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# -*- coding: utf-8 -*-
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
from __future__ import division
import numpy as np
from .mesh import MeshVisual
from ..geometry import MeshData
class SurfacePlotVisual(MeshVisual):
"""Displays a surface plot on a regular x,y grid
Parameters
----------
x : ndarray | None
1D array of values specifying the x positions of vertices in the
grid. If None, values will be assumed to be integers.
y : ndarray | None
1D array of values specifying the x positions of vertices in the
grid. If None, values will be assumed to be integers.
z : ndarray
2D array of height values for each grid vertex.
colors : ndarray
(width, height, 4) array of vertex colors.
Notes
-----
All arguments are optional.
Note that if vertex positions are updated, the normal vectors for each
triangle must be recomputed. This is somewhat expensive if the surface
was initialized with smooth=False and very expensive if smooth=True.
For faster performance, initialize with compute_normals=False and use
per-vertex colors or a material that does not require normals.
"""
def __init__(self, x=None, y=None, z=None, colors=None, **kwargs):
# The x, y, z, and colors arguments are passed to set_data().
# All other keyword arguments are passed to MeshVisual.__init__().
self._x = None
self._y = None
self._z = None
self.__vertices = None
self.__faces = None
self.__meshdata = MeshData()
kwargs.setdefault('shading', 'smooth')
MeshVisual.__init__(self, **kwargs)
self.set_data(x, y, z, colors)
def set_data(self, x=None, y=None, z=None, colors=None):
"""Update the data in this surface plot.
Parameters
----------
x : ndarray | None
1D array of values specifying the x positions of vertices in the
grid. If None, values will be assumed to be integers.
y : ndarray | None
1D array of values specifying the x positions of vertices in the
grid. If None, values will be assumed to be integers.
z : ndarray
2D array of height values for each grid vertex.
colors : ndarray
(width, height, 4) array of vertex colors.
"""
if x is not None:
if self._x is None or len(x) != len(self._x):
self.__vertices = None
self._x = x
if y is not None:
if self._y is None or len(y) != len(self._y):
self.__vertices = None
self._y = y
if z is not None:
if self._x is not None and z.shape[0] != len(self._x):
raise TypeError('Z values must have shape (len(x), len(y))')
if self._y is not None and z.shape[1] != len(self._y):
raise TypeError('Z values must have shape (len(x), len(y))')
self._z = z
if (self.__vertices is not None and
self._z.shape != self.__vertices.shape[:2]):
self.__vertices = None
if self._z is None:
return
update_mesh = False
new_vertices = False
# Generate vertex and face array
if self.__vertices is None:
new_vertices = True
self.__vertices = np.empty((self._z.shape[0], self._z.shape[1], 3),
dtype=np.float32)
self.generate_faces()
self.__meshdata.set_faces(self.__faces)
update_mesh = True
# Copy x, y, z data into vertex array
if new_vertices or x is not None:
if x is None:
if self._x is None:
x = np.arange(self._z.shape[0])
else:
x = self._x
self.__vertices[:, :, 0] = x.reshape(len(x), 1)
update_mesh = True
if new_vertices or y is not None:
if y is None:
if self._y is None:
y = np.arange(self._z.shape[1])
else:
y = self._y
self.__vertices[:, :, 1] = y.reshape(1, len(y))
update_mesh = True
if new_vertices or z is not None:
self.__vertices[..., 2] = self._z
update_mesh = True
if colors is not None:
self.__meshdata.set_vertex_colors(colors)
update_mesh = True
# Update MeshData
if update_mesh:
self.__meshdata.set_vertices(
self.__vertices.reshape(self.__vertices.shape[0] *
self.__vertices.shape[1], 3))
MeshVisual.set_data(self, meshdata=self.__meshdata)
def generate_faces(self):
cols = self._z.shape[1]-1
rows = self._z.shape[0]-1
faces = np.empty((cols*rows*2, 3), dtype=np.uint)
rowtemplate1 = (np.arange(cols).reshape(cols, 1) +
np.array([[0, 1, cols+1]]))
rowtemplate2 = (np.arange(cols).reshape(cols, 1) +
np.array([[cols+1, 1, cols+2]]))
for row in range(rows):
start = row * cols * 2
faces[start:start+cols] = rowtemplate1 + row * (cols+1)
faces[start+cols:start+(cols*2)] = rowtemplate2 + row * (cols+1)
self.__faces = faces