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pygame top down shooting [duplicate]

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Problems with moving an enemy towards a character in pygame
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Pygame doesn't let me use float for rect.move, but I need it
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Closed 8 months ago.
So I have a functioning shooting mechanic in python pygame for a top down shooter, where I am using the mouse position to aim the bullets by working out the angles, however when I do this, the bullets are shooting slightly off where the mouse position is. for instance: the mouse would be where the red arrow is drawn and the bullets will be shooting by a small amount in the wrong direction
Any help would be appreciated
code below:
main.py:
#-------------Imports-------------#
import pygame,sys
#import globals
from background import*
from player import*
#-------------Constants-------------#
WIDTH,HEIGHT = 500,500
WINDOW = pygame.display.set_mode((WIDTH,HEIGHT))
CLOCK = pygame.time.Clock()
BLACK = (0, 0, 0)
#-------------Instances-------------#
bg = Background()
player = Player()
#-------------Functions-------------#
def draw():
WINDOW.fill(BLACK)
bg.update(WINDOW)
player.update(WINDOW)
pygame.display.update()
#-------------Main Game Loop-------------#
def main():
#globals.intialise()
while 1:
CLOCK.tick(1)
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
draw()
#globals.game_ticks += 1
if __name__ == "__main__":
main()
player.py
#-------------Imports-------------#
import pygame,math
#import globals
#-------------Constants-------------#
WIDTH,HEIGHT = 500,500
PLAYER_COLOUR = (255, 212, 112)
BLACK = (0,0,0)
PI = 3.14159265359
#-------------Classes-------------#
class Bullet:
def __init__(self,origin,angle):
self.speed = 20
self.x_speed,self.y_speed = self.speed*math.cos(math.radians(angle)),self.speed*math.sin(math.radians(angle))
self.rect = pygame.Rect(origin[0],origin[1],5,5)
def __del__(self):
pass
def update(self,window):
# move bullet
self.rect.x += self.x_speed
self.rect.y += self.y_speed
# draw bullet
pygame.draw.rect(window,BLACK,self.rect)
# check if bullet is out of the screen
if self.rect.x > WIDTH or self.rect.x < 0:
return -1
elif self.rect.y > HEIGHT or self.rect.y < 0:
return -1
class Player:
def __init__(self):
self.sprite = pygame.transform.scale(pygame.image.load("sprites/temp_player.png"),(50,50))
self.rect = pygame.Rect(250,250,50,50)
self.center = (self.rect.x,self.rect.y)
self.bullets = []
self.fire_rate = 12
def shoot(self,angle,window):
# update all bullets and delete if bullet is out of screen
for bullet in self.bullets:
if bullet.update(window) == -1:
self.bullets.remove(bullet)
del bullet
# instantiate bullet if mouse button pressed
#if pygame.mouse.get_pressed()[0] and globals.game_ticks % self.fire_rate == 0:
if pygame.mouse.get_pressed()[0]:
self.bullets.append(Bullet(self.rect.center,-angle))
def update(self,window):
mx,my = pygame.mouse.get_pos()
# find distance between mouse position and player position
diff_x,diff_y = mx-self.rect.x,my-self.rect.y
# word out angle between mouse and player
angle_rad = math.atan2(diff_y,diff_x)
angle = -360*angle_rad/(2*PI)
# adjust angle according to where we want to rotate the player
# when angle is bottom left
if abs(angle) > 90 and angle < 0:
a = 270-abs(angle)
# when angle is top left
elif abs(angle) > 90:
a = angle-90
# when angle is to the right
else:
a = angle - 90
# create new sprite that is rotated
rotated_image = pygame.transform.rotate(self.sprite,a)
# replace current rectangle with rotated sprite
self.rect = rotated_image.get_rect(center = self.center)
self.shoot(angle,window)
# add image to the screen
#window.blit(pygame.transform.rotate(self.sprite,a),self.rect)
background.py:
#-------------Imports-------------#
import pygame,random,ast,time,globals
#-------------Constants-------------#
WIDTH,HEIGHT = 500,500
TILE_DIMENSION = 9
TILE_SIZE = int(round(WIDTH/TILE_DIMENSION,0))
TO_EDGE = int((TILE_DIMENSION+1)/2)
#-------------Classes-------------#
class Background:
def __init__(self):
self.tiles = self.generate_screen()
self.centre = [2,2]
self.right = 0
self.up = 0
self.speed = 5
def generate_screen(self):
# generate original chunk of tiles
tiles = [[random.randint(100,200) for i in range(TILE_DIMENSION)] for j in range(TILE_DIMENSION)]
# eventually use image instead of random RGB value
return tiles
def movement(self,tile_rects):
keys = pygame.key.get_pressed()
if keys[pygame.K_a] or keys[pygame.K_LEFT]:
# if player is on tile to the left of centre
if (self.right - self.speed) < -TILE_SIZE:
# reset movement and adjust centre
self.right = 0
self.centre[0] -= 1
else:
# add to movement if not on next tile
self.right -= self.speed
# move all rectangles in background to simulate player moving
for i in range(len(tile_rects)):
for j in range(len(tile_rects[0])):
tile_rects[i][j].x += self.speed
if keys[pygame.K_d] or keys[pygame.K_RIGHT]:
# if player is on tile to the right of centre
if (self.right + self.speed) > TILE_SIZE:
# reset movement and adjust centre
self.right = 0
self.centre[0] += 1
else:
# add to movement if not on next tile
self.right += self.speed
# move all rectangles in background to simulate player moving
for i in range(len(tile_rects)):
for j in range(len(tile_rects[0])):
tile_rects[i][j].x -= self.speed
if keys[pygame.K_w] or keys[pygame.K_UP]:
# if player is on tile above the centre
if (self.up + self.speed) > TILE_SIZE:
# reset movement and adjust centre
self.up = 0
self.centre[1] -= 1
else:
# add to movement if not on next tile
self.up += self.speed
# move all rectangles in background to simulate player moving
for i in range(len(tile_rects)):
for j in range(len(tile_rects[0])):
tile_rects[i][j].y += self.speed
if keys[pygame.K_s] or keys[pygame.K_DOWN]:
# if player is on tile below the centre
if (self.up - self.speed) < -TILE_SIZE:
# reset movement and adjust centre
self.up = 0
self.centre[1] += 1
else:
# add to movement if not on next tile
self.up -= self.speed
# move all rectangles in background to simulate player moving
for i in range(len(tile_rects)):
for j in range(len(tile_rects[0])):
tile_rects[i][j].y -= self.speed
return tile_rects
def update(self,window):
# rendering in brand new map chunks
# if part of the chunk trying to be rendered in is non-existant in the 2D map array to the left
if self.centre[0]-TO_EDGE < 0:
# check how many tiles it is offset by
for i in range(0-(self.centre[0]-TO_EDGE)):
# add new column of values at the beginning of the 2D array
for i in range(len(self.tiles)):
self.tiles[i].insert(0,random.randint(120,230))
# due to whole array being shifted to the right, adjust the centre accordingly
self.centre[0] += 1
# if part of the chunk trying to be rendered is non-existant in the 2D map array to the right
if self.centre[0]+TO_EDGE >= len(self.tiles[0]):
# check how many tiles it is offset by
for i in range((self.centre[0]+TO_EDGE)-(len(self.tiles[0])-1)):
# add a new column of values at the end of the 2D array
for i in range(len(self.tiles)):
self.tiles[i].append(random.randint(120,230))
# if part of the chunk trying to be rendered in is non-existant in the 2D array at the top
if self.centre[1]-TO_EDGE < 0:
# check how many tiles it is offset by
for i in range(0-(self.centre[1]-TO_EDGE)):
# add a new row at the top of the 2D array
self.tiles.insert(0,[random.randint(120,230) for i in range(len(self.tiles[0]))])
# due to whole array shifting downwards, adjust the centre accordingly
self.centre[1] += 1
# if part of the chunk trying to be rendered in is non-existant in the 2D array at the bottom
if self.centre[1]+TO_EDGE >= len(self.tiles):
# check how many tiles it is offset by
for i in range((self.centre[1]+TO_EDGE)-(len(self.tiles)-1)):
# add a new row at the bottom of the 2D array
self.tiles.append([random.randint(120,230) for i in range(len(self.tiles[0]))])
# determining which tiles should be rendered in according to the centre(where player would be)
t = []
for i in range(TILE_DIMENSION+2):
t.append([])
for j in range(TILE_DIMENSION+2):
try:
t[i].append(self.tiles[i+(self.centre[1]-TO_EDGE)][j+(self.centre[0]-TO_EDGE)])
except:
pass
# create a rectangle for each tile that is rendered in
tile_rects = [[pygame.Rect((i-1)*TILE_SIZE-self.right,(j-1)*TILE_SIZE+self.up,TILE_SIZE,TILE_SIZE) for i in range(TILE_DIMENSION+2)] for j in range(TILE_DIMENSION+2)]
tile_rects = self.movement(tile_rects)
# draw all rectangles
for i in range(TILE_DIMENSION+2):
for j in range(TILE_DIMENSION+2):
try:
pygame.draw.rect(window,(0,int(t[i][j]),0),tile_rects[i][j])
except:
pass
the background script doesnt affect anything, its just there as a background to make it easier to see, and you may have to make your own temp_player.png image to make it compatible

Enemy Movement in Pygame Platformer 2D

Working on my first project and I'm trying to get enemy movement sorted, the code below is my current implementation. The enemy using the distance between the player position (target.pos.x) and their pos.x. Want the enemy to move left 20 paces then change direction and move right 20 paces, rinse and repeat.
self.target = game.player
def movement(self):
self.acc = vec(0, BOSS_GRAVITY)
if (-17 >= (self.pos.x - self.target.pos.x) >= -200) and self.target.hit_rect.y == self.hit_rect.y:
self.vel.x -= BOSS_SPEED * -1
self.enemy_direction = 'R'
if (200 >= (self.pos.x - self.target.pos.x) >= 17) and self.target.hit_rect.y == self.hit_rect.y:
self.vel.x += BOSS_SPEED * -1
self.enemy_direction = 'L'
self.acc.x += self.vel.x * BOSS_FRICTION
self.vel += self.acc
self.pos += self.vel
self.pos += self.vel + 0.5 * self.acc
I want my enemies to move to the right a certain amount then change velocity and go the opposite way not remain idle.

I want the enemy to move left 20 paces then change direction and move right 20 paces, rinse and repeat.
Ok, so how do we achieve that? First some definitions:
What is a "pace"? Let's start with 5 pixels.
Left is -x; Right is +x.
There's a few extra things to take care of too. What about when the object can't move in the desired direction? It can turn around.
So we need to keep a bunch of stats about this Enemy: Location, Step Count, Direction of Travel. As soon as you have a few datum points, think: Data Structure. Now I'm going to put all this into a Python class, but it could also go into a simple list. But these get unwieldy with more than a few points of data.
# As a list
enemy_image = pygame.image.load( "doomba.png" ).convert_alpha()
enemy_rect = enemy_image.get_rect()
enemy_rect.center = ( x, y )
enemy1 = [ enemy_rect, enemy_image, PACE_SIZE, TURN_SIZE ]
Much better as a class:
# As a sprite class
class Enemy( pygame.sprite.Sprite ):
def __init__( self, x, y, bitmap, pace=5, turn_after=20 ):
""" Create a new Enemy at that is drawn at (x,y) as the /bitmap/.
It moves /pace/ pixels each step, left, then right """
pygame.sprite.Sprite.__init__( self )
self.image = pygame.image.load( bitmap ).convert_alpha()
self.rect = self.image.get_rect()
self.rect.center = ( x, y ) # location
self.pace_size = pace # How big each step is
self.pace_count = 0 # distance moved
self.direction = -1 # Start moving left (-x)
self.turn_after = turn_after # distance limit
(I've made the data structure based on a PyGame Sprite because it costs only 2 lines of code, and provides lots of pre-built functionality.)
So now we have a data structure (named Enemy) that contains a location, size, bitmap, and remembers how far it's walked, and in which direction. However it doesn't yet implement any sort of movement algorithm. So let's add this.
The Sprite class wants this algorithm to be written into a function named update(). This function is called every frame to decide on the movement for that frame. This might be no-movement, or something else. It can be anything.
Here you can see we're tallying the number of paces moved into self.pace_count, and then adjusting the bitmap's x position (held in self.rect) by the length of a pace (self.pace_size). If the enemy is moving left, the pace-size needs to be subtracted, and for right, added. We can do this automatically by multiplying the amount we add by the self.direction, either -1 or 1. The direction value is set whenever the Enemy turns around.
def update( self ):
""" Implement the movement algorithm """
# Walk pace in the current direction
self.pace_count += 1
self.rect.x += self.direction * self.pace_size # Move some pixels
# We need to turn around if walked enough paces in the same direction
if ( self.pace_count >= self.turn_after ):
# Turn around!
self.direction *= -1 # reverses the pixel distance
self.pace_count = 0 # reset the pace count
# We also should change direction if we hit the screen edge
if ( self.rect.x <= 0 ):
self.direction = 1 # turn right
self.pace_count = 0
elif ( self.rect.x >= WINDOW_WIDTH - self.rect.width ):
self.direction = -1
self.pace_count = 0
So when the Enemy walks the set number of paces, the direction is reversed and the paces-tally zeroed. But we also need to turn around if we hit the side of the screen. When this happens, there is only a single obvious way to turn, so the direction is changed absolutely, rather than being reversed. This code could probably be made simpler, since it basically does almost the same things each time. But I've left it a bit longer to clearly illustrate the steps involved.
And that it's, the algorithm is implemented. Looking at a demo, it's way too fast. So let's also incorporate a real-time speed.
An easy way to control movement speed is to put in a delay between steps. First decide how often the Enemy will move (e.g.: every 100 milliseconds), stored in self.speed and then the time the last step was taken in self.pace_time. Then when it comes time to update, look at the PyGame clock to see if enough milliseconds have elapsed, and only then move the Enemy. Otherwise do nothing.
def update( self ):
""" Implement the movement algorithm """
time_now = pygame.time.get_ticks() # what time is it
if ( time_now > self.pace_time + self.speed ): # time to move again?
self.pace_time = time_now # remember move time
# Walk pace in the current direction
self.pace_count += 1
This gives a much more sedate movement. I tweaked the Enemy to move more often, but in smaller steps. So now it also does not traverse as much of the window. It's important to control speed as a function of time rather than frame-rate. For example, if I'd just made the pace size 0.2 pixels above, sure that would slow the mushroom down to some speed. But it's only accurate on my computer. What if the frame-rate was only 21 FPS, suddenly it moving 2/3 slower again. And what if the frame rate was 160 FPS? It would be back to super-fast, that's what. So keep any sort of speed and movement controlled by real-time milliseconds, not frame-rate & distance.
Anyway, that should be enough to get you going on your own movement algorithms. Please comment if there's questions about the code.
Reference Code:
import pygame
# Window size
WINDOW_WIDTH = 600
WINDOW_HEIGHT = 400
WINDOW_SURFACE = pygame.HWSURFACE|pygame.DOUBLEBUF
DARK_BLUE = ( 3, 5, 54)
class Enemy( pygame.sprite.Sprite ):
def __init__( self, x, y, pace, bitmap, turn_after=20, speed=100 ):
""" Create a new Enemy at that is drawn at (x,y) as the /bitmap/.
It moves /pace/ pixels left, then right """
pygame.sprite.Sprite.__init__( self )
self.image = pygame.image.load( bitmap ).convert_alpha()
self.rect = self.image.get_rect()
self.rect.center = ( x, y ) # location
self.pace_size = pace # How big each step is
self.pace_count = 0 # distance moved
self.direction = -1 # Start moving left (-x)
self.turn_after = turn_after # distance limit
self.speed = speed # Milliseconds per pace
self.pace_time = 0 # time of last step
def update( self ):
""" Implement the movement algorithm """
time_now = pygame.time.get_ticks() # what time is it
if ( time_now > self.pace_time + self.speed ): # is it time to move again
self.pace_time = time_now
# Walk pace in the current direction
self.pace_count += 1
self.rect.x += self.direction * self.pace_size # Move some pixels
# We need to turn around if walked enough paces in the same direction
if ( self.pace_count >= self.turn_after ):
# Turn around!
self.direction *= -1 # reverses the pixel distance
self.pace_count = 0 # reset the pace count
# We also should change direction if we hit the screen edge
if ( self.rect.x <= 0 ):
self.direction = 1 # turn right
self.pace_count = 0
elif ( self.rect.x >= WINDOW_WIDTH - self.rect.width ):
self.direction = -1
self.pace_count = 0
### initialisation
pygame.init()
pygame.mixer.init()
window = pygame.display.set_mode( ( WINDOW_WIDTH, WINDOW_HEIGHT ), WINDOW_SURFACE )
pygame.display.set_caption("Movement Algorithm Example")
### Sprite and Sprite Group
pos_x = WINDOW_WIDTH//2
pos_y = WINDOW_HEIGHT//2
pace_size = 7
enemy = Enemy( pos_x, pos_y, pace_size, "mushroom.png" )
all_sprites_group = pygame.sprite.Group()
all_sprites_group.add( enemy )
### Main Loop
clock = pygame.time.Clock()
done = False
while not done:
# Handle user-input
for event in pygame.event.get():
if ( event.type == pygame.QUIT ):
done = True
elif ( event.type == pygame.MOUSEBUTTONUP ):
# On mouse-click
pass
elif ( event.type == pygame.KEYUP ):
pass
# Movement keys
#keys = pygame.key.get_pressed()
#if ( keys[pygame.K_UP] ):
# print("up")
# Update the window, but not more than 60fps
all_sprites_group.update()
window.fill( DARK_BLUE )
all_sprites_group.draw( window )
pygame.display.flip()
# Clamp FPS
clock.tick_busy_loop(60)
pygame.quit()

How to have an object run directly away from mouse at a constant speed

I have a ship that shoots lasers. It draws a line from itself to (mouseX, mouseY). How can I have the ship accelerate in the exact opposite direction as if being pushed backwards?
I have been working through some trig and ratios but am not making much progress. Acceleration is constant so how far the mouse is doesn't matter, just the direction.
I've been primarily working on trying to create a vector that only works with integers in the range (-4,4), as I cannot have the ship move across the screen at a Float speed, and the (-4,4) range would at least give me... 16 different directions for the ship to move, though I'd like that not to be a limitation.

There's no trigonometry involved, just vectors. If you take the subtract the position of the mouse from the position of the ship
(shipX-mouseX, shipY-mouseY)
that gives you the direction in which to move the ship. Multiply it by some factor, round it to integers, and add it to the ship's current position. You may want to do this a few times, to give some continuous motion. Also, you may want the factor to vary: increase the first few ticks, and then decrease to zero.

The vector of acceleration will be in the direction from the mouse cursor to the ship, away from the mouse position - so if the line from mouse to ship is at angle theta to horizontal (where anticlockwise theta is +ve, clockwise is -ve), so will the force F acting on the ship to accelerate it. If ship has mass M then using f=ma, acceleration A will be F/M. Acceleration in x axis will be A * cos(theta), in y A * sin(theta) - then use v=u+at after every time interval for your simulation. You will have to use floating point maths for this calculation.

Here's a full example using simple vector math. Note the comments.
import pygame
import math
# some simple vector helper functions, stolen from http://stackoverflow.com/a/4114962/142637
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)) ]
class Ship(object):
def __init__(self):
self.x, self.y = (0, 0)
self.set_target((0, 0))
self.org_speed = 0.9
self.speed = self.org_speed
self.laser = (None, 0)
#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 set_target(self, pos):
self.t_x, self.t_y = pos
def update(self):
if self.speed < self.org_speed:
self.speed += min(self.org_speed, 0.3)
# if we won't move, don't calculate new vectors
if self.int_pos == self.int_target:
return
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
# apply the ship'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, s):
pygame.draw.circle(s, (255, 0 ,0), self.int_pos, 5)
end, state = self.laser
if state > 0:
pygame.draw.line(s, (255, 255, 0 if state % 2 else 255), self.pos, end, 2)
self.laser = end, state - 1
def fire(self, pos):
self.speed = -min(5, magnitude(sub(pos, self.pos)) / 10.0)
self.laser = pos, 5
pygame.init()
quit = False
s = pygame.display.set_mode((300, 300))
c = pygame.time.Clock()
ship = Ship()
FIRE = pygame.USEREVENT
pygame.time.set_timer(FIRE, 2000)
while not quit:
quit = pygame.event.get(pygame.QUIT)
if pygame.event.get(FIRE):
ship.fire(pygame.mouse.get_pos())
ship.set_target(pygame.mouse.get_pos())
pygame.event.poll()
ship.update()
s.fill((0, 0, 0))
ship.draw(s)
pygame.display.flip()
c.tick(60)

Pygame: move a spinning image around the edge of the window

I have an assignment that asks me to do the following:
Use Google's advanced image search to find a reasonably-sized image of a ball that is free to reuse and that includes transparency. Modify the sample code so that your ball slides back and forth across the bottom of the screen. It should take 2 seconds for the ball to go from the left side to the right.
Improve your animation for question 5 so that the ball rotates, accurately, as if it were rolling back and forth.
Modify your animation for question 6 so that the ball travels counterclockwise around the edge of the screen
I am at the last part. Trying to modify the animation for question 6 to do this: (1:24)
http://www.youtube.com/watch?v=CEiLc_UFNLI&feature=c4-overview&list=UUpbgjjXBL3hdTKDZ0gZvdWg
I'm stumped pretty bad. I just can't seem to understand how I will get the ball to slowly move from one point to another. The ball is an image. This is what I have so far, but it doesn't work.
"""Some simple skeleton code for a pygame game/animation
This skeleton sets up a basic 800x600 window, an event loop, and a
redraw timer to redraw at 30 frames per second.
"""
from __future__ import division
import math
import sys
import pygame
class MyGame(object):
def __init__(self):
"""Initialize a new game"""
pygame.mixer.init()
pygame.mixer.pre_init(44100, -16, 2, 2048)
pygame.init()
# set up a 640 x 480 window
self.width = 800
self.height = 600
self.img = pygame.image.load('ball.png')
self.screen = pygame.display.set_mode((self.width, self.height))
self.x = 0
self.y = 0
self.angle = 0
self.rotate_right=True
self.first = True
#0: Move bottomleft to bottomright 1: Move from bottomright to topright 2:Move from topright to topleft 3:Move from topleft to bottomleft
self.mode = 0
# use a black background
self.bg_color = 0, 0, 0
# Setup a timer to refresh the display FPS times per second
self.FPS = 30
self.REFRESH = pygame.USEREVENT+1
pygame.time.set_timer(self.REFRESH, 1000//self.FPS)
def get_mode(self):
rect = self.img.get_rect()
if self.first == True:
self.first = False
return
if (self.x, self.y) == (0, self.height - rect.height):
#Our starting point, bottom left
self.mode = 0
elif (self.x, self.y) == (self.width-rect.width, self.height-rect.height):
#Bottom right
self.mode = 1
elif (self.x, self.y) == (self.width-rect.width, 0):
#Top Right
self.mode = 2
elif (self.x, self.y) == (0,0):
#Top Left
self.mode = 3
def get_target(self):
rect = self.img.get_rect()
if self.mode == 0:
targetPosition = (0, self.height - rect.height)
elif self.mode == 1:
targetPosition = (self.width-rect.width, self.height-rect.height)
elif self.mode == 2:
targetPosition = (self.width-rect.width, 0)
elif self.mode == 3:
targetPosition = (0,0)
return targetPosition
def get_angle(self):
if self.angle == 360:
self.rotate_right = False
elif self.angle == 0:
self.rotate_right = True
if self.rotate_right == True:
self.angle+=12
else:
self.angle-=12
def run(self):
"""Loop forever processing events"""
running = True
while running:
event = pygame.event.wait()
# player is asking to quit
if event.type == pygame.QUIT:
running = False
# time to draw a new frame
elif event.type == self.REFRESH:
self.draw()
else:
pass # an event type we don't handle
def draw(self):
"""Update the display"""
# everything we draw now is to a buffer that is not displayed
self.screen.fill(self.bg_color)
#Draw img
rect = self.img.get_rect()
#Note: this can be made dynamic, but right now since this is typically a poor structure, we will use static values.
#80 is the padding, so it hits right before.
#0,0 : top left
#self.width-rect.width, 0 : top right
#0, self.height-rect.height : bottom left
#self.width-rect.width, self.height-rect.height : bottom right
targetPosition = ()
#img = pygame.transform.rotate(self.img, self.angle)
img = self.img
self.get_angle()
self.get_mode()
targetPosition = self.get_target()
print targetPosition
print self.x, self.y
if self.x < targetPosition[0]:
self.x+= targetPosition[0]-self.x//self.FPS
elif self.x > targetPosition[0]:
self.x-= targetPosition[0]+self.x//self.FPS
if self.y < targetPosition[1]:
print "s"
self.y+= targetPosition[1]-self.y//self.FPS
elif self.y > targetPosition[1]:
self.y-= targetPosition[1]+self.y//self.FPS
rect = rect.move(self.x, self.y)
self.screen.blit(img, rect)
# flip buffers so that everything we have drawn gets displayed
pygame.display.flip()
MyGame().run()
pygame.quit()
sys.exit()

What's happening is that your ball is starting at (0,0) (top left) with a target of (0,550) (bottom left), discovers that it's at a lower y than its target, and promptly proceeds to increment its position by
targetPosition[1] - (self.y // self.FPS)
which is of course equal to 550, so it immediately snaps to the bottom of the screen.
Then during the next draw loop, get_mode() comes along and says 'okay, I'm at (0, 550), so I'll go ahead and set the mode to 0'. Then get_target() comes along and says 'okay, I'm in mode 0, let's go over to (0, 550).
And then this happens again during the next draw loop, and the next, and the next ... So of course your ball doesn't go anywhere.
You'll need to do a couple of things to fix your example:
Fix your target positions in get_target(). Right now they're targeting the same points where the transitions that trigger those modes happen, so your ball won't go anywhere.
Consider your velocity statements more carefully: right now they'll behave somewhat strangely. One way to do this properly is to determine (dx, dy) - that is, the absolute vector from you to your destination - and then normalize this vector such that it points in the same direction but has a magnitude equal to your desired speed. This approach will work for any target position you want.
To elaborate on the second point:
Suppose we're at (x, y) and we're trying to get to (target_x, target_y).
Let dx = target_x - x, dy = target_y - y. This should be uncontroversial: we're just taking the difference.
Then we remember the Pythagorean theorem: given a right triangle with sides a, b, c and hypotenuse c, we recall that len(c)**2 == len(a)**2 + len(b)**2. It's the same thing with vectors: the length of a vector (x, y) is the hypotenuse of a right triangle with side lengths x and y. You can draw this on a piece of paper if you want to prove this to yourself.
Given that, we can find the length of (dx, dy): it's just L(dx, dy) = sqrt(dx*dx + dy*dy). This lends itself to a curious observation: if we multiply both dx and dy by a scalar k, we also multiply the length by k, since sqrt(dx*k*dx*k + dy*k*dy*k) == sqrt(k*k*(dx*dx + dy*dy)) == k*sqrt(dx*dx + dy*dy).
It follows that we can find a vector parallel to (dx, dy), but of length 1, by dividing both dx and dy by L(dx, dy). Precompute L to avoid some potential issues. Multiply this new vector by whatever you want your speed to be: this is your desired velocity.

Add collision detection to sprite, pyGame

bassically im trying to add collision detection to the sprite below, using the following:
self.rect = bounds_rect
collide = pygame.sprite.spritecollide(self, wall_list, False)
if collide:
# yes
print("collide")
However it seems that when the collide is triggered it continuously prints 'collide' over and over when instead i want them to simply not be able to walk through the object, any help?
def update(self, time_passed):
""" Update the creep.
time_passed:
The time passed (in ms) since the previous update.
"""
if self.state == Creep.ALIVE:
# Maybe it's time to change the direction ?
#
self._change_direction(time_passed)
# Make the creep point in the correct direction.
# Since our direction vector is in screen coordinates
# (i.e. right bottom is 1, 1), and rotate() rotates
# counter-clockwise, the angle must be inverted to
# work correctly.
#
self.image = pygame.transform.rotate(
self.base_image, -self.direction.angle)
# Compute and apply the displacement to the position
# vector. The displacement is a vector, having the angle
# of self.direction (which is normalized to not affect
# the magnitude of the displacement)
#
displacement = vec2d(
self.direction.x * self.speed * time_passed,
self.direction.y * self.speed * time_passed)
self.pos += displacement
# When the image is rotated, its size is changed.
# We must take the size into account for detecting
# collisions with the walls.
#
self.image_w, self.image_h = self.image.get_size()
global bounds_rect
bounds_rect = self.field.inflate(
-self.image_w, -self.image_h)
if self.pos.x < bounds_rect.left:
self.pos.x = bounds_rect.left
self.direction.x *= -1
elif self.pos.x > bounds_rect.right:
self.pos.x = bounds_rect.right
self.direction.x *= -1
elif self.pos.y < bounds_rect.top:
self.pos.y = bounds_rect.top
self.direction.y *= -1
elif self.pos.y > bounds_rect.bottom:
self.pos.y = bounds_rect.bottom
self.direction.y *= -1
self.rect = bounds_rect
collide = pygame.sprite.spritecollide(self, wall_list, False)
if collide:
# yes
print("collide")
elif self.state == Creep.EXPLODING:
if self.explode_animation.active:
self.explode_animation.update(time_passed)
else:
self.state = Creep.DEAD
self.kill()
elif self.state == Creep.DEAD:
pass
#------------------ PRIVATE PARTS ------------------#
# States the creep can be in.
#
# ALIVE: The creep is roaming around the screen
# EXPLODING:
# The creep is now exploding, just a moment before dying.
# DEAD: The creep is dead and inactive
#
(ALIVE, EXPLODING, DEAD) = range(3)
_counter = 0
def _change_direction(self, time_passed):
""" Turn by 45 degrees in a random direction once per
0.4 to 0.5 seconds.
"""
self._counter += time_passed
if self._counter > randint(400, 500):
self.direction.rotate(45 * randint(-1, 1))
self._counter = 0
def _point_is_inside(self, point):
""" Is the point (given as a vec2d) inside our creep's
body?
"""
img_point = point - vec2d(
int(self.pos.x - self.image_w / 2),
int(self.pos.y - self.image_h / 2))
try:
pix = self.image.get_at(img_point)
return pix[3] > 0
except IndexError:
return False
def _decrease_health(self, n):
""" Decrease my health by n (or to 0, if it's currently
less than n)
"""
self.health = max(0, self.health - n)
if self.health == 0:
self._explode()
def _explode(self):
""" Starts the explosion animation that ends the Creep's
life.
"""
self.state = Creep.EXPLODING
pos = ( self.pos.x - self.explosion_images[0].get_width() / 2,
self.pos.y - self.explosion_images[0].get_height() / 2)
self.explode_animation = SimpleAnimation(
self.screen, pos, self.explosion_images,
100, 300)
global remainingCreeps
remainingCreeps-=1
if remainingCreeps == 0:
print("all dead")

A check for collision is only a check to see if two rectangular sprites have a common area.
There isn't a built in collision that unables player input during collision. You have to write that yourself.
You should probably want to change the player coordinates when a collision takes place. An example:
Let's say we play mario. When the state of mario is JUMPING check for collision. Somewhere we will store the speed of mario in the y axis. When the collision returns True, with any of the blocks, we now set the speed to 0, and the y to the top/bottom of a block. If it will be the bottom, we still keep JUMPING, so it can fall back to the ground.
My tip for the creeper is to have some oldx and oldy value, to return to when the collision takes place. That way the creeper will never go into a wall. Another approach would be to simply change the direction when a collision takes place, but that may not always work.