"""
.. _texture_example:

Applying Textures
~~~~~~~~~~~~~~~~~

Plot a mesh with an image projected onto it as a texture.
"""

from matplotlib.pyplot import get_cmap
import numpy as np
import pyvista as pv
from pyvista import examples

# %%
# Texture mapping is easily implemented using PyVista. Many of the geometric
# objects come preloaded with texture coordinates, so quickly creating a
# surface and displaying an image is simply:

# load a sample texture
tex = examples.download_masonry_texture()

# create a surface to host this texture
surf = pv.Cylinder()

surf.plot(texture=tex)


# %%
# But what if your dataset doesn't have texture coordinates? Then you can
# harness the :func:`pyvista.DataSetFilters.texture_map_to_plane` filter to
# properly map an image to a dataset's surface.
# For example, let's map that same image of bricks to a curvey surface:

# create a structured surface
x = np.arange(-10, 10, 0.25)
y = np.arange(-10, 10, 0.25)
x, y = np.meshgrid(x, y)
r = np.sqrt(x**2 + y**2)
z = np.sin(r)
curvsurf = pv.StructuredGrid(x, y, z)

# Map the curved surface to a plane - use best fitting plane
curvsurf.texture_map_to_plane(inplace=True)

curvsurf.plot(texture=tex)

# %%
# Display scalar data along with a texture by ensuring the
# ``interpolate_before_map`` setting is ``False`` and specifying both the
# ``texture`` and ``scalars`` arguments.

elevated = curvsurf.elevation()

elevated.plot(
    scalars='Elevation', cmap='terrain', texture=tex, interpolate_before_map=False
)


# %%
# Note that this process can be completed with any image texture.

# use the puppy image
tex = examples.download_puppy_texture()
curvsurf.plot(texture=tex)


# %%
# Textures from Files
# +++++++++++++++++++
#
# What about loading your own texture from an image? This is often most easily
# done using the :func:`pyvista.read_texture` function - simply pass an image
# file's path, and this function with handle making a :vtk:`vtkTexture` for you to
# use.

image_file = examples.mapfile
tex = pv.read_texture(image_file)
curvsurf.plot(texture=tex)


# %%
# NumPy Arrays as Textures
# ++++++++++++++++++++++++
#
# Want to use a programmatically built image? :class:`pyvista.ImageData`
# objects can be converted to textures using :func:`pyvista.image_to_texture`
# and 3D NumPy (X by Y by RGB) arrays can be converted to textures using
# :func:`pyvista.numpy_to_texture`.

# create an image using numpy,
xx, yy = np.meshgrid(np.linspace(-200, 200, 20), np.linspace(-200, 200, 20))
A, b = 500, 100
zz = A * np.exp(-0.5 * ((xx / b) ** 2.0 + (yy / b) ** 2.0))

# Creating a custom RGB image
cmap = get_cmap('nipy_spectral')
norm = lambda x: (x - np.nanmin(x)) / (np.nanmax(x) - np.nanmin(x))
hue = norm(zz.ravel())
colors = (cmap(hue)[:, 0:3] * 255.0).astype(np.uint8)
image = colors.reshape((xx.shape[0], xx.shape[1], 3), order='F')

# Convert 3D numpy array to texture
tex = pv.numpy_to_texture(image)

# Render it
curvsurf.plot(texture=tex)

# %%
# Create a GIF Movie with updating textures
# +++++++++++++++++++++++++++++++++++++++++
# Generate a moving gif from an active plotter with updating textures.

mesh = curvsurf.extract_surface(algorithm=None)

# Create a plotter object
pl = pv.Plotter(notebook=False, off_screen=True)

actor = pl.add_mesh(mesh, smooth_shading=True, color='white')

# Open a gif
pl.open_gif('texture.gif')

# Update Z and write a frame for each updated position
nframe = 15
for phase in np.linspace(0, 2 * np.pi, nframe + 1)[:nframe]:
    # create an image using numpy,
    z = np.sin(r + phase)
    mesh.points[:, -1] = z.ravel()

    # Creating a custom RGB image
    zz = A * np.exp(-0.5 * ((xx / b) ** 2.0 + (yy / b) ** 2.0))
    hue = norm(zz.ravel()) * 0.5 * (1.0 + np.sin(phase))
    colors = (cmap(hue)[:, 0:3] * 255.0).astype(np.uint8)
    image = colors.reshape((xx.shape[0], xx.shape[1], 3), order='F')

    # Convert 3D numpy array to texture
    actor.texture = pv.numpy_to_texture(image)

    # must update normals when smooth shading is enabled
    mesh.compute_normals(cell_normals=False, inplace=True)
    pl.write_frame()
    pl.clear()

# Closes and finalizes movie
pl.close()

# %%
# Textures with Transparency
# ++++++++++++++++++++++++++
#
# Textures can also specify per-pixel opacity values. The image must
# contain a 4th channel specifying the opacity value from 0 [transparent] to
# 255 [fully visible]. To enable this feature just pass the opacity array as the
# 4th channel of the image as a 3 dimensional matrix with shape [nrows, ncols, 4]
# :func:`pyvista.numpy_to_texture`.
#
# Here we can download an image that has an alpha channel:
rgba = examples.download_rgba_texture()
rgba.n_components

# %%

# Render it
curvsurf.plot(texture=rgba, show_grid=True)


# %%
# Repeating Textures
# ++++++++++++++++++
#
# What if you have a single texture that you'd like to repeat across a mesh?
# Simply define the texture coordinates for all nodes explicitly.
#
# Here we create the texture coordinates to fill up the grid with several
# mappings of a single texture. In order to do this we must define texture
# coordinates outside of the typical ``(0, 1)`` range:

axial_num_puppies = 4
xc = np.linspace(0, axial_num_puppies, curvsurf.dimensions[0])
yc = np.linspace(0, axial_num_puppies, curvsurf.dimensions[1])

xxc, yyc = np.meshgrid(xc, yc)
puppy_coords = np.c_[yyc.ravel(), xxc.ravel()]

# %%
# By defining texture coordinates that range ``(0, 4)`` on each axis, we will
# produce 4 repetitions of the same texture on this mesh.
#
# Then we must associate those texture coordinates with the mesh through the
# :attr:`pyvista.DataSet.active_texture_coordinates` property.

curvsurf.active_texture_coordinates = puppy_coords

# %%
# Now display all the puppies.

# use the puppy image
tex = examples.download_puppy_texture()
curvsurf.plot(texture=tex, cpos='xy')


# %%
# Spherical Texture Coordinates
# +++++++++++++++++++++++++++++
# We have a built in convienance method for mapping textures to spherical
# coordinate systems much like the planar mapping demoed above.
mesh = pv.Sphere()
tex = examples.download_masonry_texture()

mesh.texture_map_to_sphere(inplace=True)
mesh.plot(texture=tex)


# %%
# The helper method above does not always produce the desired texture
# coordinates, so sometimes it must be done manually. Here is a great, user
# contributed example from `this support issue <https://github.com/pyvista/pyvista-support/issues/257>`_
#
# Manually create the texture coordinates for a globe map. First, we create
# the mesh that will be used as the globe. Note the `start_theta` for a slight
# overlappig
sphere = pv.Sphere(
    radius=1,
    theta_resolution=120,
    phi_resolution=120,
    start_theta=270.001,
    end_theta=270,
)

# Initialize the texture coordinates array
sphere.active_texture_coordinates = np.zeros((sphere.points.shape[0], 2))

# Populate by manually calculating
for i in range(sphere.points.shape[0]):
    sphere.active_texture_coordinates[i] = [
        0.5 + np.arctan2(-sphere.points[i, 0], sphere.points[i, 1]) / (2 * np.pi),
        0.5 + np.arcsin(sphere.points[i, 2]) / np.pi,
    ]

# And let's display it with a world map
tex = examples.load_globe_texture()
sphere.plot(texture=tex)
# %%
# .. tags:: plot
