====== File input and output FAQ ======

===== What file formats are supported by L3DT? =====

Please consult [[l3dt:formats:support|this page]] in the user-guide for the latest list. Note additional formats may be available with the help of [[bundywiki>plugins]].





===== Why is the y-axis inverted in my map file? =====

Depending on the map-viewing application you use, L3DT maps map appear to be inverted in the y-axis. This is because L3DT uses a //right-handed// [[wp>Cartesian_coordinate_system#Orientation_and_.22handedness.22|coordinate system]], following the convention in mathematics and the physical sciences, which puts pixel (0, 0) at the bottom left-hand corner of the screen (i.e. the southwest). Most 2D graphics applications use a //left-handed// system with y-inverted so that pixel (0, 0) is at the top-left of the screen (i.e. northwest).

To make L3DT more compatible with this other coordinate system, L3DT includes an 'invert y-axis' option for most file formats. To edit this option, use the 'options...' button in the [[l3dt:userguide:io:export:active|export wizard]] or the [[l3dt:userguide:io:preferences|file preferences]] dialog. 


===== How do I export the height map in another format? =====

From the menu, select the '//File->Export->Export map layer//' option, then the 'Heightfield' option. This will open the //export map// wizard, which is [[l3dt:userguide:io:export:active|described here]]. The supported file formats are listed on the [[l3dt:formats:support|file formats page]].

===== Does L3DT support 16-bit image exports for height maps? =====

Yes, L3DT supports the export of heightfields as 16-bit PNG, PGM, and RAW image files.

===== Does L3DT support disk-paging of terrain and textures? =====

Yes, disk-paging has been an integral feature of L3DT since [[l3dt:history:v2.1|release 2.1]] (Nov 2003). In L3DT, paged maps are called //mosaics// because they are split into //tiles// that are loaded into RAM as required and saved back to the disk-drive when not needed. To make a mosaic map, see the following tutorial pages:

    * [[l3dt:userguide:newmap:perlin|Making a perlin map]].
    * [[l3dt:userguide:newmap:design_inflate#making_a_mosaic_map|Making a design map]].
    * [[l3dt:userguide:io:import:dm|Importing a design map]].
    * [[l3dt:userguide:ops:mosaic#Splitting a map into a mosaic]].
    * [[l3dt:userguide:ops:tx#Generating the texture map]].

The technical details of the disk paging implementation are discussed on the [[l3dt:algorithms:mosaics|mosaic algorithms]] page.