pixelserver2/apps/lines.py

#!/usr/bin/env python3

import os
import sys
import random 
import time
import random
import colorsys

Nx = int(sys.argv[1])
Ny = int(sys.argv[2])

PixelsPerFrame = 20
NumLines = 7
LineGenerationRate = 0.2
time_ms = 20
try:
    time_ms = int(sys.argv[3])
except:
    pass
buffer = bytearray(b"\x00" * (3 * Nx * Ny))

def SetPixel(x, y, r, g, b):
    idx = x+Nx*y
    buffer[3*idx+0] = r
    buffer[3*idx+1] = g
    buffer[3*idx+2] = b


class Line:
    def __init__(self):
        self.color = random.random()*0.3+0.7
        self.dir = random.randint(0, 3)
        if self.dir == 0:
            self.posx = 0
            self.posy = random.randint(0, Ny-1)
        if self.dir == 1:
            self.posx = Nx-1
            self.posy = random.randint(0, Ny-1)
        if self.dir == 2:
            self.posx = random.randint(0, Nx-1)
            self.posy = 0
        if self.dir == 3:
            self.posx = random.randint(0, Nx-1)
            self.posy = Ny-1

    def step(self):
        self.color *= 0.995
        pixel = int(self.color*255)
        SetPixel(self.posx, self.posy, pixel, pixel, pixel)
        if self.dir == 0:
            self.posx += 1
        if self.dir == 1:
            self.posx -= 1
        if self.dir == 2:
            self.posy += 1
        if self.dir == 3:
            self.posy -= 1

    def alive(self):
        return self.posx >= 0 and self.posx < Nx and self.posy >= 0 and self.posy < Ny

lines = []
while True:
    for i in range(PixelsPerFrame):
        x = random.randint(0, Nx-1)
        y = random.randint(0, Ny-1)
        r, g, b = colorsys.hsv_to_rgb(random.random(), 0.7, 0.5)
        r = int(r*255)
        g = int(g*255)
        b = int(b*255)
        SetPixel(x, y, r, g, b)
    for line in lines:
        line.step()
        if not line.alive():
            lines.remove(line)
    if len(lines) < NumLines and random.random() < LineGenerationRate:
        lines.append(Line())
    os.write(1, buffer)
    time.sleep(time_ms*0.001)