open cmd and run:
pip install pygame
pip install pgzero
then make a circle
import pgzrun
WIDTH = 400
HEIGHT = 400
def draw():
screen.clear()
x = WIDTH/2
y = WIDTH/2
pos = (x,y)
radius = 30
screen.draw.circle(pos, radius, 'white')
pgzrun.go()
Now lets move it:
import pgzrun
import random
WIDTH = 400
HEIGHT = 400
x = WIDTH/2
y = WIDTH/2
def on_mouse_down(pos):
global x,y
(mouse_x, mouse_y) = pos
x = mouse_x
y = mouse_y
def draw():
screen.clear()
pos = (x,y)
radius = 30
screen.draw.circle(pos, radius, 'white')
pgzrun.go()
Move it with keyboard
import pgzrun
import random
WIDTH = 400
HEIGHT = 400
STEP = 10
x = WIDTH/2
y = WIDTH/2
def on_key_down(key):
global x,y
if key == keys.LEFT:
x -= STEP
elif key == keys.RIGHT:
x += STEP
elif key == keys.UP:
# coordinates start 0,0 on the upper left corner
y -= STEP
elif key == keys.DOWN:
y += STEP
def draw():
screen.clear()
pos = (x,y)
radius = 30
screen.draw.circle(pos, radius, 'white')
pgzrun.go()
Lets say we have 400 width and 300 height window
(0,0)
+---------------------------+
| |
| |
| |
| |
| |
| |
+---------------------------+
(400, 300)
top left corner is y = 0 and x = 0, bottom right is x = 400 and y = 300. So when we move 'UP' with the keyboard we actually have to decrease y instead of increasing it like in turtle, where 0,0 is in the center of the screen, so top left is (-half_x, -half_y) and bottom right is (half_x, half_y)
Smooth movement.
import pgzrun
import random
WIDTH = 400
HEIGHT = 400
STEP = 10
x = WIDTH/2
y = WIDTH/2
def update():
global x,y
if keyboard.LEFT:
x -= STEP
elif keyboard.RIGHT:
x += STEP
elif keyboard.UP:
y -= STEP
elif keyboard.DOWN:
y += STEP
def draw():
screen.clear()
pos = (x,y)
radius = 30
screen.draw.circle(pos, radius, 'white')
pgzrun.go()
pgzero will call your update function 60 times per second, and now it will just check at the time of the call, is keyboard.UP, and if it is it will just move. Which is completely different, where each time you press the up key the on_key_down function is called. So previously you had ot press the key every time to move, now you can just hold it.
Where do those keyboard and screen magic variables come from? In python there is such thing as __builtin__ which literally adds new keywords, kind of like input or print, when you import pgzrun it will import also those builtins. Actor, Rect, keyboard etc.. you can check them at https://pygame-zero.readthedocs.io/en/stable/builtins.html
COLLIDE!
import pgzrun
import random
WIDTH = 400
HEIGHT = 400
STEP = 10
x = WIDTH/2
y = WIDTH/2
box = Rect((20,20),(100,100))
game_over = False
def update():
global x, y, game_over
if keyboard.LEFT:
x -= STEP
elif keyboard.RIGHT:
x += STEP
elif keyboard.UP:
y -= STEP
elif keyboard.DOWN:
y += STEP
if box.collidepoint((x,y)):
game_over = True
def draw():
screen.clear()
pos = (x,y)
radius = 30
screen.draw.rect(box, color="red")
screen.draw.circle(pos, radius, 'white')
if game_over:
screen.draw.text("GAME OVER", (50, 30), color="blue")
pgzrun.go()
Catch the snake
Make images/ folder and download the images from https://github.com/jackdoe/programming-for-kids. When you say Actor("c1") it will look for c1.png in images/ folder in the current directory.
import pgzrun
import random
HEIGHT = 200
WIDTH = 200
score = 0
speed = 1
elf = Actor("c1")
snake = Actor("snake")
elf.x = WIDTH/2
elf.y = HEIGHT/2
def place_snake():
snake.x = random.randint(10,WIDTH-10)
snake.y = random.randint(10,HEIGHT-10)
place_snake()
def update():
global game_over, speed, score
if keyboard.left:
elf.x = elf.x-speed
if keyboard.right:
elf.x = elf.x+speed
if keyboard.up:
elf.y = elf.y-speed
if keyboard.down:
elf.y= elf.y+speed
if keyboard.R:
speed = 1
score = 0
if elf.colliderect(snake):
score += 1
speed += 1
place_snake()
def draw():
screen.fill('black')
elf.draw()
snake.draw()
screen.draw.text("Score: "+ str(score), color="white", topleft=(10,10))
pgzrun.go()
Many Snakes
import pgzrun
import random
HEIGHT = 200
WIDTH = 200
score = 1
speed = 1
elf = Actor("c1")
snakes = []
elf.x = WIDTH/2
elf.y = HEIGHT/2
def place_snakes():
global snakes
snakes = []
for i in range(score):
snake = Actor("snake")
snake.x = random.randint(10,WIDTH-10)
snake.y = random.randint(10,HEIGHT-10)
snakes.append(snake)
place_snakes()
def update():
global game_over, speed, score, snakes
if keyboard.left:
elf.x = elf.x-speed
if keyboard.right:
elf.x = elf.x+speed
if keyboard.up:
elf.y = elf.y-speed
if keyboard.down:
elf.y= elf.y+speed
if keyboard.R:
speed = 1
score = 0
snakes = []
place_snakes()
for s in snakes:
if elf.colliderect(s):
score += 1
speed += 1
place_snakes()
def draw():
screen.fill('black')
elf.draw()
for s in snakes:
s.draw()
screen.draw.text("Score: "+ str(score), color="white", topleft=(10,10))
pgzrun.go()
import pgzrun
import random
HEIGHT = 200
WIDTH = 200
score = 0
speed = 1
game_over = False
elf = Actor("c1")
snake = Actor("snake")
elf.x = WIDTH/2
elf.y = HEIGHT/2
def place_snake():
snake.x = random.randint(10,WIDTH-10)
snake.y = random.randint(10,HEIGHT-10)
place_snake()
def update():
global game_over, speed, score
if keyboard.left:
elf.x = elf.x-speed
if keyboard.right:
elf.x = elf.x+speed
if keyboard.up:
elf.y = elf.y-speed
if keyboard.down:
elf.y= elf.y+speed
if keyboard.R:
speed = 1
score = 0
if elf.colliderect(snake):
score += 1
speed += 1
place_snake()
def draw():
screen.fill('black')
elf.draw()
snake.draw()
screen.draw.text("Score: "+ str(score), color="white", topleft=(10,10))
pgzrun.go()
Catch as many snakes as you can in 5 seconds.
import pgzrun
import random
HEIGHT = 200
WIDTH = 200
game_over = False
score = 0
speed = 1
elf = Actor("c1")
snake = Actor("snake")
elf.x = WIDTH/2
elf.y = HEIGHT/2
def place_snake():
snake.x = random.randint(10,WIDTH-10)
snake.y = random.randint(10,HEIGHT-10)
place_snake()
def time_is_up():
global game_over
game_over = True
def update():
global game_over, speed, score
if keyboard.left:
elf.x = elf.x-speed
if keyboard.right:
elf.x = elf.x+speed
if keyboard.up:
elf.y = elf.y-speed
if keyboard.down:
elf.y= elf.y+speed
if keyboard.R:
speed = 1
score = 0
if elf.colliderect(snake):
score += 1
speed += 1
place_snake()
def draw():
screen.fill('black')
elf.draw()
snake.draw()
screen.draw.text("Score: "+ str(score), color="white", topleft=(10,10))
if game_over:
screen.fill('blue')
screen.draw.text("GAME OVER, Score: "+ str(score), color="white", topleft=(10,10))
clock.schedule(time_is_up, 5)
pgzrun.go()
You see we just overwrite the screen with 'blue' and write another text, but you can still move in the back and the score will update if you catch a sneak.
If you want to stop the hero to move outside of the window, simply restrict elf.x and elf.y to be smaller than 0 or bigger than WIDTH and HEIGHT
Example:
def update():
...
if keyboard.left:
elf.x = elf.x-speed
if elf.x > WIDTH:
elf.x = WIDTH
Cross the road. Work with your parent to find images for the game, you need few cars, fox and a door. If not just use the existing assets from your images/ folder
import pgzrun
import random
HEIGHT = 1000
WIDTH = 1200
score = 0
step = 5
coin_speed = 1
fox = Actor("fox")
gate = Actor("door")
gate.y = HEIGHT - 50
gate.x = WIDTH/2 - 20
cars=[
[Actor("car-2"),Actor("car-5"),Actor("car-3")],
[Actor("car-1"),Actor("car-5")],
[Actor("car-3"),Actor("car-4"),Actor("car-2")],
]
for a in cars:
for (coin_index,f) in enumerate(a):
f.x += coin_index * int(WIDTH/len(a)) + 30
def move_coins():
for (index,a) in enumerate(cars):
for (coin_index, f) in enumerate(a):
f.y = (index * int(HEIGHT/len(cars))) + int(HEIGHT/len(cars))/2
f.x += coin_speed
if f.x > WIDTH:
f.x = 0
game_over = False
move_coins()
def update():
global score
global step
global game_over
global coin_speed
if keyboard.left:
fox.x = fox.x-step
if fox.x <0:
fox.x=0
if keyboard.right:
fox.x = fox.x+step
if fox.x >WIDTH:
fox.x=WIDTH
if keyboard.up:
fox.y =fox.y-step
if fox.y <0:
fox.y=0
if keyboard.down:
fox.y= fox.y+step
if fox.y >HEIGHT:
fox.y=HEIGHT
if keyboard.R:
game_over = False
score = 0
fox.x = 0
fox.y = 0
coin_speed = 1
for i in cars:
for s in i:
if fox.colliderect(s):
game_over = 1 == 1
if fox.colliderect(gate):
fox.x = 0
fox.y = 0
score += 1
coin_speed += 2
move_coins()
def draw():
screen.fill('black')
fox.draw()
gate.draw()
for i in cars:
for k in i:
k.draw()
screen.draw.text("Score: "+ str(score), color="white", topleft=(10,10))
if game_over:
screen.fill("blue")
screen.draw.text("Final Score: "+ str(score), color="white", topleft=(10,10),fontsize=60)
pgzrun.go()