Sprite Rigger

A sprite rigger & animator desktop application.

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Save File Format (.sprig)

The project state is stored in a single container file with extension .sprig.

File Layout

filename.sprig
┌───────────────────────────────────────────────┐
│ Header                                        │
│   - magic         (x bytes)                   │
│   - version       (uint32_t)                  │
│   - manifestSize  (uint64_t)                  │
│   - chunksSize    (uint64_t)                  │
├───────────────────────────────────────────────┤
│ Manifest (binary)                             │
│   - entries: { key, offset, size }            │
├───────────────────────────────────────────────┤
│ Chunk 1 (raw/compressed bytes)                │
├───────────────────────────────────────────────┤
│ Chunk 2 (raw/compressed bytes)                │
├───────────────────────────────────────────────┤
│ ...                                           │
└───────────────────────────────────────────────┘

• Header

  • magic: identifies the file type (e.g., "SPRIG\0\0").
  • version: save file format version.
  • manifestSize: size of the manifest block in bytes.

• Manifest Describes all chunks in the file. Each entry includes:

  • name: logical name of the chunk (e.g., "settings", "svo")
  • type: data type (e.g., json, binary)
  • offset: byte offset from start of file
  • size: length of the chunk in bytes

• Chunks Contain the actual serialized data. Each chunk may be stored raw or compressed.

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Serializer TODO

• Compression: Add per-chunk compression (LZ4/zlib).
• Header: Include magic string + version for compatibility checks.
• Manifest: Store { name, type, offset, size } for all chunks.
• Future versions: Allow migration between file format versions.
• Atomic save: Write to .tmp file, then rename on success.

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Roadmap

• Implement serializer/deserializer
• Add compression/decompression layer
• Add checksum per chunk for corruption detection
• Support incremental save if necessary
• Need to add Deferred deletion
• Animation system store a raw pointer, this may pose a problem, may want to use Weak Handles (Generation IDs)

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