TEXTURE1 and TEXTURE2
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The TEXTURE1 and TEXTURE2 lumps define how wall patches from the WAD file should combine to form wall textures.
In an era where space is expensive, a map texture inside a WAD is to a texture seen inside the game, as a MOD file is to an MP3 file. In other words, it is decomposed into smaller textures in such a way that repeating areas are only stored once. At startup time (to be precise, during "R_Init: Init DOOM refresh daemon"), the patches inside the WAD are read and combined into Wall Textures, or how the source code refers to, 'map textures'.
Contents |
[edit] Binary data
The binary contents of the TEXTURE1 and TEXTURE2 lumps start with a header of flexible size, followed by all of the map textures.
| TEXTURE1 or TEXTURE2 | |||
|---|---|---|---|
| Offset | Length | Name | Content |
| 0x00 | 4 | numtextures | An integer holding a the number of map textures. |
| 0x04 | 4 * numtextures | offset[ ] | An array of integers containing the offsets to the map textures in this lump. |
| offset[0] offset[1] ... | Flexible | mtexture[ ] | An array with the map texture structures. (see next table) |
All integers are 4 bytes long in x86-style little-endian order. Their values can never exceed 231-1, since Doom reads them as signed ints. Short integers are 2 bytes long and are otherwise equal to integers.
[edit] Map textures structure, binary data
The binary contents of the maptexture_t structure starts with a header of 22 bytes, followed by all the the map patches.
| maptexture_t | |||
|---|---|---|---|
| Offset | Length | Name | Content |
| 0x00 | 8 | name | An ASCII string defining the name of the map texture. Only the characters A-Z (uppercase), 0-9, and [ ] - _ should be used in lump names. When a string is less than 8 bytes long, it should be null-padded to the eighth byte. |
| 0x08 | 4 | masked | A boolean (0=false, 1=true) defining ? |
| 0x0C | 2 | width | A short integer defining the total width of the map texture. |
| 0x0E | 2 | height | A short integer defining the total height of the map texture. |
| 0x10 | 4 | columndirectory | Obsolete, ignored by all DOOM versions |
| 0x14 | 2 | patchcount | the number of map patches that make up this map texture |
| 0x16 | 10 * patchcount | patches[ ] | array with the map patch structures for this texture. (see next table) |
[edit] Map patches structure, binary data
The binary contents of the mappatch_t structure contains 10 bytes defining how the patch should be drawn inside the texture.
| mappatch_t | |||
|---|---|---|---|
| Offset | Length | Name | Content |
| 0x00 | 2 | originx | A short int defining the horizontal offset of the patch relative to the upper-left of the texture |
| 0x02 | 2 | originy | A short int defining the vertical offset of the patch relative to the upper-left of the texture |
| 0x04 | 2 | patch | A short int defining the patch number (as listed in PNAMES) to draw |
| 0x06 | 2 | stepdir | A short int defining ? |
| 0x08 | 2 | colormap | A short int defining ? |
