[Plib-devel] ssgLoad3ds portability

[Troy Y. <tro...@ho...>]

I suppose that this is probably of most interest to Dave
but there may be others of you that are potentially coding
yourselves into the same boat.

I managed to get the SG and SSG libraries compiled on
HPUX 10.20 on a C180 class workstation.  The HP is *very*
particular about having certain things start on word
boundaries.  I had to make the following changes to
ssgLoad3ds.cxx to get it to run without coring and to
correctly load a model.  These particular changes were
made to the version of this file distributed in plib 1.1.11 -
I don't know if additional changes are necessary for the most
recent version.

Most of the changes relate to how get() is used.  Instead
of passing a pointer that might not be on a word boundary
to get(), data is copied from the input buffer into a local
temporary variable of the correct type and the address of
that variable is passed to get().  Rather than list every
change, I'll give an example and a list of functions
effected.

Original:

static int parse_uscale( char **p, unsigned long length )
{
  texture_scale[ num_materials - 1 ][0] = get((float*)*p);
  return PARSE_OK;
}

Becomes:

static int parse_uscale( char **p, unsigned long length )
{
  float  lTmpFloat;

  memcpy((void *) &lTmpFloat, (void *) *p, sizeof(float));
  texture_scale[ num_materials - 1 ][0] = get(&lTmpFloat);
  return PARSE_OK;
}

Other functions effected:
parse_vscale(): 1 instance   (line 261)
parse_uoffst(): 1 instance   (line 267)
parse_voffst(): 1 instance   (line 273)
parse_rgb1():   3 instances  (line 305, 306, 307)
parse_shininess(): 1 instance (line 348)
parse_transparency(): 1 instance (line 356)
parse_vert_list(): 4 instances (line 422, 428, 429, 430)
parse_smooth_list(): 1 instance (line 445)
parse_face_list(): 7 instances (line 504, 515 - 518, 541, 542)
parse_map_list(): 3 instances (line 565, 571, 572)
parse_face_materials(): 2 instances (line 628, 653)
parse_chunks(): 2 instances (line 732, 733)

There are several casts that must be modified.
(line 423, 440, 503, 566, 627)

I also had to fix a small problem with one of the get()
functions.

Original:

static float get(float *f) {
  if (is_little_endian)
    return *f;
  else {
    unsigned long p = (unsigned long)*f;
    endian_swap(&p);
    return p;
  }
}

Fixed:

static float get(float *f) {
  if (is_little_endian)
    return *f;
  else {
    float lTmpFloat = *f;
    endian_swap((unsigned long *) &lTmpFloat);
    return lTmpFloat;
  }
}

After all that, I've also attached the file with my mods and
an output of diff.

Let me know if you need anything else.

Troy.