ronbrogan/openh2

Open Source Tools and Engine for Halo 2

OpenH2

OpenH2 is an open source game engine and tooling for Halo 2. It serves as a personal project of reverse engineering the Halo 2 (Vista) map file format. I am explicitly avoiding any reverse engineering of binaries or distributed tooling.

Tag Architecture

Reading of a map into tags is currently defined via set of Tag types with attributes on the properties. A deserializer type is generated at compile time by the OpenBlam.Serialization package that was created for this project.

SceneryTag.cs

Tools

Scenario Explorer

The Scenario Explorer is the main tool used for reverse engineering the tag formats. It contains an integrated hex viewer with best-effort auto-detection of tag sections and references. In "Discovery mode" the tag tree is built based on auto-detection of tag references. In "Exploration mode" the tree is built via the static tag references in the types. The tool is built with AvaloniaUI.

MccBulkPatcher

In order to research changes to tags and scripts, patching functionality is present in the project. This is surfaced in the MccBulkPatcher tool that can be used to apply arbitrary tag and script patches to MCC Halo 2 maps. This is currently used to create the mods I've published from base maps. (SpeedMod and Sword Playground)

Miscellaneous tooling

There are a number of other dumping and analysis tools also in the solution, but they're not intended for long term use and will eventually be removed.

Progress History

December 2020

Script execution is implemented, debug views for bones, colliders, and triggers added. Work on animations is in progress.

https://youtu.be/64IwoZsDBwI

Armory Demo - November 2020

Demo of the Armory (01a_tutorial) mission running in the OpenH2 engine This is the first demo of the following features:

• Script Execution
• 3D Audio Subsystem
• AI Unit Bootstrapping

https://www.youtube.com/watch?v=l8jZkum3AOk

July 2020

Attempted to implement an ad-hoc physics engine. After abandoning that work was done to integrate PhysX into the engine. Work on parsing game scripts is underway.

https://www.youtube.com/watch?v=nqIXdxn6a88

December 2019

Fixed mesh loading, now loading all mesh parts, item and vehicle placements, fix for mesh normals, new shader mapping system, more scenario tag loading

https://www.youtube.com/watch?v=eaFrBpENgwY

November 2019

All static geometry and crate objects loading, with textures (although shaders with multiple textures aren't quite right). Animated meshes are incorrect, such as the Zanzibar house gate.

https://www.youtube.com/watch?v=EiBVZlxRlTA

July 2019

Basic map geometry and some textures loading

https://www.youtube.com/watch?v=j3ZXj8xkp6c

openh2's Issues

Replace generic GetMethod calls with new overload

Resolving MethodInfo for generic methods is unwieldy, a new GetMethod overload is added in netstandard2.1 that makes it much cleaner:

https://docs.microsoft.com/en-us/dotnet/api/system.type.getmethod?view=netstandard-2.1
public System.Reflection.MethodInfo GetMethod (string name, int genericParameterCount, Type[] types);

Information request

Hi!! Nice project! This is targeting linux/opengl/vulkan too? also.. How far you are by now??

Better in-air acceleration

In-air acceleration should decay, over N frames, the delta velocity it causes. In H2 releasing a direction in-air causes you to fall directly down instead of conserving momentum

Determine how to use lightmapping textures

A very small amount of textures are clearly incorrect. The theory is that these textures are "swizzled"

Investigate Virtualization for Tag Tree and Hex Viewer in Scenario Explorer

Avalonia 0.9 introduces the ItemsRepeater control, which seems to support virtualization. HexViewer performance is terrible with large objects (such as scnr or sbsp tags) and is currently capped at how much data it will show. Virtualizing the hex rows would allow any size tag to be visualized and explored.

Tag tree will need to be reimplemented as a custom control to support virtualization

Implement SHAD tag preview in ScenarioExplorer

Previewing of BITM tags in Scenario Explorer is implemented, however previewing a full shader tag is not supported.

Using the new SHAD -> material mapping functionality in MaterialFactory, a preview of the shader can be implemented right in ScenarioExplorer.

If hot-reloading of the material mapping can be implemented, this can be a good way to easily create new mappings for missing shaders.

Create material mappings for all shader tags

Shader tags reference a Shader Template (stem) tag. This shader template can be used to key a mapping on how a given shader can be mapped to an OpenH2 Material object. Currently, this is implemented as a separate config, where STEM tag IDs are mapped to shader bitmap/input indices:

src\OpenH2.Core\Configs\material-config.json

All maps should be loaded, and mappings or aliases added to ensure that all shaders render correctly.

• 00a_introduction.map
• 01a_tutorial.map
• 01b_spacestation.map
• 03a_oldmombasa.map
• 03b_newmombasa.map
• 04a_gasgiant.map
• 04b_floodlab.map
• 05a_deltaapproach.map
• 05b_deltatowers.map
• 06a_sentinelwalls.map
• 06b_floodzone.map
• 07a_highcharity.map
• 07b_forerunnership.map
• 08a_deltacliffs.map
• 08b_deltacontrol.map
• ascension.map
• backwash.map
• beavercreek.map
• BoardingAction.map
• burial_mounds.map
• coagulation.map
• colossus.map
• containment.map
• cyclotron.map
• deltatap.map
• dune.map
• elongation.map
• foundation.map
• gemini.map
• headlong.map
• lockout.map
• midship.map
• needle.map
• street_sweeper.map
• triplicate.map
• turf.map
• warlock.map
• waterworks.map
• zanzibar.map

ReadModelResource Method Is Generated Multiple Times

This method is generated multiple times because it's generated for Model and BSP tags:

We need to ensure that this cannot happen, need to keep track of what's been generated and skip if needed

Implment Skybox as real object in world

In H2, the skybox is an actual object in the world. This can be observed by glitches where you can project an object into the sky by getting it inside the skybox.

https://www.youtube.com/watch?v=TPaiQ0bBbAw
https://www.youtube.com/watch?v=zsXKV8e9cuI

Current implementation is done by rendering the skybox at the position of the camera first, then rendering everything else after.

README.md

Hi,

Please add README with description and features, thanks!

Greets! 👍

Change Serializer CodeGen from IL Emitting to .NET 5 Source Generators

Once the solution is moved to .NET 5 (preview?), migrate existing IL Emit serializer code generation to Source Generators.

Out-of-tag resource deserialization

Tags can reference data in arbitrary locations in the map file. Currently, these out-of-tag resources are ignored. Support needs to be added to read these resources as well.