This file is for programmers that would like to use this file

format, to include them into their programs/demos.

The purpose of this new object format is to provide an optimised

object, for the different displaying modes, with expansion possi-

bilities, and the needed informations for 3d-clipping, animation,

and so on. The comments are preceded by a semi-colon:





;Here is the explanation of the different fileds:

;the length of the fields is given in bytes, in brackets.



  "3DX01" + '\0', Null terminated identifier. (6)

  

;Now we got three different descriptions of the object, depending

;on the distance viewer-object: there is no point of drawing

;120 faces that are not bigger than one pixel, because the object

;is too far away.



;Short range description:

  NOBJS_0    How many objects are there?        (2)

  {  

    NAME,    A null terminated name for the object

             len(name + null char) <= 15        (15)

    NPTS,    How many 3d points are there?      (2)

    NFFCS,   How many faces are there for the shaded faces

             representation?                    (2)

    NWFCS,   How many faces are there for the wireframe

             representation?                    (2)



;The faces can have any number of vertices, they can be triangles,

;squares,... so we need to know, to know exactly how big the memory

;allocation should be, how big the sum of the number of vertices of

;every face is:

;  if VFi,VWi is the number of vertices of the ith face for the

;  shaded representation resp. the wireframe representation, then we

;  need:

    NFOFFS,  = VF1+VF2+...VFn , n=NFFCS        (2)

    NWOFFS,  = VW1+VW2+...VWn , n=NWFCS        (2)



;Boundings of the object:

    XMAX,XMIN,YMAX,YMIN,ZMAX,ZMIN,             (2 each=12)

            

;Coordinates (=Crd.) of the gravity center of the object:

    [Xg,Yg,Zg],                                (2 each=6)



;Crd. of the three light sources:

    [Xl,Yl,Zl]*3,                              (6*3=18)



;Crd. of the points of the object (points table):

    [X,Y,Z]*NPTS,                              (6*NPTS)



;Description of the shaded faces:

    [

      COL,      coulour of the face            (2)

      NOFFS,    # of vertices in the face      (2)



;Here we have the description of the polygon. the ith OFFSET is the offset

;in the points table of the ith vertex.

;!!! Important !!! OFFSET is the offset of the *point* not the

;offset of the first coordinate:

; x1,y1,z1 <---- OFFSET == 0

; x2,y2,z2 <---- OFFSET == 1, and not equal 6 (6 bytes further)!

      (OFFSET)*NFOFFS,                         (2*NFOFFS)

      (Nx,Ny,Nz), Normal vector of the face    (2*3=6)

      (Xg,Yg,Zg), Gravity center of the face   (2*3=6)

    ]*NFFCS,



;Description of the wireframe faces:

    [

      NOFFS,    # of vertices in the face      (2)

      

;Here we need to know, for each vertex in the face, if there has to be

;a drawn line from the actual point to the next point in the list.

;Ex:

;          1                                 2

;          *---------------------------------*

;         /             Face 1                \

;        /                                     \

;      4*--This line should only be drawn once--*3

;      /                                       /

;     /                 Face 2                /

;    *---------------------------------------*

;From point 3 to point 4, there'll be no line for face 1, so here,

;CONT=0 on point 3. "no line from 3 to 4"

;Description of Face1:

;NOFFS==4

;(OFFSET==1,CONT==1)

;(OFFSET==2,CONT==1)

;(OFFSET==3,CONT==1)

;(OFFSET==4,CONT==0)

;and every line of Face2 is drawn.

;Of course, on situations like this:

;          1                                 2

;   *-----*---------------------------------*

;  /Face /             Face 1                \

; /  3  /                                     \

;*----4*--This line should only be drawn once--*3

;     /                                       /

;    /                 Face 2                /

;   *---------------------------------------*

;instead of having "no line from 3 to 4" and "no line from 4 to 1", 

;the OFFSET 4 will simply not be present, so the face 1 will be:

;Description of Face1:

;NOFFS==3

;(OFFSET==1,CONT==1)

;(OFFSET==2,CONT==1)

;(OFFSET==3,CONT==0)

;OFFSET has the same meaning as above.

;and every line of Face2 and Fcae3 is drawn.

    (OFFSET,CONT)*NWOFFS                       (4*NWOFFS)

    ]*NWFCS



;This additional zone is always structured this way (if not empty,

;that is, its length is 0):

    

    additional zone=

    [

     -LEN          length of additional zone    (4)

     -a 9 BYTES, null terminated string identifier:

      ("BSPTREE" , "MAPTGA" ,"" (if empty)...)  (9)

     -LEN bytes    actual description of the zone

     -[additional zone]   ;next additional zone (might be empty)

    ]

  }*NOBJS_0

  

;The description of the medium and the long range objects is the same.

  NOBJS_1,

          {...}*NOBJS_1

  NOBJS_2,

          {...}*NOBJS_2





                                        Nikopol (Flatliner)



Ok, that's it. If you have a good idea of an expansion to the format,

please send it to me (with its format). My mail adresses are:



email:

  lmuniz@vub.ac.be    on internet

smail:

  Luis Muniz

  564 chaussee de Boondael

  B-1050 Brussels

  Belgium

  

  from august/september on:

  54, rue Dillens

  B-1050 Brussels

  Belgium