Adds volume control to PICO-8 on the gameshell

pico-8-volume.py

# you need to `sudo pip install pyxhook` as it's used to intercept the volume presses
# you will also want to update your launcher to call this script (I just have mine in the pico-8 directory
# and have my PICO-8.sh run:
# SDL_VIDEODRIVER=x11 DISPLAY=:0 python /home/cpi/pico-8/pico-8-volume.py
# video of what it looks like: https://www.youtube.com/watch?v=BAoYapdMiPM

import pygame
import os
import pyxhook
import alsaaudio
import subprocess
import time
from threading import Timer

PROCESS = None
PROCESS_CHECK = None

HOOK = None
VOLUME_SCREEN = None
VOLUME_TIMER = None


def kill_listener():
    HOOK.cancel()


def keypress_handler(e):
    global VOLUME_TIMER, PROCESS

    volume = None
    if e.Key == 'P_Subtract':
        volume = get_volume() - 3
    elif e.Key == 'P_Add':
        volume = get_volume() + 3

    if volume is not None:
        set_volume(volume)
        if VOLUME_TIMER:
            update_volume()
            hide_volume_timer()
        else:
            show_volume()


def normalize_volume(value):
    return min(100, max(0, value))


def get_volume():
    m = alsaaudio.Mixer()
    return int(m.getvolume()[0])


def set_volume(value):
    m = alsaaudio.Mixer()
    value = normalize_volume(value)
    m.setvolume(value)


def show_volume():
    global VOLUME_TIMER, VOLUME_SCREEN
    pygame.init()
    os.environ['SDL_VIDEO_WINDOW_POS'] = "0,200"
    VOLUME_SCREEN = pygame.display.set_mode((320, 40), pygame.NOFRAME)
    update_volume()
    hide_volume_timer()


def update_volume():
    VOLUME_SCREEN.fill(pygame.Color("black"))
    if get_volume():
        width = (320 - 60) * get_volume() / 100
        pygame.draw.rect(VOLUME_SCREEN, (0, 255, 128), pygame.Rect(30, 10, width, 20))
    pygame.display.flip()


def hide_volume_timer():
    global VOLUME_TIMER
    if VOLUME_TIMER:
        VOLUME_TIMER.cancel()
    update_volume()
    VOLUME_TIMER = Timer(2.0, hide_volume)
    VOLUME_TIMER.start()


def check_application():
    if PROCESS.poll() is 0:
        print("killing application")
        kill_listener()
        exit()

    PROCESS_CHECK = Timer(0.5, check_application)
    PROCESS_CHECK.start()


def hide_volume():
    global VOLUME_TIMER
    VOLUME_TIMER = None
    pygame.quit()


PROCESS = subprocess.Popen(["/home/cpi/pico-8/pico8_dyn -splore -draw_rect 32,0,256,240"], shell=True)
check_application()

HOOK = pyxhook.HookManager()
HOOK.KeyDown = keypress_handler
HOOK.HookKeyboard
HOOK.start()