"""Generate the silhouette of a mesh
as seen along a specified direction

Axes font: """
# Author: Zhi-Qiang Zhou (https://github.com/zhouzq-thu)
from vedo import *

settings.default_font = "Kanopus"

s = Hyperboloid().rotate_x(20)
pts = s.points
n = len(pts)

plt = Plotter(title="Example of project_on_plane()")
plt += [s, __doc__ + settings.default_font]

# orthogonal projection ###############################
plane1 = Plane(pos=(2, 0, 2), normal=(1, 0, 1), s=[5, 5]).alpha(0.1)
so = s.clone().project_on_plane(plane1).c("y")
plt += [plane1, so, so.silhouette("2d")]
pts1 = so.silhouette("2d").points

# perspective projection ##############################
plane2 = Plane(pos=(3, 3, 3), normal=(1, 1, 1), s=[5, 5]).alpha(0.1)
point = [6, 6, 6]
sp = s.clone().project_on_plane(plane2, point=point).c("m")
plt += [plane2, sp, sp.silhouette("2d")]

# oblique projection ##################################
plane3 = Plane(pos=(4, 8, -4), normal=(-1, 0, 1), s=[5, 5]).alpha(0.1)
sob = s.clone().project_on_plane(plane3, direction=(1, 2, -1)).c("g")
plt += [plane3, sob, sob.silhouette("2d")]
pts2 = sob.silhouette("2d").points

# draw the lines
for i in range(0, n, int(n / 20)):
    plt += Line(pts1[i], pts[i]).color("black",0.2)
    plt += Line(point,   pts[i]).color("black",0.2)
    plt += Line(pts2[i], pts[i]).color("black",0.2)

plt.show(
    axes=dict(
        xtitle="X-axis in :mum",
        ytitle="Y-axis in :mum",
        ztitle="Z-axis in :mum",
        yzgrid=False,
        text_scale=1.5,
    ),
).close()