83 lines
2.7 KiB
Python
83 lines
2.7 KiB
Python
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# -*- coding: utf-8 -*-
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"""
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This module implements a plasma effect renderer.
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"""
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from __future__ import division
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from __future__ import absolute_import
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from __future__ import print_function
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from __future__ import unicode_literals
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from builtins import range
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from math import sin, pi, sqrt
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from asciimatics.renderers.base import DynamicRenderer
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from asciimatics.screen import Screen
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class Plasma(DynamicRenderer):
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"""
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Renderer to create a "plasma" effect using sinusoidal functions.
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The implementation here uses the same techniques described in
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http://lodev.org/cgtutor/plasma.html
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"""
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# The ASCII grey scale from darkest to lightest.
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_greyscale = ' .:;rsA23hHG#9&@'
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# Colours for different environments
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_palette_8 = [
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(Screen.COLOUR_BLUE, Screen.A_NORMAL),
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(Screen.COLOUR_BLUE, Screen.A_NORMAL),
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(Screen.COLOUR_MAGENTA, Screen.A_NORMAL),
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(Screen.COLOUR_MAGENTA, Screen.A_NORMAL),
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(Screen.COLOUR_RED, Screen.A_NORMAL),
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(Screen.COLOUR_RED, Screen.A_BOLD),
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]
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_palette_256 = [
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(18, 0),
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(19, 0),
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(20, 0),
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(21, 0),
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(57, 0),
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(93, 0),
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(129, 0),
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(201, 0),
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(200, 0),
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(199, 0),
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(198, 0),
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(197, 0),
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(196, 0),
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(196, 0),
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(196, 0),
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]
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def __init__(self, height, width, colours):
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"""
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:param height: Height of the box to contain the plasma.
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:param width: Width of the box to contain the plasma.
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:param colours: Number of colours the screen supports.
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"""
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super(Plasma, self).__init__(height, width)
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self._palette = self._palette_256 if colours >= 256 else self._palette_8
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self._t = 0
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def _render_now(self):
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# Internal function for creating a sine wave radiating out from a point
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def f(x1, y1, xp, yp, n):
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return sin(sqrt((x1 - self._canvas.width * xp) ** 2 +
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4 * ((y1 - self._canvas.height * yp) ** 2)) * pi / n)
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self._t += 1
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for y in range(self._canvas.height - 1):
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for x in range(self._canvas.width - 1):
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value = abs(f(x + self._t / 3, y, 1 / 4, 1 / 3, 15) +
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f(x, y, 1 / 8, 1 / 5, 11) +
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f(x, y + self._t / 3, 1 / 2, 1 / 5, 13) +
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f(x, y, 3 / 4, 4 / 5, 13)) / 4.0
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fg, attr = self._palette[
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int(round(value * (len(self._palette) - 1)))]
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char = self._greyscale[int((len(self._greyscale) - 1) * value)]
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self._write(char, x, y, fg, attr, 0)
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return self._plain_image, self._colour_map
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