101 lines
2.7 KiB
Python
101 lines
2.7 KiB
Python
|
#!/usr/bin/env python
|
||
|
|
""" pg.examples.stars
|
||
|
|
|
||
|
|
We are all in the gutter,
|
||
|
|
but some of us are looking at the stars.
|
||
|
|
-- Oscar Wilde
|
||
|
|
|
||
|
|
A simple starfield example. Note you can move the 'center' of
|
||
|
|
the starfield by leftclicking in the window. This example show
|
||
|
|
the basics of creating a window, simple pixel plotting, and input
|
||
|
|
event management.
|
||
|
|
"""
|
||
|
|
import random
|
||
|
|
import math
|
||
|
|
import pygame as pg
|
||
|
|
|
||
|
|
# constants
|
||
|
|
WINSIZE = [640, 480]
|
||
|
|
WINCENTER = [320, 240]
|
||
|
|
NUMSTARS = 150
|
||
|
|
|
||
|
|
|
||
|
|
def init_star(steps=-1):
|
||
|
|
"creates new star values"
|
||
|
|
dir = random.randrange(100000)
|
||
|
|
steps_velocity = 1 if steps == -1 else steps * 0.09
|
||
|
|
velmult = steps_velocity * (random.random() * 0.6 + 0.4)
|
||
|
|
vel = [math.sin(dir) * velmult, math.cos(dir) * velmult]
|
||
|
|
|
||
|
|
if steps is None:
|
||
|
|
return [vel, [WINCENTER[0] + (vel[0] * steps), WINCENTER[1] + (vel[1] * steps)]]
|
||
|
|
return [vel, WINCENTER[:]]
|
||
|
|
|
||
|
|
|
||
|
|
def initialize_stars():
|
||
|
|
"creates a new starfield"
|
||
|
|
random.seed()
|
||
|
|
stars = [init_star(steps=random.randint(0, WINCENTER[0])) for _ in range(NUMSTARS)]
|
||
|
|
move_stars(stars)
|
||
|
|
return stars
|
||
|
|
|
||
|
|
|
||
|
|
def draw_stars(surface, stars, color):
|
||
|
|
"used to draw (and clear) the stars"
|
||
|
|
for _, pos in stars:
|
||
|
|
pos = (int(pos[0]), int(pos[1]))
|
||
|
|
surface.set_at(pos, color)
|
||
|
|
|
||
|
|
|
||
|
|
def move_stars(stars):
|
||
|
|
"animate the star values"
|
||
|
|
for vel, pos in stars:
|
||
|
|
pos[0] = pos[0] + vel[0]
|
||
|
|
pos[1] = pos[1] + vel[1]
|
||
|
|
if not 0 <= pos[0] <= WINSIZE[0] or not 0 <= pos[1] <= WINSIZE[1]:
|
||
|
|
vel[:], pos[:] = init_star()
|
||
|
|
else:
|
||
|
|
vel[0] = vel[0] * 1.05
|
||
|
|
vel[1] = vel[1] * 1.05
|
||
|
|
|
||
|
|
|
||
|
|
def main():
|
||
|
|
"This is the starfield code"
|
||
|
|
# create our starfield
|
||
|
|
stars = initialize_stars()
|
||
|
|
|
||
|
|
# initialize and prepare screen
|
||
|
|
pg.init()
|
||
|
|
screen = pg.display.set_mode(WINSIZE)
|
||
|
|
pg.display.set_caption("pygame Stars Example")
|
||
|
|
white = 255, 240, 200
|
||
|
|
black = 20, 20, 40
|
||
|
|
screen.fill(black)
|
||
|
|
|
||
|
|
clock = pg.time.Clock()
|
||
|
|
|
||
|
|
# main game loop
|
||
|
|
done = 0
|
||
|
|
while not done:
|
||
|
|
draw_stars(screen, stars, black)
|
||
|
|
move_stars(stars)
|
||
|
|
draw_stars(screen, stars, white)
|
||
|
|
pg.display.update()
|
||
|
|
for e in pg.event.get():
|
||
|
|
if e.type == pg.QUIT or (e.type == pg.KEYUP and e.key == pg.K_ESCAPE):
|
||
|
|
done = 1
|
||
|
|
break
|
||
|
|
if e.type == pg.MOUSEBUTTONDOWN and e.button == 1:
|
||
|
|
WINCENTER[:] = list(e.pos)
|
||
|
|
clock.tick(50)
|
||
|
|
pg.quit()
|
||
|
|
|
||
|
|
|
||
|
|
# So `python -m pygame.example.stars` will work.
|
||
|
|
if __name__ == "__main__":
|
||
|
|
main()
|
||
|
|
|
||
|
|
# I prefer the time of insects to the time of stars.
|
||
|
|
#
|
||
|
|
# -- Wisława Szymborska
|