WAL

WAL is a texture file format used by Quake II to store brush textures. A single WAL file contains one miptex, as well as three metadata values. The first two metadata values are bitflags, indicating information about a brush's face (surface flags) and a brush's contents (content flags). The third metadata value is an integer value, traditionally used for determining the brightness of texlights (although some compilers use it for other purposes on non-emissive surfaces, such as for smoothing groups in Arghrad).

The surface flags and content flags found in WAL files would serve the basis for the material map compile flags used by Source 1.

Texture flags

These sections list and describe the various standard surface and content flags used in Quake II, as well as the equivalent VMT parameters to achieve the same result in Source 1.

Surface flags

Surface flags on different faces of a brush generally do not need to match.

Content flags

Content flags on different faces of a brush almost always need to match. Mismatched contents will result in compiler errors, and leaves it up to the compiler to decide what contents a brush should have. The exception to this rule is the "current" flags.