Daggerfall:WOODS.WLD format

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This is a description of the format of the WOODS.WLD file found in the ARENA2 directory of Elder Scrolls: Daggerfall by Bethesda. The information here is not complete or 100% percent accurate, although the basic format appears to be well understood.

False-colour output of WOODS.WLD

Contents

[edit] Header

The first 0x90 (144) bytes of the file are composed of a Header structure.

Header Structure
Offset Type Name Description
0-3 UInt32 OffsetSize This is the size of the offset list which immediately follows the header. Since each element is 4 bytes long, ( Width * Height ) should equal ( OffsetSize ÷ 4 ).
4-7 UInt32 Width This indicates the width of the Altitude Map. This should be 1000.
8-11 UInt32 Height This indicates the height of the Altitude Map. This should be 500.
12-15 UInt32 NullValue1 This value should be 0x00000000.
16-19 UInt32 DataSectionOneOffset This is the offset to the Data Section 1 section, relative to the start of the file.
20-23 UInt32 Unknown1 Unknown Purpose.
24-27 UInt32 Unknown2 Unknown Purpose.
28-31 UInt32 AltitudeMapOffset This is the offset to the Altitude Map section, relative to the start of the file.
32-143 UInt32[ 28 ] NullValue2 Each element of this array should be 0x00000000.

[edit] Data Offsets

Immediately following the Header, is a contiguous list of UInt32 values. There should be Header.Width * Header.Height (500000) elements. Each element is an offset (relative to the start of the file) to a PixelData structure. Each element corresponds by ordinal to an Altitude Map element; that is to say the tenth offset in this contiguous list describes the tenth pixel in the Altitude Map array. Daggerfall expects these elements to be stored in left-to-right, top-to-bottom order. Editors should follow this convention. This does not mean element n must specify a disk location which precedes n+1; it merely means element n specifies a row which is "above" row n+1 in the output bitmap.

[edit] Data Section 1

This section contains unknown data. It may be related to the Altitude Map Data. The section is 1024 bytes in size (0x0400).

DataSectionOne Structure
Offset Type Name Description
0-15 UInt8[ 16 ] Unknown Unknown Purpose
16-1023 UInt8[ 252 ] NullValue Each element should be 0x00.

[edit] Altitude Map

As the name suggests, this section contains altitude data for a small, 1000x500 pixel, map of the Iliac Bay. Each byte represents one pixel, with Header.Width * Header.Height pixels in total. Low values are low altitudes, high values are high altitudes, with 0x00 through 0x02 considered water.

These values are further modified by the PixelData.ElevationNoise array, which (if considered) expands the map into 5000x2500 pixels.

The values are stored in left-to-right, top-to-bottom order. That is to say the first 1000 elements describe the first (top-most) row of the map, and the second 1000 elements describe the second row of the map, and so on.

[edit] Pixel Data

For each of the pixels in the Altitude Map, there is a corresponding PixelData element (0x2F, 47 bytes in size). Offsets to each PixelData structure is found immediately following the Header as a contiguous list of UInt32 offsets.

PixelData structure
Offset Type Name Description
0-1 UInt16 Unknown1 Unknown Purpose.
2-5 UInt32 NullValue1 Always 0x00000000.
6-7 UInt16 FileIndex Valid values are defined by the FileIndex Enumeration, below.
8 UInt8 Climate Valid values are defined by the Climate Enumeration, below.
9 UInt8 ClimateNoise This field is used to provide variance to the weather specific to that pixel. Observed values are {0x20, 0x40, 0x60, 0x80, 0xa0, 0xc0}.
10-21 UInt32[ 3 ] NullValue2 Each element is always 0x00000000.
22-46 Int8[ 5 ][ 5 ] ElevationNoise Each signed byte element of this two-dimensional array provides noise for the pixel's Altitude field, thus giving the overland hills, valleys, etc. For some reason the resultant 5000x2500 pixel map has a strange grid-like pattern imposed on it by this field. The ElevationNoise elements are stored in left-to-right, top-to-bottom order.

[edit] FileIndex Enumeration

The FileIndex enumeration does not identify the texture file to use when displaying the ground for that specific map pixel. It is a decoy. This data is actually in CLIMATE.PAK.

FileIndex enumeration
Value Description Texture File
2 Desert TEXTURE.002
102 Mountain TEXTURE.102
302 Temperate TEXTURE.302
402 Jungle TEXTURE.402

[edit] Climate Enumeration

The Climate enumeration is not used by Daggerfall when generating weather and seasons for the pixel. Weather and seasons are determined by the data within the CLIMATE.PAK file.

Climate Enumeration
Value Description
0 Temperate/Jungle
1 Mountain
2 Desert

[edit] Working with WOODS.WLD

Everything one needs to create the Iliac Bay in a 3D environment, such as DirectX or OpenGL, is present.

[edit] Building the Map

One can use the data present in WOODS.WLD to generate an almost complete map for the Iliac Bay. This documentation will assume the standard 3D coordinate format of (X, Y, Z), where X represents the east-west axis, Y represents the altitude axis, and Z represents the north-south axis. Daggerfall World Units are proportionate to the United States Inch, and the valid domain for each axis is defined as: Dom(X) ≡ (51200, 32389120), Dom(Y) ≡ (-80, 1228), and Dom(Z) ≡ (40961, 16332801).

First one reads the AltitudeMap to retrieve the base altitude for the Iliac Bay. Each element within the AltitudeMap refers to a PixelData element, so one must then next read the PixelData. One then adds to each element of the PixelData.ElevationNoise array the value reported by the pixel's corresponding entry in the AltitudeMap. One now has the base elevation for every location within the game.

The next step is a matter of scaling. Each pixel in this resultant 5000 x 2500 bitmap equal to 6467.584 inches by 6516.736 inches. This places the Iliac Bay's total area at 131235.66656463626160595857565555 square miles (between California and Nevada in total size, with the defined land area about 1.6 times that of England).

[edit] Adding Locations

To determine which of these map pixels a Location from MAPS.BSA (or the player's character for that matter) occupies one must simply translate from Daggerfall World Units to the above Map Units.

First, one must subtract 51200 from the location's X coordinate, and 40961 from the location's Y coordinate. The next step is then to divide the X coordinate by 5000 and divide the Y coordinate by 2500. One now has the specific pixel location in Map Units.

At this point one has the location for the lower-left corner of the location's first Block, as defined by the location's ExteriorData Block* arrays. Blocks are stored in west-to-east, south-to-north order. Each Block has a uniform size.

[edit] Textures

The specific textures to load for the ground planes, the flats, and the structures is determined by the CLIMATE.PAK file.

[edit] See Also

  1. Land creation notes

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