Start event when button is clicked with pygame

Question

Hey guys am new to pygame.I have developed a simple game in which the ball bounce each other.It works fine.

I have added a ui with buttons with options like new ga

Answer 1

So your problem is that, first you always draw the balls and second you don't check for a mouse click. An easy way to do this check is to call pygame.event.get([pygame.MOUSEBUTTONDOWN]) right where you check if the mouse position is over one of the options. If it returns something else than None stop displaying the options and start displaying the balls.

So you would do something like that: import pygame import math from itertools import cycle

OPTIONS = 0
BALLS = 1

def magnitude(v):
    return math.sqrt(sum(v[i]*v[i] for i in range(len(v))))

def add(u, v):
    return [ u[i]+v[i] for i in range(len(u)) ]

def sub(u, v):
    return [ u[i]-v[i] for i in range(len(u)) ]    

def dot(u, v):
    return sum(u[i]*v[i] for i in range(len(u)))

def normalize(v):
    vmag = magnitude(v)
    return [ v[i]/vmag  for i in range(len(v)) ]

screen = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()  



class Ball(object):
    def __init__(self, path):
        self.x, self.y = (0, 0)
        self.img = pygame.image.load('/home/wastl/Documents/DSC_0051.JPG')
        self.speed = 2.5
        self.color = (200, 200, 200)
        self.path = cycle(path)
        self.set_target(next(self.path))
        #self.sound = pygame.mixer.music.load('yeah.mp3')


    @property
    def pos(self):
        return self.x, self.y

# for drawing, we need the position as tuple of ints
# so lets create a helper property
    @property
    def int_pos(self):
        return map(int, self.pos)

    @property
    def target(self):
        return self.t_x, self.t_y

    @property
    def int_target(self):
        return map(int, self.target)   

    def next_target(self):
        self.set_target(self.pos)
        self.set_target(next(self.path))

    def set_target(self, pos):
        self.t_x, self.t_y = pos

    def update(self):
    # if we won't move, don't calculate new vectors
        if self.int_pos == self.int_target:
            return self.next_target()

        target_vector = sub(self.target, self.pos) 

    # a threshold to stop moving if the distance is to small.
    # it prevents a 'flickering' between two points
        if magnitude(target_vector) < 2: 
            return self.next_target()

    # apply the balls's speed to the vector
        move_vector = [c * self.speed for c in normalize(target_vector)]

    # update position
        self.x, self.y = add(self.pos, move_vector)

    def draw(self):
        screen.blit(self.img, self.int_pos)
        #pygame.mixer.music.play()

class Option:



    def __init__(self, text, pos):
        self.hovered = False
        self.text = text
        self.pos = pos
        self.set_rect()
        self.draw()

    def draw(self):
        self.set_rend()
        screen.blit(self.rend, self.rect)

    def set_rend(self):
        self.rend = menu_font.render(self.text, True, self.get_color())

    def get_color(self):
        if self.hovered:
            return (255, 255, 255)
        else:
            return (100, 100, 100)

    def set_rect(self):
        self.set_rend()
        self.rect = self.rend.get_rect()
        self.rect.topleft = self.pos

pygame.init()
quit = False
path = [(26, 43),(105, 110),(45, 225),(145, 295),(266, 211),(178, 134),(250,5),(147,12)] 

path2 = [(26, 43),(105, 10),(45, 125),(150, 134),(150, 26),(107, 12)]


ball = Ball(path)

ball.speed = 1.9

ball2 = Ball(path2)

ball2.color = (200, 200, 0)

balls = [ball, ball2]


screen = pygame.display.set_mode((480, 320))

menu_font = pygame.font.Font(None, 40)

options = [Option("NEW GAME", (140, 105)), Option("LOAD GAME", (135, 155)),
       Option("OPTIONS", (145, 205))]

STATE = OPTIONS

while not quit:

    pygame.event.pump()
    screen.fill((0, 0, 0))

    if STATE == OPTIONS:

        for option in options:
            if option.rect.collidepoint(pygame.mouse.get_pos()):
                option.hovered = True
                if pygame.event.get([pygame.MOUSEBUTTONDOWN]) and option.text == "NEW GAME":
                    STATE = BALLS
            else:
                option.hovered = False
            option.draw()
            pygame.display.update()

    elif STATE == BALLS:
        map(Ball.update, balls)

        screen.fill((0, 0, 0))

        map(Ball.draw, balls)

        pygame.display.flip()


    quit = pygame.event.get(pygame.QUIT)
    pygame.event.poll()

    clock.tick(60)