Why does this happen when a message is broadcasted forever? (wait until block couldn't be ran)

Eason_9

when green flag clicked
forever
broadcast (process v) // This message is supposed to broadcast every single frame.
end

when I receive [broadcast v]
if <mouse down> then // If the mouse button is clicked, 10 is added to the sprite's x value. But for some reason, the change x by 10 block is ignored.
wait until <not<mouse down>>
change x by (10)
end

Why does this happen? I think it's because the process message is broadcasted every single frame which resets the message and doesn't continue it.

I found a workaround by creating a new message for the “wait until not mouse down” and “change x by 10” blocks, so that it can continue there.

But is there a more in-depth explanation of why this happens? Why wouldn't the script just continue when another instance of it is broacasted?

Play with it yourself and you'll know what I mean

Last edited by Eason_9 (Jan. 21, 2025 03:01:02)

awesome-llama

Eason_9 wrote:
I think it's because the process message is broadcasted every single frame which resets the message and doesn't continue it.

Correct. That's just the way it is designed. I don't know how that decision was reached.

https://github.com/scratchfoundation/scratch-vm/blob/develop/src/blocks/scratch3_event.js#L60

event_whenbroadcastreceived: {
    restartExistingThreads: true
}

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