Code for How to Make a Planet Simulator with PyGame in Python Tutorial

planet_simulator.py

# Imports
import sys
import pygame

# We will work with the Vector2 because it has some useful functions.
from pygame.math import Vector2

from random import randrange

import ctypes

# Enable High Dots Per Inch so the image displayed on the window is sharper.
ctypes.windll.shcore.SetProcessDpiAwareness(1)

# Configuration
pygame.init()
fps = 60
fpsClock = pygame.time.Clock()

# Window Size
windowdim = Vector2(800, 800)
screen = pygame.display.set_mode((int(windowdim.x), int(windowdim.y)))

# all the Planets are stored here
# They will append themselves.
planets = []

# The Planet Class which will handle drawing and calculating planets.
class Planet():
    def __init__(self, position, delta=Vector2(0, 0), radius=10, imovable=False):

        # Where the planet is at the moment
        self.position = position

        # The Radius determines how much this planet effects others
        self.radius = radius

        # The Velocity
        self.delta = delta

        # If this planet is moving
        self.imovable = imovable

        # If this planet can be eaten by others.
        self.eatable = False


        # Appending itself to the list so its process
        # function will later be called in a loop.
        planets.append(self)


    def process(self):
        # This function will be called once every frame 
        # and it is responsible for calculating where the planet will go.

        # No Movement Calculations will happen if the planet doesnt move at all.
        # it also wont be eaten.
        if not self.imovable:
            for i in planets:

                if not i is self:
                    try:
                        if self.eatable:
                            if self.position.distance_to(i.position) < self.radius + i.radius:
                                print('Eaten')

                                i.radius += self.radius

                                planets.remove(self)

                        dir_from_obj  = (i.position - self.position).normalize() * 0.01 * (i.radius / 10)
                        self.delta += dir_from_obj

                    except:
                        print('In the same spot')

            self.position += self.delta

        # Drawing the planet at the current position.
        pygame.draw.circle(
            screen,
            [255, 255, 255],
            self.position,
            self.radius,
        )

# Sun and two opposing Planets
""" Planet(Vector2(400, 400), radius=50, imovable=True)

Planet(Vector2(400, 200), delta=Vector2(3, 0), radius=10)
Planet(Vector2(400, 600), delta=Vector2(-3, 0), radius=10) """

# Sun and four opposing Planets
""" Planet(Vector2(400, 400), radius=50, imovable=True)

Planet(Vector2(400, 200), delta=Vector2(3, 0), radius=10)
Planet(Vector2(400, 600), delta=Vector2(-3, 0), radius=10)
Planet(Vector2(600, 400), delta=Vector2(0, 3), radius=10)
Planet(Vector2(200, 400), delta=Vector2(0, -3), radius=10) """

# Two Suns and two planets
""" Planet(Vector2(600, 400), radius=20, imovable=True)
Planet(Vector2(200, 400), radius=20, imovable=True)

Planet(Vector2(400, 200), delta=Vector2(0, 0), radius=10)
Planet(Vector2(400, 210), delta=Vector2(1, 2), radius=5) """

# Grid
gridDimension = 10
gridgap = 80
for x in range(gridDimension):
    for y in range(gridDimension):
        Planet(Vector2(gridgap * x + 40, gridgap * y + 40), radius=3, imovable=True)

Planet(Vector2(200, 200), delta=Vector2(randrange(-3, 3), 2), radius=5)

# Game loop.
while  True:
    screen.fill((0, 0, 0))
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    for p in planets:
        p.process()

    pygame.display.flip()
    fpsClock.tick(fps)