How to simulate more realistic movement of an object? - python

I am writing a game environment, in which a person (worker) should move inside the area in a random direction, until it crosses with one of green-coloured obstacles (defined as pygame.draw.rect(screen, GREEN, [510,150,75,52]) and pygame.draw.rect(screen, GREEN, [450,250,68,40])).
Until now I can simulate a random movement of a worker, but it moves somehow irregularly and non-smoothly, jumping around the same area and slowly shifting to the right bottom corner.
How can I update the function create_randomPATH to support a more realistic smooth movement of a worker inside the screen area? I tried to increase a tick size till 70 or even more (clock.tick(70)) as it is indicated in one of threads, but it does not seem to solve the problem.
import pygame, random
import sys
WHITE = (255, 255, 255)
GREEN = (20, 255, 140)
GREY = (210, 210 ,210)
RED = (255, 0, 0)
PURPLE = (255, 0, 255)
SCREENWIDTH=1000
SCREENHEIGHT=578
class Worker(pygame.sprite.Sprite):
def __init__(self, image_file, location):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.image.load(image_file)
self.rect = self.image.get_rect()
self.rect.left, self.rect.top = location
def create_randomPATH(self,x,y):
randomX = random.randint(1,5)
randomY = random.randint(1,5)
if random.uniform(0,1)>0.5:
valX = x + randomX
valY = y + randomY
else:
valX = x - randomX
valY = y - randomY
return valX, valY
class Background(pygame.sprite.Sprite):
def __init__(self, image_file, location):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.image.load(image_file)
self.rect = self.image.get_rect()
self.rect.left, self.rect.top = location
pygame.init()
size = (SCREENWIDTH, SCREENHEIGHT)
screen = pygame.display.set_mode(size)
screen_rect=screen.get_rect()
pygame.display.set_caption("TEST")
worker = Worker("worker.png", [0,0])
w_x = worker.rect.left
w_y = worker.rect.top
bg = Background("background.jpg", [0,0])
carryOn = True
clock=pygame.time.Clock()
while carryOn:
for event in pygame.event.get():
if event.type==pygame.QUIT:
carryOn=False
pygame.display.quit()
pygame.quit()
quit()
# Draw floor layout
screen.blit(pygame.transform.scale(bg.image, (SCREENWIDTH, SCREENHEIGHT)), bg.rect)
# Draw obstacles
pygame.draw.rect(screen, GREEN, [510,150,75,52])
pygame.draw.rect(screen, GREEN, [450,250,68,40])
w_x,w_y = worker.create_randomPATH(w_x,w_y)
# worker should not go outside the screen area
worker.rect.clamp_ip(screen_rect)
screen.blit(worker.image, (w_x,w_y))
# Refresh Screen
pygame.display.flip()
clock.tick(5)
pygame.display.quit()
pygame.quit()
quit()

Take screen.blit(worker.image, (w_x,w_y)) and put it in it's own method. Then you can create a loop to loop from the oldX and oldY to the new position found by create_randomPATH You can even make the direction to move random by making them move in the x or y direction randomly each time.
Below is a rough example, but you probably have to modify it to match your code.
def UpdatePerson(image, x, y):
screen.blit(image, x, y)
while carryOn:
...
...
oldX = w_x
oldY = w_y
w_x,w_y = worker.create_randomPATH(w_x,w_y)
while(oldX < w_x || oldY < w_y):
randomDir = random.randint(1,2)
if randomDir == 1 && oldX < w_x:
UpdatePerson(worker.image, oldX, w_y)
oldX += 1
elif randomDir == 2 && oldY < w_x
UpdatePerson(worker.image, w_x, oldY)
oldY += 1

You could use an extra direction variable in your code which says in which direction the player is currently moving. One of four values: up, right, down or left. Every once in a while update that direction variable. Meanwhile move only one coordinate at a time in that direction.
def create_randomPATH(self, x, y, dir):
if random.uniform(0,1)>0.8:
# there is a 20% chance every time that direction is changed
dir = random.randInt(1,4)
if dir == 1:
return x, y+1, dir # up
if dir == 2:
return x+1, y, dir # right
if dir == 3:
return x, y-1, dir # down
if dir == 4:
return x-1, y, dir # left
In your code you would also need a global direction variable, initially it should also have a value 1, 2, 3 or 4:
w_x,w_y,w_dir = worker.create_randomPATH(w_x,w_y,w_dir)
By moving only one step on every iteration, we assure that the movement speed is always constant. In your code, it was varying from 1 to 5 steps. Also if you move a few steps in a given direction straight, it would seem more natural than changing the direction very suddenly very often. Try to play with the percentage (currently 20% chance) of how often the direction is changed and see if it makes the movement even smoother.
EDIT:
Because of the randomness of the movement, eventually the moving object will reach the borders of the game and might leave the screen. Adjust the position after each movement:
w_x,w_y,w_dir = worker.create_randomPATH(w_x,w_y,w_dir)
if (w_x + worker.rect.width > SCREENWIDTH): w_x = SCREENWIDTH - worker.rect.width
if (w_x < 0): w_x = 0
if (w_y + worker.rect.height > SCREENHEIGHT): w_y = SCREENHEIGHT - worker.rect.height
if (w_y < 0): w_y = 0
Then the object will not exit the screen and will eventually randomly move in other directions again. Because each direction is equally likely, it will move all around the screen properly.

Related

Why does this bug happen when I click on two sprites at the same time?

I'm making a simple game using pygame where you keep clicking on tiles as fast as you can until you miss a tile. this is the progress I've made so far. sometimes when I click on a tile (usually when 2 tiles are next to each other and you click between them) one of them does what they're supposed to while the other just disappears from the screen.
import pygame
import random
import sys
#Setting up all possible Tile positions
grid = [[0,0], [0,150], [0,300], [0,450], [0,600],
[150,0],[150,150],[150,300],[150,450],[150,600],
[300,0],[300,150],[300,300],[300,450],[300,600],
[450,0],[450,150],[450,300],[450,450],[450,600],
[600,0],[600,150],[600,300],[600,450],[600,600]]
taken = []
#Classes
class Cursor(pygame.sprite.Sprite):
def __init__(self, pic):
super().__init__()
self.image = pygame.image.load(pic).convert_alpha()
self.image = pygame.transform.scale(self.image, (50,50))
self.rect = self.image.get_rect()
def destroyTile(self):
pygame.sprite.spritecollide(cursor, tileGroup, True)
def update(self):
self.rect.topleft = pygame.mouse.get_pos()
class Tiles(pygame.sprite.Sprite):
def __init__(self, tileSize, color, x, y):
super().__init__()
self.image = pygame.Surface(([tileSize, tileSize]))
self.image.fill(color)
self.rect = self.image.get_rect()
self.rect.topleft = [x, y]
def drawTiles():
takenLen = len(taken)
while takenLen != 3:
m = random.randint(0,24)
x, y = grid[m]
if grid[m] not in taken:
blackTile = Tiles(150, black, x, y)
blackTile.add(tileGroup)
taken.append(grid[m])
takenLen += 1
def handleTiles():
mx, my = pygame.mouse.get_pos()
modx = mx % 150
mody = my % 150
x = mx - modx
y = my - mody
taken.remove([x, y])
drawTiles()
def drawRedTile():
mx, my = pygame.mouse.get_pos()
modx = mx % 150
mody = my % 150
x = mx - modx
y = my - mody
redTile = Tiles(150, red, x, y)
redTile.add(tileGroup)
#Colours
white = (255, 255, 255)
black = (0, 0, 0)
red = (255, 0, 0)
blue = (0, 0, 255)
grey = (46, 46, 46)
#Initializing Pygame
pygame.init()
clock = pygame.time.Clock()
#Screen
screenWidth = 750
screenHeight = 900
screen = pygame.display.set_mode((screenWidth, screenHeight))
pygame.display.set_caption("Tiles Game")
whiteSurface = pygame.Surface((750, 750))
whiteSurface.fill(white)
pygame.mouse.set_visible(False)
#Blue line
line = pygame.Surface((750, 10))
line.fill(blue)
#Groups
tileGroup = pygame.sprite.Group()
cursor = Cursor("cursor.png")
cursorGroup = pygame.sprite.Group()
cursorGroup.add(cursor)
score = 0
drawTiles()
while True:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
if event.type == pygame.MOUSEBUTTONDOWN:
score += 1
print(score)
print(taken)
print(tileGroup)
cursor.destroyTile()
handleTiles()
#Background
screen.fill(grey)
screen.blit(whiteSurface, (0,0))
screen.blit(line, (0,750))
tileGroup.draw(screen)
cursorGroup.draw(screen)
cursorGroup.update()
pygame.display.update()
In the code I tried using print statements to see if the tile that seems to have disappeared is still there. When this happens, I assume that the tile is not in its group anymore since the number of sprites in the tile group went from 3 to 2. But the list showing all the taken positions still shows that there are 3 positions that are taken. I can still click on the tile if I just click on the space where there should be a tile and the tile comes back. I thought the game should exit when a tile isn't clicked on but it doesn't if there is an "invisible" tile in that position.
How do I make it so that this bug doesn't happen and every new tile made is visible?
The problem is that the cursor has an area and can hit more than one block at a time. So in destroyTile more than 1 block can be removed at once:
def destroyTile(self):
pygame.sprite.spritecollide(cursor, tileGroup, True)
However, the function handleTiles cannot handle this, because it can only remove one block position from the taken list. I suggest to simplify the code and recreate the taken list completely from tileGroup when blocks are removed:
def handleTiles():
taken.clear()
for tile in tileGroup:
x, y = tile.rect.topleft
taken.append([x, y])
drawTiles()

My screen glitches out when I try to run my subprogram code

I'm working on a subprogram code that will make this happy face bounce around the screen and turn different colours. For some reason, the screen turns into that black glitchy screen and when I press exit at the top the face shows for a quick second before the program shuts down. I can't figure out why this is, here is my code and I've included a picture of what happens at first when I run it:
""" Program to show a very basic function
Most of the program is exactly the same as other programs we have done
The main difference is the grouping of code into a function called
drawHappy() to draw a few shapes together
In the main loop we "call" this function whenever we want to draw this
group of shapes
"""
# import the necessary modules
import pygame
import sys
import math
import random
from random import randint
# initialize pygame
pygame.init()
# set the size for the surface (screen)
# note this screen is resizable by the user
screen = pygame.display.set_mode((800, 600), pygame.RESIZABLE)
# set the caption for the screen
pygame.display.set_caption("Happy Face")
#screen width and height
screenW = screen.get_width()
screenH = screen.get_height()
# define colours you will be using
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)
BLUE = (0, 0, 255)
BLACK = (0, 0, 0)
YELLOW = (255, 255, 0)
# funtion to draw a the "happy face"
# it has 4 parameters passed to it xPos, yPos, radius, and colour
# notice all the shapes are drawn "relative" to the xPos and yPos and the radius
def drawHappy(xPos,yPos,r,colour):
pygame.draw.circle(screen,colour,(xPos,yPos),r,1)
eyeRadius = int(1/6*r)
eyeX = int(xPos-1/3*r)
eyeY = int(yPos- 1/3*r)
pygame.draw.circle(screen,colour,(eyeX,eyeY),eyeRadius,1)
eyeX = int(xPos + 1/3*r)
pygame.draw.circle(screen,colour,(eyeX,eyeY),eyeRadius,1)
wMouth = 1.5*r
xMouth = xPos - 3/4*r
yMouth = yPos - 3/4*r
pygame.draw.arc(screen,colour,(xMouth,yMouth,wMouth,wMouth),math.pi,2*math.pi,1)
randomR = randint(1,300)
r = randomR
randomX = randint(r, 800-r)
randomY = randint(r, 600-r)
dx = 0
dy = 0
x = 100
y = 100
speed = 3
x2 = randomX
y2 = randomY
dx2 = speed
dy2 = -speed
colour_list = [YELLOW, BLACK, BLUE, RED, GREEN]
randomcolour = random.choice(colour_list)
colour = RED
# set up clock to control frames per second
clock = pygame.time.Clock()
FPS = 120
# set main loop to True so it will run
main = True
# main loop
while main:
for event in pygame.event.get(): # check for any events (i.e key press, mouse click etc.)
if event.type == pygame.QUIT: # check to see if it was "x" at top right of screen
main = False # set the "main" variable to False to exit while loop
clock.tick(FPS)
screen.fill(WHITE)
oldx = x
oldy = y
x += dx
y += dy
if x >= 800-r or x <= 0+r:
x = oldx
if y >= 600-r or y <= 0+r:
y = oldy
x2 += dx2
y2 += dy2
if x >= 800-r or x <= 0+r:
dx2 = -dx2
randomcolour = random.choice(colour_list)
colour = randomcolour
if y2 >= 600-r or y2 <= 0+r:
dy2 = -dy2
randomcolour = random.choice(colour_list)
colour = randomcolour
# "call" the function "drawHappy()" to draw the happy face
# this is where we would normally do a pygame.draw or a screen.blit()
# we are "passing" the function 4 values to use(x,y,radius, colour)
# it will use these to know where to draw the happy face
drawHappy(x2,y2,r,colour)
pygame.display.flip()
# quit pygame and exit the program (i.e. close everything down)
pygame.quit()
sys.exit()
First of all, you need to call your draw function inside the loop. Your current code shows only a glimpse of "drawing" because it gets executed once you exit the main loop.
So, put your drawHappy() inside of main loop:
while main:
for event in pygame.event.get(): # check for any events (i.e key press, mouse click etc.)
if event.type == pygame.QUIT: # check to see if it was "x" at top right of screen
main = False # set the "main" variable to False to exit while loop
drawHappy(x2,y2,r,colour)
pygame.display.update()
clock.tick(FPS)
screen.fill(WHITE)
Now you will get a random size "smiley" on the screen, But now it will move on exit only, for the same reason it wouldn't display earlier. Next thing is to make it bounce (move). For this you'll need some kind of update of the coordinates, just like you did in the last part of your code, except they also need to be updated during the loop, not after it.
I suggest making a Class because then it will be easier to manipulate the object.
Also, I found it easier to separate draw and update_coordinates code into separate functions and them call them from main loop for example.
Hope this helps, and if you need more help, ask.
Here, I made a quick solution using parts of your code, there is plenty room for improvement especially for update_smiley_position() method where you can control how "smiley" moves.
Also, if you need multiple objects, a list should be passed instead of single object.
import pygame as pg
import math
import random
pg.init()
clock = pg.time.Clock()
window = pg.display.set_mode((800, 600), pg.RESIZABLE)
pg.display.set_caption("Happy Face")
SCREEN_W = window.get_width()
SCREEN_H = window.get_height()
class Smiley:
def __init__(self, x, y, r, color):
self.x = x
self.y = y
self.r = r
self.color = color
self.create_smiley()
def create_smiley(self):
self.eye_radius = int(1/6 * self.r)
self.eye_x1 = int(self.x - 1/3 * self.r)
self.eye_x2 = int(self.x + 1/3 *self.r)
self.eye_y = int(self.y - 1/3 *self.r)
self.mouth_width = 1.5 * self.r
self.mouth_x = self.x - self.r * 0.75
self.mouth_y = self.y - self.r * 0.75
def draw_smiley(self, win):
pg.draw.circle(win, self.color, (self.x, self.y), self.r, 1)
pg.draw.circle(win, self.color, (self.eye_x1, self.eye_y), self.eye_radius, 1)
pg.draw.circle(win, self.color, (self.eye_x2, self.eye_y), self.eye_radius, 1)
pg.draw.arc(win, self.color, (self.mouth_x, self.mouth_y, self.mouth_width, self.mouth_width), math.pi, 2*math.pi, 1)
def update_smiley_position(self):
if self.x >= SCREEN_H - self.r or self.x <= 0 + self.r:
self.x = random.randint(100, 400)
else:
self.x += 5
if self.y >= SCREEN_W - self.r or self.y <= 0 + self.r:
self.y = random.randint(100, 400)
else:
self.y -= 5
self.create_smiley()
def draw(win, smiley):
win.fill(pg.Color("white"))
smiley.draw_smiley(win)
smiley.update_smiley_position()
pg.display.update()
def main_loop(win, smiley):
clock.tick(30)
for event in pg.event.get():
if event.type == pg.QUIT:
return False
draw(win, smiley)
return True
r = random.randint(1, 300)
x = random.randint(r, SCREEN_W - r)
y = random.randint(r, SCREEN_H - r)
smiley = Smiley(x, y, r, pg.Color("red"))
while main_loop(window, smiley):
pass
pg.quit()

Pygame, Collision between 2 objects in the same group

So, i am trying to create a game where aliens spawn from 3 specific places. Each Alien will spawn randomly in one of the 3. But there will always be at least one alien, that will spawn on top of another one. I want to delete that alien and spawn him randomly in another spawn point. If it is empty he will stay if not the process will be repeated. The thing is that i cannot find a way to detect collision of 2 objects that are in the same group.
I just started learning pygame so 1) My question may be stupid 2) My way of spawning probably is very inefficient
Here is the Alien class:
class Alien(pygame.sprite.Sprite):
def __init__(self):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.Surface((80,60))
self.image.fill(GREY)
self.rect = self.image.get_rect()
spawn_point1 = x1,y1 = -30, 70
spawn_point2 = x2,y2 = -30, 150
spawn_point3 = x3,y3 = -30, 230
random_spawn = random.choice([spawn_point1,spawn_point2,spawn_point3])
self.rect.center = random_spawn
self.speedx = 10
def update(self):
spawn_point1 = x1,y1 = -30, 70
spawn_point2 = x2,y2 = -30, 150
spawn_point3 = x3,y3 = -30, 230
self.speedx = 10
random_spawn = random.choice([spawn_point1,spawn_point2,spawn_point3])
self.rect.x += self.speedx
if self.rect.x > WIDTH + 20:
self.rect.center = random_spawn
And here is the part where i detect collision(This part doesnt work)
aliens_col = pygame.sprite.groupcollide(aliens, aliens, True, False)
for i in aliens_col:
alien = Alien()
aliens.add(alien)
all_sprites.add(aliens)
Here is an implementation of the Bounding Box test.
import random
class Rectangle:
def __init__(self, height, width, x, y):
self.height = height
self.width = width
self.x = x
self.y = y
def collided_with_another_rectangle(self, rect):
""" Assumes rectangles are same size or that this rectangle is smaller than the other rectangle"""
if self.x > (rect.x + rect.width):
# Is to the right of the other rectangle
return False
elif (self.x + self.width) < rect.x:
# is to the left of the other rectangle
return False
elif (self.y + self.height) < rect.y:
# is above the other rectangle
return False
elif self.y > (rect.y + rect.height):
# is below the other rectangle
return False
else:
return True
collision_count = 0
for i in range(0, 1000):
# Here I pick random locations on a 1000X1000 screen for the first rectangle
x1 = random.randint(0, 1000)
y1 = random.randint(0, 1000)
# Here I pick random locations on a 1000X1000 screen for the second rectangle
rect1 = Rectangle(100, 100, x1, y1)
x2 = random.randint(0, 1000)
y2 = random.randint(0, 1000)
rect2 = Rectangle(100, 100, x2, y2)
"""
I use the collided with another rectangle function to test if the first rectangle is above,below,
to the right or to the left of the other rectangle. If neither of these are true then the rectangles
have collided.
"""
if rect1.collided_with_another_rectangle(rect2):
collision_count += 1
print("Rect1 X and Y:" + str(x1) + " " + str(y1))
print("Rect2 X and Y:" + str(x2) + " " + str(y2))
print("collided")
print("Collision Count:" + str(collision_count))
I'm still not absolutely sure what you want to achieve, but I think this example will be helpful to you.
When a sprite leaves the screen, I call the reset_pos method in which I iterate over the three spawn points to set the position to one spawn after the other and then I use another for loop to iterate over the sprites to check if one collides.
If a sprite collides, I continue with the next spawn point.
If no sprite collides, I just return from the method.
If no spawn is free, I remove the sprite (but you can do something else).
import random
import pygame
from pygame.math import Vector2
pygame.init()
WIDTH, HEIGHT = 640, 480
class Alien(pygame.sprite.Sprite):
def __init__(self, aliens):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.Surface((80, 60))
self.image.fill((120, random.randrange(255), random.randrange(255)))
self.rect = self.image.get_rect()
self.spawn_points = [(-30, 70), (-30, 150), (-30, 230)]
self.aliens = aliens
self.reset_pos()
self.speedx = 10
def update(self):
self.rect.x += self.speedx
if self.rect.x > WIDTH + 20:
self.reset_pos()
def reset_pos(self):
random.shuffle(self.spawn_points) # Shuffle the spawns.
for spawn in self.spawn_points:
# Set the position to one of the spawns.
self.rect.center = spawn
# Check if this sprite collides with another one.
for sprite in self.aliens:
if sprite is self: # Skip self.
continue
if self.rect.colliderect(sprite.rect):
break # Break out of the loop if the spawn is occupied.
else: # The else means no 'break' occurred in the for loop above,
# so the spawn must be free.
return # Break out of the method if the spawn is free.
# I just remove the sprite if no spawn is free. You can do something else here.
self.kill()
def main():
screen = pygame.display.set_mode((640, 480))
clock = pygame.time.Clock()
aliens = pygame.sprite.Group()
for _ in range(3):
# I pass the aliens group to the sprite because we need to
# iterate over it to see if a sprite collides.
alien = Alien(aliens)
aliens.add(alien)
all_sprites = pygame.sprite.Group(aliens)
done = False
while not done:
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
elif event.type == pygame.MOUSEBUTTONDOWN:
al = Alien(aliens)
all_sprites.add(al)
aliens.add(al)
all_sprites.update()
screen.fill((30, 30, 30))
all_sprites.draw(screen)
pygame.display.flip()
clock.tick(30)
if __name__ == '__main__':
main()
pygame.quit()
When using the same group in both of the group-paramaters of groupcollide it will always consider the sprite it is checking in group_a as colliding with that same sprite in group_b. This results in groupcollide always returning a collision.
To get around this I created a new function in pygame's sprite.py that ignores single collisions and only returns collisions >= 2. My only change was to add:
if len(collision) >=2:
And then the required tab for the following line(s).
The code I added to sprite.py is pasted below but the tab for the def intra_groupcollide is one too far:
def intra_groupcollide(groupa, groupb, dokilla, dokillb, collided=None):
"""detect collision between a group and itself.
This is modified from groupcollide but excludes collisions <=1
pygame.sprite.groupcollide(groupa, groupb, dokilla, dokillb):
return dict
"""
crashed = {}
# pull the collision function in as a local variable outside
# the loop as this makes the loop run faster
sprite_collide_func = spritecollide
if dokilla:
for group_a_sprite in groupa.sprites():
collision = sprite_collide_func(group_a_sprite, groupb,
dokillb, collided)
if collision:
if len(collision) >=2:
crashed[group_a_sprite] = collision
group_a_sprite.kill()
else:
for group_a_sprite in groupa:
collision = sprite_collide_func(group_a_sprite, groupb,
dokillb, collided)
if collision:
if len(collision) >=2:
crashed[group_a_sprite] = collision
#print(crashed)
return crashed
Then in my own python program, I simply replaced groupcollide with intra_groupcollide. I set both kill paramaters as 'false' because in my usage I'm bouncing them off each other. I have not tested this code with them set to 'true'.
I found sprite.py in my file system by following this answer:
Where are the python modules stored?

Pygame. How to make a rect change direction on collision (boundary check)

Part of an assignment I'm working on is making a ball bounce around the screen, I can make it move, but my boundary test doesn't seem to be working: the ball simply moves in direction instead of changing direction. So to clarify, what I want to ball to do is change direction as it hits the screen edge.
import sys
import pygame
SCREEN_SIZE = 750, 550
BALL_DIAMETER = 16
BALL_RADIUS = BALL_DIAMETER // 2
MAX_BALL_X = SCREEN_SIZE[0] - BALL_DIAMETER
MAX_BALL_Y = SCREEN_SIZE[1] - BALL_DIAMETER
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
LEFT = 11
RIGHT = 12
pygame.init()
clock = pygame.time.Clock()
pygame.display.init()
font = pygame.font.SysFont("impact", 20)
pygame.display.set_caption("Breakout")
screen = pygame.display.set_mode(SCREEN_SIZE)
class Ball:
def __init__(self):
''' '''
self.ball = pygame.Rect(300, 730 -
BALL_DIAMETER,
BALL_DIAMETER, BALL_DIAMETER)
# Draw ball
def draw_ball(self):
pygame.draw.circle(screen,
WHITE, (self.ball.left
+ BALL_RADIUS, self.ball.top +
BALL_RADIUS), BALL_RADIUS)
# Updates the coordinates by adding the speed components
def move_ball(self, x, y):
self.xspeed = x
self.yspeed = y
self.ball = self.ball.move(self.xspeed, self.yspeed)
# bounds check
if self.ball.left <= 0:
self.ball.left = 0
self.xspeed = -self.xspeed
elif self.ball.left >= MAX_BALL_X:
self.ball.left = MAX_BALL_X
self.xspeed = -self.xspeed
if self.ball.top < 0:
self.ball.top = 0
self.yspeed = -self.yspeed
elif self.ball.top >= MAX_BALL_Y:
self.ball.top = MAX_BALL_Y
self.yspeed = -self.yspeed
# shows a message on screen, for testing purposes
class Text:
def show_message(self, message):
self.font = pygame.font.SysFont("impact", 20)
font = self.font.render(message,False, WHITE)
screen.blit(font, (200, 400))
class Game:
def __init__(self):
''' '''
def run(self):
b = Ball()
while 1:
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
keys = pygame.key.get_pressed()
# fps lock, screen fill and method call for input
clock.tick(60)
screen.fill(BLACK)
b.draw_ball()
b.move_ball(5, -5)
# used to keep track of various elements
# Text().show_message("P: " + str(p))
pygame.display.flip()
# Creates instance of the game class, and runs it
if __name__ == "__main__":
Game().run()
Your only call to move_ball uses a constant vector.
Since you never change the call parameters, the ball moves only that way.
b.move_ball(5, -5)
Yes, you change the vector components within move_ball when you hit a wall. However, on the next call, you change them back to the original values and move the ball in the original direction.
You have to initialize the vector outside move_ball, and then let the routine access the existing vector when it's called.

Software Design and Development Major: Pygame Smudge Trails

First off, i have searched online and this website for solutions and the ones i have tried are not working so i decided to post my individual question and code. This program was created using Python 3.2.2 and the corresponding compatible version of pygame. I also realize a more efficient method would be to use sprites, sprite groups and 'dirty rect' updating but i unable to convert the program and so i will continue without the added benefits of such functions.
Problem: Smudge trails where the 'asteroids' are moving are left behind.
Hypothesis: Background is blitted onto the screen however the asteroids are blitted onto the Background.
Please Reply - btw i'm a highschooler from AUS :D
import pygame
import random
import math
pygame.init()
height = 550
width = 750
screen = pygame.display.set_mode((width, height))
background = pygame.image.load("Planet.jpg")
Clock = pygame.time.Clock()
class asteroid(pygame.sprite.Sprite):
def __init__(self, x, y, size):
pygame.sprite.Sprite.__init__(self)
self.x = x
self.y = y
self.size = 15
self.speed = 0.0
self.angle = 0
self.colour = (171, 130, 255)
self.thickness = 0
def display(self):
pygame.draw.circle(background, self.colour, (int(self.x),int(self.y)), self.size, self.thickness)
pygame.draw.circle(background, (255, 255, 255), (int(self.x),int(self.y)), self.size, 1)
def move(self):
self.x += math.sin(self.angle) * self.speed
self.y -= math.cos(self.angle) * self.speed
def boundaries(self):
if self.x > width - self.size:
self.x = 0 + self.size
elif self.x < self.size:
self.x = width - self.size
if self.y > height - self.size:
self.y = 0 + self.size
elif self.y <self.size:
self.y = height - self.size
num_target = 5
my_particles = []
num_particles = len(my_particles)
while num_particles < 5:
for n in range(num_target):
size = 20
x = random.randint(size, height - size)
y = random.randint(size, width - size)
target = asteroid(x, y, size)
target.speed = random.uniform(1.0, 1.0)
target.angle = random.uniform(0, math.pi*2)
my_particles.append(target)
num_particles = num_particles + 1
def main():
pygame.display.set_caption("Anyu's Game")
screen.blit(background, (0,0))
pygame.display.update()
score = (pygame.time.get_ticks()/1000)
print (score)
while True:
pygame.display.update()
screen.blit(background, (0,0))
MouseP = pygame.mouse.get_pos()
frames = Clock.get_fps
pygame.mouse.set_visible
score = (pygame.time.get_ticks()/1000)
print (score)
print (MouseP)
for target in my_particles:
target.move()
target.boundaries()
target.display()
pygame.display.update()
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit();
if __name__=='__main__':
main()
Basically, you are right! The circles are drawn directly onto the background, and everytime new circles are drawn, the old circles remain. Resulting in the smudges/trails.
You can just change background to screen in your draw method. This will fix it.
But it is really worth using the Sprite classes as intended. I've made a few changes to your code to switch it over for you. With these changes it runs without trails :)
Here are the changes and explainations:
Add this near the top:
#Create a new `pygame.Surface`, and draw a circle on it, then set transparency:
circle = pygame.Surface((30,30))
circle = circle.convert()
pygame.draw.circle(circle, (171, 130, 255), (int(15),int(15)), 15, 0)
circle.set_colorkey(circle.get_at((0, 0)), pygame.RLEACCEL)
Add this to the asteroid, __init__ method:
#Sets the asteroid image, and then the asteroids co-ords (these are in `rect`)
self.image = circle
self.rect = self.image.get_rect()
Add this to the end of def move(self):
self.rect[0] = self.x
self.rect[1] = self.y
change:
my_particles = []
to:
#This is a special pygame container class, it has a draw() method that tracks changed areas of the screen.
my_particles = pygame.sprite.RenderUpdates()
change:
my_particles.append(target)
to:
my_particles.add(target)
change:
while True:
pygame.display.update()
screen.blit(background, (0,0))
MouseP = pygame.mouse.get_pos()
frames = Clock.get_fps
pygame.mouse.set_visible
score = (pygame.time.get_ticks()/1000)
print (score)
print (MouseP)
for target in my_particles:
target.move()
target.boundaries()
target.display()
pygame.display.update()
to:
#initial screen draw:
screen.blit(background, (0,0))
pygame.display.update()
while True:
#remove previous drawn sprites and replaces with background:
my_particles.clear(screen, background)
MouseP = pygame.mouse.get_pos()
frames = Clock.get_fps
pygame.mouse.set_visible
score = (pygame.time.get_ticks()/1000)
print (score)
print (MouseP)
for target in my_particles:
target.move()
target.boundaries()
#draws changed sprites to the screen:
pygame.display.update(my_particles.draw(screen))
Remove the display method as it is no longer needed.
This will also run a lot faster than the your earlier code, as the time taken to draw something is proportional to the size of the drawing area, and previously it was drawing the whole background everytime - now it only draws the sprites and changes to the background!
Hope this helps :)
This already has an answer but this can be useful instead of other methods.
Make sure when you blit the images onto the screen, flip the display after blitting everything.
I would consider making a draw() function
Like this:
def draw(self):
# Blit images
self.screen.blit(image)
# Flip display
pygame.display.flip()
This will flip the display every frame and then draw the next frame without a trail.
Also quick notes, remember to do image = pygame.image.load(image).convert or .convert_alpha() else after adding more images the game will slow down.
Also, if you do import pygame as pg you don't have to type out pygame each time, instead you can just type pg.

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