Python code specifics, when in the browser with pygbag runtime

on some platforms pygbag is not in the PATH, so use python -m pygbag instead of just pygbag.

My game does not start automatically

This is the default, because browser will not start any music until user says so by interacting clicking/gamepad/keyboard with game tab

but i really don’t have any music on game start

then prepend --ume_block=0 on pygbag command line and your game will auto start.

Sound problems for versions < 0.1.5

SDL2 is hard realtime, so sometimes the game asks too much from average devices and is a bit late on frame : As a result SFX get garbled, solution : upgrade to 0.1.5 or use external javascript sound manager.

Possible other solution: replace sdl2_audio by openal, PR welcomed …

I get very low fps, but only on web …

make you have removed all debug print() or logging to console, printing to terminal or javascript console is very costly in term of performance

I have custom modules or something looks like it is missing from stdlib

Just add everything you need alongside your, including hand picked stdlib modules. We did not put everything from stdlib in order to keep a small size for mobile connections. you can find extra stdlib modules in from [pygbag version]

but I want numpy or binary modules

Just add everything you need alonside you, including binary modules. They just have to match python version pygbag is loading if they are not wasm abi3 modules. Sometimes you may have to wait for maintener (like pymunk), build your own with python-wasm-sdk, extract a wheel from or pyodide’s build, or maybe just ask/offer a link to it here

File uploading

sample : image file viewer

import platform

def on_upload_files(ev):
    print("on_upload_files", ev)
    if ev.mimetype.startswith('image/'):
        # we can display that

platform.EventTarget.addEventListener(None, "upload", on_upload_files )
platform.window.dlg_multifile.hidden = false

File downloading

sample : async downloading of (r) utf-8 textfiles or (rb) binary files

import platform
from pathlib import Path
cdn = Path("")

async def main():
    async with platform.fopen( cdn / "repodata.json", "r") ) as textfile:
        print( len( ) )

sample : DEPRECATED synchronous download of non binary files

from pathlib import Path
cdn = Path("")

import urllib.request
outfile, _ = urllib.request.urlretrieve(cdn / "repodata.json", outfile)

# or just: 
# outfile = "/tmp/pip.json"
# shell.wget(f"-O{outfile}", cdn / "repodata.json")

import json
with open(outfile) as data:
    repo = json.loads( )

print( json.dumps(repo["packages"], sort_keys=True, indent=4) )

sample : chroma keying the display of a progress bar over a webpage

import pygame
import sys
screen = pygame.display.set_mode([1024, 600], pygame.SRCALPHA, 32)
screen.set_colorkey( (0,0,0,0), pygame.RLEACCEL )
screen.fill( (0,0,0,0) )
if (web := sys.platform in ('emscripten','wasi')):
    from platform import window

async def main():
    global ctx, web
    rng = 10 # resolution of progress bar
    slot = (1024-200)/rng
    for i in range(rng):

        marginx = 100
        marginy = 200
        pygame.draw.rect(screen,(10,10,10),( marginx-10, marginy-10, (rng*slot)+20, 110 ) )
        pygame.draw.rect(screen,(0,255,0), ( marginx, marginy, (1+i)*slot, 90) )
        if web:
            window.chromakey(None, *screen.get_colorkey(), 30)
        await asyncio.sleep(1)

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