#  Author:
#
#    Christian Hill
#
from wave_2d_pde import WaveEqn2D
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
#
print ( '' )
print ( 'reflecting():' )
print ( '  Wave equation in 2D with reflecting boundary conditions.' )
#
A = 80
T = 50
freq = 2 * np.pi / T

nx = 200
ny = 200
dt = 1
sim = WaveEqn2D ( nx, ny, dt=dt, use_mur_abc=False )

fig, ax = plt.subplots()
ax.axis("off")
ax.set_title ( 'Wave equation, reflecting BC' )

img = ax.imshow ( sim.u[0], vmin=0, vmax=40, cmap='Blues_r' )

def update(i):
    """Advance the simulation by one tick."""
    # A regular sinusoidal signal at the centre of the domain.
    sim.u[0, ny//2, nx//2] = A * np.sin(i * freq)
    sim.update()

def init():
    """
    Initialization, because we're blitting and need references to the
    animated objects.
    """
    return img,

def animate(i):
    """Draw frame i of the animation."""
    update(i)
    img.set_data(sim.u[0])
    return img,

interval = sim.dt
nframes = 1000

ani = animation.FuncAnimation (
  fig, 
  animate, 
  frames = nframes,
  repeat = False,
  init_func = init,
  interval = interval,
  blit = True )

plt.show()