Initial commit

.gitignore

@@ -0,0 +1 @@
+__pycache__

main.py

@@ -0,0 +1,51 @@
+# import math
+import pygame
+from planet import Planet
+
+pygame.init()
+
+WIDTH, HEIGHT = 800, 800
+
+WINDOW = pygame.display.set_mode((WIDTH, HEIGHT))
+pygame.display.set_caption("Planet simulation")
+
+YELLOW = (255, 255, 0)
+BLUE = (0, 0, 255)
+RED = (255, 0, 0)
+GRAY = (80, 78, 81)
+WHITE = (255, 255, 255)
+
+def main():
+    run = True
+    clock = pygame.time.Clock()
+
+
+    sun = Planet(0, 0, 30, YELLOW, 1.98892e30, True)
+    earth = Planet(-1 * Planet.AU, 0, 16, BLUE, 5.9742e24)
+    earth.y_vel = 29.783e3
+    mars = Planet(-1.524 * Planet.AU, 0, 12, RED, 6.39e23)
+    mars.y_vel = 24.077e3
+    mercury = Planet(0.387 * Planet.AU, 0, 8, GRAY, 3.3e23)
+    mercury.y_vel = -47.4e3
+    venus = Planet(0.723 * Planet.AU, 0, 14, WHITE, 4.8685e24)
+    venus.y_vel = -35.02e3
+
+    planets = [sun, earth, mars, mercury, venus]
+
+    while run:
+        # Cap the loop at 60 Hz
+        clock.tick(60)
+        WINDOW.fill((0, 0, 0))
+
+        for event in pygame.event.get():
+            if event.type == pygame.QUIT: run = False
+
+        for planet in planets:
+            planet.update_position(planets)
+            planet.draw(WINDOW)
+
+        pygame.display.update()
+
+    pygame.quit()
+
+main()

planet.py

@@ -0,0 +1,77 @@
+import pygame
+import math
+
+# FONT = pygame.font.SysFont("dejavu", 16)
+
+WIDTH, HEIGHT = 800, 800
+
+class Planet():
+    # Astronomical unit (~ dist Earth - Sun)
+    AU = 149.6e6 * 1000
+    G = 6.67428e-11
+    SCALE = 250 / AU # 1 AU = 100 px
+    TIMESTEP = 3600 * 24 # 1 day
+
+    def __init__(self, x, y, radius, color, mass, isSun = False) -> None:
+        self.x = x
+        self.y = y
+        self.radius = radius
+        self.color = color
+        self.mass = mass
+
+        self.orbit = []
+        self.isSun = isSun
+        self.distance_to_sun = 0
+
+        self.x_vel = 0
+        self.y_vel = 0
+    
+    def draw(self, win):
+        x = self.x * self.SCALE + WIDTH / 2
+        y = self.y * self.SCALE + HEIGHT / 2
+
+        if len(self. orbit) > 2:
+            updated_points = []
+            for point in self.orbit:
+                x, y = point
+                x = x * self.SCALE + WIDTH / 2
+                y = y * self.SCALE + HEIGHT / 2
+                updated_points.append((x, y))
+            pygame.draw.lines(win, self.color, False, updated_points, 2)
+
+        pygame.draw.circle(win, self.color, (x, y), self.radius)
+
+        # if not self.isSun:
+        #     distance_text = FONT.render(f"{round(self.distance_to_sun / 1000, 1)}km", 1, (255, 255, 255))
+        #     win.blit(distance_text, (x - distance_text.get_width() / 2, y - distance_text.get_height() / 2))
+
+    def attraction(self, other):
+        other_x, other_y = other.x, other.y
+        distance_x = other_x - self.x
+        distance_y = other_y - self.y
+        distance = math.sqrt(distance_x**2 + distance_y**2)
+
+        if other.isSun: self.distance_to_sun = distance
+
+        force = self.G * self.mass * other.mass / distance**2
+
+        theta = math.atan2(distance_y, distance_x)
+        force_x = math.cos(theta) * force
+        force_y = math.sin(theta) * force
+
+        return force_x, force_y
+
+    def update_position(self, planets):
+        total_fx = total_fy = 0
+        for planet in planets:
+            if self == planet: continue
+            fx, fy = self.attraction(planet)
+            total_fx += fx
+            total_fy += fy
+        self.x_vel += total_fx / self.mass * self.TIMESTEP
+        self.y_vel += total_fy / self.mass * self.TIMESTEP
+
+        self.x += self.x_vel * self.TIMESTEP
+        self.y += self.y_vel * self.TIMESTEP
+
+        self.orbit.append((self.x, self.y))