| 63 |
|
Initializing the parser is the most important part of writing an MGF |
| 64 |
|
program, and it is done through the mg_ehand array and a call to mg_init. |
| 65 |
|
The global mg_ehand variable is an array of pointers to entity handler |
| 66 |
< |
functions. The arguments to these functions is always the same, an |
| 66 |
> |
functions. The arguments to these functions are always the same, an |
| 67 |
|
argument count and an array of argument pointers (ala main). The return |
| 68 |
|
value for these integer functions is one of the error codes defined in |
| 69 |
|
parser.h, or MG_OK if the entity was handled correctly. You must |
| 107 |
|
c_cmaterial variable will be pointing to a structure with all the |
| 108 |
|
current settings. (Note that you would have to also set the color |
| 109 |
|
mg_ehand entries to c_hcolor if you intended to support color |
| 110 |
< |
materials.) |
| 110 |
> |
materials.) A list of related mg_ehand assignments is given below: |
| 111 |
|
|
| 112 |
+ |
mg_ehand[MG_E_COLOR] = c_hcolor; |
| 113 |
+ |
mg_ehand[MG_E_CCT] = c_hcolor; |
| 114 |
+ |
mg_ehand[MG_E_CMIX] = c_hcolor; |
| 115 |
+ |
mg_ehand[MG_E_CSPEC] = c_hcolor; |
| 116 |
+ |
mg_ehand[MG_E_CXY] = c_hcolor; |
| 117 |
+ |
mg_ehand[MG_E_ED] = c_hmaterial; |
| 118 |
+ |
mg_ehand[MG_E_MATERIAL] = c_hmaterial; |
| 119 |
+ |
mg_ehand[MG_E_NORMAL] = c_hvertex; |
| 120 |
+ |
mg_ehand[MG_E_POINT] = c_hvertex; |
| 121 |
+ |
mg_ehand[MG_E_RD] = c_hmaterial; |
| 122 |
+ |
mg_ehand[MG_E_RS] = c_hmaterial; |
| 123 |
+ |
mg_ehand[MG_E_SIDES] = c_hmaterial; |
| 124 |
+ |
mg_ehand[MG_E_TD] = c_hmaterial; |
| 125 |
+ |
mg_ehand[MG_E_TS] = c_hmaterial; |
| 126 |
+ |
mg_ehand[MG_E_VERTEX] = c_hvertex; |
| 127 |
+ |
|
| 128 |
|
In addition to the three handler functions, context.c contains a |
| 129 |
|
few support routines that make life simpler. For vertices, there |
| 130 |
|
is the c_getvertex call, which returns a pointer to a named vertex |
| 137 |
|
simply returns 1 or 0 based on whether the passed color structure |
| 138 |
|
is close to grey or not. Finally, there is the c_clearall routine, |
| 139 |
|
which clears and frees all context data structures, and is the |
| 140 |
< |
principle action of the parser's mg_clear function. |
| 140 |
> |
principal action of the parser's mg_clear function. |
| 141 |
|
|
| 142 |
|
Transform Support |
| 143 |
|
================= |
| 223 |
|
of the above would help to merge them. The most sure-fire approach to |
| 224 |
|
linking identical vertices is therefore to hash the point and normal |
| 225 |
|
values directly and use the functions in lookup.c to associate them. |
| 226 |
< |
You will have to write your own hash function, and I recommend making |
| 226 |
> |
You will have to write your own hash function, and we recommend making |
| 227 |
|
one that allows a little slop so that nearly identical points hash to |
| 228 |
|
the same value. |
| 229 |
|
|
| 233 |
|
|
| 234 |
|
The simplest is a translator from MGF to MGF called mgfilt.c, which |
| 235 |
|
produces on the standard output only those entities from the standard |
| 236 |
< |
input that are supported according to the command line arguments. For |
| 237 |
< |
example, one could remove everything but the raw, flat polygonal |
| 236 |
> |
input that are supported according to the first command line argument. |
| 237 |
> |
For example, one could remove everything but the raw, flat polygonal |
| 238 |
|
geometry with the following command: |
| 239 |
|
|
| 240 |
< |
mgfilt v p f xf < any.mgf > faces.mgf |
| 240 |
> |
mgfilt v,p,f,xf any.mgf > faces.mgf |
| 241 |
|
|
| 242 |
|
Note that the xf entity must also be included, for its support is |
| 243 |
|
required by all geometric entities. |
| 255 |
|
worked out. The intent is to offer it free of charge to all those who |
| 256 |
|
wish to use it (with no guarantees, of course). However, we may decide |
| 257 |
|
that copyright protections are necessary to prevent unauthorized versions |
| 258 |
< |
of the parser that do not properly support the MGF standard from getting |
| 259 |
< |
spread around. Since this is a pre-release, we trust that you will not |
| 260 |
< |
share it with anyone without getting our permission first. |
| 258 |
> |
of the parser, which do not properly support the MGF standard, from |
| 259 |
> |
getting spread around. Since this is a pre-release, we trust that you |
| 260 |
> |
will not share it with anyone without getting our permission first. |
| 261 |
|
|
| 262 |
|
Questions |
| 263 |
|
========= |
