progs/objviewer: Wavefront .obj file loader/viewer demo

Adapted from code written by Nate Robins.  See README.txt.

1 files changed, 1917 insertions, 0 deletions

diff --git a/progs/objviewer/glm.c b/progs/objviewer/glm.c
new file mode 100644
index 00000000000..7f36cdf28e4
--- /dev/null
+++ b/progs/objviewer/glm.c
@@ -0,0 +1,1917 @@
+/*    
+ *  GLM library.  Wavefront .obj file format reader/writer/manipulator.
+ *
+ *  Written by Nate Robins, 1997.
+ *  email: [email protected]
+ *  www: http://www.pobox.com/~ndr
+ */
+
+/* includes */
+#include <math.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "glm.h"
+#include "readtex.h"
+
+
+typedef unsigned char boolean;
+#define TRUE 1
+#define FALSE 0
+
+
+/* Some <math.h> files do not define M_PI... */
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+/* defines */
+#define T(x) model->triangles[(x)]
+
+
+/* enums */
+enum { X, Y, Z, W };			/* elements of a vertex */
+
+
+/* typedefs */
+
+/* _GLMnode: general purpose node
+ */
+typedef struct _GLMnode {
+  uint           index;
+  boolean        averaged;
+  struct _GLMnode* next;
+} GLMnode;
+
+/* strdup is actually not a standard ANSI C or POSIX routine
+   so implement a private one.  OpenVMS does not have a strdup; Linux's
+   standard libc doesn't declare strdup by default (unless BSD or SVID
+   interfaces are requested). */
+static char *
+stralloc(const char *string)
+{
+  char *copy;
+
+  copy = malloc(strlen(string) + 1);
+  if (copy == NULL)
+    return NULL;
+  strcpy(copy, string);
+  return copy;
+}
+
+/* private functions */
+
+/* _glmMax: returns the maximum of two floats */
+static float
+_glmMax(float a, float b) 
+{
+  if (a > b)
+    return a;
+  return b;
+}
+
+/* _glmAbs: returns the absolute value of a float */
+static float
+_glmAbs(float f)
+{
+  if (f < 0)
+    return -f;
+  return f;
+}
+
+/* _glmDot: compute the dot product of two vectors
+ *
+ * u - array of 3 floats (float u[3])
+ * v - array of 3 floats (float v[3])
+ */
+static float
+_glmDot(float* u, float* v)
+{
+  assert(u);
+  assert(v);
+
+  /* compute the dot product */
+  return u[X] * v[X] + u[Y] * v[Y] + u[Z] * v[Z];
+}
+
+/* _glmCross: compute the cross product of two vectors
+ *
+ * u - array of 3 floats (float u[3])
+ * v - array of 3 floats (float v[3])
+ * n - array of 3 floats (float n[3]) to return the cross product in
+ */
+static void
+_glmCross(float* u, float* v, float* n)
+{
+  assert(u);
+  assert(v);
+  assert(n);
+
+  /* compute the cross product (u x v for right-handed [ccw]) */
+  n[X] = u[Y] * v[Z] - u[Z] * v[Y];
+  n[Y] = u[Z] * v[X] - u[X] * v[Z];
+  n[Z] = u[X] * v[Y] - u[Y] * v[X];
+}
+
+/* _glmNormalize: normalize a vector
+ *
+ * n - array of 3 floats (float n[3]) to be normalized
+ */
+static void
+_glmNormalize(float* n)
+{
+  float l;
+
+  assert(n);
+
+  /* normalize */
+  l = (float)sqrt(n[X] * n[X] + n[Y] * n[Y] + n[Z] * n[Z]);
+  n[0] /= l;
+  n[1] /= l;
+  n[2] /= l;
+}
+
+/* _glmEqual: compares two vectors and returns TRUE if they are
+ * equal (within a certain threshold) or FALSE if not. An epsilon
+ * that works fairly well is 0.000001.
+ *
+ * u - array of 3 floats (float u[3])
+ * v - array of 3 floats (float v[3]) 
+ */
+static boolean
+_glmEqual(float* u, float* v, float epsilon)
+{
+  if (_glmAbs(u[0] - v[0]) < epsilon &&
+      _glmAbs(u[1] - v[1]) < epsilon &&
+      _glmAbs(u[2] - v[2]) < epsilon) 
+  {
+    return TRUE;
+  }
+  return FALSE;
+}
+
+/* _glmWeldVectors: eliminate (weld) vectors that are within an
+ * epsilon of each other.
+ *
+ * vectors    - array of float[3]'s to be welded
+ * numvectors - number of float[3]'s in vectors
+ * epsilon    - maximum difference between vectors 
+ *
+ */
+static float*
+_glmWeldVectors(float* vectors, uint* numvectors, float epsilon)
+{
+  float* copies;
+  uint   copied;
+  uint   i, j;
+
+  copies = (float*)malloc(sizeof(float) * 3 * (*numvectors + 1));
+  memcpy(copies, vectors, (sizeof(float) * 3 * (*numvectors + 1)));
+
+  copied = 1;
+  for (i = 1; i <= *numvectors; i++) {
+    for (j = 1; j <= copied; j++) {
+      if (_glmEqual(&vectors[3 * i], &copies[3 * j], epsilon)) {
+	goto duplicate;
+      }
+    }
+
+    /* must not be any duplicates -- add to the copies array */
+    copies[3 * copied + 0] = vectors[3 * i + 0];
+    copies[3 * copied + 1] = vectors[3 * i + 1];
+    copies[3 * copied + 2] = vectors[3 * i + 2];
+    j = copied;				/* pass this along for below */
+    copied++;
+
+  duplicate:
+    /* set the first component of this vector to point at the correct
+       index into the new copies array */
+    vectors[3 * i + 0] = (float)j;
+  }
+
+  *numvectors = copied-1;
+  return copies;
+}
+
+/* _glmFindGroup: Find a group in the model
+ */
+static GLMgroup*
+_glmFindGroup(GLMmodel* model, char* name)
+{
+  GLMgroup* group;
+
+  assert(model);
+
+  group = model->groups;
+  while(group) {
+    if (!strcmp(name, group->name))
+      break;
+    group = group->next;
+  }
+
+  return group;
+}
+
+/* _glmAddGroup: Add a group to the model
+ */
+static GLMgroup*
+_glmAddGroup(GLMmodel* model, char* name)
+{
+  GLMgroup* group;
+
+  group = _glmFindGroup(model, name);
+  if (!group) {
+    group = (GLMgroup*)malloc(sizeof(GLMgroup));
+    group->name = stralloc(name);
+    group->material = 0;
+    group->numtriangles = 0;
+    group->triangles = NULL;
+    group->next = model->groups;
+    model->groups = group;
+    model->numgroups++;
+  }
+
+  return group;
+}
+
+/* _glmFindGroup: Find a material in the model
+ */
+static uint
+_glmFindMaterial(GLMmodel* model, char* name)
+{
+  uint i;
+
+  for (i = 0; i < model->nummaterials; i++) {
+    if (!strcmp(model->materials[i].name, name))
+      goto found;
+  }
+
+  /* didn't find the name, so set it as the default material */
+  printf("_glmFindMaterial():  can't find material \"%s\".\n", name);
+  i = 0;
+
+found:
+  return i;
+}
+
+
+/* _glmDirName: return the directory given a path
+ *
+ * path - filesystem path
+ *
+ * The return value should be free'd.
+ */
+static char*
+_glmDirName(char* path)
+{
+  char* dir;
+  char* s;
+
+  dir = stralloc(path);
+
+  s = strrchr(dir, '/');
+  if (s)
+    s[1] = '\0';
+  else
+    dir[0] = '\0';
+
+  return dir;
+}
+
+
+/* _glmReadMTL: read a wavefront material library file
+ *
+ * model - properly initialized GLMmodel structure
+ * name  - name of the material library
+ */
+static void
+_glmReadMTL(GLMmodel* model, char* name)
+{
+  FILE* file;
+  char* dir;
+  char* filename;
+  char  buf[128], buf2[128];
+  uint nummaterials, i;
+  GLMmaterial *mat;
+
+  dir = _glmDirName(model->pathname);
+  filename = (char*)malloc(sizeof(char) * (strlen(dir) + strlen(name) + 1));
+  strcpy(filename, dir);
+  strcat(filename, name);
+  free(dir);
+
+  /* open the file */
+  file = fopen(filename, "r");
+  if (!file) {
+    fprintf(stderr, "_glmReadMTL() failed: can't open material file \"%s\".\n",
+	    filename);
+    exit(1);
+  }
+  free(filename);
+
+  /* count the number of materials in the file */
+  nummaterials = 1;
+  while(fscanf(file, "%s", buf) != EOF) {
+    switch(buf[0]) {
+    case '#':				/* comment */
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    case 'n':				/* newmtl */
+      fgets(buf, sizeof(buf), file);
+      nummaterials++;
+      sscanf(buf, "%s %s", buf, buf);
+      break;
+    default:
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    }
+  }
+
+  rewind(file);
+
+  /* allocate memory for the materials */
+  model->materials = (GLMmaterial*)calloc(nummaterials, sizeof(GLMmaterial));
+  model->nummaterials = nummaterials;
+
+  /* set the default material */
+  for (i = 0; i < nummaterials; i++) {
+    model->materials[i].name = NULL;
+    model->materials[i].shininess = 0;
+    model->materials[i].diffuse[0] = 0.8;
+    model->materials[i].diffuse[1] = 0.8;
+    model->materials[i].diffuse[2] = 0.8;
+    model->materials[i].diffuse[3] = 1.0;
+    model->materials[i].ambient[0] = 0.2;
+    model->materials[i].ambient[1] = 0.2;
+    model->materials[i].ambient[2] = 0.2;
+    model->materials[i].ambient[3] = 0.0;
+    model->materials[i].specular[0] = 0.0;
+    model->materials[i].specular[1] = 0.0;
+    model->materials[i].specular[2] = 0.0;
+    model->materials[i].specular[3] = 0.0;
+  }
+  model->materials[0].name = stralloc("default");
+
+  /* now, read in the data */
+  nummaterials = 0;
+
+  mat = &model->materials[nummaterials];
+
+  while(fscanf(file, "%s", buf) != EOF) {
+    switch(buf[0]) {
+    case '#':				/* comment */
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    case 'n':				/* newmtl */
+      fgets(buf, sizeof(buf), file);
+      sscanf(buf, "%s %s", buf, buf);
+      nummaterials++;
+      model->materials[nummaterials].name = stralloc(buf);
+      break;
+    case 'N':
+      fscanf(file, "%f", &model->materials[nummaterials].shininess);
+      /* wavefront shininess is from [0, 1000], so scale for OpenGL */
+      model->materials[nummaterials].shininess /= 1000.0;
+      model->materials[nummaterials].shininess *= 128.0;
+      mat = &model->materials[nummaterials];
+      break;
+    case 'K':
+      switch(buf[1]) {
+      case 'd':
+	fscanf(file, "%f %f %f",
+	       &model->materials[nummaterials].diffuse[0],
+	       &model->materials[nummaterials].diffuse[1],
+	       &model->materials[nummaterials].diffuse[2]);
+	break;
+      case 's':
+	fscanf(file, "%f %f %f",
+	       &model->materials[nummaterials].specular[0],
+	       &model->materials[nummaterials].specular[1],
+	       &model->materials[nummaterials].specular[2]);
+	break;
+      case 'a':
+	fscanf(file, "%f %f %f",
+	       &model->materials[nummaterials].ambient[0],
+	       &model->materials[nummaterials].ambient[1],
+	       &model->materials[nummaterials].ambient[2]);
+	break;
+      default:
+	/* eat up rest of line */
+	fgets(buf, sizeof(buf), file);
+	break;
+      }
+      break;
+    case 'd':  /* alpha? */
+	fscanf(file, "%f",
+	       &model->materials[nummaterials].diffuse[3]);
+        break;
+    case 'm':  /* texture map */
+       fscanf(file, "%s", buf2);
+       /*printf("map %s\n", buf2);*/
+       mat->map_kd = strdup(buf2);
+       break;
+
+    default:
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    }
+  }
+}
+
+
+/* _glmWriteMTL: write a wavefront material library file
+ *
+ * model      - properly initialized GLMmodel structure
+ * modelpath  - pathname of the model being written
+ * mtllibname - name of the material library to be written
+ */
+static void
+_glmWriteMTL(GLMmodel* model, char* modelpath, char* mtllibname)
+{
+  FILE* file;
+  char* dir;
+  char* filename;
+  GLMmaterial* material;
+  uint i;
+
+  dir = _glmDirName(modelpath);
+  filename = (char*)malloc(sizeof(char) * (strlen(dir) + strlen(mtllibname)));
+  strcpy(filename, dir);
+  strcat(filename, mtllibname);
+  free(dir);
+
+  /* open the file */
+  file = fopen(filename, "w");
+  if (!file) {
+    fprintf(stderr, "_glmWriteMTL() failed: can't open file \"%s\".\n",
+	    filename);
+    exit(1);
+  }
+  free(filename);
+
+  /* spit out a header */
+  fprintf(file, "#  \n");
+  fprintf(file, "#  Wavefront MTL generated by GLM library\n");
+  fprintf(file, "#  \n");
+  fprintf(file, "#  GLM library copyright (C) 1997 by Nate Robins\n");
+  fprintf(file, "#  email: [email protected]\n");
+  fprintf(file, "#  www:   http://www.pobox.com/~ndr\n");
+  fprintf(file, "#  \n\n");
+
+  for (i = 0; i < model->nummaterials; i++) {
+    material = &model->materials[i];
+    fprintf(file, "newmtl %s\n", material->name);
+    fprintf(file, "Ka %f %f %f\n", 
+	    material->ambient[0], material->ambient[1], material->ambient[2]);
+    fprintf(file, "Kd %f %f %f\n", 
+	    material->diffuse[0], material->diffuse[1], material->diffuse[2]);
+    fprintf(file, "Ks %f %f %f\n", 
+	    material->specular[0],material->specular[1],material->specular[2]);
+    fprintf(file, "Ns %f\n", material->shininess);
+    fprintf(file, "\n");
+  }
+}
+
+
+/* _glmFirstPass: first pass at a Wavefront OBJ file that gets all the
+ * statistics of the model (such as #vertices, #normals, etc)
+ *
+ * model - properly initialized GLMmodel structure
+ * file  - (fopen'd) file descriptor 
+ */
+static void
+_glmFirstPass(GLMmodel* model, FILE* file) 
+{
+  uint    numvertices;		/* number of vertices in model */
+  uint    numnormals;			/* number of normals in model */
+  uint    numtexcoords;		/* number of texcoords in model */
+  uint    numtriangles;		/* number of triangles in model */
+  GLMgroup* group;			/* current group */
+  unsigned  v, n, t;
+  char      buf[128];
+
+  /* make a default group */
+  group = _glmAddGroup(model, "default");
+
+  numvertices = numnormals = numtexcoords = numtriangles = 0;
+  while(fscanf(file, "%s", buf) != EOF) {
+    switch(buf[0]) {
+    case '#':				/* comment */
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    case 'v':				/* v, vn, vt */
+      switch(buf[1]) {
+      case '\0':			/* vertex */
+	/* eat up rest of line */
+	fgets(buf, sizeof(buf), file);
+	numvertices++;
+	break;
+      case 'n':				/* normal */
+	/* eat up rest of line */
+	fgets(buf, sizeof(buf), file);
+	numnormals++;
+	break;
+      case 't':				/* texcoord */
+	/* eat up rest of line */
+	fgets(buf, sizeof(buf), file);
+	numtexcoords++;
+	break;
+      default:
+	printf("_glmFirstPass(): Unknown token \"%s\".\n", buf);
+	exit(1);
+	break;
+      }
+      break;
+    case 'm':
+      fgets(buf, sizeof(buf), file);
+      sscanf(buf, "%s %s", buf, buf);
+      model->mtllibname = stralloc(buf);
+      _glmReadMTL(model, buf);
+      break;
+    case 'u':
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    case 'g':				/* group */
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      sscanf(buf, "%s", buf);
+      group = _glmAddGroup(model, buf);
+      break;
+    case 'f':				/* face */
+      v = n = t = 0;
+      fscanf(file, "%s", buf);
+      /* can be one of %d, %d//%d, %d/%d, %d/%d/%d %d//%d */
+      if (strstr(buf, "//")) {
+	/* v//n */
+	sscanf(buf, "%u//%u", &v, &n);
+	fscanf(file, "%u//%u", &v, &n);
+	fscanf(file, "%u//%u", &v, &n);
+	numtriangles++;
+	group->numtriangles++;
+	while(fscanf(file, "%u//%u", &v, &n) > 0) {
+	  numtriangles++;
+	  group->numtriangles++;
+	}
+      } else if (sscanf(buf, "%u/%u/%u", &v, &t, &n) == 3) {
+	/* v/t/n */
+	fscanf(file, "%u/%u/%u", &v, &t, &n);
+	fscanf(file, "%u/%u/%u", &v, &t, &n);
+	numtriangles++;
+	group->numtriangles++;
+	while(fscanf(file, "%u/%u/%u", &v, &t, &n) > 0) {
+	  numtriangles++;
+	  group->numtriangles++;
+	}
+      } else if (sscanf(buf, "%u/%u", &v, &t) == 2) {
+	/* v/t */
+	fscanf(file, "%u/%u", &v, &t);
+	fscanf(file, "%u/%u", &v, &t);
+	numtriangles++;
+	group->numtriangles++;
+	while(fscanf(file, "%u/%u", &v, &t) > 0) {
+	  numtriangles++;
+	  group->numtriangles++;
+	}
+      } else {
+	/* v */
+	fscanf(file, "%u", &v);
+	fscanf(file, "%u", &v);
+	numtriangles++;
+	group->numtriangles++;
+	while(fscanf(file, "%u", &v) > 0) {
+	  numtriangles++;
+	  group->numtriangles++;
+	}
+      }
+      break;
+
+    default:
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    }
+  }
+
+#if 0
+  /* announce the model statistics */
+  printf(" Vertices: %d\n", numvertices);
+  printf(" Normals: %d\n", numnormals);
+  printf(" Texcoords: %d\n", numtexcoords);
+  printf(" Triangles: %d\n", numtriangles);
+  printf(" Groups: %d\n", model->numgroups);
+#endif
+
+  /* set the stats in the model structure */
+  model->numvertices  = numvertices;
+  model->numnormals   = numnormals;
+  model->numtexcoords = numtexcoords;
+  model->numtriangles = numtriangles;
+
+  /* allocate memory for the triangles in each group */
+  group = model->groups;
+  while(group) {
+    group->triangles = (uint*)malloc(sizeof(uint) * group->numtriangles);
+    group->numtriangles = 0;
+    group = group->next;
+  }
+}
+
+/* _glmSecondPass: second pass at a Wavefront OBJ file that gets all
+ * the data.
+ *
+ * model - properly initialized GLMmodel structure
+ * file  - (fopen'd) file descriptor 
+ */
+static void
+_glmSecondPass(GLMmodel* model, FILE* file) 
+{
+  uint    numvertices;		/* number of vertices in model */
+  uint    numnormals;			/* number of normals in model */
+  uint    numtexcoords;		/* number of texcoords in model */
+  uint    numtriangles;		/* number of triangles in model */
+  float*  vertices;			/* array of vertices  */
+  float*  normals;			/* array of normals */
+  float*  texcoords;			/* array of texture coordinates */
+  GLMgroup* group;			/* current group pointer */
+  uint    material;			/* current material */
+  uint    v, n, t;
+  char      buf[128];
+
+  /* set the pointer shortcuts */
+  vertices     = model->vertices;
+  normals      = model->normals;
+  texcoords    = model->texcoords;
+  group        = model->groups;
+
+  /* on the second pass through the file, read all the data into the
+     allocated arrays */
+  numvertices = numnormals = numtexcoords = 1;
+  numtriangles = 0;
+  material = 0;
+  while(fscanf(file, "%s", buf) != EOF) {
+    switch(buf[0]) {
+    case '#':				/* comment */
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    case 'v':				/* v, vn, vt */
+      switch(buf[1]) {
+      case '\0':			/* vertex */
+	fscanf(file, "%f %f %f", 
+	       &vertices[3 * numvertices + X], 
+	       &vertices[3 * numvertices + Y], 
+	       &vertices[3 * numvertices + Z]);
+	numvertices++;
+	break;
+      case 'n':				/* normal */
+	fscanf(file, "%f %f %f", 
+	       &normals[3 * numnormals + X],
+	       &normals[3 * numnormals + Y], 
+	       &normals[3 * numnormals + Z]);
+	numnormals++;
+	break;
+      case 't':				/* texcoord */
+	fscanf(file, "%f %f", 
+	       &texcoords[2 * numtexcoords + X],
+	       &texcoords[2 * numtexcoords + Y]);
+	numtexcoords++;
+	break;
+      }
+      break;
+    case 'u':
+      fgets(buf, sizeof(buf), file);
+      sscanf(buf, "%s %s", buf, buf);
+      material = _glmFindMaterial(model, buf);
+      if (!group->material)
+         group->material = material;
+      /*printf("material %s = %u\n", buf, material);*/
+      break;
+    case 'g':				/* group */
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      sscanf(buf, "%s", buf);
+      group = _glmFindGroup(model, buf);
+      group->material = material;
+      /*printf("GROUP %s  material %u\n", buf, material);*/
+      break;
+    case 'f':				/* face */
+      v = n = t = 0;
+      fscanf(file, "%s", buf);
+      /* can be one of %d, %d//%d, %d/%d, %d/%d/%d %d//%d */
+      if (strstr(buf, "//")) {
+	/* v//n */
+	sscanf(buf, "%u//%u", &v, &n);
+	T(numtriangles).vindices[0] = v;
+	T(numtriangles).nindices[0] = n;
+	fscanf(file, "%u//%u", &v, &n);
+	T(numtriangles).vindices[1] = v;
+	T(numtriangles).nindices[1] = n;
+	fscanf(file, "%u//%u", &v, &n);
+	T(numtriangles).vindices[2] = v;
+	T(numtriangles).nindices[2] = n;
+	group->triangles[group->numtriangles++] = numtriangles;
+	numtriangles++;
+	while(fscanf(file, "%u//%u", &v, &n) > 0) {
+	  T(numtriangles).vindices[0] = T(numtriangles-1).vindices[0];
+	  T(numtriangles).nindices[0] = T(numtriangles-1).nindices[0];
+	  T(numtriangles).vindices[1] = T(numtriangles-1).vindices[2];
+	  T(numtriangles).nindices[1] = T(numtriangles-1).nindices[2];
+	  T(numtriangles).vindices[2] = v;
+	  T(numtriangles).nindices[2] = n;
+	  group->triangles[group->numtriangles++] = numtriangles;
+	  numtriangles++;
+	}
+      } else if (sscanf(buf, "%u/%u/%u", &v, &t, &n) == 3) {
+	/* v/t/n */
+	T(numtriangles).vindices[0] = v;
+	T(numtriangles).tindices[0] = t;
+	T(numtriangles).nindices[0] = n;
+	fscanf(file, "%u/%u/%u", &v, &t, &n);
+	T(numtriangles).vindices[1] = v;
+	T(numtriangles).tindices[1] = t;
+	T(numtriangles).nindices[1] = n;
+	fscanf(file, "%u/%u/%u", &v, &t, &n);
+	T(numtriangles).vindices[2] = v;
+	T(numtriangles).tindices[2] = t;
+	T(numtriangles).nindices[2] = n;
+	group->triangles[group->numtriangles++] = numtriangles;
+	numtriangles++;
+	while(fscanf(file, "%u/%u/%u", &v, &t, &n) > 0) {
+	  T(numtriangles).vindices[0] = T(numtriangles-1).vindices[0];
+	  T(numtriangles).tindices[0] = T(numtriangles-1).tindices[0];
+	  T(numtriangles).nindices[0] = T(numtriangles-1).nindices[0];
+	  T(numtriangles).vindices[1] = T(numtriangles-1).vindices[2];
+	  T(numtriangles).tindices[1] = T(numtriangles-1).tindices[2];
+	  T(numtriangles).nindices[1] = T(numtriangles-1).nindices[2];
+	  T(numtriangles).vindices[2] = v;
+	  T(numtriangles).tindices[2] = t;
+	  T(numtriangles).nindices[2] = n;
+	  group->triangles[group->numtriangles++] = numtriangles;
+	  numtriangles++;
+	}
+      } else if (sscanf(buf, "%u/%u", &v, &t) == 2) {
+	/* v/t */
+	T(numtriangles).vindices[0] = v;
+	T(numtriangles).tindices[0] = t;
+	fscanf(file, "%u/%u", &v, &t);
+	T(numtriangles).vindices[1] = v;
+	T(numtriangles).tindices[1] = t;
+	fscanf(file, "%u/%u", &v, &t);
+	T(numtriangles).vindices[2] = v;
+	T(numtriangles).tindices[2] = t;
+	group->triangles[group->numtriangles++] = numtriangles;
+	numtriangles++;
+	while(fscanf(file, "%u/%u", &v, &t) > 0) {
+	  T(numtriangles).vindices[0] = T(numtriangles-1).vindices[0];
+	  T(numtriangles).tindices[0] = T(numtriangles-1).tindices[0];
+	  T(numtriangles).vindices[1] = T(numtriangles-1).vindices[2];
+	  T(numtriangles).tindices[1] = T(numtriangles-1).tindices[2];
+	  T(numtriangles).vindices[2] = v;
+	  T(numtriangles).tindices[2] = t;
+	  group->triangles[group->numtriangles++] = numtriangles;
+	  numtriangles++;
+	}
+      } else {
+	/* v */
+	sscanf(buf, "%u", &v);
+	T(numtriangles).vindices[0] = v;
+	fscanf(file, "%u", &v);
+	T(numtriangles).vindices[1] = v;
+	fscanf(file, "%u", &v);
+	T(numtriangles).vindices[2] = v;
+	group->triangles[group->numtriangles++] = numtriangles;
+	numtriangles++;
+	while(fscanf(file, "%u", &v) > 0) {
+	  T(numtriangles).vindices[0] = T(numtriangles-1).vindices[0];
+	  T(numtriangles).vindices[1] = T(numtriangles-1).vindices[2];
+	  T(numtriangles).vindices[2] = v;
+	  group->triangles[group->numtriangles++] = numtriangles;
+	  numtriangles++;
+	}
+      }
+      break;
+
+    default:
+      /* eat up rest of line */
+      fgets(buf, sizeof(buf), file);
+      break;
+    }
+  }
+
+#if 0
+  /* announce the memory requirements */
+  printf(" Memory: %d bytes\n",
+	 numvertices  * 3*sizeof(float) +
+	 numnormals   * 3*sizeof(float) * (numnormals ? 1 : 0) +
+	 numtexcoords * 3*sizeof(float) * (numtexcoords ? 1 : 0) +
+	 numtriangles * sizeof(GLMtriangle));
+#endif
+}
+
+
+
+
+/* public functions */
+
+/* glmUnitize: "unitize" a model by translating it to the origin and
+ * scaling it to fit in a unit cube around the origin.  Returns the
+ * scalefactor used.
+ *
+ * model - properly initialized GLMmodel structure 
+ */
+float
+glmUnitize(GLMmodel* model)
+{
+  uint  i;
+  float maxx, minx, maxy, miny, maxz, minz;
+  float cx, cy, cz, w, h, d;
+  float scale;
+
+  assert(model);
+  assert(model->vertices);
+
+  /* get the max/mins */
+  maxx = minx = model->vertices[3 + X];
+  maxy = miny = model->vertices[3 + Y];
+  maxz = minz = model->vertices[3 + Z];
+  for (i = 1; i <= model->numvertices; i++) {
+    if (maxx < model->vertices[3 * i + X])
+      maxx = model->vertices[3 * i + X];
+    if (minx > model->vertices[3 * i + X])
+      minx = model->vertices[3 * i + X];
+
+    if (maxy < model->vertices[3 * i + Y])
+      maxy = model->vertices[3 * i + Y];
+    if (miny > model->vertices[3 * i + Y])
+      miny = model->vertices[3 * i + Y];
+
+    if (maxz < model->vertices[3 * i + Z])
+      maxz = model->vertices[3 * i + Z];
+    if (minz > model->vertices[3 * i + Z])
+      minz = model->vertices[3 * i + Z];
+  }
+
+  /* calculate model width, height, and depth */
+  w = _glmAbs(maxx) + _glmAbs(minx);
+  h = _glmAbs(maxy) + _glmAbs(miny);
+  d = _glmAbs(maxz) + _glmAbs(minz);
+
+  /* calculate center of the model */
+  cx = (maxx + minx) / 2.0;
+  cy = (maxy + miny) / 2.0;
+  cz = (maxz + minz) / 2.0;
+
+  /* calculate unitizing scale factor */
+  scale = 2.0 / _glmMax(_glmMax(w, h), d);
+
+  /* translate around center then scale */
+  for (i = 1; i <= model->numvertices; i++) {
+    model->vertices[3 * i + X] -= cx;
+    model->vertices[3 * i + Y] -= cy;
+    model->vertices[3 * i + Z] -= cz;
+    model->vertices[3 * i + X] *= scale;
+    model->vertices[3 * i + Y] *= scale;
+    model->vertices[3 * i + Z] *= scale;
+  }
+
+  return scale;
+}
+
+/* glmDimensions: Calculates the dimensions (width, height, depth) of
+ * a model.
+ *
+ * model      - initialized GLMmodel structure
+ * dimensions - array of 3 floats (float dimensions[3])
+ */
+void
+glmDimensions(GLMmodel* model, float* dimensions)
+{
+  uint i;
+  float maxx, minx, maxy, miny, maxz, minz;
+
+  assert(model);
+  assert(model->vertices);
+  assert(dimensions);
+
+  /* get the max/mins */
+  maxx = minx = model->vertices[3 + X];
+  maxy = miny = model->vertices[3 + Y];
+  maxz = minz = model->vertices[3 + Z];
+  for (i = 1; i <= model->numvertices; i++) {
+    if (maxx < model->vertices[3 * i + X])
+      maxx = model->vertices[3 * i + X];
+    if (minx > model->vertices[3 * i + X])
+      minx = model->vertices[3 * i + X];
+
+    if (maxy < model->vertices[3 * i + Y])
+      maxy = model->vertices[3 * i + Y];
+    if (miny > model->vertices[3 * i + Y])
+      miny = model->vertices[3 * i + Y];
+
+    if (maxz < model->vertices[3 * i + Z])
+      maxz = model->vertices[3 * i + Z];
+    if (minz > model->vertices[3 * i + Z])
+      minz = model->vertices[3 * i + Z];
+  }
+
+  /* calculate model width, height, and depth */
+  dimensions[X] = _glmAbs(maxx) + _glmAbs(minx);
+  dimensions[Y] = _glmAbs(maxy) + _glmAbs(miny);
+  dimensions[Z] = _glmAbs(maxz) + _glmAbs(minz);
+}
+
+/* glmScale: Scales a model by a given amount.
+ * 
+ * model - properly initialized GLMmodel structure
+ * scale - scalefactor (0.5 = half as large, 2.0 = twice as large)
+ */
+void
+glmScale(GLMmodel* model, float scale)
+{
+  uint i;
+
+  for (i = 1; i <= model->numvertices; i++) {
+    model->vertices[3 * i + X] *= scale;
+    model->vertices[3 * i + Y] *= scale;
+    model->vertices[3 * i + Z] *= scale;
+  }
+}
+
+/* glmReverseWinding: Reverse the polygon winding for all polygons in
+ * this model.  Default winding is counter-clockwise.  Also changes
+ * the direction of the normals.
+ * 
+ * model - properly initialized GLMmodel structure 
+ */
+void
+glmReverseWinding(GLMmodel* model)
+{
+  uint i, swap;
+
+  assert(model);
+
+  for (i = 0; i < model->numtriangles; i++) {
+    swap = T(i).vindices[0];
+    T(i).vindices[0] = T(i).vindices[2];
+    T(i).vindices[2] = swap;
+
+    if (model->numnormals) {
+      swap = T(i).nindices[0];
+      T(i).nindices[0] = T(i).nindices[2];
+      T(i).nindices[2] = swap;
+    }
+
+    if (model->numtexcoords) {
+      swap = T(i).tindices[0];
+      T(i).tindices[0] = T(i).tindices[2];
+      T(i).tindices[2] = swap;
+    }
+  }
+
+  /* reverse facet normals */
+  for (i = 1; i <= model->numfacetnorms; i++) {
+    model->facetnorms[3 * i + X] = -model->facetnorms[3 * i + X];
+    model->facetnorms[3 * i + Y] = -model->facetnorms[3 * i + Y];
+    model->facetnorms[3 * i + Z] = -model->facetnorms[3 * i + Z];
+  }
+
+  /* reverse vertex normals */
+  for (i = 1; i <= model->numnormals; i++) {
+    model->normals[3 * i + X] = -model->normals[3 * i + X];
+    model->normals[3 * i + Y] = -model->normals[3 * i + Y];
+    model->normals[3 * i + Z] = -model->normals[3 * i + Z];
+  }
+}
+
+/* glmFacetNormals: Generates facet normals for a model (by taking the
+ * cross product of the two vectors derived from the sides of each
+ * triangle).  Assumes a counter-clockwise winding.
+ *
+ * model - initialized GLMmodel structure
+ */
+void
+glmFacetNormals(GLMmodel* model)
+{
+  uint  i;
+  float u[3];
+  float v[3];
+  
+  assert(model);
+  assert(model->vertices);
+
+  /* clobber any old facetnormals */
+  if (model->facetnorms)
+    free(model->facetnorms);
+
+  /* allocate memory for the new facet normals */
+  model->numfacetnorms = model->numtriangles;
+  model->facetnorms = (float*)malloc(sizeof(float) *
+				       3 * (model->numfacetnorms + 1));
+
+  for (i = 0; i < model->numtriangles; i++) {
+    model->triangles[i].findex = i+1;
+
+    u[X] = model->vertices[3 * T(i).vindices[1] + X] -
+           model->vertices[3 * T(i).vindices[0] + X];
+    u[Y] = model->vertices[3 * T(i).vindices[1] + Y] -
+           model->vertices[3 * T(i).vindices[0] + Y];
+    u[Z] = model->vertices[3 * T(i).vindices[1] + Z] -
+           model->vertices[3 * T(i).vindices[0] + Z];
+
+    v[X] = model->vertices[3 * T(i).vindices[2] + X] -
+           model->vertices[3 * T(i).vindices[0] + X];
+    v[Y] = model->vertices[3 * T(i).vindices[2] + Y] -
+           model->vertices[3 * T(i).vindices[0] + Y];
+    v[Z] = model->vertices[3 * T(i).vindices[2] + Z] -
+           model->vertices[3 * T(i).vindices[0] + Z];
+
+    _glmCross(u, v, &model->facetnorms[3 * (i+1)]);
+    _glmNormalize(&model->facetnorms[3 * (i+1)]);
+  }
+}
+
+/* glmVertexNormals: Generates smooth vertex normals for a model.
+ * First builds a list of all the triangles each vertex is in.  Then
+ * loops through each vertex in the the list averaging all the facet
+ * normals of the triangles each vertex is in.  Finally, sets the
+ * normal index in the triangle for the vertex to the generated smooth
+ * normal.  If the dot product of a facet normal and the facet normal
+ * associated with the first triangle in the list of triangles the
+ * current vertex is in is greater than the cosine of the angle
+ * parameter to the function, that facet normal is not added into the
+ * average normal calculation and the corresponding vertex is given
+ * the facet normal.  This tends to preserve hard edges.  The angle to
+ * use depends on the model, but 90 degrees is usually a good start.
+ *
+ * model - initialized GLMmodel structure
+ * angle - maximum angle (in degrees) to smooth across
+ */
+void
+glmVertexNormals(GLMmodel* model, float angle)
+{
+  GLMnode*  node;
+  GLMnode*  tail;
+  GLMnode** members;
+  float*  normals;
+  uint    numnormals;
+  float   average[3];
+  float   dot, cos_angle;
+  uint    i, avg;
+
+  assert(model);
+  assert(model->facetnorms);
+
+  /* calculate the cosine of the angle (in degrees) */
+  cos_angle = cos(angle * M_PI / 180.0);
+
+  /* nuke any previous normals */
+  if (model->normals)
+    free(model->normals);
+
+  /* allocate space for new normals */
+  model->numnormals = model->numtriangles * 3; /* 3 normals per triangle */
+  model->normals = (float*)malloc(sizeof(float)* 3* (model->numnormals+1));
+
+  /* allocate a structure that will hold a linked list of triangle
+     indices for each vertex */
+  members = (GLMnode**)malloc(sizeof(GLMnode*) * (model->numvertices + 1));
+  for (i = 1; i <= model->numvertices; i++)
+    members[i] = NULL;
+  
+  /* for every triangle, create a node for each vertex in it */
+  for (i = 0; i < model->numtriangles; i++) {
+    node = (GLMnode*)malloc(sizeof(GLMnode));
+    node->index = i;
+    node->next  = members[T(i).vindices[0]];
+    members[T(i).vindices[0]] = node;
+
+    node = (GLMnode*)malloc(sizeof(GLMnode));
+    node->index = i;
+    node->next  = members[T(i).vindices[1]];
+    members[T(i).vindices[1]] = node;
+
+    node = (GLMnode*)malloc(sizeof(GLMnode));
+    node->index = i;
+    node->next  = members[T(i).vindices[2]];
+    members[T(i).vindices[2]] = node;
+  }
+
+  /* calculate the average normal for each vertex */
+  numnormals = 1;
+  for (i = 1; i <= model->numvertices; i++) {
+    /* calculate an average normal for this vertex by averaging the
+       facet normal of every triangle this vertex is in */
+    node = members[i];
+    if (!node)
+      fprintf(stderr, "glmVertexNormals(): vertex w/o a triangle\n");
+    average[0] = 0.0; average[1] = 0.0; average[2] = 0.0;
+    avg = 0;
+    while (node) {
+      /* only average if the dot product of the angle between the two
+         facet normals is greater than the cosine of the threshold
+         angle -- or, said another way, the angle between the two
+         facet normals is less than (or equal to) the threshold angle */
+      dot = _glmDot(&model->facetnorms[3 * T(node->index).findex],
+ 		    &model->facetnorms[3 * T(members[i]->index).findex]);
+      if (dot > cos_angle) {
+	node->averaged = TRUE;
+	average[0] += model->facetnorms[3 * T(node->index).findex + 0];
+	average[1] += model->facetnorms[3 * T(node->index).findex + 1];
+	average[2] += model->facetnorms[3 * T(node->index).findex + 2];
+	avg = 1;			/* we averaged at least one normal! */
+      } else {
+	node->averaged = FALSE;
+      }
+      node = node->next;
+    }
+
+    if (avg) {
+      /* normalize the averaged normal */
+      _glmNormalize(average);
+
+      /* add the normal to the vertex normals list */
+      model->normals[3 * numnormals + 0] = average[0];
+      model->normals[3 * numnormals + 1] = average[1];
+      model->normals[3 * numnormals + 2] = average[2];
+      avg = numnormals;
+      numnormals++;
+    }
+
+    /* set the normal of this vertex in each triangle it is in */
+    node = members[i];
+    while (node) {
+      if (node->averaged) {
+	/* if this node was averaged, use the average normal */
+	if (T(node->index).vindices[0] == i)
+	  T(node->index).nindices[0] = avg;
+	else if (T(node->index).vindices[1] == i)
+	  T(node->index).nindices[1] = avg;
+	else if (T(node->index).vindices[2] == i)
+	  T(node->index).nindices[2] = avg;
+      } else {
+	/* if this node wasn't averaged, use the facet normal */
+	model->normals[3 * numnormals + 0] = 
+	  model->facetnorms[3 * T(node->index).findex + 0];
+	model->normals[3 * numnormals + 1] = 
+	  model->facetnorms[3 * T(node->index).findex + 1];
+	model->normals[3 * numnormals + 2] = 
+	  model->facetnorms[3 * T(node->index).findex + 2];
+	if (T(node->index).vindices[0] == i)
+	  T(node->index).nindices[0] = numnormals;
+	else if (T(node->index).vindices[1] == i)
+	  T(node->index).nindices[1] = numnormals;
+	else if (T(node->index).vindices[2] == i)
+	  T(node->index).nindices[2] = numnormals;
+	numnormals++;
+      }
+      node = node->next;
+    }
+  }
+  
+  model->numnormals = numnormals - 1;
+
+  /* free the member information */
+  for (i = 1; i <= model->numvertices; i++) {
+    node = members[i];
+    while (node) {
+      tail = node;
+      node = node->next;
+      free(tail);
+    }
+  }
+  free(members);
+
+  /* pack the normals array (we previously allocated the maximum
+     number of normals that could possibly be created (numtriangles *
+     3), so get rid of some of them (usually alot unless none of the
+     facet normals were averaged)) */
+  normals = model->normals;
+  model->normals = (float*)malloc(sizeof(float)* 3* (model->numnormals+1));
+  for (i = 1; i <= model->numnormals; i++) {
+    model->normals[3 * i + 0] = normals[3 * i + 0];
+    model->normals[3 * i + 1] = normals[3 * i + 1];
+    model->normals[3 * i + 2] = normals[3 * i + 2];
+  }
+  free(normals);
+
+  printf("glmVertexNormals(): %d normals generated\n", model->numnormals);
+}
+
+
+/* glmLinearTexture: Generates texture coordinates according to a
+ * linear projection of the texture map.  It generates these by
+ * linearly mapping the vertices onto a square.
+ *
+ * model - pointer to initialized GLMmodel structure
+ */
+void
+glmLinearTexture(GLMmodel* model)
+{
+  GLMgroup *group;
+  float dimensions[3];
+  float x, y, scalefactor;
+  uint i;
+  
+  assert(model);
+
+  if (model->texcoords)
+    free(model->texcoords);
+  model->numtexcoords = model->numvertices;
+  model->texcoords=(float*)malloc(sizeof(float)*2*(model->numtexcoords+1));
+  
+  glmDimensions(model, dimensions);
+  scalefactor = 2.0 / 
+    _glmAbs(_glmMax(_glmMax(dimensions[0], dimensions[1]), dimensions[2]));
+
+  /* do the calculations */
+  for(i = 1; i <= model->numvertices; i++) {
+    x = model->vertices[3 * i + 0] * scalefactor;
+    y = model->vertices[3 * i + 2] * scalefactor;
+    model->texcoords[2 * i + 0] = (x + 1.0) / 2.0;
+    model->texcoords[2 * i + 1] = (y + 1.0) / 2.0;
+  }
+  
+  /* go through and put texture coordinate indices in all the triangles */
+  group = model->groups;
+  while(group) {
+    for(i = 0; i < group->numtriangles; i++) {
+      T(group->triangles[i]).tindices[0] = T(group->triangles[i]).vindices[0];
+      T(group->triangles[i]).tindices[1] = T(group->triangles[i]).vindices[1];
+      T(group->triangles[i]).tindices[2] = T(group->triangles[i]).vindices[2];
+    }    
+    group = group->next;
+  }
+
+#if 0
+  printf("glmLinearTexture(): generated %d linear texture coordinates\n",
+	  model->numtexcoords);
+#endif
+}
+
+/* glmSpheremapTexture: Generates texture coordinates according to a
+ * spherical projection of the texture map.  Sometimes referred to as
+ * spheremap, or reflection map texture coordinates.  It generates
+ * these by using the normal to calculate where that vertex would map
+ * onto a sphere.  Since it is impossible to map something flat
+ * perfectly onto something spherical, there is distortion at the
+ * poles.  This particular implementation causes the poles along the X
+ * axis to be distorted.
+ *
+ * model - pointer to initialized GLMmodel structure
+ */
+void
+glmSpheremapTexture(GLMmodel* model)
+{
+  GLMgroup* group;
+  float theta, phi, rho, x, y, z, r;
+  uint i;
+  
+  assert(model);
+  assert(model->normals);
+
+  if (model->texcoords)
+    free(model->texcoords);
+  model->numtexcoords = model->numnormals;
+  model->texcoords=(float*)malloc(sizeof(float)*2*(model->numtexcoords+1));
+     
+  /* do the calculations */
+  for (i = 1; i <= model->numnormals; i++) {
+    z = model->normals[3 * i + 0];	/* re-arrange for pole distortion */
+    y = model->normals[3 * i + 1];
+    x = model->normals[3 * i + 2];
+    r = sqrt((x * x) + (y * y));
+    rho = sqrt((r * r) + (z * z));
+      
+    if(r == 0.0) {
+	theta = 0.0;
+	phi = 0.0;
+    } else {
+      if(z == 0.0)
+	phi = M_PI / 2.0;
+      else
+	phi = acos(z / rho);
+      
+#if WE_DONT_NEED_THIS_CODE
+      if(x == 0.0)
+	theta = M_PI / 2.0;	/* asin(y / r); */
+      else
+	theta = acos(x / r);
+#endif
+      
+      if(y == 0.0)
+	theta = M_PI / 2.0;	/* acos(x / r); */
+      else
+	theta = asin(y / r) + (M_PI / 2.0);
+    }
+    
+    model->texcoords[2 * i + 0] = theta / M_PI;
+    model->texcoords[2 * i + 1] = phi / M_PI;
+  }
+  
+  /* go through and put texcoord indices in all the triangles */
+  group = model->groups;
+  while(group) {
+    for (i = 0; i < group->numtriangles; i++) {
+      T(group->triangles[i]).tindices[0] = T(group->triangles[i]).nindices[0];
+      T(group->triangles[i]).tindices[1] = T(group->triangles[i]).nindices[1];
+      T(group->triangles[i]).tindices[2] = T(group->triangles[i]).nindices[2];
+    }
+    group = group->next;
+  }
+
+#if 0  
+  printf("glmSpheremapTexture(): generated %d spheremap texture coordinates\n",
+	 model->numtexcoords);
+#endif
+}
+
+/* glmDelete: Deletes a GLMmodel structure.
+ *
+ * model - initialized GLMmodel structure
+ */
+void
+glmDelete(GLMmodel* model)
+{
+  GLMgroup* group;
+  uint i;
+
+  assert(model);
+
+  if (model->pathname)   free(model->pathname);
+  if (model->mtllibname) free(model->mtllibname);
+  if (model->vertices)   free(model->vertices);
+  if (model->normals)    free(model->normals);
+  if (model->texcoords)  free(model->texcoords);
+  if (model->facetnorms) free(model->facetnorms);
+  if (model->triangles)  free(model->triangles);
+  if (model->materials) {
+    for (i = 0; i < model->nummaterials; i++)
+      free(model->materials[i].name);
+  }
+  free(model->materials);
+  while(model->groups) {
+    group = model->groups;
+    model->groups = model->groups->next;
+    free(group->name);
+    free(group->triangles);
+    free(group);
+  }
+
+  free(model);
+}
+
+static GLMmaterial *
+glmDefaultMaterial(void)
+{
+   GLMmaterial *m = (GLMmaterial *) calloc(1, sizeof(GLMmaterial));
+   
+   m->diffuse[0] = 0.75;
+   m->diffuse[1] = 0.75;
+   m->diffuse[2] = 0.75;
+   m->diffuse[3] = 1.0;
+
+   m->specular[0] = 1.0;
+   m->specular[1] = 1.0;
+   m->specular[2] = 1.0;
+   m->specular[3] = 1.0;
+
+   m->shininess = 5;
+
+   return m;
+}
+
+
+/* glmReadOBJ: Reads a model description from a Wavefront .OBJ file.
+ * Returns a pointer to the created object which should be free'd with
+ * glmDelete().
+ *
+ * filename - name of the file containing the Wavefront .OBJ format data.  
+ */
+GLMmodel* 
+glmReadOBJ(char* filename)
+{
+  GLMmodel* model;
+  FILE*     file;
+
+  /* open the file */
+  file = fopen(filename, "r");
+  if (!file) {
+    fprintf(stderr, "glmReadOBJ() failed: can't open data file \"%s\".\n",
+	    filename);
+    exit(1);
+  }
+
+#if 0
+  /* announce the model name */
+  printf("Model: %s\n", filename);
+#endif
+
+  /* allocate a new model */
+  model = (GLMmodel*)malloc(sizeof(GLMmodel));
+  model->pathname      = stralloc(filename);
+  model->mtllibname    = NULL;
+  model->numvertices   = 0;
+  model->vertices      = NULL;
+  model->numnormals    = 0;
+  model->normals       = NULL;
+  model->numtexcoords  = 0;
+  model->texcoords     = NULL;
+  model->numfacetnorms = 0;
+  model->facetnorms    = NULL;
+  model->numtriangles  = 0;
+  model->triangles     = NULL;
+  model->nummaterials  = 0;
+  model->materials     = NULL;
+  model->numgroups     = 0;
+  model->groups        = NULL;
+  model->position[0]   = 0.0;
+  model->position[1]   = 0.0;
+  model->position[2]   = 0.0;
+  model->scale         = 1.0;
+
+  /* make a first pass through the file to get a count of the number
+     of vertices, normals, texcoords & triangles */
+  _glmFirstPass(model, file);
+
+  /* allocate memory */
+  model->vertices = (float*)malloc(sizeof(float) *
+				     3 * (model->numvertices + 1));
+  model->triangles = (GLMtriangle*)malloc(sizeof(GLMtriangle) *
+					  model->numtriangles);
+  if (model->numnormals) {
+    model->normals = (float*)malloc(sizeof(float) *
+				      3 * (model->numnormals + 1));
+  }
+  if (model->numtexcoords) {
+    model->texcoords = (float*)malloc(sizeof(float) *
+					2 * (model->numtexcoords + 1));
+  }
+
+  /* rewind to beginning of file and read in the data this pass */
+  rewind(file);
+
+  _glmSecondPass(model, file);
+
+  /* close the file */
+  fclose(file);
+
+  if (!model->materials) {
+     model->materials = glmDefaultMaterial();
+     model->nummaterials = 1;
+  }
+
+  return model;
+}
+
+/* glmWriteOBJ: Writes a model description in Wavefront .OBJ format to
+ * a file.
+ *
+ * model    - initialized GLMmodel structure
+ * filename - name of the file to write the Wavefront .OBJ format data to
+ * mode     - a bitwise or of values describing what is written to the file
+ *            GLM_NONE     -  render with only vertices
+ *            GLM_FLAT     -  render with facet normals
+ *            GLM_SMOOTH   -  render with vertex normals
+ *            GLM_TEXTURE  -  render with texture coords
+ *            GLM_COLOR    -  render with colors (color material)
+ *            GLM_MATERIAL -  render with materials
+ *            GLM_COLOR and GLM_MATERIAL should not both be specified.  
+ *            GLM_FLAT and GLM_SMOOTH should not both be specified.  
+ */
+void
+glmWriteOBJ(GLMmodel* model, char* filename, uint mode)
+{
+  uint    i;
+  FILE*     file;
+  GLMgroup* group;
+
+  assert(model);
+
+  /* do a bit of warning */
+  if (mode & GLM_FLAT && !model->facetnorms) {
+    printf("glmWriteOBJ() warning: flat normal output requested "
+	   "with no facet normals defined.\n");
+    mode &= ~GLM_FLAT;
+  }
+  if (mode & GLM_SMOOTH && !model->normals) {
+    printf("glmWriteOBJ() warning: smooth normal output requested "
+	   "with no normals defined.\n");
+    mode &= ~GLM_SMOOTH;
+  }
+  if (mode & GLM_TEXTURE && !model->texcoords) {
+    printf("glmWriteOBJ() warning: texture coordinate output requested "
+	   "with no texture coordinates defined.\n");
+    mode &= ~GLM_TEXTURE;
+  }
+  if (mode & GLM_FLAT && mode & GLM_SMOOTH) {
+    printf("glmWriteOBJ() warning: flat normal output requested "
+	   "and smooth normal output requested (using smooth).\n");
+    mode &= ~GLM_FLAT;
+  }
+
+  /* open the file */
+  file = fopen(filename, "w");
+  if (!file) {
+    fprintf(stderr, "glmWriteOBJ() failed: can't open file \"%s\" to write.\n",
+	    filename);
+    exit(1);
+  }
+
+  /* spit out a header */
+  fprintf(file, "#  \n");
+  fprintf(file, "#  Wavefront OBJ generated by GLM library\n");
+  fprintf(file, "#  \n");
+  fprintf(file, "#  GLM library copyright (C) 1997 by Nate Robins\n");
+  fprintf(file, "#  email: [email protected]\n");
+  fprintf(file, "#  www:   http://www.pobox.com/~ndr\n");
+  fprintf(file, "#  \n");
+
+  if (mode & GLM_MATERIAL && model->mtllibname) {
+    fprintf(file, "\nmtllib %s\n\n", model->mtllibname);
+    _glmWriteMTL(model, filename, model->mtllibname);
+  }
+
+  /* spit out the vertices */
+  fprintf(file, "\n");
+  fprintf(file, "# %d vertices\n", model->numvertices);
+  for (i = 1; i <= model->numvertices; i++) {
+    fprintf(file, "v %f %f %f\n", 
+	    model->vertices[3 * i + 0],
+	    model->vertices[3 * i + 1],
+	    model->vertices[3 * i + 2]);
+  }
+
+  /* spit out the smooth/flat normals */
+  if (mode & GLM_SMOOTH) {
+    fprintf(file, "\n");
+    fprintf(file, "# %d normals\n", model->numnormals);
+    for (i = 1; i <= model->numnormals; i++) {
+      fprintf(file, "vn %f %f %f\n", 
+	      model->normals[3 * i + 0],
+	      model->normals[3 * i + 1],
+	      model->normals[3 * i + 2]);
+    }
+  } else if (mode & GLM_FLAT) {
+    fprintf(file, "\n");
+    fprintf(file, "# %d normals\n", model->numfacetnorms);
+    for (i = 1; i <= model->numnormals; i++) {
+      fprintf(file, "vn %f %f %f\n", 
+	      model->facetnorms[3 * i + 0],
+	      model->facetnorms[3 * i + 1],
+	      model->facetnorms[3 * i + 2]);
+    }
+  }
+
+  /* spit out the texture coordinates */
+  if (mode & GLM_TEXTURE) {
+    fprintf(file, "\n");
+    fprintf(file, "# %d texcoords\n", model->numtexcoords);
+    for (i = 1; i <= model->numtexcoords; i++) {
+      fprintf(file, "vt %f %f\n", 
+	      model->texcoords[2 * i + 0],
+	      model->texcoords[2 * i + 1]);
+    }
+  }
+
+  fprintf(file, "\n");
+  fprintf(file, "# %d groups\n", model->numgroups);
+  fprintf(file, "# %d faces (triangles)\n", model->numtriangles);
+  fprintf(file, "\n");
+
+  group = model->groups;
+  while(group) {
+    fprintf(file, "g %s\n", group->name);
+    if (mode & GLM_MATERIAL)
+      fprintf(file, "usemtl %s\n", model->materials[group->material].name);
+    for (i = 0; i < group->numtriangles; i++) {
+      if (mode & GLM_SMOOTH && mode & GLM_TEXTURE) {
+	fprintf(file, "f %d/%d/%d %d/%d/%d %d/%d/%d\n",
+		T(group->triangles[i]).vindices[0], 
+		T(group->triangles[i]).nindices[0], 
+		T(group->triangles[i]).tindices[0],
+		T(group->triangles[i]).vindices[1],
+		T(group->triangles[i]).nindices[1],
+		T(group->triangles[i]).tindices[1],
+		T(group->triangles[i]).vindices[2],
+		T(group->triangles[i]).nindices[2],
+		T(group->triangles[i]).tindices[2]);
+      } else if (mode & GLM_FLAT && mode & GLM_TEXTURE) {
+	fprintf(file, "f %d/%d %d/%d %d/%d\n",
+		T(group->triangles[i]).vindices[0],
+		T(group->triangles[i]).findex,
+		T(group->triangles[i]).vindices[1],
+		T(group->triangles[i]).findex,
+		T(group->triangles[i]).vindices[2],
+		T(group->triangles[i]).findex);
+      } else if (mode & GLM_TEXTURE) {
+	fprintf(file, "f %d/%d %d/%d %d/%d\n",
+		T(group->triangles[i]).vindices[0],
+		T(group->triangles[i]).tindices[0],
+		T(group->triangles[i]).vindices[1],
+		T(group->triangles[i]).tindices[1],
+		T(group->triangles[i]).vindices[2],
+		T(group->triangles[i]).tindices[2]);
+      } else if (mode & GLM_SMOOTH) {
+	fprintf(file, "f %d//%d %d//%d %d//%d\n",
+		T(group->triangles[i]).vindices[0],
+		T(group->triangles[i]).nindices[0],
+		T(group->triangles[i]).vindices[1],
+		T(group->triangles[i]).nindices[1],
+		T(group->triangles[i]).vindices[2], 
+		T(group->triangles[i]).nindices[2]);
+      } else if (mode & GLM_FLAT) {
+	fprintf(file, "f %d//%d %d//%d %d//%d\n",
+		T(group->triangles[i]).vindices[0], 
+		T(group->triangles[i]).findex,
+		T(group->triangles[i]).vindices[1],
+		T(group->triangles[i]).findex,
+		T(group->triangles[i]).vindices[2],
+		T(group->triangles[i]).findex);
+      } else {
+	fprintf(file, "f %d %d %d\n",
+		T(group->triangles[i]).vindices[0],
+		T(group->triangles[i]).vindices[1],
+		T(group->triangles[i]).vindices[2]);
+      }
+    }
+    fprintf(file, "\n");
+    group = group->next;
+  }
+
+  fclose(file);
+}
+
+/* glmWeld: eliminate (weld) vectors that are within an epsilon of
+ * each other.
+ *
+ * model      - initialized GLMmodel structure
+ * epsilon    - maximum difference between vertices
+ *              ( 0.00001 is a good start for a unitized model)
+ *
+ */
+void
+glmWeld(GLMmodel* model, float epsilon)
+{
+  float* vectors;
+  float* copies;
+  uint   numvectors;
+  uint   i;
+
+  /* vertices */
+  numvectors = model->numvertices;
+  vectors    = model->vertices;
+  copies = _glmWeldVectors(vectors, &numvectors, epsilon);
+
+  printf("glmWeld(): %d redundant vertices.\n", 
+	 model->numvertices - numvectors - 1);
+
+  for (i = 0; i < model->numtriangles; i++) {
+    T(i).vindices[0] = (uint)vectors[3 * T(i).vindices[0] + 0];
+    T(i).vindices[1] = (uint)vectors[3 * T(i).vindices[1] + 0];
+    T(i).vindices[2] = (uint)vectors[3 * T(i).vindices[2] + 0];
+  }
+
+  /* free space for old vertices */
+  free(vectors);
+
+  /* allocate space for the new vertices */
+  model->numvertices = numvectors;
+  model->vertices = (float*)malloc(sizeof(float) * 
+				     3 * (model->numvertices + 1));
+
+  /* copy the optimized vertices into the actual vertex list */
+  for (i = 1; i <= model->numvertices; i++) {
+    model->vertices[3 * i + 0] = copies[3 * i + 0];
+    model->vertices[3 * i + 1] = copies[3 * i + 1];
+    model->vertices[3 * i + 2] = copies[3 * i + 2];
+  }
+
+  free(copies);
+}
+
+
+void
+glmReIndex(GLMmodel *model)
+{
+  uint i, j, n;
+  GLMgroup* group;
+  float *newNormals = NULL;
+  float *newTexcoords = NULL;
+  const uint numv = model->numvertices;
+
+  if (model->numnormals > 0)
+     newNormals = (float *) malloc((numv + 1) * 3 * sizeof(float));
+
+  if (model->numtexcoords > 0)
+     newTexcoords = (float *) malloc((numv + 1) * 2 * sizeof(float));
+
+  for (group = model->groups; group; group = group->next) {
+
+    n = group->numtriangles;
+
+    group->triIndexes = (uint *) malloc(n * 3 * sizeof(uint));
+
+    group->minIndex = 10000000;
+    group->maxIndex = 0;
+
+    for (i = 0; i < n; i++) {
+
+       for (j = 0; j < 3; j++) {
+          uint vindex = T(group->triangles[i]).vindices[j];
+          uint nindex = T(group->triangles[i]).nindices[j];
+          uint tindex = T(group->triangles[i]).tindices[j];
+
+          float *nrm = &model->normals[nindex * 3];
+          float *tex = &model->texcoords[tindex * 2];
+
+          if (newNormals) {
+             assert(vindex * 3 + 2 < (numv + 1) * 3);
+             newNormals[vindex * 3 + 0] = nrm[0];
+             newNormals[vindex * 3 + 1] = nrm[1];
+             newNormals[vindex * 3 + 2] = nrm[2];
+          }
+          if (newTexcoords) {
+             newTexcoords[vindex * 2 + 0] = tex[0];
+             newTexcoords[vindex * 2 + 1] = tex[1];
+          }
+
+          T(group->triangles[i]).nindices[j] = vindex;
+          T(group->triangles[i]).tindices[j] = vindex;
+
+          group->triIndexes[i * 3 + j] = vindex;
+
+          if (vindex > group->maxIndex)
+             group->maxIndex = vindex;
+          if (vindex < group->minIndex)
+             group->minIndex = vindex;
+       }
+    }
+  }
+
+  if (newNormals) {
+     free(model->normals);
+     model->normals = newNormals;
+     model->numnormals = model->numvertices;
+  }
+
+  if (newTexcoords) {
+     free(model->texcoords);
+     model->texcoords = newTexcoords;
+     model->numtexcoords = model->numvertices;
+  }
+}
+
+
+
+void
+glmPrint(const GLMmodel *model)
+{
+  uint i, j, grp, n;
+  GLMgroup* group;
+  uint totalTris = 0;
+
+  grp = 0;
+
+  printf("%u vertices\n", model->numvertices);
+  printf("%u normals\n", model->numnormals);
+  printf("%u texcoords\n", model->numtexcoords);
+
+  for (group = model->groups; group; group = group->next, grp++) {
+     printf("Group %u:\n", grp);
+     printf("  Min index %u, max index %u\n", group->minIndex, group->maxIndex);
+
+#if 0
+    if (mode & GLM_MATERIAL) {
+      glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, 
+		   model->materials[group->material].ambient);
+      glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, 
+		   model->materials[group->material].diffuse);
+      glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, 
+		   model->materials[group->material].specular);
+       glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 
+  		  model->materials[group->material].shininess);
+    }
+
+    if (mode & GLM_COLOR) {
+      glColor3fv(model->materials[group->material].diffuse);
+    }
+#endif
+    totalTris += group->numtriangles;
+
+    printf("  %u triangles\n", group->numtriangles);
+    n = group->numtriangles;
+    if (n > 10)
+      n = 10;
+
+    for (i = 0; i < n; i++) {
+
+       printf("    %u: vert ", i);
+       for (j = 0; j < 3; j++) {
+          printf("%u ", T(group->triangles[i]).vindices[j]);
+       }
+
+       printf("    normal ");
+       for (j = 0; j < 3; j++) {
+          printf("%u ", T(group->triangles[i]).nindices[j]);
+       }
+
+       printf("    tex ");
+       for (j = 0; j < 3; j++) {
+          printf("%u ", T(group->triangles[i]).tindices[j]);
+       }
+
+       printf("\n");
+    }
+  }
+  printf("Total tris: %u\n", totalTris);
+}
+
+
+
+#if 0
+  /* normals */
+  if (model->numnormals) {
+  numvectors = model->numnormals;
+  vectors    = model->normals;
+  copies = _glmOptimizeVectors(vectors, &numvectors);
+
+  printf("glmOptimize(): %d redundant normals.\n", 
+	 model->numnormals - numvectors);
+
+  for (i = 0; i < model->numtriangles; i++) {
+    T(i).nindices[0] = (uint)vectors[3 * T(i).nindices[0] + 0];
+    T(i).nindices[1] = (uint)vectors[3 * T(i).nindices[1] + 0];
+    T(i).nindices[2] = (uint)vectors[3 * T(i).nindices[2] + 0];
+  }
+
+  /* free space for old normals */
+  free(vectors);
+
+  /* allocate space for the new normals */
+  model->numnormals = numvectors;
+  model->normals = (float*)malloc(sizeof(float) * 
+				    3 * (model->numnormals + 1));
+
+  /* copy the optimized vertices into the actual vertex list */
+  for (i = 1; i <= model->numnormals; i++) {
+    model->normals[3 * i + 0] = copies[3 * i + 0];
+    model->normals[3 * i + 1] = copies[3 * i + 1];
+    model->normals[3 * i + 2] = copies[3 * i + 2];
+  }
+
+  free(copies);
+  }
+
+  /* texcoords */
+  if (model->numtexcoords) {
+  numvectors = model->numtexcoords;
+  vectors    = model->texcoords;
+  copies = _glmOptimizeVectors(vectors, &numvectors);
+
+  printf("glmOptimize(): %d redundant texcoords.\n", 
+	 model->numtexcoords - numvectors);
+
+  for (i = 0; i < model->numtriangles; i++) {
+    for (j = 0; j < 3; j++) {
+      T(i).tindices[j] = (uint)vectors[3 * T(i).tindices[j] + 0];
+    }
+  }
+
+  /* free space for old texcoords */
+  free(vectors);
+
+  /* allocate space for the new texcoords */
+  model->numtexcoords = numvectors;
+  model->texcoords = (float*)malloc(sizeof(float) * 
+				      2 * (model->numtexcoords + 1));
+
+  /* copy the optimized vertices into the actual vertex list */
+  for (i = 1; i <= model->numtexcoords; i++) {
+    model->texcoords[2 * i + 0] = copies[2 * i + 0];
+    model->texcoords[2 * i + 1] = copies[2 * i + 1];
+  }
+
+  free(copies);
+  }
+#endif
+
+#if 0
+  /* look for unused vertices */
+  /* look for unused normals */
+  /* look for unused texcoords */
+  for (i = 1; i <= model->numvertices; i++) {
+    for (j = 0; j < model->numtriangles; i++) {
+      if (T(j).vindices[0] == i || 
+	  T(j).vindices[1] == i || 
+	  T(j).vindices[1] == i)
+	break;
+    }
+  }
+#endif