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()
alphablend = Transparency(blendSource=GL_SRC_ALPHA,blendDest=GL_ONE_MINUS_SRC_ALPHA)

GravityAccel = Vector([0, -9.8, 0])
WaterDensity = 1
WaterDrag = 1
AirDrag = 0.1

class Object:
	def __init__(self, pos=Vector([0,0,0]), vel=Vector([0,0,0]), mass=1.0, radius=1.0, material=Material()):
		self.pos = pos
		self.vel = vel
		self.mass = mass
		self.radius = radius
		self.material = material
	def draw(self):
		self.material.apply()
		glPushMatrix()
		glTranslatef(self.pos[0], self.pos[1], self.pos[2])
		gluSphere(quadric, self.radius, 16, 8)
		glPopMatrix()
		self.material.disable()
	def update(self, dt):
		force = Vector([0, 0, 0])
		force += GravityAccel * self.mass
		if self.pos[1] < 0:
			volume = 4 * math.pi * self.radius * self.radius * self.radius / 3
			force += -GravityAccel * WaterDensity * volume
			force += -self.vel * WaterDrag
		else:
			force += -self.vel * AirDrag
		acc = force / self.mass
		self.vel += acc * dt
		self.pos += self.vel * dt

objects = []
objects.append(Object(pos=Vector([-4, 16, 0]), mass=1.0, radius=1.0, material=Material(diffuse=Color.Red)))
objects.append(Object(pos=Vector([4, 16, 0]), mass=1.0, radius=3.0, material=Material(diffuse=Color.Green)))

active = False

def draw():
    Color.Black.clear()
    camera.apply()

    light.apply()
    for o in objects: o.draw()
    
    alphablend.apply()
    glColor4f(0, 0, 1, 0.5)
    glBegin(GL_QUADS)
    glVertex3f(-25, -25, 10)
    glVertex3f(25, -25, 10)
    glVertex3f(25, 0, 10)
    glVertex3f(-25, 0, 10)
    glEnd()
    alphablend.disable()

    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 o in objects:
            o.update(dt)
    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()