PyGame : Effects - part 001.

Today I come one simple and nice tutorial about pygame python module over python version 3.4.
The python script just makes two effects.
First is one fade effect from transparent to black. I also added one green color.
Another effect come with the dizzy star base math python module and random python module.
Because this combined colors green and blue are funny I make star blue.
The script is simple :

• created variables;
• make pygame windows; 
• make fade background function;
• make one class for shape ( and this can be updated );
• make loop the game and escape key option;
•  ... and finally, add shape class and variable into loop pygame script.

Let's see the script:

# Cătălin George Feștilă 
# http://free-tutorials.org

import pygame
import random
import math
from pygame.locals import *

#initialize pygame and random seed
pygame.init()
random.seed()

#transparent to black for fade effect
def background_fade():
    rec = pygame.Surface(screensize)
    if frame != 0:
        rec.set_alpha(10)
        rec.fill((0,0,0))
    else:
        rec.set_alpha(255)
        rec.fill(draw_color)
    screen.blit(rec,(0,0))
    del rec

#all mathmatical shapes
class shape():
    xy = [0,0]   #location
    rot = [0.0,0.0] #rotation
    color = '.'   #color/shape value
    dim_size = 1
 #constructor
    def __init__(self,xy,dim_size,color):
        self.xy = xy
        self.dim_size = dim_size
        
        self.rot = [(random.random()*(math.pi)),.002]
        self.color = color
 
 #define shape
    def set_shape(self,color):
        self.color = color
    
 #draw shape    
    def draw(self):
        #rotation
        self.rot[0] += self.rot[1]
        if self.rot[0] > math.pi*2:
            self.rot[0] -= math.pi*2
        #blue/star
        if self.color == 'blue':
            for x in range(5):
                pygame.draw.aaline(screen,(0,0,255),\
                        (((math.cos(self.rot[0]+(x*((math.pi*2)/5)))*self.dim_size)+self.xy[0]),\
                        ((math.sin(self.rot[0]+(x*((math.pi*2)/5)))*self.dim_size)+self.xy[1])),\
                        (((math.cos(self.rot[0]+((x+2)*((math.pi*2)/5)))*self.dim_size)+self.xy[0]),\
                        ((math.sin(self.rot[0]+((x+2)*((math.pi*2)/5)))*self.dim_size)+self.xy[1])),\
                        1)

#start main pygame effect
while 1:
    #create variable for pygame
    screensize = (640,480)
    screen = pygame.display.set_mode(screensize, 0, 32)
    clock = pygame.time.Clock()
    #set frame 
    frame = 0
    draw_color = [0,255,0]
    #reftime = pygame.time.get_ticks()
    text = pygame.font.Font(None,25)
    #start drawing
    while 1:
        clock.tick(30)
        shapetest=shape((320,240),100,'blue')
        shapetest.draw()
        #check if is pressed any key 
        pygame.event.get()
        #if is press escape key
        if pygame.key.get_pressed()[pygame.K_ESCAPE]:
            pygame.quit()
            exit()
        #print clock.get_fps() on windows title
        pygame.display.set_caption(str(clock.get_fps()))   
        pygame.display.update()
        #start fade background
        background_fade()
        #change var frame for background_fade
        frame += 1
        #stop when frame is 100
        if frame == 100:
         break

    frame = 0
    
    pygame.display.update()
    background_fade()

    frame += 1

I make one screenshot to see how it's working.