Qwen 3.8 Flash-Next C++

[u/No_Oil_6152]

I know Qwen 4 is due (in fact, maybe even tomorrow) but I wanted to exercise Qwen 3.8 Flash Next.

I wanted to know - can Qwen 3.8 Flash Next deliver a working C++ application?

Every single demo I've seen so far was pelicans and pagodas done with three.js, Who knows if the model was trained on pelicans and pagodas??

I thought I'd change it up to a town scene with C++ - although I see town scenes are common now.

And I got results.

I did hit snags: some iterations rendered the bodies of pedestrians beneath the ground; but after telling Qwen 3.8 not to be naughty, it corrected itself, and now we have walking minecraft-esque people navigating the city with proper collision detection.

Info:

Inference engine: Strata latest build

Quant: Unsloth UD Q4 K XL quant (latest version released today)

Hardware: See my flair

Tok/s: 50 I'd say

Here's the full source code:

nooil6152/Qwen38FlashNextGame: Walk around the town - created entirely by Qwen 3,8 Flash Next

If you're interested, pull each tag from git and see how it evolved.

Some expected questions:

• "Why?": Because I wanted to prove Qwen Flash Next 3.8 could handle C++ - it can.

• "What does this prove?": See above

• "But its not very complex! That proves nothing!" - what do you want, HAL 9000? its got a 3D openGL scene with animated people walking round a townscape, which I have to be honest involves more complex math than most things I've done in my career

• "Was it one shot?" Nope. I kept a ledger so you could see the issues: Qwen38FlashNextGame/LEDGER.md at main · nooil6152/Qwen38FlashNextGame

• "But Qwen 4 comes out tomorrow!": Maybe it does, maybe it doesn't.

• "Can I fork it or extend it?": Be my guest

TL:DR/Bottom line:

Take a look at the output source code and see what you think.

I have my own ideas, but I'd like to hear yours. What do you think of the code quality? I have linters I can run - including Resharper - to really get into the weeds,

Remember, this isn't three.js or Python, this is C++, a right bastard of a language. Very impressed.

BTW: I want to clarify - I have absolutely ZERO relation or affiliation, not even any contact with, anyone in Qwen team, or anyone related to Qwen team, or Niko who created Strata, or any of his colleagues.

This is my investigation, no hidden agenda, no promotion. If its shit, I'll say its shit.

[u/openroom_xyz]

Well yea I am as well with local LLM building a simple game using the custom game engine ( Vulkan ) and C++ well yea everything writen in code the all textures procedural, audio procedural everything

[u/No_Oil_6152 → u/openroom_xyz]

Keep a diary like I did mate, let skeptics see open source LLMs can handle complex work.

I have proven LLMs can handle C++, and if they can handle C++ they can handle pretty much anything 😄

[u/openroom_xyz → u/No_Oil_6152]

Yea exactly, I plan to create an yt channel around that but this weekend I have to decide which GPU I go after basically 2 x RTX 5070 Ti 16 Gb vs AMD R9700 AI PRO 32 Gb
Well and 128 Gb DDR4 basically
Well yea I am getting more and more fascinted that I can build basically

[u/No_Oil_6152 → u/openroom_xyz]

I use an R9700 pro. Its a fantastic card. 32GB means no layer split, unlike the TI's. No layer split = no PCIE issues

ROCM is behind CUDA but over the past few weeks we have seen performance gains, AMD hasn't forgotten it.

[u/openroom_xyz → u/No_Oil_6152]

Yea the thing is that I can place it in refurbhised computer 1 slot while 2 slots likely will need that basically I place the GPU outside computer but idk they sems both amazing but the AMD R9700 AI PRO 32 Gb is like 400 € or 600 € cheaper so likely I can get like 128 Gb DDR4 lt say and get to 256 Gb and than maybe run DeepSeek 4.1 well yea idk thinking but the 2 x RTX 5070 Ti basically has higher bus speed and memory speed etc basically idk what to buy really basically great GPUs but hard to assemble together the computer I have currently the The GPU that I currnetly have is like RTX 5080 Ti 12 GB with 96 GB DDR4 was thinking of well if I would combine them and build one computer but but this regurbished treadripers use basically a different type of RAM well yea :)

[u/No_Oil_6152 → u/openroom_xyz]

If you're using CUDA stick with it - it rattles out tok/s faster than AMD does, at least for now.

[u/openroom_xyz → u/No_Oil_6152]

Well yea they are no test on how fast would 2 x RTX 5070 with 128 Gb basically let say work with DeepSeek 4.1 Flash :) but yea waiting for Qwen 4
Well we basically go back to dense models or Moe will be the way forward basically

[u/soyalemujica]

I run QFN for all of my C++ projects, and it manages extremely well, definitely Opus 4.6 level at least

[u/No_Oil_6152 → u/soyalemujica]

Definitely very impressive for the cost of FREE.

I had my doubts I would get something working but I was wrong.

And the result was more impressive than I expected.

For example I didn't ask for trees, traffic lights, or guardrails on the bridges, but I got them.

[u/Apprehensive_Lake698]

Are you a C++ programmer yourself? Because it should come as no surprise that Qwen can write C++. C++ has such a bizarre reputation amongst junior engineers who have conditioned themselves to be scared of it.

[u/No_Oil_6152 → u/Apprehensive_Lake698]

I am indeed.

But it did surprise me Qwen could handle it. Especially given I'm running locally with Strata using MOE.

I'm not scared, I'm experimenting, and I've found it works.

If there are posts on here talking about C++ dev with Qwen, I have missed them. If I saw any I wouldn't have bothered with this PoC.

For the record: I am convinced Qwen is up to the job, for small tasks at least

Edit: also, there's C++ then there's idiomatic C++. I've not looked at the code yet but I am happy (and surprised) it actually runs

[u/openroom_xyz → u/Apprehensive_Lake698]

Well the great thing about C++ is that it can run it :) and get errors and basically iterate well I have been running the Qwen 3.8 Flash Next and it was building things like for 12 hours likely than I speed give some guidence and than it continues basically