Pixxizi — Advanced

#What you'll learn

• How Pixxizi builds atlases for each engine and which coordinate system the data uses.
• Exactly which files a level becomes in each engine.
• How shadow children, nine-slice UI frames, bitmap fonts and dialogue are exported.
• What the manifest, README and credits contain, and how changed-only builds decide what changed.
• Where your package is stored and how to keep it safe.

#Before you start

• Read the Pixxizi Intermediate guide first: art checks, shadows, levels, fonts, budgets and versions.
• Know your engine's import basics; each export's README walks through the steps.

#How-tos

#How to predict atlases and coordinates

1. Godot 4: one atlas per group. Phaser and LÖVE: one atlas for the whole package. Unity and Generic: one sheet per sprite (Unity uses untrimmed cells so pivots in the .meta file are exact). GameMaker and Defold: one PNG per frame, because those engines pack atlases themselves.
2. Gameplay data (boxes, pivots, sockets) is in pixels with y pointing down, except Unity and Defold, where it is converted to y up.
3. Scale multiplies the art and every box, pivot and socket together.
4. Extrude repeats edge pixels around each frame or tile, which prevents seams when the engine filters or scales.

#How to find a level's files in each engine

1. Tick the engine in Export and build.
2. Open the ZIP's levels folder (for example pixx_assets/levels/<name>/ in Godot or Assets/Pixx/levels/<name>/ in Unity).
3. Use the table below to see which file to load.

• Tile numbers match Tiled's (the first tile is 1; 0 is empty).
• Collision cells are merged into as few rectangles as possible.
• Object positions are in pixels. Height and raw collision layers ride along as map properties in the Tiled formats.
• Godot's TileMap node is converted to TileMapLayer automatically in Godot 4.3 and newer.

#How to export shadow children

1. A paired Pixxado shadow becomes a sprite named <sprite>_shadow with the same animations, frame order and pivots as its parent, placed right after it.
2. In Godot, the parent's scene gets a Shadow node drawn behind the sprite, and its script keeps the shadow on the same frame.
3. The manifest lists every pair (sprite, shadow, layer), and each frame's gameplay data names its shadow.
4. An unpaired shadow layer is exported as a normal sprite, with a note in Check.

#How to export UI frames, fonts and dialogue

1. UI frames become images with nine-slice margins; each engine's own nine-slice setting is filled in where it has one.
2. Fonts become full-line-height glyph cells, then a BMFont file with each glyph's advance, offsets and the kerning pairs. Negative bearings become BMFont xoffset values, so letters that overhang still line up.
3. Dialogue is exported as JSON for every engine, as Yarn for every engine, and as Ren'Py for Generic. Portraits and voice blips come along as files.

#How to read the manifest and extras

1. Every ZIP has a pixx_manifest.json: each asset, which app it came from, its export name, plus the shadow pairs and levels when there are any.
2. The README lists the import steps for that engine; a credits file lists every credit carried by the assets (for example from Pixxava).
3. Runnable starter project adds a small runnable project for Godot, Phaser and LÖVE.
4. Only assets changed since v… compares each asset's output fingerprint with the last build. Renaming tags doesn't change the output, so it doesn't trigger a rebuild; changing pixels, settings, loop points or names does.

#How to keep your package safe

1. Pixxizi keeps one package per browser: the light settings in local storage and the asset data in the browser's database (assets can be several MB each).
2. Clearing site data removes them, so save regularly with Cloud, or download the package file.
3. A cloud package is a zip with project.json and one .pxasset per asset in assets/, so it can be opened on any device, or its assets pulled out individually.
4. Game packs you add are expanded into their members, so every member is checked on its own.

#Workflows

#A shared pipeline that ends in Pixxizi

1. Build the asset chain in Flow: art → Pixxeta → Pixxado → Pixxula → Pixxizi, with a quality gate before Pixxizi.
2. Each person sends their result to Flow; the Pixxizi owner adds the finished outputs from Library.
3. Export with Only assets changed since v… and attach the ZIP to the run as the final result.

#One package, several engines

1. Tick every engine you need and One ZIP with every engine.
2. Keep naming engine-neutral (Naming & folders: snake_case, no type prefixes) so scripts in each engine find the same names.
3. Use the manifest as the single list of what exists, for loading screens or asset tests.

#Hand-tuning a heavy build

1. Set a Size budget and export once to see where you are.
2. Use per-asset Export settings (this asset) to give big backgrounds a lower Scale or skip PNG8 only where colours band.
3. Loop long music; cut silent tails in Pixxibu or Pixxune.

#Tips and shortcuts

• Fixes from the Check tab are undoable with Ctrl+Z.
• The search box finds assets by name, tag or the app they came from.
• Use the default pivot applies the package's pivot setting (bottom-centre by default) to sprites without one.
• Double the atlas limit is the one-click fix for frames bigger than the atlas.

#Troubleshooting

• Unity colliders are flipped: the data is already y-up for Unity; don't flip it again in your scripts.
• Defold level is upside down: use the exported .tilemap, which already flips rows; don't use the raw map JSON in Defold.
• A changed-only build skipped my change: only tag changes are ignored. If you edited art in another app, send the new version to Pixxizi so the asset updates.
• Fonts overlap in the engine: load the BMFont file so the engine uses the advances, offsets and kerning.
• Assets vanished from the package: browser data was cleared. Reopen the package from Cloud or the downloaded file.

#Related guides

• Pixxizi Beginner · Pixxizi Intermediate
• Pixxeta · Pixxado · Pixxori · Pixxula · Pixxypo
• Pixx Flow · Cloud projects and your Library