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Painting voxels

Goal​

Click to color a ground cell; paint persists and syncs to other clients.

Send paint​

On click, convert world position to chunk/voxel coords (chapter 4) and call:

The client.udp.* and client.voxels.* calls in this chapter use the app-scoped token from chapters 2–3; the identity session token is rejected for gameplay.

await client.udp.sendVoxelUpdate({
  appId: '<your-app-id>',
  chunk: { x: String(chunkX), y: String(chunkY), z: '0' },
  uuid: actorUuid,
  voxel: { x: voxelX, y: voxelY, z: 0 },
  voxelType: paletteIndex,
  voxelState: base64Rgba,
  sequenceNumber: seq,
});

Color encoding: Voxel color format.

Receive​

On VoxelUpdateNotification, update local canvas immediately.

Hydrate on join​

Load existing paint with client.voxels.listByDistance:

await client.voxels.listByDistance({
  appId: '<your-app-id>',
  centerCoordinate: { x: '0', y: '0', z: '0' },
  maxDistance: 3,
});

Exit criteria​

  • Click paints a cell
  • Reload shows prior paint
  • Second client sees strokes live

Next: Viewport edge scroll