#MonthOfCode day 24 - space

day_24.py

import pygame
from time import sleep
import random
from math import cos,sin,pi
DISP_WIDTH = 800
DISP_HEIGHT = 600

class MobileElement:
    MOMENTUM = 0.985
    '''abstract class representing something that moves'''
    def __init__(self, x_init,y_init, vx_init, vy_init):
        self.vx, self.vy = vx_init, vy_init
        self.x,self.y = float(x_init), float(y_init)
        self.disp_x, self.disp_y = int(round(x_init)), int(round(y_init))
        self.color= tuple( [random.randint(64,255) for i in xrange(3) ]  )

    def updatePosition( self ):
        self.x += self.vx
        self.y += self.vy
        self.vx *= MobileElement.MOMENTUM
        self.vy *= MobileElement.MOMENTUM

    def markToDisplay( self, surface):
        raise Exception('please implement this function')


class SpaceShip(MobileElement):
    '''models a moving triangle that can turn, accelerate and spawn particles'''

    BASECOLOR = pygame.Color('blue')
    BASE_SPEED = 10
    DELTA_ROTATION = 0.1

    def __init__(self, x_init, y_init):
        MobileElement.__init__(self, x_init, y_init, 0., 0. )
        self.color = SpaceShip.BASECOLOR

        self.angle = 0.
        self.rotating_right = False
        self.rotating_left = False
        self.accelerating = False
        self.time_accel = 0
        self.pts_calculators = [
            lambda x,y,angle: ( x + ( 0. *  cos(angle) - (-30.) * sin(angle) ),
                 y + ( 0 * sin(angle) + (-40.) * cos(angle))  ),
            lambda x,y,angle: ( x + ( -15.0 * cos(angle) - 10. * sin(angle) ),
                 y + ( -15.0 * sin(angle) + 10. * cos(angle))  ),
            lambda x,y,angle: ( x + ( 15.0 * cos(angle) - 10. * sin(angle) ),
                 y + ( 15.0 * sin(angle) + 10. * cos(angle))  )
             ]

    def startAcceleration(self):
        self.color = pygame.Color('lightblue')
        self.accelerating = True

    def stopAcceleration(self):
        self.color = SpaceShip.BASECOLOR
        self.accelerating = False
        self.time_accel = 0

    def markToDisplay(self, surface):
        pygame.draw.polygon( surface,
            self.color,
            [ f(self.x,self.y, self.angle) for f in self.pts_calculators ]  )

    def updatePosition( self ):
        if(self.rotating_right):
            self.angle+= SpaceShip.DELTA_ROTATION
            if self.angle>2*pi:
                self.angle = self.angle-(2*pi)

        if(self.rotating_left):
            self.angle-= SpaceShip.DELTA_ROTATION
            if self.angle<0:
                self.angle = (2*pi) -self.angle

        if self.accelerating:
            ship_front = self.pts_calculators[0]( self.x, self.y, self.angle)
            bonus_vx =  ship_front[0]-self.x
            bonus_vy =  ship_front[1]-self.y 
            if (self.time_accel< 4096 ):
                self.time_accel+= 1
            self.vx += ( 0.000001 * SpaceShip.BASE_SPEED * self.time_accel * bonus_vx)
            self.vy += ( 0.000001 * SpaceShip.BASE_SPEED * self.time_accel * bonus_vy)
        MobileElement.updatePosition( self)
        # making the SPACE a torus-like topology
        if( self.y<0 ):
            self.y=DISP_HEIGHT-1
        elif(self.y>=DISP_HEIGHT):
            self.y=0
        if( self.x<0 ):
            self.x=DISP_WIDTH-1
        elif(self.x>=DISP_WIDTH):
            self.x=0

def refreshScreen():
    window.fill(  pygame.Color('black') )
    ship.markToDisplay(window )
    pygame.display.flip() 

# init. pygame libr; create the screen and diplays a help message in the console
pygame.init() 
window = pygame.display.set_mode( (DISP_WIDTH, DISP_HEIGHT) )
ship = SpaceShip( DISP_WIDTH/2, DISP_HEIGHT/2 )
program_done = False
refreshScreen()
while not program_done: 
    for event in pygame.event.get(): 
        if event.type == pygame.QUIT: 
            program_done = True
            break 
        if event.type is pygame.KEYDOWN:
            if( pygame.key.get_pressed()[ pygame.K_UP ] ):
                ship.startAcceleration()
            if( pygame.key.get_pressed()[ pygame.K_RIGHT ] ):
                ship.rotating_right=True
            if( pygame.key.get_pressed()[ pygame.K_LEFT ] ):
                ship.rotating_left=True
        if event.type is pygame.KEYUP:
            if( not pygame.key.get_pressed()[ pygame.K_UP ] ):
                ship.stopAcceleration()
            if( not pygame.key.get_pressed()[ pygame.K_RIGHT ] ):
                ship.rotating_right=False
            if( not pygame.key.get_pressed()[ pygame.K_LEFT ] ):
                ship.rotating_left=False
    ship.updatePosition()
    refreshScreen()
    sleep(0.01)