用Processing来形成背景图

思路

用random函数生成随机数，根据其值来决定是往哪个方向移动

dx，dy用于记录四个方向

代码

int dis = 10;
int nowX, nowY, preX, preY;

int dx[] = {0, 0, -1, 1};
int dy[] = {1, -1, 0, 0};

void setup() 
{
    size(1920, 1080);
    nowX = preX = width / 2;
    nowY = preY = height / 2;
    frameRate(30);
}

void draw() 
{
    int val = int(random(0, 4));
    nowX += dx[val] * dis;
    nowY += dy[val] * dis;
    line(nowX, nowY, preX, preY);
    preX = nowX;
    preY = nowY;
}