def main():
pygame.init()
SCREEN_WIDTH = 1000
SCREEN_HEIGHT = 700
SCREEN_CENTRE = Vector2(SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2)
# Scale in pixels per metre
# 100 pix = 1 AU
UNIVERSE = Universe(CONST.AU / 100, 2**23)
CAMERA = Camera(SCREEN_CENTRE)
DISPLAY = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))
CLOCK = pygame.time.Clock()
FPS = 120
moveData = {
"mouseHeld": False,
"tempRelMass": 1,
"tempBody": None,
"lastPos": (0, 0),
"currentPos": (0, 0),
"lastTime": -1,
"currentTime": 0
}
bodies = []
font = pygame.font.SysFont("monospace", 15)
while True:
DISPLAY.fill(BLACK)
realDeltaT = (CLOCK.get_time() / 1000)
UNIVERSE.update(realDeltaT)
deltaT = UNIVERSE.deltaT(realDeltaT)
for e in pygame.event.get():
if e.type == pygame.QUIT:
pygame.quit()
elif e.type == pygame.KEYDOWN:
if e.key == pygame.K_PERIOD:
UNIVERSE.accelTime(2)
elif e.key == pygame.K_COMMA:
UNIVERSE.accelTime(1 / 2)
elif e.type == pygame.MOUSEBUTTONDOWN:
if e.button == 1:
moveData["mouseHeld"] = True
moveData["tempRelMass"] = 1
moveData["currentPos"] = e.pos
moveData["lastPos"] = e.pos
moveData["lastTime"] = -1
moveData["currentTime"] = UNIVERSE.totalTime
# The body's position will be set later before drawing
moveData["tempBody"] = Body(
Vector2(), moveData["tempRelMass"] * CONST.ME)
elif e.button == 4:
if moveData["mouseHeld"]:
if pygame.KMOD_SHIFT & pygame.key.get_mods():
moveData["tempRelMass"] *= 2**(2 / 3)
else:
moveData["tempRelMass"] *= 2**(1 / 3)
moveData["tempBody"].setMass(moveData["tempRelMass"] *
CONST.ME)
else:
CAMERA.resize(2)
elif e.button == 5:
if moveData["mouseHeld"]:
if pygame.KMOD_SHIFT & pygame.key.get_mods():
moveData["tempRelMass"] /= 2**(2 / 3)
else:
moveData["tempRelMass"] /= 2**(1 / 3)
moveData["tempBody"].setMass(moveData["tempRelMass"] *
CONST.ME)
else:
CAMERA.resize(1 / 2)
elif e.type == pygame.MOUSEBUTTONUP:
if e.button == 1:
moveData["mouseHeld"] = False
tempBody = moveData["tempBody"]
beginPos = Vector2(moveData["lastPos"])
endPos = Vector2(moveData["currentPos"])
# Calculate last velocity of mouse
if not (pygame.KMOD_CTRL & pygame.key.get_mods()):
if moveData["currentTime"] - moveData["lastTime"] == 0:
print("Oops... zero-division avoided!")
else:
dampener = 2
distance = UNIVERSE.screenToWorld(
(endPos - beginPos)) / (CAMERA.scale *
dampener)
velocity = distance / (moveData["currentTime"] -
moveData["lastTime"])
tempBody.velocity = velocity
bodies.append(tempBody)
moveData["tempBody"] = None
print("Created body with mass {:.4e}kg".format(
tempBody.mass))
elif e.type == pygame.MOUSEMOTION:
if moveData["mouseHeld"]:
moveData["lastPos"] = moveData["currentPos"]
moveData["lastTime"] = moveData["currentTime"]
moveData["currentPos"] = e.pos
moveData["currentTime"] = UNIVERSE.totalTime
CAMERA.handleInput(realDeltaT)
# Update pos always, and now so that we can take into account any camera moves
if moveData["mouseHeld"]:
bodyPos = UNIVERSE.screenToWorld(
CAMERA.reverseDrawPos(moveData["currentPos"]))
moveData["tempBody"].setPos(bodyPos)
if moveData["tempBody"]:
moveData["tempBody"].draw(DISPLAY, CAMERA, UNIVERSE)
for body in bodies:
body.update(deltaT, bodies)
for body in bodies:
body.draw(DISPLAY, CAMERA, UNIVERSE)
lineY = SCREEN_HEIGHT - 10
pygame.draw.line(DISPLAY, WHITE, (10, lineY), (110, lineY), 2)
drawText(DISPLAY,
readableDistance(UNIVERSE.scale * 100 / CAMERA.scale), font,
(120, lineY - 10), WHITE)
# Draw UI
drawText(DISPLAY, "Time scale: {}x".format(UNIVERSE.timeScale), font,
(10, 10), WHITE)
drawText(
DISPLAY,
"Time elapsed: {}".format(secondsToTimeString(UNIVERSE.totalTime)),
font, (10, 30), WHITE)
# drawText(DISPLAY, "Camera scale: {:.2e}x".format(CAMERA.scale), font, (SCREEN_WIDTH - 10, 10), WHITE, False)
pygame.display.update()
CLOCK.tick(FPS)
