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

gravity = Vector([0, -9.8, 0])

tex = Texture2D('waterdrop.png')

class particle:
    def __init__(self, pos=Vector([0,0,0])):
        self.pos = pos
        self.vel = Vector([uniform(-3,3), 5, uniform(-3,3)])
        self.removeTime = time.time() + uniform(0.5,2)
    def update(self, dt):
        self.pos += self.vel * dt
        self.vel += gravity * dt

class particleSystem:
    def __init__(self, num=1):
        self.particles = []
        self.addParticles(num)
    def addParticles(self, num):
        for i in range(0,num):
            p = particle()
            self.particles.append(p)
    def draw(self):
        glColor3f(1,1,1)
        tex.apply()
        glEnable(GL_BLEND)
        glBlendFunc(GL_ONE, GL_ONE)
        glDepthMask(GL_FALSE)
        glBegin(GL_QUADS)
        for p in self.particles:
            glTexCoord2f(0,0)
            glVertex3f(p.pos[0]-0.2, p.pos[1]-0.2, p.pos[2])
            glTexCoord2f(1,0)
            glVertex3f(p.pos[0]+0.2, p.pos[1]-0.2, p.pos[2])
            glTexCoord2f(1,1)
            glVertex3f(p.pos[0]+0.2, p.pos[1]+0.2, p.pos[2])
            glTexCoord2f(0,1)
            glVertex3f(p.pos[0]-0.2, p.pos[1]+0.2, p.pos[2])
        glEnd()
        glDepthMask(GL_TRUE)
        glDisable(GL_BLEND)
        tex.disable()
    def update(self, dt):
        for p in self.particles:
            p.update(dt)
        t = time.time()
        for i in range(len(self.particles)-1, -1, -1):
            if (self.particles[i].removeTime <= t) or (self.particles[i].pos[1] < 0):
                del self.particles[i]
                self.addParticles(1)

systems = [particleSystem(100)]

camera = PerspCamera()
camera.moveBackward(5)
camera.moveUp(1)


def draw():
    Color.Green.clear()

    camera.apply()

    for s in systems: s.draw()

    glutSwapBuffers()


def keyboard(key, x, y):
    global viewDistance
    if key == chr(27):
        sys.exit(0)
    elif key == '.':
        camera.moveForward(1)
    elif key == ',':
        camera.moveBackward(1)

def specialkey(key,x,y):
    global cameraVelX, cameraVelY
    if key == GLUT_KEY_LEFT:
        cameraVelY += 90
    elif key == GLUT_KEY_RIGHT:
        cameraVelY -= 90
    elif key == GLUT_KEY_UP:
        cameraVelX += 90
    elif key == GLUT_KEY_DOWN:
        cameraVelX -= 90

def specialkeyUp(key,x,y):
    global cameraVelX, cameraVelY
    if key == GLUT_KEY_LEFT:
        cameraVelY -= 90
    elif key == GLUT_KEY_RIGHT:
        cameraVelY += 90
    elif key == GLUT_KEY_UP:
        cameraVelX -= 90
    elif key == GLUT_KEY_DOWN:
        cameraVelX += 90


cameraVelX = 0.0
cameraVelY = 0.0
prevTime = time.time()

def update():
    global viewRotX, viewRotY, cameraVelX, cameraVelY
    global prevTime
    t = time.time()
    dt = t - prevTime
    prevTime = t
    camera.pitch(cameraVelX * dt)
    camera.turn(cameraVelY * dt)
    for s in systems: s.update(dt)
    for i in range(len(systems)-1, -1, -1):
        if len(systems[i].particles) == 0:
            del systems[i]
    glutPostRedisplay()

glutInit([])
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH)
glutInitWindowSize(400,400)
glutCreateWindow(sys.argv[0])
glutDisplayFunc(draw)
glutKeyboardFunc(keyboard)
glutSpecialFunc(specialkey)
glutSpecialUpFunc(specialkeyUp)
glutIgnoreKeyRepeat(1)
glutIdleFunc(update)
glEnable(GL_DEPTH_TEST)
glutMainLoop()