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Map save/reload stream lua function problem


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I'm trying to get lua examples for Map's Save and Reload functions working. If you try the example from https://www.ultraengine.com/learn/Map_Save?lang=lua , sol complains about args (with a StreamBuffer at least). It's not clear to me what to feed it for in-memory stuff.

I assume it's outdated because it's trying to call this

scene:Save(stream, "game.sav")


But save and reload do not take a string whatsoever as a second arg in lua docs. I assume changing the examples to do something like this is the way?


local buffer = CreateBuffer(1024)
local stream = CreateBufferStream(buffer)

-- Create a scene
local scene = CreateMap()

-- .... 

-- Save the starting scene to an in memory buffer

This appears to work, but it's unclear to me how to do the next two things:

1. seek to beginning of stream: I tried this `stream = CreateStreamBuffer(stream)`. an API to seek to beginning of oft-reused buffers for cute tricks would be nice though

2. Actually reload a map from memory? `Map:Reload(Stream)` complains about args as well when trying a stream arg, it appears only the unary string function exists.

I understand I can work around it with disk like so, maybe the old API was shorthand for this. But I'd like to avoid all disk I/O for reasons


-- Main loop
while not window:Closed() and not window:KeyDown(KEY_ESCAPE) do
    -- Reload the starting scene when space key is pressed
    if window:KeyHit(KEY_SPACE) then


If something like "`scene:Reload(stream, LOAD_DEFAULT)`" worked again that would be the money. Appreciate any input

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I do not know why the example in the documentation is wrong. I fixed it, thank you for pointing that out:

It will take a few hours to re-cache in the docs system, but the link there will take you straight to the source content.

My job is to make tools you love, with the features you want, and performance you can't live without.

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  • Solution

Yeah, it should work if you use CreateBufferStream to create a stream. This command does not require a buffer as an argument, and it is better not to provide one.

Then, before saving or loading call stream:Seek(0) to make sure the file position is at the beginning of the file.

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My job is to make tools you love, with the features you want, and performance you can't live without.

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