11 releases
0.2.6 | Apr 2, 2024 |
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0.2.5 | Jan 15, 2022 |
0.2.1 | Oct 26, 2021 |
0.1.4 | Oct 24, 2021 |
#254 in Parser implementations
51 downloads per month
Used in shambler
66KB
1.5K
SLoC
Shalrath
A rusty, spiky, heat-seeking quake map parser
shalrath
is a rust representation, [nom
] parser and string serializer for Quake map
files.
It's written in pure Rust, and enforces the use of safe code crate-wide via #![forbid(unsafe_code)]
.
Rust Representation
The Rust representation lives in the repr
module,
and is a set of structs that represent the contents of a map
file.
The overall class structure - with some of the more specific innermost types omitted for simplicity - looks something like this:
Map
└ Entity (1..*)
├ Properties (1..1)
│ └ Property (0..*)
└ Brushes (1..1)
└ Brush (0..*)
└ BrushPlane (4..*)
Entity
is a game object that can contain Property
s and Brush
es.
Property
s are key-value pairs stored as String
s.
Brush
es are convex shapes defined by the intersection of a set of TexturePlane
s - 3D planes with associated texture mapping data.
At least one Entity
- known as the worldspawn
- must exist in any given map
, and represents all of its structural Brush
es.
Structural Brush
es are static geometry with no associated behavior.
In Quake terms, entities are given behavior by assigning them a classname
property, which is used by the game code to assign an actor class that reads from other properties attached to the object.
These entities are separated into two categories:
Point Entities
areEntity
s that have aclassname
, but noBrush
es.- These are used to represent actors like the player, enemies, or item pickups.
Brush Entities
areEntity
s that have both aclassname
andBrush
es.- These are used to represent special world geometry like moving doors, elevators, and similar.
But, that's just for context, more of which can be found in the map file spec.
Ultimately, what you do with the Rust representation after parsing data into it is down to needs of your project.
To that end, struct members are public in the case of named fields, and exposed via Deref
for collection wrappers like Properties
and Brushes
.
Parsing
The simplest way to parse a map
file into AST is by way of the FromStr
trait:
use shalrath::repr::*;
let map =
"{\"classname\" \"worldspawn\"\n{\n( 0 1 2 ) ( 3 4 5 ) ( 6 7 8 ) TEXTURE 0 0 0 1 1\n}\n}"
.parse::<Map>()
.expect("Failed to parse map");
assert_eq!(
map,
Map::new(vec![Entity {
properties: Properties::new(vec![Property {
key: "classname".into(),
value: "worldspawn".into()
}]),
brushes: Brushes::new(vec![Brush::new(vec![
BrushPlane {
plane: Triangle {
v0: Point {
x: 0.0,
y: 1.0,
z: 2.0
},
v1: Point {
x: 3.0,
y: 4.0,
z: 5.0
},
v2: Point {
x: 6.0,
y: 7.0,
z: 8.0
},
},
texture: "TEXTURE".into(),
texture_offset: TextureOffset::Standard { u: 0.0, v: 0.0 },
angle: 0.0,
scale_x: 1.0,
scale_y: 1.0,
extension: Extension::Standard,
}
])])
}])
)
For a lower-level alternative, the parser
module contains the [nom
] functions used by the FromStr
implementations,
which can be used to parse plaintext data into individual AST structs.
Of these, parse_map
is the primary entrypoint, and is equivalent to str::parse::<Map>()
:
use shalrath::parser::repr::parse_map;
let map_string = include_str!("../test_data/abstract-test.map");
let (_, map_ast) = parse_map(map_string).expect("Failed to parse map");
println!("{:#?}", map_ast);
String Serialization
The Rust representation can be serialized back into a text-based map
representation via the Display
or ToString
traits:
use shalrath::repr::Map;
let map_string = include_str!("../test_data/abstract-test.map");
let map_ast = map_string.parse::<Map>().expect("Failed to parse map file");
let serialized_map_string = map_ast.to_string();
println!("{}", serialized_map_string);
In addition, round-trip parsing the resulting string back into the corresponding AST is a lossless operation,
and is included as a standard part of shalrath
's integration tests:
use shalrath::repr::Map;
let map_string = include_str!("../test_data/abstract-test.map");
let map_ast = map_string.parse::<Map>().expect("Failed to parse map file");
let serialized_map_string = map_ast.to_string();
let roundtrip_map_ast = serialized_map_string.parse::<Map>().expect("Failed to parse map file");
assert_eq!(map_ast, roundtrip_map_ast);
Format Support
Several variants of the base Quake 1 map
format exist that retain the same core structure, but modify how brush planes are encoded.
shalrath
supports these by categorizing them by UV format (represented by the TextureOffset
enum):
UV Format | Notes |
---|---|
Standard | Faces project textures based on the closest world X/Y/Z plane. |
Valve | Faces project textures based on custom U/V axes, allowing for skewing and more accurate texturing of curved surfaces. |
...and brush plane extension data, represented by the Extension
enum:
Brush Plane Extension | Notes |
---|---|
Standard | Brush planes contain no extra data. |
Hexen 2 | Brush planes contain an extra numerical value whose usage is unknown. |
Quake 2 | Brush planes contain content_flags and surface_flags bitmasks, and a floating point value . |
Daikatana | Brush planes contain three unknown values, and floating point RGB values |
Other formats like Quake 3
and Daikatana
exist, but are effectively variants of the above, and will be handled transparently by the parser.
Serde Support
For cases where serializing and deserializing from non-map
formats is required,
shalrath
includes serde::Serialize
and serde::Deserialize
derives for all types in the repr
module.
These can be enabled by applying the serde
feature flag to the shalrath
dependency in Cargo.toml
.
Streaming
Currently shalrath
only implements complete
parsers that expect a full set of input data.
streaming
implementations are planned, but currently pending further research.
Dependencies
~1.2–2MB
~40K SLoC