78 lines
2.3 KiB
Python
78 lines
2.3 KiB
Python
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import pygame
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import math
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# FONT = pygame.font.SysFont("dejavu", 16)
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WIDTH, HEIGHT = 800, 800
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class Planet():
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# Astronomical unit (~ dist Earth - Sun)
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AU = 149.6e6 * 1000
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G = 6.67428e-11
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SCALE = 250 / AU # 1 AU = 100 px
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TIMESTEP = 3600 * 24 # 1 day
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def __init__(self, x, y, radius, color, mass, isSun = False) -> None:
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self.x = x
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self.y = y
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self.radius = radius
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self.color = color
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self.mass = mass
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self.orbit = []
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self.isSun = isSun
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self.distance_to_sun = 0
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self.x_vel = 0
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self.y_vel = 0
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def draw(self, win):
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x = self.x * self.SCALE + WIDTH / 2
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y = self.y * self.SCALE + HEIGHT / 2
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if len(self. orbit) > 2:
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updated_points = []
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for point in self.orbit:
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x, y = point
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x = x * self.SCALE + WIDTH / 2
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y = y * self.SCALE + HEIGHT / 2
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updated_points.append((x, y))
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pygame.draw.lines(win, self.color, False, updated_points, 2)
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pygame.draw.circle(win, self.color, (x, y), self.radius)
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# if not self.isSun:
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# distance_text = FONT.render(f"{round(self.distance_to_sun / 1000, 1)}km", 1, (255, 255, 255))
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# win.blit(distance_text, (x - distance_text.get_width() / 2, y - distance_text.get_height() / 2))
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def attraction(self, other):
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other_x, other_y = other.x, other.y
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distance_x = other_x - self.x
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distance_y = other_y - self.y
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distance = math.sqrt(distance_x**2 + distance_y**2)
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if other.isSun: self.distance_to_sun = distance
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force = self.G * self.mass * other.mass / distance**2
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theta = math.atan2(distance_y, distance_x)
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force_x = math.cos(theta) * force
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force_y = math.sin(theta) * force
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return force_x, force_y
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def update_position(self, planets):
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total_fx = total_fy = 0
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for planet in planets:
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if self == planet: continue
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fx, fy = self.attraction(planet)
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total_fx += fx
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total_fy += fy
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self.x_vel += total_fx / self.mass * self.TIMESTEP
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self.y_vel += total_fy / self.mass * self.TIMESTEP
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self.x += self.x_vel * self.TIMESTEP
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self.y += self.y_vel * self.TIMESTEP
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self.orbit.append((self.x, self.y))
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