Pixxura — Advanced

#What you'll learn

• How to export normal maps and light masks for lighting inside a game engine.
• The Stack (shader config) and sprite-sheet JSON formats, field by field.
• How animated sprites and timed effects decide the number of frames.
• Why the preview and the bake can differ in speed but never in pixels.
• How to keep a reusable lighting library across projects and teammates.

#Before you start

• Work through Pixxura — Intermediate: lighting rigs, normal-map methods and the effect stack.
• You need a plan that includes Pixxura.
• For engine lighting, know how your engine reads normal maps (most use the same convention as Pixxura; see below).

#How-tos

#How to export a normal map for engine lighting

1. Set up the normal map in the Normal map panel and check it in View → Normals.
2. Open Bake & export, choose Normal map and a Scale (1×, 2×, 3×, 4×, 6× or 8×), then Download.
3. The PNG uses the common OpenGL convention: red points right, green points up, blue points out of the screen. Godot and Unity read this directly. If your engine expects DirectX-style maps (green down), flip the green channel.
4. The map includes the Padding around the sprite, so export the sprite itself at the same padding and scale to keep them aligned.

#How to export a light mask

1. In Bake & export, choose Light mask.
2. You get only the light falling on the sprite, without its colours.
3. Use it in your engine or another app as a separate layer, for example added on top of the sprite for a glow pass, or to drive an emissive map.

#How to save and reuse a lighting setup

1. Choose Stack (shader config) in Bake & export and Download. You get a .pxura.json file with no pixels in it.
2. Load it into any project with Import stack… (in the Bake & export dialog).
3. The file uses the format pixxura-stack, version 1, and holds:

#How to read the sprite-sheet export

1. Choose Sprite sheet + JSON, a Scale and Columns (One row, 4, 8 or 16).
2. You get a zip with name_sheet.png and name_sheet.json.
3. The JSON has app (pixxura), frames (the count), frameWidth, frameHeight, cols, rows, durations (one per frame, in milliseconds) and config, the same lighting setup as a stack file, so the sheet documents how it was lit.

#How to control how many frames you get

1. A still sprite with steady lights and no timed effects exports as one frame.
2. As soon as anything moves (a flickering or pulsing light, a timed effect, or an animated sprite), it becomes animated.
3. The number of frames is the larger of the sprite's own frame count and Loop frames in the Canvas panel.
4. Every timed effect and light animation is calculated as whole cycles over the loop, so frame 1 always follows the last frame cleanly.
5. Displacement effects (Wave, Heat haze, Ripple) move whole pixels, so no in-between colours appear.

#How to get the fastest preview

1. The GPU preview badge shows whether your device's graphics chip draws the live preview. Turn it off from its toggle if a device draws incorrectly.
2. The graphics chip speeds up the lighting (shadows and halos included) and simple colour effects at the top of the stack; the rest runs on the main processor afterwards.
3. Palette snapping (Sprite palette or a library Palette) always runs on the main processor, so it's slower to preview.
4. Exports always use the main-processor method, which is the reference: a bake is pixel-identical on every device.

#Workflows

#Real-time lights in Godot

1. Light and tune the sprite in Pixxura so it looks right on its own.
2. Export the sprite (PNG (this frame) or Sprite sheet + JSON) and the Normal map at the same scale.
3. In Godot, assign the normal map to the sprite's texture as its normal map; add Light2D nodes. Godot's lights now shade the sprite using Pixxura's shape.

#A lighting kit for a whole team

1. Make one stack per mood and save each as Stack (shader config).
2. Share the files, or save a project to the Cloud so teammates can open it from their account.
3. In Flow, add Pixxura as a step after the art step; each teammate's result goes to the next step with Send result to Flow.

#Lit sprites into a game package

1. Light the animation, then Send to App → The lit animation (frames) to Pixxizi.
2. Pixxizi packages it for your engine. Add hitboxes in Pixxeta before packaging if needed.

#Tips and shortcuts

• Limits: sprites up to 480 × 480; Padding 0 to 32; Loop frames 2 to 64; FPS 1 to 30; export Scale up to 8×.
• Light halos are drawn as solid rings that are always partly see-through, so Outline, Drop shadow and Pixel glow never treat a halo as part of the sprite.
• Your current project is saved on this device automatically ("Restored your last session" appears when you come back). A cloud save is a zip with stack.json, the sprite's frames and any imported normal map.
• Send to App offers the lit sprite or animation as frames, This frame (image), or The palette.
• Library opens an image, frames or a sheet as the sprite, or a palette for Snap.

#Troubleshooting

• Engine lighting looks inverted vertically. Your engine expects green-down normal maps; flip the green channel.
• The normal map and the sprite don't line up in the engine. Export both at the same Scale, and remember both include the Padding.
• The export has far more frames than expected. A flickering light or a timed effect made it animated. Set lights to Steady and untick timed effects for a still.
• Import stack fails with "not a Pixxura stack file". Only .pxura.json files from Stack (shader config) can be imported; a sprite-sheet JSON isn't a stack file.
• The preview is slow but the badge says GPU. Snap set to a palette and effects lower in the stack run on the main processor; switch Snap off while you work.

#Related guides

• Pixxura — Beginner · Pixxura — Intermediate
• Pixxado · Pixxizi · Pixxeta · Pixx Flow