昨天围观简书线上元宵晚会，嘿嘿乐了一晚上，没写字。先水水一篇，近来在研究柏林噪声，看到的好例子（忘记地址了，稍后补上），先学习一下。

运行效果

一、分析

1、框架

  采用的pygame游戏框架，循环执行画图，按ESC推出

2、柏林噪声

  模块random_pos，调用柏林噪声函数，随机生成平滑的位置点（x，y）。

3、画方框

  模块draw_rec，有透明度。

4、填充方框

  模块fill_rect，填充方框，渐变，alpha值减少，透明度由低到高。

5、动态

  随机生成点画方框，下一个点是由柏林噪声函数生成，画面显示出方框平滑移动的动态效果。

二、代码

import pygame
from pygame.locals import *
import random
from noise import snoise2

pygame.init()
screen = pygame.display.set_mode((0,0),FULLSCREEN)  # Surface
W,H = screen.get_size()
canvas = screen.convert_alpha()
pygame.display.set_caption('my game')

x_scale,y_scale,scale = W/2,H/2,512
seed_x,seed_y = random.random(),random.random()
px,py = random.randint(0,100),random.randint(0,100)

def random_pos():
    global px,py
    px += 1
    py += 1
    x = int(W/2 - snoise2(px/scale,seed_y)*x_scale)
    y = int(H/2 - snoise2(seed_x,py/scale)*y_scale)
    return x,y

def draw_rect(x,y,width,height,alpha):
    pygame.draw.rect(canvas,(0,255,0,alpha),(x,y,width,height),3)


def fill_rect(x,y,n):
    wstep = W/n
    hstep = H/n
    sw = x / n
    sh = y / n
    sa = 200/n
    for i in range(n+1,0,-1):
        alpha = sa * i
        draw_rect(x-i*sw,y-i*sh,i*wstep,i*hstep,alpha)

x0,y0 = W/2,H/2

n = 30
bright = n
time_count = 0

pygame.mouse.set_visible(False)

clock = pygame.time.Clock()
running = True
while running:
    for event in pygame.event.get():
        if event.type == QUIT:
            running = False
        if event.type == KEYDOWN:
            if event.key == K_ESCAPE:
                running = False
    screen.fill(0)

    canvas.fill((0,0,0,0))
    # x0,y0 = pygame.mouse.get_pos()
    x0,y0 = random_pos()
    fill_rect(x0,y0,n)

    screen.blit(canvas,(0,0))
    pygame.display.update()
    clock.tick(60)
    
pygame.quit()

三、参考资料：

1、WilenWu-CSDN博客_python 柏林噪声：https://blog.csdn.net/qq_41518277/article/details/82779516
2、http://libnoise.sourceforge.net/index.html
3、https://www.cnblogs.com/leoin2012/p/7218033.html
4、Sengo的CSDN博客：https://blog.csdn.net/Sengo_GWU/article/details/80153638
5、《不只是噪声，更是数学美》：https://blog.csdn.net/qq_34302921/article/details/80849139