Mu/PygameZero/Kenney.nl demo code

joystick_demo.py

"""
Demo code for Mu/PygameZero using kenney.nl graphics.

There's a short video demo at https://www.youtube.com/watch?v=b2IPNCJtUL4.

NOTE: this relies on two patches to Mu which aren't yet in 
      the main PgZero repository, one which adds joystick
      support, and another which adds a flip property to
      the Actor class.
"""

# Alien graphics from kenney.nl's platformer art deluxe pack
#     https://kenney.nl/assets/platformer-art-deluxe
alien = Actor('p3_stand')
alien.pos = 100,100
alien.speed = [0, 0]
alien.move_distance = 0
alien.facing_left = False
alien.jumping = False
alien.jump_speed = (0,0)
alien.start_jump_y = 0

# laser sprite from rawdanitsu at opengameart.org:
#     https://opengameart.org/content/lasers-and-beams
laser = Actor('laser')
laser.firing = False
laser.speed = 0

WIDTH = 800
HEIGHT = 600

def draw():
    screen.clear()
    screen.fill((0,0,0))
    
    if laser.firing:
        laser.draw()
    
    if alien.jumping:
        alien.image = 'p3_jump'
    elif sum(alien.speed) == 0:
        alien.image = 'p3_stand'
    else:
        # update walking frame every 12 pixels
        walk_pos = (int(alien.move_distance / 12)) % 11 + 1
        alien.image = 'p3_walk{:0>2}'.format(walk_pos)
    alien.draw()

def update():
    if alien.jumping:
        alien.x += alien.jump_speed[0]
        alien.y += alien.jump_speed[1]
        alien.jump_speed[1] += 1.0
        if alien.y > alien.start_jump_y:
            # below our starting jump height, so stop
            alien.jumping = False
            alien.y = alien.start_jump_y
    else:
        if alien.speed == (0,0):
            # stopped
            alien.move_distance = 0     # reset walk distance
        else:
            # moving
            alien.x += alien.speed[0]
            alien.y += alien.speed[1]
            alien.move_distance += abs(alien.speed[0]) + abs(alien.speed[1])
            if alien.speed[0] < 0:
                alien.facing_left = True
            elif alien.speed[0] > 0:
                alien.facing_left = False
    
    if alien.right > WIDTH:
        alien.right = WIDTH
    if alien.left < 0:
        alien.left = 0
    if not alien.jumping:
        # ^^ this lets the alien pop temporarily out of the top of the screen,
        # rather than hit their head on the border.
        if alien.top < 0:
            alien.top = 0
        if alien.bottom > HEIGHT:
            alien.bottom = HEIGHT
    
    alien.flip = alien.facing_left
    
    laser.x += laser.speed
    if not screen.bounds().colliderect(laser):
        laser.firing = False
        laser.speed = 0
    
def on_joy_button_down(joy, button):
    print("Mu button down:", joy, button)
    #print(alien.speed)
    if button == joybutton.ZERO:
        laser.pos = alien.pos
        laser.firing = True
        laser.speed = 40
        if alien.facing_left:
            laser.speed *= -1

    if button == joybutton.ONE and not alien.jumping:
        alien.jumping = True
        # jump height is proportional to how fast we run, but should
        # be a minimum of half run speed
        jumpy = 10 + abs(alien.speed[0])
        alien.jump_speed = [alien.speed[0], -jumpy]
        alien.start_jump_y = alien.y + 0.1
        
def on_joy_button_up(joy, button):
    print("Mu button up:", joy, button)

def sanitise_axis(value):
    # make a small 'dead spot' in the middle or we'll drift
    if -0.05 < value < 0.05:
        return 0
    else:
        return value

def on_joy_axis_motion(joy, axis, value):
    print("Mu joystick move:", joy, axis, value)
    if axis == axis.X:
        alien.speed[0] = sanitise_axis(value) * 10
    if axis == axis.Y:
        alien.speed[1] = sanitise_axis(value) * 10

def on_mouse_down():
    print("Mouse button clicked!")

def on_joy_hat_motion(joy, hat, value):
    print(joy, hat, value)