Category : Printer + Display Graphics
Archive   : DEMO4.ZIP
Filename : WORLD.DOC

 
Output of file : WORLD.DOC contained in archive : DEMO4.ZIP
World File Format
Version 1.00 -- August, 1992
Written by Bernie Roehl

The "demo4" program supports a very simple kind of world description file
format in order to specify the location of objects in a virtual environment
as well as various other scene characteristics.

This format should *not* be adopted as any kind of "standard"; there is some
excellent discussion taking place in the Usenet newsgroup "sci.virtual-worlds"
that will eventually lead to a standard specification. This is just a
quick hack.

The file is entirely ascii. Each 'record' is one line; anything after the
first '#' is treated as a comment and ignored. Blank lines are also ignored.

The format is intended to be highly extensible; any line which cannot be
recognized should simply be ignored.

Each line (i.e. record) contains some information about the scene; the
possible types of records are listed below. Note that new ones may be
added at any time, but that the definitions given below should not change.

Everything is case-insensitive; keywords are shown below in uppercase, but
are generally entered in lowercase.

PALETTE filename
Loads a 256-entry binary palette file (3 bytes (R,G,B) for each entry).
The file is binary. Note that alternate palettes may not handle shading
as well as the default.

SKYCOLOR index
Specifies which of the 256 available colors should be used for the "sky".

GROUNDCOLOR index
Specifies which of the 256 available colors should be used for the
"ground". If the sky and ground color are identical, a solid screen
clear is used; this is a bit faster.

AMBIENT value
Specifies the level of the ambient light; 76 is the default, and a good
value to use.

WORLDSCALE value
Specifies the world scale as a floating-point number. The value is
expressed in millimeters per unit. The default is 1.00, probably a
good choice. This is only used for stereoscopic viewing.

LIGHT x,y,z
Specifies the location of the light source in long integer world
coordinates.

WINDOW x,y,width,height
Specifies the location and size of the viewing window in screen
coordinates.

START x,y,z pan,tilt,roll zoom
Specifies your starting location, viewing direction and zoom factor.
The x,y,z values are long integers giving coordinates, the
pan,tilt,roll values are floating-point angles, and the zoom is a
floating-point number.

HITHER value
Specifies the near clipping distance as a long integer in world
coordinates. The value should typically be 10 or more.

YON value
Specifies the far clipping distance as a long integer in world
coordinates. The value should typically be 1000000 or more.

EYESPACING value
Specifies the distance between your eyes in millimeters (only needed
for steroscopic viewing). The default value is 55.

SCREENDIST value
Specifies the distance from your eyes to the screen in millimeters
(only needed for stereoscopic viewing). The default value is 700.

SCREENWIDTH value
Specifies the width of the screen in pixels (only needed for stereoscopic
viewing). The default is 250.

CONVERGENCE value
Specifies the convergence distance (only needed for stereoscopic
viewing). Should usually be the same as the SCREENDIST value;
however, 1200 or so may be easier on the eyes.

OBJECT [objname=]filename sx,sy,sz rx,ry,rz tx,ty,tz depthtype mappings parent
Loads an object from a .plg file with the given filename. If the
"objname=" is present, it assigns the newly-loaded object that name for
future reference. The sx,sy,sz values are floating-point scale factors
to increase or decrease the size of the object as it's loaded. The rx,
ry,rz values are the angles to rotate the object around each of the three
axes; rx is done first, then ry and finally rz. The tx,ty,tz values
translate (move) the object to a new location; this is done after the
scaling and rotation. The depthtype field controls how the depth-
sorting for the object is to be handled, and is described elsewhere.
The "mappings" feature is explained below. The "parent" field is
the name of the object that this object is a child of. If omitted,
the child moves independently. If the parentname is the word "fixed",
then the object is fixed in space and cannot be moved; this is more
efficient in terms of memory usage, since no segment (i.e. motion
control) structure needs to be allocated. All fields are
optional, but you must include all the fields prior to the last one
you wish to use (i.e. you can only leave things off the end, not off
the beginning or out of the middle).

FIGURE [figname=]filename sx,sy,sz rx,ry,rz tx,ty,tz parentname
Loads a segmented figure from a .fig file with the given filename.
All the parameters have the same meaning as for the OBJECT record
described above.

POLYOBJ npts surface x1,y1,z1 x2,y2,z2 [...] x8,y8,z8
Directly specifies a polygon to be placed in the scene. The value
npts is the number of points (maximum 8), the surface is a surface name
(see below on surfaces) and the vertices are given in long integer
world coordinate form.

INCLUDE filename
Includes the specified file as if its contents appeared at the current
point in the current file.

SPLIT x,y,z nx,ny,nz flags
Defines a split; see "split.doc" for details. All objects defined
after a SPLIT line and before an ENDSPLITS line (or another SPLIT line)
will be considered to be "on" that split. The x,y,z values are the
location of a point (in long integer world coordinates), and the
nx,ny,nz values are a normal to the plane.

SPLITPTS x1,y1,z1 x2,y2,z2 x3,y3,z3 flags
An alternative way of defining a split, by giving three vertices (again,
in long integer world coordinates).

ENDSPLITS
Marks the end of a sequence of splits.

AREA x,y,z name
Assigns a name to an area (a chunk of space created by a set of
clipping planes). The x,y,z are again long integer world coordintes,
and specify any point within the area.

FLOOR name a,b,c,d
Specifies the coordinates of a plane equation describing the slope of
the floor in the area of the given name.

FLOORPTS name x1,y1,z1 x2,y2,z2 x3,y3,z3
An alternative way of specifying the floor plane equation, by giving
three points in the plane.

CEILING name a,b,c,d
As for FLOOR, but for the ceiling.

CEILINGPTS name x1,y1,z1 x2,y2,z2 x3,y3,z3
As for FLOORPTS, but for the ceiling.


Surfaces and Mappings

A two-level scheme for mapping surface colors is used; at first it may seem
complex, but it provides greater flexibility for the future.

Each polygon in a .plg file can have either an ordinary color value as
described in "colors.doc" (e.g. 0x1234), or a value with the top bit set
(e.g. 0x8007) which indicates that the bottom 15 bits are intended as an
index into a color mapping table. There can be a number of these mapping
tables, and each object can refer to a different map.

The color mapping table maps the index into a surface name; if one were
going to a ray-tracing application, this could be used as-is. In the case
of REND386, we must map that surface name into a color value of the type
described in "colors.doc".

So, the first-stage mapping is from index to name, and the second is from
name to value.

The first stage is done with any of several mapping tables
(possibly one per object, though in most cases multiple objects will
use the same mapping table). A map is created with a SURFACEMAP record,
and entries are placed in it with SURFACE records. Note that when you load
an object, the color mapping table name can be specified; this allows you to
have (for example) five chairs all loaded from the same .plg file but with
different coloration).

The second stage is done with a single, global mapping table created by
a series of SURFACEDEF records.

The record formats are as follows:

SURFACEDEF name value
Defines a new surface; maps a surface name (such as "wood") to a numeric
value of the type described in "colors.doc" (such as 0x12DF).

SURFACEMAP name
Marks the start of a new surface map. All subsequent SURFACE entries
will be placed in this map.

SURFACE index name
Defines an entry in the current surface map, which takes an index value
(the bottom 15 bits of the value in the .plg file) and maps it into a
surface name (which is in turn mapped to a 16-bit color value).


Future Work

That's it; other types exist, but they're purely experimental at this stage.
Future releases of the REND386 demo program may or may not support this
format, and if they do they will certainly implement extensions to it.

As usual, direct any questions to Bernie ([email protected]) or to
Dave ([email protected]).


  3 Responses to “Category : Printer + Display Graphics
Archive   : DEMO4.ZIP
Filename : WORLD.DOC

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/