(W, xAxis)
Z, A1 = Intersect(c1, a1)
B1 = Midpoint(Z, A1)
b1 = Line(B1, j)
T2: "" + or
d1 = Circle(B1, b / 1.6)
e1 = OrthogonalLine(I, q)
f1 = Circle(I, 7.7)
C1, D1 = Intersect(f1, e1)
g1 = CircleArc(O, D1, C1)
E1 = (-61.58263143968603, 33.528870469502934)
F1 = (-29.71035186868373, 33.528870469502934)
G1 = (-29.863583982005856, 26.326961143363004)
H1 = (-61.4293993263639, 26.173729030040878)
poly1, e1_1, f1_1, g1_1, h1 = Polygon(E1, F1, G1, H1)
poly2, e1_2, f1_2, g1_2, h1_1 = Polygon(E1, F1, G1, H1)
Vitesse = 0.4 (slider from 0 to 5, step 0.1)