View source for Miptex

'''Miptex''' is an 8-bit texture format used by {{quake|4.1}} and {{gldsrc|4.1}}. They can be stored individually with a {{code|.mip}} file, but most tools and engines expect them to be embedded in a [[BSP]] or [[WAD]].

Miptex are always a multiple of 16, and contains the full-size texture plus 3 smaller [[mipmaps]], although these mipmaps are only used by the [[software renderer]] (the [[OpenGL]] renderer uses the GPU to generate 32-bit mipmaps). Some programs also will use these mipmaps, such as {{trenchbroom|4}}.

Half-Life extends the miptex format to add a dedicated palette, instead of relying upon an external shared palette. This is an uncompressed 768 byte array of 256 24-bit RGB values, like {{quakewiki|Quake palette|Quake's palette.lmp}}.

== Technical ==
{{License|type=gpl|version=2}}
The header of a miptex lump can be represented by the following C struct (from {{path|client/bspfile|h}} in the Quake I source code release):
<source lang=c>
#define	MIPLEVELS	4
typedef struct miptex_s
{
	char		name[16];
	unsigned	width, height;
	unsigned	offsets[MIPLEVELS];		// four mip maps stored
} miptex_t;
</source>
{{note|{{mono|unsigned}} is 32-bits.}}
It is then followed by raw 8-bit image data for each mipmap, at the offsets relative to the start of the lump.

For WAD3 miptex, the final mipmap is immediately followed by a 16-bit signed short enumerating the number of palette indices (should always be 256). That is then followed by raw RGB888 image data, representing the palette. 

{{important|1=Even though the palette is always supposed to be 256 values (256 * 3 = 768 bytes), some wad editors will pad out the data with garbage at the end of the lump. Therefore, palette size should not be assumed based upon data size.{{ref|1}}}}

== Derivatives ==
{{quake2|4.1}} encapsulates a modified version of miptex in a file format called [[WAL]], which is always stored individually per texture and contains additional surface metadata for compilers. Variations of [[WAL]], such as Daikatana WALs, M8, and M32, are used in other {{quake2engine|4.1}} games, and add some additional features.

== References ==
# [https://github.com/TrenchBroom/TrenchBroom/issues/4254 Fail to read palette for some texture lumps in some Valve WADs · Issue #4254 · TrenchBroom/TrenchBroom]

[[Category:Glossary]]
[[Category:File formats]]