Creating Levels

Creating a level for Hallways is simple. A level is just a collection of files hosted on the internet, tied together by a central manifest.

Manifest

Here is an example manifest:

{
    "_version": "coco",
    "model": "model.glb",
    "collider": "collision.glb",
    "material": {
        "MyMaterial": {
            "frames": ["texture1.png", "texture2.png"],
            "animation_speed": 1.0,
            "color": [255, 255, 255, 255],
            "texture_addressing": "Linear"
        }
    },
    "portal": {
        "portal_a": {
            "collider": "portal_a.glb",
            "target": { "href": "other_level.json", "name": "portal_b" }
        }
    }
}

Manifest Fields

Field	Status	Use
_version	required	Manifest version. Must be "coco".
model	required	Level render model (.glb).
collider	optional	Separate collision model (.glb). If omitted, model is used for collision.
spawn	optional	Player spawn position [x, y, z]. Defaults to origin.
track	optional	Background music file. Must be an Ogg container with Vorbis audio.
material	required	Material map keyed by glTF material name.
portal	required	Portal map. May be empty, but cannot contain more than 4 entries.
portal.<name>.collider	required	Portal collider (.glb).
portal.<name>.target	optional	Destination object with href and name.

Materials

Each material entry is keyed by a glTF material name from the level model. Every material referenced by the model should have a matching entry.

{
    "frames": ["frame1.png", "frame2.png"],
    "animation_speed": 1.0,
    "color": [255, 255, 255, 255],
    "texture_addressing": "Linear"
}

frames defaults to an empty list.
animation_speed defaults to 0.5.
color defaults to white.
texture_addressing is Linear or Nearest and defaults to Linear.
Diffuse alpha is evaluated after texture and color tinting, so both the texture alpha and color alpha can affect the final result.
A final diffuse alpha of 0.0 is discarded entirely, which is useful for cut-out holes and masks.
A final diffuse alpha of 1.0 is rendered as opaque geometry.
A final diffuse alpha between 0.0 and 1.0 is rendered as transparent geometry with OIT.

Texture Limits

Texture dimensions must match one of these sizes. The max column is the maximum number of textures at that size per level.

Size	Max
2048x2048	1
1024x1024	4
512x512	8
256x256	32
128x128	64
64x64	256

Portals

Portal geometry can be any coplanar polygon.
Portals must be Horizontal wall-aligned surfaces or Vertical floor/ceiling-aligned surfaces.
Vertical portals need one magenta vertex (#FF00FFFF) so player rotation can be derived.
target.href is a relative URL to the destination manifest.
target.name is the destination portal name in that manifest.
Horizontal portals only link to horizontal portals.
Vertical portals only link to vertical portals, and their normals must match.
Linked portals should have the same polygon shape.

Tips

Keep vertex counts low.
Vertices that should meet must share the exact same position.
Keep open space on both sides of every portal.
Use a separate collider mesh for complex scenes so visual detail does not all become collision geometry.
Host levels on any static file host. GitHub Pages is a good place to start.