EvilHop

EvilHop is a C# .NET library for reading, writing, and manipulating HIP archive files, the binary asset container format used in several games developed by Heavy Iron Studios.

Status

EvilHop is alpha software. Breaking changes are expected, and there is no NuGet package yet.

The block layer is complete: every serializer round-trips every archive tested byte-for-byte, including unknown fields and padding. The asset layer opens an archive through a session, parsing its blocks into typed Assets and rebuilding them unconditionally on commit.

Asset codec support falls into three states, per type:

• Typed - the asset's fields are modeled and read/written individually. Most gameplay-relevant types are here.
• Payload - the asset wraps an embedded file (a RenderWare model, a Bink video, audio) that is imported and exported as a whole blob rather than parsed field-by-field. This is the intended shape for these types, not a gap: BinkVideo, BSP, JSP, Model, RawImage, Sound, StreamingSound, StreamingTexture, Texture.
• Untyped - no codec exists yet. The asset reads through its shape's generic prefix if available and remains byte-preserved. Not yet supported: most Dynamic types.

A handful of Typed assets are only partially modeled, marked with a // TODO: Partial implementation comment at their definition:

• AnimationAsset - ROTU and Ratatouille's revised SKB layout isn't modeled.
• CutsceneAsset - chunked media data is unmodeled and preserved as unparsed bytes.
• CutsceneTableAsset - trailing TimeChunk-offset, visibility, and break tables are unmodeled.
• NPCAsset - N100F Prototype-only fields aren't parsed.
• OneLinerAsset - a trailing 67-byte trailer isn't modeled.
• ParticleSystemAsset - particle commands are undecoded and stored as raw bytes.

Supported Games

• Scooby-Doo! Night of 100 Frights
• SpongeBob SquarePants: Battle for Bikini Bottom
• The SpongeBob SquarePants Movie
• The Incredibles
• The Incredibles: Rise of the Underminer
• Ratatouille (January 18, 2006 prototype)

Example

EvilHop exposes a HIP archive's bytes two ways. The block layer is the container exactly as it sits on disk - a tree of tagged blocks - and is complete and permissive. The asset layer sits on top of it: opening a session parses those blocks into typed Assets with names, positions, and links, maintaining offsets, sizes, and checksums for you rather than leaving them for you to get wrong. The two are mutually exclusive - while a session is open, it owns the blocks that describe assets.

Reading an archive, listing its pickups, and doubling the Scooby Snack count of every snack gate:

using EvilHop;
using EvilHop.Assets;
using EvilHop.Serialization;

using var file = File.OpenRead("hb01.HIP");
var archive = Archive.Load(file, new BFBBSerializer());

using var session = archive.OpenAssets();

var pickups = session.Layers.SelectMany(layer => layer.Assets).OfType<PickupAsset>();

foreach (var pickup in pickups)
{
    Console.WriteLine($"{pickup.Name} ({pickup.Kind}) at {pickup.Position} - worth {pickup.PickupValue}");

    if (pickup.Kind == PickupAsset.PickupKind.SnackGate)
        pickup.PickupValue *= 2;
}

session.Commit();

using var output = File.Create("hb01.out.HIP");
archive.Save(output);

Documentation

The architecture is documented in living documents that are updated in the same change that moves the code they describe:

• docs/overview.md - the whole library, one level deep.
• docs/architecture.md - the design decisions behind how it is built.
• docs/glossary.md - every block and the asset/serialization jargon.

Building

Requires the .NET 10 SDK.

dotnet build
dotnet test

License

EvilHop's code is licensed under the MIT License. A small number of third-party test fixtures are licensed separately under more restrictive, project-only terms - see THIRD_PARTY_NOTICES.md for details.