import sys, time, math
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *
from dmsgl import *

camera = OrthoCamera(-25,25, -25,25, -25,25)

light = Light()

GRAV_CONSTANT = 1


class Planet:
	def __init__(self, pos=Vector([0,0,0]), vel=Vector([0,0,0]), mass=1.0, material=Material()):
		self.pos = pos
		self.vel = vel
		self.mass = mass
		self.material = material
	def draw(self):
		self.material.apply()
		glPushMatrix()
		glTranslatef(self.pos[0], self.pos[1], self.pos[2])
		gluSphere(quadric, 1.0, 16, 8)
		glPopMatrix()
		self.material.disable()
	def update(self, dt, planets):
		force = Vector([0, 0, 0])
		for p in planets:
			if p != self:
				f = GRAV_CONSTANT * self.mass * p.mass / self.pos.distanceSquared(p.pos)
				dir = p.pos - self.pos
				dir.normalize()
				force += dir * f
		acc = force / self.mass
		self.vel += acc * dt
		self.pos += self.vel * dt

planets = []
planets.append(Planet(mass=10000, material=Material(diffuse=Color.Yellow)))
planets.append(Planet(pos=Vector([10,0,0]), vel=Vector([0,28,0]), mass=100.0, material=Material(diffuse=Color.Green)))
planets.append(Planet(pos=Vector([-14,0,0]), vel=Vector([0,-24,0]), mass=50.0, material=Material(diffuse=Color.Cyan)))
planets.append(Planet(pos=Vector([0,-16,0]), vel=Vector([-30,0,0]), mass=2.0, material=Material(diffuse=Color.White)))

active = False

def draw():
    Color.Black.clear()
    camera.apply()
    
    light.apply()
    for p in planets: p.draw()

    glutSwapBuffers()


def keyboard(key, x, y):
    global active
    if key == chr(27):
        sys.exit(0)
    elif key == ' ':
        active = not active

prevTime = time.time()

def update():
    global prevTime, active
    t = time.time()
    dt = t - prevTime
    prevTime = t
    if active:
        for p in planets:
            p.update(dt, planets)
    glutPostRedisplay()

glutInit([])
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH)
glutInitWindowSize(400,400)
glutCreateWindow(sys.argv[0])
glutDisplayFunc(draw)
glutKeyboardFunc(keyboard)
glutIdleFunc(update)
glEnable(GL_DEPTH_TEST)
quadric = gluNewQuadric()
glutMainLoop()