I have been making a simulation or the n body problem and i have found that when i use a while loop and update the position at each step of the while loop it crashes. If i use a for loop it renders its position where it should be at the end of the for loop.
Here is the code:
import direct.directbase.DirectStart
from direct.showbase import DirectObject
from direct.interval.IntervalGlobal import *
from direct.gui.DirectGui import *
from direct.showbase.DirectObject import DirectObject
import time
import sys
import math
global masses
global dt
global models
global xcel
global xcel2
xcel = []
xcel2 = []
models = []
masses = []
positions = []
velocities = []
dt = 0.001
class mass(DirectObject):
def __init__(self):
base.setBackgroundColor(0, 0, 0)
camera.setPos ( 0, -100, 0 )
camera.setHpr ( 0, 0, 0 )
def createMass(self, name, mass, pos, vel):
self.name = name
self.mass = mass
self.pos = pos
positions.append(pos)
global positions
self.vel = vel
velocities.append(vel)
global velocities
def scaleRenderTexture(self, scale, tex):
self.model = loader.loadModel("models/sphere")
self.model.reparentTo(render)
texture = loader.loadTexture("models/" + tex)
self.model.setTexture(texture, 1)
self.model.setPos(self.pos[0], self.pos[1], self.pos[2])
self.model.setScale(scale)
masses.append(self.mass)
models.append(self.model)
class sun(mass):
def __init__(self):
mass.__init__(self)
self.createMass( 'sun', 1988920, [0, 0, 0], [0, 0, 0])
self.scaleRenderTexture(1, 'sun.jpg')
class mercury(mass):
def __init__(self):
mass.__init__(self)
self.createMass( 'mercury', 0.3302, [3.241862599523176, -5.623459942709265, -0.7569237943021074], [3.246868365706273*0.000001, 2.673977456413460*0.000001, -7.943396297475591*0.00000001])
self.scaleRenderTexture(0.5, 'mercury.jpg')
class venus(mass):
def __init__(self):
mass.__init__(self)
self.createMass('venus', 4.8685, [-1.034106071554218*10, -3.026887560710919, 5.553453628782571*0.1], [9.607057270995346*0.0000001, 9.607057270995346*0.000001, -1.017130175803783*0.0000001])
self.scaleRenderTexture(1, 'venus.jpg')
class earth(mass):
def __init__(self):
self.createMass('earth', 5.9736, [-1.156305861637755*10, -9.663398491949379, 3.476874978550299*0.0001], [ 1.862492028315679*0.000001, -2.296083935603351*0.000001, 9.235729792600083*0.00000000001])
self.scaleRenderTexture(1, 'earth.jpg')
class moon(mass):
def __init__(self):
mass.__init__(self)
self.createMass('moon', 0.07349, [-1.159098389232509*10, -9.637310345944113, -2.989940894073912*0.001], [1.798178987142885*0.000001, -2.375339761912065*0.000001, -2.207441445869889*0.000000001])
self.scaleRenderTexture(0.5, 'moon.jpg')
class mars(mass):
def __init__(self):
self.createMass('mars', 0.64185, [-2.422905158679938*10, -3.744196041373893, 5.164753385142086*0.1], [ 4.606798644725879*0.0000001, -2.187755639279240*0.000001, -5.715066713235196*0.00000001])
self.scaleRenderTexture(1, 'mars.jpg')
class jupiter(mass):
def __init__(self):
self.createMass('jupiter', 1898.6, [4.622321051914394*10, 5.871875615908649*10, -1.278226639349561], [-1.043365341857297*0.000001, 8.709856358914491*0.0000001, 1.972500372665064*0.00000001])
self.scaleRenderTexture(1, 'jupiter.jpg')
class saturn(mass):
def __init__(self):
self.createMass('saturn', 568.46, [-1.301371599111853*100, -6.476615242349228*10, 6.307409695374766], [3.772024323255900*0.0000001, -8.663132035152103*0.0000001, 5.618951648515438*0.00000000001])
self.scaleRenderTexture(1, 'saturn.jpg')
class uranus(mass):
def __init__(self):
self.createMass('uranus', 86.832, [2.992063464452280*100, 2.476994299596707*10, -3.783759032649831], [-6.199323493736431*0.000000001, 6.475569300476019*0.0000001, 3.210008048765792*0.000000001])
self.scaleRenderTexture(1, 'uranus.jpg')
class neptune(mass):
def __init__(self):
self.createMass('neptune', 102.43, [ 3.919464564967463*100, -2.185268039220477*100, -4.530872464442687], [2.601721469279150*0.0000001, 4.785231712545664*0.0000001, -1.579822877152521*0.000000001])
self.scaleRenderTexture(1, 'neptune.jpg')
class pluto(mass):
def __init__(self):
self.createMass('pluto', 0.0125, [ 6.480526105894912*10, -4.765510811963443*100, 3.226311175584855*10], [5.496347900202217*0.0000001, -3.260693806903501*0.00000001, -1.558804760367132*0.0000001])
self.scaleRenderTexture(0.5, 'pluto.jpg')
def calcA(bodies):
s = [0,0,0]
me = [0,0,0]
v = [0,0,0]
e = [0,0,0]
mo = [0,0,0]
ma = [0,0,0]
ju = [0,0,0]
s = [0,0,0]
u = [0,0,0]
n = [0,0,0]
p = [0,0,0]
xcel = [s, me, v, e, mo, ma, ju, s, u, n, p]
xcel2 = xcel
aX = 0
aY = 0
aZ = 0
for i in range(len(masses)):
xcel[i] = [aX, aY, aZ]
aX = 0
aY = 0
aZ = 0
for j in range(len(masses)):
if i!=j:
a = models[i].getPos()
b = models[j].getPos()
rx = b[0]-a[0]
ry = b[1]-a[1]
rz = b[2]-a[2]
r = math.sqrt(rx*rx+ry*ry+rz*rz)
xRatio = rx/(ry+rz)
yRatio = ry/(rx+rz)
zRatio = rz/(rx+ry)
acceleration = (9.81*float(masses[i]))/(r*r)
aX = aX + acceleration*xRatio
aY = aY + acceleration*yRatio
aZ = aZ + acceleration*zRatio
return(xcel)
def calcNextPos(models, xcel, velocities, dt):
for i in range(len(models)):
for j in range(3):
positions[i][j] = positions[i][j] + velocities[i][j]*dt + xcel[i][j]*0.5*dt*dt
updatePos(positions)
def calcNextVel(velocities, xcel, xcel2, dt):
for i in range(len(models)):
for j in range(3):
velocities[i][j] = velocities[i][j] + 0.5*(xcel[i][j] + xcel2[i][j])*dt
xcel = xcel2
def updatePos(positions):
for i in range(len(models)):
for j in range(3):
models[i].setPos(positions[i][0], positions[i][1], positions[i][2])
bodies = []
sun = sun()
mercury = mercury()
venus = venus()
earth = earth()
moon = moon()
mars = mars()
jupiter = jupiter()
saturn = saturn()
uranus = uranus()
neptune = neptune()
pluto = pluto()
xcel = calcA(bodies)
def mainLoop(xcel, models, masses, velocities):
calcNextPos(models, xcel, velocities, dt)
xcel2 = calcA(bodies)
calcNextVel(velocities, xcel, xcel2, dt)
run()Please if anyone could give me some help, as i dont quit understand how im supposed to call the mainLoop() with it crashing.
Thanks