BSP flags (Quake and GoldSrc)
Surface flags
Despite having a 32-bit integer available to be used, most flags go unused. Vanilla Quake engines and GoldSrc only use TEX_SPECIAL.
| Bit | Flag name | Dev comment | Notes |
|---|---|---|---|
| 0x00000001 | TEX_SPECIAL | sky or slime, no lightmap or 256 subdivision | Surface does not have a lightmap.
Used by
|
| 0x00000002 | TEX_MISSING | johnfitz -- this texinfo does not have a texture | Used by fitzquake and derivatives to indicate a missing texture |
| 0x00000800 | ??? | N/A | Used by VERTEXNORMALS BSPX lump to indicate a face that should have smooth shading based upon its vertex normals. |
| 0x00004000 | TEX_SHOULDHIDE | this flag is temporary; it might be set after CSG, but will be dropped after BSP | Used by VHLT; set if zhlt_hidden is set. Tells HLBSP to not add the face to any visleaves, and will result in HLRAD not reflecting light off of the face.
Texture names with the suffix _HIDDEN will yield the same result, without using this surface flag. |
Contents types
Contents are stored as a signed 32-bit integer, and are always negative.
Entities are always CONTENTS_SOLID; in 
GoldSrc, the skin KV to override the contents of any brush entity that doesn't explicitly override it, but the entity collision type must also be set accordingly.
| Value | Internal name | Dev comment | Notes |
|---|---|---|---|
| -1 | CONTENTS_EMPTY | Non-solid, and doesn't affect VIS. | |
| -2 | CONTENTS_SOLID | Default. | |
| -3 | CONTENTS_WATER | A liquid, usually water. Textures with the ! prefix are usually water when part of worldspawn, unless they are slime, lava, or a current. | |
| -4 | CONTENTS_SLIME | Like water, deals damage to the player and some monsters when touched. | |
| -5 | CONTENTS_LAVA | Like slime, but deals double the damage. | |
| -6 | CONTENTS_SKY | ||
| -7 | CONTENTS_ORIGIN | removed at csg time | Replaces an entity's origin KV, then is removed by CSG (does not exist in compiled BSP).
In GoldSrc, if a brush has this contents at runtime, it will be treated like water (and is referred to in FGDs as "volumetric light"). |
| -8 | CONTENTS_CLIP | changed to contents_solid | |
| -9 | CONTENTS_CURRENT_0 | Acts like water combined with a trigger_push with a speed of 2048 in the given direction. In Quake, this is treated as regular water, being commented out with an #ifdef QUAKE2. | |
| -10 | CONTENTS_CURRENT_90 | ||
| -11 | CONTENTS_CURRENT_180 | ||
| -12 | CONTENTS_CURRENT_270 | ||
| -13 | CONTENTS_CURRENT_UP | ||
| -14 | CONTENTS_CURRENT_DOWN | ||
| -15 | CONTENTS_TRANSLUCENT (not in  ) |
Like water, but never solid. Despite this, it still affects VIS. | |
| -16 | CONTENTS_LADDER (not in ) |
Climbable. Usually set via the game code for the func_ladder entity. | |
| -17 | CONTENTS_FLYFIELD (not in ) |
Zero gravity | |
| -18 | CONTENTS_GRAVITY_FLYFIELD (not in ) |
||
| -19 | CONTENTS_FOG (not in ) |
Ambient Types
Ambients are stored as an array of 4 unsigned bytes, indicating volume. Only Quake uses them, and it only uses AMBIENT_SKY and AMBIENT_WATER, which are hardcoded in the engine to play specific sounds when a visleaf containing the given ambient type is in the current PVS.
Confirm:Probably only affected by world brushes, so probably not cast by func_water.| Index | Name | Notes |
|---|---|---|
| 0 | AMBIENT_WATER | Normally cast by any liquid (* prefix in ; ! prefix in ), unless they are slime or lava.
|
| 1 | AMBIENT_SKY | Normally cast by sky brushes (sky prefix) |
| 2 | AMBIENT_SLIME | Normally cast by slime brushes (*slime prefix in ; !slime prefix in )
|
| 3 | AMBIENT_LAVA | Normally cast by lava brushes (*lava prefix in ; !lava prefix in )
|