雨模拟

通过设置50个散点的比例和不透明度来模拟表面上的雨滴。

作者：Nicolas P. Rougier

雨模拟示例

  1. import numpy as np
  2. import matplotlib.pyplot as plt
  3. from matplotlib.animation import FuncAnimation
  5. # Fixing random state for reproducibility
  6. np.random.seed(19680801)
  9. # Create new Figure and an Axes which fills it.
  10. fig = plt.figure(figsize=(7, 7))
  11. ax = fig.add_axes([0, 0, 1, 1], frameon=False)
  12. ax.set_xlim(0, 1), ax.set_xticks([])
  13. ax.set_ylim(0, 1), ax.set_yticks([])
  15. # Create rain data
  16. n_drops = 50
  17. rain_drops = np.zeros(n_drops, dtype=[('position', float, 2),
  18.                                       ('size',     float, 1),
  19.                                       ('growth',   float, 1),
  20.                                       ('color',    float, 4)])
  22. # Initialize the raindrops in random positions and with
  23. # random growth rates.
  24. rain_drops['position'] = np.random.uniform(0, 1, (n_drops, 2))
  25. rain_drops['growth'] = np.random.uniform(50, 200, n_drops)
  27. # Construct the scatter which we will update during animation
  28. # as the raindrops develop.
  29. scat = ax.scatter(rain_drops['position'][:, 0], rain_drops['position'][:, 1],
  30.                   s=rain_drops['size'], lw=0.5, edgecolors=rain_drops['color'],
  31.                   facecolors='none')
  34. def update(frame_number):
  35.     # Get an index which we can use to re-spawn the oldest raindrop.
  36.     current_index = frame_number % n_drops
  38.     # Make all colors more transparent as time progresses.
  39.     rain_drops['color'][:, 3] -= 1.0/len(rain_drops)
  40.     rain_drops['color'][:, 3] = np.clip(rain_drops['color'][:, 3], 0, 1)
  42.     # Make all circles bigger.
  43.     rain_drops['size'] += rain_drops['growth']
  45.     # Pick a new position for oldest rain drop, resetting its size,
  46.     # color and growth factor.
  47.     rain_drops['position'][current_index] = np.random.uniform(0, 1, 2)
  48.     rain_drops['size'][current_index] = 5
  49.     rain_drops['color'][current_index] = (0, 0, 0, 1)
  50.     rain_drops['growth'][current_index] = np.random.uniform(50, 200)
  52.     # Update the scatter collection, with the new colors, sizes and positions.
  53.     scat.set_edgecolors(rain_drops['color'])
  54.     scat.set_sizes(rain_drops['size'])
  55.     scat.set_offsets(rain_drops['position'])
  58. # Construct the animation, using the update function as the animation director.
  59. animation = FuncAnimation(fig, update, interval=10)
  60. plt.show()

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