Normal [[graphic_patch]]es, [[wall_texture]]s and [[flat]]s can be replaced with [[tga]] (Truevision Targa),
[[png]] (Portable Network Graphics) or [[pcx]] (Zsoft Paintbrush) images. The resolution of these external images can be higher than the resolution of the original graphics. 


====== Supported image file formats ======


The engine currently supports these image formats:



^ Pixel depth^ PCX^ PNG^ TGA |
| 8-bit (paletted)<sup>(1)</sup>| Yes| Yes| — |
| 16-bit| —| —| — |
| 24-bit| —| Yes| Yes<sup>(2)</sup> |
| 32-bit ([[alpha_channel]])| —| Yes| Yes<sup>(2)</sup> |



Notes:
  -  The palette does not have to match the palette of the game.
  -  TGAs must be type 2 (uncompressed, unmapped RGB).

Note that 32-bit images are just 24-bit images with an additional 8 bits
per pixel for the [[alpha_channel]]. 

The recommended format for high-resolution textures is paletted
[[png]]. It is the easiest format in which to distribute the textures due
to its small size. Since the palette doesn't have to be the same as
the game's, it should be enough for many textures.


====== Visible size ======


The high-resolution textures can be of any size. The engine will
render them scaled so that they fit the size of the original
texture. This means the aspect ratio of the new texture doesn't have
to be the same as of the original texture. Note that the engine will
have to resize all textures so that their dimensions are powers of two
(e.g. 32, 64, 128, 256). This means TGA/PNG textures whose width and
height are already powers of two can be loaded faster.


====== Transparency ======


Color keying is done if the file name of the image ends in "-ck", for
example **brnbigc-ck.png**. Both cyan (0,255,255) and purple
(255,0,255) are used as key colors. 

An alternative way to have transparency
is to use an alpha channel. In it, white (255) means opaque and black
(0) is fully transparent. All values in between can be used, too, for
partly translucent pixels. When using an alpha channel, the "-ck"
suffix is not needed.


====== Example: Replacing a wall texture ======


To create a high-resolution texture for the wall texture STARTAN3
you'd place a TGA file named **STARTAN3.tga** or a PNG file named
**STARTAN3.png** into the **Textures** directory.


====== Flats ======


The file names of images that replace [[flat]]s must begin with "Flat-",
e.g. to replace the flat FLOOR7_2 you'd need to have a TGA file
**Flat-FLOOR7_2.tga** in the **Textures** directory. If there
are both [[png]] and [[tga]] versions of the same texture, the engine will use
the [[png]] version.

[[version_1_8.6]] added the **Flats** external [[resource_category]].  In
order to replace FLOOR7_2, it is enough to put **FLOOR7_2.png**
into the **Flats** directory; no prefix is necessary.

 **Note:** The file names of high-resolution textures must match the [[texture]] names, not the names of the [[patch]]es that make up the textures. For example: DOOR2_5 is a patch name, DOOR3 is the texture that uses DOOR2_5.


====== Command line options ======


To disable high-resolution textures use the command line option
//-nohightex//. The option //-texdir// can be used to change the
directory from which the textures are searched.


====== See also ======

  *  [[addons]]