voxel engine devlog #2

Threading turned into rendering turned into lighting turned into an actual world with caves in it, all in one sitting. This was NOT the plan but here we are lol.

Threading: got gen + meshing off the main thread onto a real worker pool. Workers are just pure functions, voxels in results out through queues, so the only actual cross-thread headache was stopping a chunk from getting unloaded while another job was still reading it (fixed with a refcount). World output came out byte-identical to before which is exactly what I wanted, just moved where the work happens not what it produces. Worst case frame during a full re-stream is under 1ms now.

One draw call: this was the fun one. Went from 349 draw calls (one per chunk, kind of wacko ngl) down to 1. GPU buffer stays persistently mapped, culling got moved into a compute shader, and the indirect draw pulls its own visible count straight off the GPU so it never even touches the CPU. Same exact pixels as before, just the CPU isn’t sitting there doing a bunch of pointless work anymore.

Cave culling: engine now figures out which chunks you could actually see air through and just doesn’t draw the rest. Above ground that’s about 40% fewer chunks. My sealed test room underground was cutting 98%+ but that number came back down once real caves existed instead of one clean sealed box, which makes sense since it’s following actual connectivity now instead of a best case demo.

Lighting: sky + block light through BFS, baked straight into the mesh so there’s no separate lighting pass at render time. Threw in a glow block to test with. Removing a light source zeroes it out exactly and adding it back restores it exactly, verified both instead of assuming it just works.

Terrain + you can hit stuff now: swapped the flat test world for actual noise based terrain, caves carved with 3D noise instead of flat tunnels. Added raycasting so you can break/place blocks. Player movement runs on a fixed timestep so framerate literally cannot change how fast you move.

Next up: lighting is flat per face right now, want that smoothed per corner eventually. also got one frame time spike during heavy cave streaming I need to go check out before it turns into an actual problem once flying through caves is a thing.

voxel engine first devlog yayyyyyy!!!!!!

Deadahh just wanted to put everything from the last few days into one initial devlog so I don’t have to keep yap too much.

Started with basic OpenGL 4.6 and GLFW, instead of using string lookups for shaders which is clown behavior, everything uses explicit locations. I also set up a headless smoke test so the CI can render offscreen, check its own pixels, and pass without popping up a window and being too goofy.

For debugging, I threw in an ImGui menu to track frames, draw calls, and memory without making the heap allocator crash out. Steady-state heap allocations are at zero right now + also flipped the depth buffer to reversed-D because standard depth buffers kaboom at long distances and make the textures Z-fight.

The Mesher thingy

The first mesher I built was literally just a mesher. A regular mesher. There was nothing special about it. It just emitted 6 expanded vertices per face which took up way too much space (615 KB a chunk) and was slow.

I improved it and made a binary greedy mesher that packs an entire quad into a single 64-bit integer. It uses 64-bit bitwise column ops to merge faces instantly. 2.7x fewer triangles and 33x less memory. It’s so fast it takes like 0.05ms and I also ripped out VBOs completely for SSBO vertex pulling, meaning the GPU just reconstructs the geometry on the fly.

There was one issue where the greedy mesher left microscopic sub-pixel holes everywhere so I kept seeing pinhole cracks, so I just bloated every quad by 0.001 so they overlap and cover it up (surely this works well enough).

Chunks & Compressing

Having raw voxel arrays was eating my RAM alive, so I used palette compression. If a chunk is entirely air or entirely stone, it just stores one ID now. If it’s mixed, it bit-packs the indices, this dropped voxel memory by 20x. We’re streaming a 21x21x4 chunk radius (like 2,100 chunks) and it only takes 6.6 MB.

Added a chunk streaming manager so it loads in a ring around you. I had to put strict budgets on generation and meshing per frame, otherwise the game just freezes when you move too fast + CPU frustum culling means we only actually draw the chunks you’re looking at.

What’s Next?

Right now the engine is in the state of being too good and being too bad at the same time. It’s doing like 349 individual draw calls per frame (one for every visible chunk). It works, but it’s got some quirks that I need to kaboom first.

Next up is building a persistent arena buffer and GPU-driven culling so we can collapse the entire world into ONE single draw call using indirect drawing.

Second and final devlog (i think)
So this started as “what if a website could tell you why you missed” and got wildly out of hand. Everything below runs at retrace-osu.vercel.app now. Recap of the whole thing:
The replay engine: The core of the site. You drop a .osr and it gets decoded entirely in your browser, the beatmap is auto-fetched by its hash, and then a reconstruction engine re-judges the whole play from the raw cursor and key data: every circle, slider follow-circle and spinner spin. It handles note stacking, stable’s notelock behavior, and mod clock rates properly, and the reconstructed judgements come out within a hit or two of the real scoreboard numbers. From that you get UR, timing bias, early/late split, per-section breakdown, and pattern splits (jumps, streams, bursts, spaced control) that know the difference between a 180bpm stream and that same stream with DT on.
The autopsy tools: A replay viewer with the actual slider paths, approach circles, miss markers and cursor trail, that now works like a proper video editor: quarter speed, frame stepping, keyboard shortcuts, and clickable miss timestamps that jump you to two seconds before each choke. You can even load a second replay of the same map as a green ghost cursor and watch where your lines diverge. There’s a playfield miss map, a hands panel that tells you your k1/k2 split, whether you single-tap or alternate and at what bpm you give in and switch, and whether you snap or flow aim, all measured from the frames.
The coach: Every analysis ends with strengths, leaks and practice drills derived from the measurements, plus an AI review that gets fed only measured facts (mod-adjusted stars, real clock rate, strain curve) so it can’t hallucinate numbers. My favorite part is the difficulty overlay: it draws the map’s strain curve behind your per-section UR, so it can tell you whether you fall apart at the hard parts (skill wall) or the easy parts (focus problem). Those need completely different fixes and no other tool makes the distinction.
Farm maps: Sign in and it profiles your top 100: your real mod combos with each one’s median accuracy, your comfort star band, and your aim/speed lean measured with rosu-pp. Then it prices candidate maps under your actual mods at your actual accuracy and, this is the important bit, ranks them by the real gain to your weighted total, not the raw pp fantasy. A “400pp play” that nets you 0.6pp gets buried. There’s also a chokes tab that finds plays in your bests worth fixing, and a ceiling number showing your total if you cleaned all of them.
Informatics: Type any username: mod-combination picker over their top 100 (exact combos, HD means HD only), pp milestones, 90-day rank graph, and trivia like their oldest surviving play, their most farmed mapper, their grade split and how much of their profile one play carries. Countries get a top-50 deep scan: hidden prodigies by pp per hour, the “national anthem” (the map half the country has in their bests), the oldest relic score still standing, the closest rivalry (Pakistan has two players literally 0pp apart), scene depth, farm diversity. Plus a side-by-side player compare page.
History: Every analyzed replay saves to your browser, nothing uploaded. Bulk-drop your whole Replays folder and it aggregates: which weaknesses recur across your plays, your UR trend, and per-map progress when you’ve analyzed the same map more than once.
Everything else: osu!-style UI with the triangles, 30-day sessions with token refresh, PNG share cards, link embeds, installable as an app, and a disk cache so the osu! API doesn’t hate me.The whole thing is client-first: your replays never leave your machine, the server only does pp math and API relaying. Go break it and tell me what’s wrong.

Made the base UI (heavy inspiration from the main osu website) and started working on parsing every replay. Made the site automatically fetch maps from the replays via the API (and get user profile data in the same way). Now I need to make it actually analyze replays and give criticism/improvement tips based on those replays, maybe an in-browser replay viewer so the coach thingy could give you specific timestamps of where you messed up

FIRST RELEASE!!!!
Fleshed it all out with full settings, QOL features, small oomph here and there + First Release :3

INSANE PROGRESS!!!!!
The device specific isolation finally works, the library I was using wasn’t working well so I had to replace it with a different one but rewriting the backend was very quick because they were very similar and I had most of the foundations down. I added Macros, Layers and tried fleshing it out as much as possible.
All that’s left is a bit of polish, testing and trying to make the UI not look the exact same as Wootility (oops)

Worked on bettering the UI and detecting, Device Isolation now works in sync with the UI but theres a problem with it isolating multiple devices at the same time.

worked on setting up the base UI and setting up the isolation layers to separate inputs from different keyboard devices (ongoing). Took alot of inspiration from wootility.