"""
.. _pbr_example:

Physically Based Rendering
~~~~~~~~~~~~~~~~~~~~~~~~~~

VTK 9 introduced Physically Based Rendering (PBR) and we have exposed
that functionality in PyVista. Read the `blog about PBR
<https://blog.kitware.com/vtk-pbr/>`_ for more details.

PBR is only supported for :class:`pyvista.PolyData` and can be
triggered via the ``pbr`` keyword argument of ``add_mesh``. Also use
the ``metallic`` and ``roughness`` arguments for further control.

Let's show off this functionality by rendering a high quality mesh of
a statue as though it were metallic.

"""

from itertools import product

import pyvista as pv
from pyvista import examples

# Load the statue mesh
mesh = examples.download_nefertiti()
mesh.rotate_x(-90.0, inplace=True)  # rotate to orient with the skybox

# Download skybox
cubemap = examples.download_sky_box_cube_map()


# %%
# Let's render the mesh with a base color of "linen" to give it a metal looking
# finish.
pl = pv.Plotter()
pl.add_actor(cubemap.to_skybox())
pl.set_environment_texture(cubemap)  # For reflecting the environment off the mesh
pl.add_mesh(mesh, color="linen", pbr=True, metallic=0.8, roughness=0.1, diffuse=1)

# Define a nice camera perspective
cpos = [(-313.40, 66.09, 1000.61), (0.0, 0.0, 0.0), (0.018, 0.99, -0.06)]

pl.show(cpos=cpos)


# %%
# Show the variation of the metallic and roughness parameters.
#
# Plot with metallic increasing from left to right and roughness
# increasing from bottom to top.

colors = ["red", "teal", "black", "orange", "silver"]

pl = pv.Plotter()
pl.set_environment_texture(cubemap)

for i, j in product(range(5), range(6)):
    sphere = pv.Sphere(radius=0.5, center=(0.0, 4 - i, j))
    pl.add_mesh(sphere, color=colors[i], pbr=True, metallic=i / 4, roughness=j / 5)

pl.view_vector((-1, 0, 0), (0, 1, 0))
pl.show()


# %%
# Combine custom lighting and physically based rendering.

# download louis model
mesh = examples.download_louis_louvre()
mesh.rotate_z(140, inplace=True)


plotter = pv.Plotter(lighting=None)
plotter.set_background("black")
plotter.add_mesh(mesh, color="linen", pbr=True, metallic=0.5, roughness=0.5, diffuse=1)


# set up lighting
light = pv.Light((-2, 2, 0), (0, 0, 0), "white")
plotter.add_light(light)

light = pv.Light((2, 0, 0), (0, 0, 0), (0.7, 0.0862, 0.0549))
plotter.add_light(light)

light = pv.Light((0, 0, 10), (0, 0, 0), "white")
plotter.add_light(light)


# plot with a good camera position
plotter.camera_position = [(9.51, 13.92, 15.81), (-2.836, -0.93, 10.2), (-0.22, -0.18, 0.959)]
cpos = plotter.show()

# %%
# .. raw:: html
#
#     <center>
#       <a target="_blank" href="https://colab.research.google.com/github/pyvista/pyvista-tutorial/blob/gh-pages/notebooks/tutorial/03_figures/bonus/d_pbr.ipynb">
#         <img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Open In Colab"/ width="150px">
#       </a>
#     </center>