# Plotter Lighting Systems
# ========================

# The `pyvista.Plotter` class comes with three options for the default
# lighting system:
# a light kit consisting of a headlight and four camera lights,
# an illumination system containing three lights arranged around the camera,
# no lighting.
# With meshes that don't have depth information encoded in their color the
# importance of an appropriate lighting setup becomes paramount for accurate
# visualization.

# Light kit
# ---------

# The default `lighting='light kit'` option recreates a lighting setup that
# corresponds to a vtkLightKit. We can check what type of lights this
# lighting comprises:
import pyvista as pv
from pyvista import examples

# default: light kit
pl = pv.Plotter()
light_types = [light.light_type for light in pl.renderer.lights]

# Remove from plotters so output is not produced in docs
pv.plotting.plotter._ALL_PLOTTERS.clear()

light_types

# Add a white terrain to the scene:
mesh = examples.download_st_helens().warp_by_scalar()
pl = pv.Plotter()
pl.add_mesh(mesh, color='white')
pl.show()

# Three-lights illumination
# -------------------------

# Switching to three-lights illumination gives a different character to the
# figure, in this case showing less contrast when viewing the mountain from
# the top, but having more contrast with views closer to the side. This becomes
# especially clear when exploring the figures interactively.
pl = pv.Plotter(lighting='three lights')
pl.add_mesh(mesh, color='white')
pl.show()

# Again we can check what kind of lights this setting uses:
pl = pv.Plotter(lighting='three lights')
light_types = [light.light_type for light in pl.renderer.lights]

# Remove from plotters so output is not produced in docs
pv.plotting.plotter._ALL_PLOTTERS.clear()

light_types

# Custom lighting
# ---------------

# We can introduce our own lighting from scratch by disabling any
# lighting on plotter initialization. Adding a single scene light to a
# scene will often result in ominous visuals due to objects having
# larger regions in shadow.
pl = pv.Plotter(lighting='none', window_size=(1000, 1000))
pl.add_mesh(mesh, color='white', smooth_shading=True)
light = pv.Light()
light.set_direction_angle(30, -20)
pl.add_light(light)
pl.show()

# Custom lighting with shadows
# ----------------------------

# Here, we `enable_shadows` to enhance the effect that the lighting
# angle has.  It has a subtle, but realistic effect.  Notice the sharp
# shadows due to the mountaintop.
pl = pv.Plotter(lighting='none', window_size=(1000, 1000))
pl.add_mesh(mesh, color='white', smooth_shading=True)
light = pv.Light()
light.set_direction_angle(20, -20)
pl.add_light(light)
pl.enable_shadows()
pl.show()

# ----------------------------------------------------------------------
# Generated by sphinx-examples-as-code https://github.com/pyvista/sphinx-examples-as-code