/*    
 *  GLM library.  Wavefront .obj file format reader/writer/manipulator.
 *
 *  Written by Nate Robins, 1997.
 *  email: ndr@pobox.com
 *  www: http://www.pobox.com/~ndr
 */


/* includes */
#include <cmath>
#include <cstdio>
#include <cstring>
#include <cassert>
using namespace std;
#include "glm.h"

#ifndef M_PI
#define M_PI 3.1415926
#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 {
  GLuint           index;
  GLboolean        averaged;
  struct _GLMnode* next;
} GLMnode;


/* private functions */

/* _glmMax: returns the maximum of two floats */
static GLfloat
_glmMax(GLfloat a, GLfloat b) 
{
  if (a > b)
    return a;
  return b;
}

/* _glmAbs: returns the absolute value of a float */
static GLfloat
_glmAbs(GLfloat f)
{
  if (f < 0)
    return -f;
  return f;
}

/* _glmDot: compute the dot product of two vectors
 *
 * u - array of 3 GLfloats (GLfloat u[3])
 * v - array of 3 GLfloats (GLfloat v[3])
 */
static GLfloat
_glmDot(GLfloat* u, GLfloat* 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 GLfloats (GLfloat u[3])
 * v - array of 3 GLfloats (GLfloat v[3])
 * n - array of 3 GLfloats (GLfloat n[3]) to return the cross product in
 */
static GLvoid
_glmCross(GLfloat* u, GLfloat* v, GLfloat* 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 GLfloats (GLfloat n[3]) to be normalized
 */
static GLvoid
_glmNormalize(GLfloat* n)
{
  GLfloat l;

  assert(n);

  /* normalize */
  l = (GLfloat)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 GL_TRUE if they are
 * equal (within a certain threshold) or GL_FALSE if not. An epsilon
 * that works fairly well is 0.000001.
 *
 * u - array of 3 GLfloats (GLfloat u[3])
 * v - array of 3 GLfloats (GLfloat v[3]) 
 */
static GLboolean
_glmEqual(GLfloat* u, GLfloat* v, GLfloat epsilon)
{
  if (_glmAbs(u[0] - v[0]) < epsilon &&
      _glmAbs(u[1] - v[1]) < epsilon &&
      _glmAbs(u[2] - v[2]) < epsilon) 
  {
    return GL_TRUE;
  }
  return GL_FALSE;
}

/* _glmWeldVectors: eliminate (weld) vectors that are within an
 * epsilon of each other.
 *
 * vectors    - array of GLfloat[3]'s to be welded
 * numvectors - number of GLfloat[3]'s in vectors
 * epsilon    - maximum difference between vectors 
 *
 */
GLfloat*
_glmWeldVectors(GLfloat* vectors, GLuint* numvectors, GLfloat epsilon)
{
  GLfloat* copies;
  GLuint   copied;
  GLuint   i, j;

  copies = (GLfloat*)malloc(sizeof(GLfloat) * 3 * (*numvectors + 1));
  memcpy(copies, vectors, (sizeof(GLfloat) * 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] = (GLfloat)j;
  }

  *numvectors = copied-1;
  return copies;
}

/* Find a group in the model
 */
GLMmodel::GLMgroup* _glmFindGroup (GLMmodel* model, char* name)
{
  GLMmodel::GLMgroup* group;

  group = model->groups;
  while(group) {
    if (!strcmp(name, group->name))
      break;
    group = group->next;
  }

  return group;
}

/* Add a group to the model
 */
GLMmodel::GLMgroup* _glmAddGroup (GLMmodel* model, char* name)
{
  GLMmodel::GLMgroup* group;

  group = _glmFindGroup(model, name);
  if (!group) {
    group = (GLMmodel::GLMgroup*)malloc(sizeof(GLMmodel::GLMgroup));
    group->name = strdup(name);
    group->material = 0;
    group->numtriangles = 0;
    group->triangles = NULL;
    group->next = model->groups;
    model->groups = group;
    model->numgroups++;
  }

  return group;
}

/* Find a material in the model
 */
GLuint _glmFindMaterial (GLMmodel* model, char* name)
{
  GLuint 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;
}


/* Return the directory given a path
 *
 * path - filesystem path
 *
 * The return value should be free'd.
 */
char* _glmDirName (const char* path)
{
	char* dir;
	char* s;
	char* s2;

	dir = strdup(path);

	s = strrchr(dir, '/');
	s2 = strrchr(dir, '\\');
	if(s && s2)
	{
		char* s3 = strrchr(s, '\\');
		if(s3)
			s3[1] = '\0';
		else
			s[1] = '\0';
	}
	else if(!s && s2)
		s2[1] = '\0';
	else if(s && !s2)
		s[1] = '\0';
	else
		dir[0] = '\0';

	return dir;
}


/* Read a wavefront material library file
 *
 * model - properly initialized GLMmodel structure
 * name  - name of the material library
 */
GLvoid _glmReadMTL (GLMmodel* model, char* name)
{
  FILE* file;
  char* dir;
  char* filename;
  char  buf[128];
  GLuint nummaterials, i;

  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*)malloc(sizeof(GLMmaterial) * nummaterials);
  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] = 1.0;
    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] = 1.0;
  }
  model->materials[0].name = strdup("default");

  /* now, read in the data */
  nummaterials = 0;
  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 = strdup(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;
      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;
    default:
      /* eat up rest of line */
      fgets(buf, sizeof(buf), file);
      break;
    }
  }

  /* close the file */
  fclose(file);
}

/* 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
 */
GLvoid _glmWriteMTL (GLMmodel* model, const char* modelpath, const char* mtllibname)
{
  FILE* file;
  char* dir;
  char* filename;
  GLMmaterial* material;
  GLuint 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: ndr@pobox.com\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");
  }
}


/* 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 
 */
GLvoid _glmFirstPass (GLMmodel* model, FILE* file) 
{
  GLuint    numvertices;		/* number of vertices in model */
  GLuint    numnormals;			/* number of normals in model */
  GLuint    numtexcoords;		/* number of texcoords in model */
  GLuint    numtriangles;		/* number of triangles in model */
  GLMmodel::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 = strdup(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, "%d//%d", &v, &n);
	fscanf(file, "%d//%d", &v, &n);
	fscanf(file, "%d//%d", &v, &n);
	numtriangles++;
	group->numtriangles++;
	while(fscanf(file, "%d//%d", &v, &n) > 0) {
	  numtriangles++;
	  group->numtriangles++;
	}
      } else if (sscanf(buf, "%d/%d/%d", &v, &t, &n) == 3) {
	/* v/t/n */
	fscanf(file, "%d/%d/%d", &v, &t, &n);
	fscanf(file, "%d/%d/%d", &v, &t, &n);
	numtriangles++;
	group->numtriangles++;
	while(fscanf(file, "%d/%d/%d", &v, &t, &n) > 0) {
	  numtriangles++;
	  group->numtriangles++;
	}
      } else if (sscanf(buf, "%d/%d", &v, &t) == 2) {
	/* v/t */
	fscanf(file, "%d/%d", &v, &t);
	fscanf(file, "%d/%d", &v, &t);
	numtriangles++;
	group->numtriangles++;
	while(fscanf(file, "%d/%d", &v, &t) > 0) {
	  numtriangles++;
	  group->numtriangles++;
	}
      } else {
	/* v */
	fscanf(file, "%d", &v);
	fscanf(file, "%d", &v);
	numtriangles++;
	group->numtriangles++;
	while(fscanf(file, "%d", &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 = (GLuint*)malloc(sizeof(GLuint) * group->numtriangles);
    group->numtriangles = 0;
    group = group->next;
  }
}

/* Second pass at a Wavefront OBJ file that gets all the data.
 *
 * model - properly initialized GLMmodel structure
 * file  - (fopen'd) file descriptor 
 */
GLvoid _glmSecondPass (GLMmodel* model, FILE* file)
{
  GLuint    numvertices;		/* number of vertices in model */
  GLuint    numnormals;			/* number of normals in model */
  GLuint    numtexcoords;		/* number of texcoords in model */
  GLuint    numtriangles;		/* number of triangles in model */
  GLfloat*  vertices;			/* array of vertices  */
  GLfloat*  normals;			/* array of normals */
  GLfloat*  texcoords;			/* array of texture coordinates */
  GLMmodel::GLMgroup* group;		/* current group pointer */
  GLuint    material;			/* current material */
  GLuint    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 file, read all data into 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);
      group->material = material = _glmFindMaterial(model, buf);
      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;
      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, "%d//%d", &v, &n);
	T(numtriangles).vindices[0] = v;
	T(numtriangles).nindices[0] = n;
	fscanf(file, "%d//%d", &v, &n);
	T(numtriangles).vindices[1] = v;
	T(numtriangles).nindices[1] = n;
	fscanf(file, "%d//%d", &v, &n);
	T(numtriangles).vindices[2] = v;
	T(numtriangles).nindices[2] = n;
	group->triangles[group->numtriangles++] = numtriangles;
	numtriangles++;
	while(fscanf(file, "%d//%d", &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, "%d/%d/%d", &v, &t, &n) == 3) {
	/* v/t/n */
	T(numtriangles).vindices[0] = v;
	T(numtriangles).tindices[0] = t;
	T(numtriangles).nindices[0] = n;
	fscanf(file, "%d/%d/%d", &v, &t, &n);
	T(numtriangles).vindices[1] = v;
	T(numtriangles).tindices[1] = t;
	T(numtriangles).nindices[1] = n;
	fscanf(file, "%d/%d/%d", &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, "%d/%d/%d", &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, "%d/%d", &v, &t) == 2) {
	/* v/t */
	T(numtriangles).vindices[0] = v;
	T(numtriangles).tindices[0] = t;
	fscanf(file, "%d/%d", &v, &t);
	T(numtriangles).vindices[1] = v;
	T(numtriangles).tindices[1] = t;
	fscanf(file, "%d/%d", &v, &t);
	T(numtriangles).vindices[2] = v;
	T(numtriangles).tindices[2] = t;
	group->triangles[group->numtriangles++] = numtriangles;
	numtriangles++;
	while(fscanf(file, "%d/%d", &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, "%d", &v);
	T(numtriangles).vindices[0] = v;
	fscanf(file, "%d", &v);
	T(numtriangles).vindices[1] = v;
	fscanf(file, "%d", &v);
	T(numtriangles).vindices[2] = v;
	group->triangles[group->numtriangles++] = numtriangles;
	numtriangles++;
	while(fscanf(file, "%d", &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(GLfloat) +
	 numnormals   * 3*sizeof(GLfloat) * (numnormals ? 1 : 0) +
	 numtexcoords * 3*sizeof(GLfloat) * (numtexcoords ? 1 : 0) +
	 numtriangles * sizeof(GLMtriangle));
#endif
}




/* public functions */

GLMmodel::GLMmodel (const string & filename)
  : pathname(strdup(filename.c_str())),
    mtllibname(NULL),
    numvertices(0),
    vertices(NULL),
    numnormals(0),
    normals(NULL),
    numtexcoords(0),
    texcoords(NULL),
    numfacetnorms(0),
    facetnorms(NULL),
    numtriangles(0),
    triangles(NULL),
    nummaterials(0),
    materials(NULL),
    numgroups(0),
    groups(NULL)
{
    position[0] = position[1] = position[2] = 0;
    readOBJ(filename.c_str());
    //unitize();
    generateFacetNormals();
    generateVertexNormals();
}

/* Deletes structure.
 */
GLMmodel::~GLMmodel ()
{
  GLMmodel::GLMgroup* group;
  GLuint i;

  if (pathname)   free(pathname);
  if (mtllibname) free(mtllibname);
  if (vertices)   free(vertices);
  if (normals)    free(normals);
  if (texcoords)  free(texcoords);
  if (facetnorms) free(facetnorms);
  if (triangles)  free(triangles);
  if (materials) {
    for (i = 0; i < nummaterials; i++)
      free(materials[i].name);
  }
  free(materials);
  while(groups) {
    group = groups;
    groups = groups->next;
    free(group->name);
    free(group->triangles);
    free(group);
  }
}

/* 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.
 */
GLfloat GLMmodel::unitize ()
{
  GLuint  i;
  GLfloat maxx, minx, maxy, miny, maxz, minz;
  GLfloat cx, cy, cz, w, h, d;
  GLfloat scale;

  /* get the max/mins */
  maxx = minx = vertices[3 + X];
  maxy = miny = vertices[3 + Y];
  maxz = minz = vertices[3 + Z];
  for (i = 1; i <= numvertices; i++) {
    if (maxx < vertices[3 * i + X])
      maxx = vertices[3 * i + X];
    if (minx > vertices[3 * i + X])
      minx = vertices[3 * i + X];

    if (maxy < vertices[3 * i + Y])
      maxy = vertices[3 * i + Y];
    if (miny > vertices[3 * i + Y])
      miny = vertices[3 * i + Y];

    if (maxz < vertices[3 * i + Z])
      maxz = vertices[3 * i + Z];
    if (minz > vertices[3 * i + Z])
      minz = 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 <= numvertices; i++) {
    vertices[3 * i + X] -= cx;
    vertices[3 * i + Y] -= cy;
    vertices[3 * i + Z] -= cz;
    vertices[3 * i + X] *= scale;
    vertices[3 * i + Y] *= scale;
    vertices[3 * i + Z] *= scale;
  }

  return scale;
}

/* Calculates the dimensions (width, height, depth) of model.
 * dimensions - array of 3 GLfloats (GLfloat dimensions[3])
 */
GLvoid GLMmodel::getDimensions (GLfloat* dimensions)
{
  assert(dimensions);

  GLuint i;
  GLfloat maxx, minx, maxy, miny, maxz, minz;

  /* get the max/mins */
  maxx = minx = vertices[3 + X];
  maxy = miny = vertices[3 + Y];
  maxz = minz = vertices[3 + Z];
  for (i = 1; i <= numvertices; i++) {
    if (maxx < vertices[3 * i + X])
      maxx = vertices[3 * i + X];
    if (minx > vertices[3 * i + X])
      minx = vertices[3 * i + X];

    if (maxy < vertices[3 * i + Y])
      maxy = vertices[3 * i + Y];
    if (miny > vertices[3 * i + Y])
      miny = vertices[3 * i + Y];

    if (maxz < vertices[3 * i + Z])
      maxz = vertices[3 * i + Z];
    if (minz > vertices[3 * i + Z])
      minz = 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);
}


/* Reverse the polygon winding for all polygons in this model.
 * Default winding is counter-clockwise.  Also changes the direction
 * of the normals.
 */ 
GLvoid GLMmodel::reverseWinding ()
{
  GLuint i, swap;

  for (i = 0; i < numtriangles; i++) {
    swap = triangles[i].vindices[0];
    triangles[i].vindices[0] = triangles[i].vindices[2];
    triangles[i].vindices[2] = swap;

    if (numnormals) {
      swap = triangles[i].nindices[0];
      triangles[i].nindices[0] = triangles[i].nindices[2];
      triangles[i].nindices[2] = swap;
    }

    if (numtexcoords) {
      swap = triangles[i].tindices[0];
      triangles[i].tindices[0] = triangles[i].tindices[2];
      triangles[i].tindices[2] = swap;
    }
  }

  /* reverse facet normals */
  for (i = 1; i <= numfacetnorms; i++) {
    facetnorms[3 * i + X] = -facetnorms[3 * i + X];
    facetnorms[3 * i + Y] = -facetnorms[3 * i + Y];
    facetnorms[3 * i + Z] = -facetnorms[3 * i + Z];
  }

  /* reverse vertex normals */
  for (i = 1; i <= numnormals; i++) {
    normals[3 * i + X] = -normals[3 * i + X];
    normals[3 * i + Y] = -normals[3 * i + Y];
    normals[3 * i + Z] = -normals[3 * i + Z];
  }
}

/* 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.
  */
GLvoid GLMmodel::generateFacetNormals ()
{
  GLuint  i;
  GLfloat u[3];
  GLfloat v[3];
  
  /* clobber any old facetnormals */
  if (facetnorms)
    free(facetnorms);

  /* allocate memory for the new facet normals */
  numfacetnorms = numtriangles;
  facetnorms = (GLfloat*)malloc(sizeof(GLfloat) *
				       3 * (numfacetnorms + 1));

  for (i = 0; i < numtriangles; i++) {
    triangles[i].findex = i+1;

    u[X] = vertices[3 * triangles[i].vindices[1] + X] -
           vertices[3 * triangles[i].vindices[0] + X];
    u[Y] = vertices[3 * triangles[i].vindices[1] + Y] -
           vertices[3 * triangles[i].vindices[0] + Y];
    u[Z] = vertices[3 * triangles[i].vindices[1] + Z] -
           vertices[3 * triangles[i].vindices[0] + Z];

    v[X] = vertices[3 * triangles[i].vindices[2] + X] -
           vertices[3 * triangles[i].vindices[0] + X];
    v[Y] = vertices[3 * triangles[i].vindices[2] + Y] -
           vertices[3 * triangles[i].vindices[0] + Y];
    v[Z] = vertices[3 * triangles[i].vindices[2] + Z] -
           vertices[3 * triangles[i].vindices[0] + Z];

    _glmCross(u, v, &facetnorms[3 * (i+1)]);
    _glmNormalize(&facetnorms[3 * (i+1)]);
  }
}

/* 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.
 *
 * angle - maximum angle (in degrees) to smooth across 
 */
GLvoid GLMmodel::generateVertexNormals (GLfloat angle)
{
  GLMnode*  node;
  GLMnode*  tail;
  GLMnode** members;
  GLfloat*  oldNormals;
  GLuint    numVNormals;
  GLfloat   average[3];
  GLfloat   dot, cos_angle;
  GLuint    i, avg;

  /* calculate the cosine of the angle (in degrees) */
  cos_angle = cos(angle * M_PI / 180.0);

  /* nuke any previous normals */
  if (normals)
    free(normals);

  /* allocate space for new normals */
  numnormals = numtriangles * 3; /* 3 normals per triangle */
  normals = (GLfloat*)malloc(sizeof(GLfloat)* 3* (numnormals+1));

  /* allocate a structure that will hold a linked list of triangle
     indices for each vertex */
  members = (GLMnode**)malloc(sizeof(GLMnode*) * (numvertices + 1));
  for (i = 1; i <= numvertices; i++)
    members[i] = NULL;
  
  /* for every triangle, create a node for each vertex in it */
  for (i = 0; i < numtriangles; i++) {
    node = (GLMnode*)malloc(sizeof(GLMnode));
    node->index = i;
    node->next  = members[triangles[i].vindices[0]];
    members[triangles[i].vindices[0]] = node;

    node = (GLMnode*)malloc(sizeof(GLMnode));
    node->index = i;
    node->next  = members[triangles[i].vindices[1]];
    members[triangles[i].vindices[1]] = node;

    node = (GLMnode*)malloc(sizeof(GLMnode));
    node->index = i;
    node->next  = members[triangles[i].vindices[2]];
    members[triangles[i].vindices[2]] = node;
  }

  /* calculate the average normal for each vertex */
  numVNormals = 1;
  for (i = 1; i <= 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(&facetnorms[3 * triangles[node->index].findex],
 		    &facetnorms[3 * triangles[members[i]->index].findex]);
      if (dot > cos_angle) {
	node->averaged = GL_TRUE;
	average[0] += facetnorms[3 * triangles[node->index].findex + 0];
	average[1] += facetnorms[3 * triangles[node->index].findex + 1];
	average[2] += facetnorms[3 * triangles[node->index].findex + 2];
	avg = 1;			/* we averaged at least one normal! */
      } else {
	node->averaged = GL_FALSE;
      }
      node = node->next;
    }

    if (avg) {
      /* normalize the averaged normal */
      _glmNormalize(average);

      /* add the normal to the vertex normals list */
      normals[3 * numVNormals + 0] = average[0];
      normals[3 * numVNormals + 1] = average[1];
      normals[3 * numVNormals + 2] = average[2];
      avg = numVNormals;
      numVNormals++;
    }

    /* 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 (triangles[node->index].vindices[0] == i)
	  triangles[node->index].nindices[0] = avg;
	else if (triangles[node->index].vindices[1] == i)
	  triangles[node->index].nindices[1] = avg;
	else if (triangles[node->index].vindices[2] == i)
	  triangles[node->index].nindices[2] = avg;
      } else {
	/* if this node wasn't averaged, use the facet normal */
	normals[3 * numVNormals + 0] = 
	  facetnorms[3 * triangles[node->index].findex + 0];
	normals[3 * numVNormals + 1] = 
	  facetnorms[3 * triangles[node->index].findex + 1];
	normals[3 * numVNormals + 2] = 
	  facetnorms[3 * triangles[node->index].findex + 2];
	if (triangles[node->index].vindices[0] == i)
	  triangles[node->index].nindices[0] = numVNormals;
	else if (triangles[node->index].vindices[1] == i)
	  triangles[node->index].nindices[1] = numVNormals;
	else if (triangles[node->index].vindices[2] == i)
	  triangles[node->index].nindices[2] = numVNormals;
	numVNormals++;
      }
      node = node->next;
    }
  }
  
  numnormals = numVNormals - 1;

  /* free the member information */
  for (i = 1; i <= 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)) */
  oldNormals = normals;
  normals = (GLfloat*)malloc(sizeof(GLfloat)* 3* (numnormals+1));
  for (i = 1; i <= numnormals; i++) {
    normals[3 * i + 0] = oldNormals[3 * i + 0];
    normals[3 * i + 1] = oldNormals[3 * i + 1];
    normals[3 * i + 2] = oldNormals[3 * i + 2];
  }
  free(oldNormals);

  printf("glmVertexNormals(): %d normals generated\n", numnormals);
}


/* Generates texture coordinates according to a linear projection of
 * the texture map.  It generates these by linearly mapping the
 * vertices onto a square.
 */
GLvoid GLMmodel::generateLinearTextureCoordinates ()
{
  GLMmodel::GLMgroup *group;
  GLfloat dimensions[3];
  GLfloat x, y, scalefactor;
  GLuint i;
  
  if (texcoords)
    free(texcoords);
  numtexcoords = numvertices;
  texcoords=(GLfloat*)malloc(sizeof(GLfloat)*2*(numtexcoords+1));
  
  getDimensions(dimensions);
  scalefactor = 2.0 / 
    _glmAbs(_glmMax(_glmMax(dimensions[0], dimensions[1]), dimensions[2]));

  /* do the calculations */
  for(i = 1; i <= numvertices; i++) {
    x = vertices[3 * i + 0] * scalefactor;
    y = vertices[3 * i + 2] * scalefactor;
    texcoords[2 * i + 0] = (x + 1.0) / 2.0;
    texcoords[2 * i + 1] = (y + 1.0) / 2.0;
  }
  
  /* go through and put texture coordinate indices in all the triangles */
  group = groups;
  while(group) {
    for(i = 0; i < group->numtriangles; i++) {
      triangles[group->triangles[i]].tindices[0] = triangles[group->triangles[i]].vindices[0];
      triangles[group->triangles[i]].tindices[1] = triangles[group->triangles[i]].vindices[1];
      triangles[group->triangles[i]].tindices[2] = triangles[group->triangles[i]].vindices[2];
    }    
    group = group->next;
  }

#if 0
  printf("glmLinearTexture(): generated %d linear texture coordinates\n",
	  numtexcoords);
#endif
}

/* 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.
 */
GLvoid GLMmodel::generateSpheremapTextureCoordinates ()
{
  GLMmodel::GLMgroup* group;
  GLfloat theta, phi, rho, x, y, z, r;
  GLuint i;
  
  if (texcoords)
    free(texcoords);
  numtexcoords = numnormals;
  texcoords=(GLfloat*)malloc(sizeof(GLfloat)*2*(numtexcoords+1));
     
  /* do the calculations */
  for (i = 1; i <= numnormals; i++) {
    z = normals[3 * i + 0];	/* re-arrange for pole distortion */
    y = normals[3 * i + 1];
    x = 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 = 3.14159265 / 2.0;
      else
	phi = acos(z / rho);
      
#if WE_DONT_NEED_THIS_CODE
      if(x == 0.0)
	theta = 3.14159265 / 2.0;	/* asin(y / r); */
      else
	theta = acos(x / r);
#endif
      
      if(y == 0.0)
	theta = 3.141592365 / 2.0;	/* acos(x / r); */
      else
	theta = asin(y / r) + (3.14159265 / 2.0);
    }
    
    texcoords[2 * i + 0] = theta / 3.14159265;
    texcoords[2 * i + 1] = phi / 3.14159265;
  }
  
  /* go through and put texcoord indices in all the triangles */
  group = groups;
  while(group) {
    for (i = 0; i < group->numtriangles; i++) {
      triangles[group->triangles[i]].tindices[0] = triangles[group->triangles[i]].nindices[0];
      triangles[group->triangles[i]].tindices[1] = triangles[group->triangles[i]].nindices[1];
      triangles[group->triangles[i]].tindices[2] = triangles[group->triangles[i]].nindices[2];
    }
    group = group->next;
  }

#if 0  
  printf("glmSpheremapTexture(): generated %d spheremap texture coordinates\n",
	 numtexcoords);
#endif
}

/* 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.
 */
void GLMmodel::readOBJ (const char * filename)
{
  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.c_str());
#endif

  /* make a first pass through the file to get a count of the number
     of vertices, normals, texcoords & triangles */
  _glmFirstPass(this, file);

  /* allocate memory */
  vertices = (GLfloat*)malloc(sizeof(GLfloat) * 3 * (numvertices + 1));
  triangles = (GLMtriangle*)malloc(sizeof(GLMtriangle) * numtriangles);
  if (numnormals) {
    normals = (GLfloat*)malloc(sizeof(GLfloat) * 3 * (numnormals + 1));
  }
  if (numtexcoords) {
    texcoords = (GLfloat*)malloc(sizeof(GLfloat) * 2 * (numtexcoords + 1));
  }

  /* rewind to beginning of file and read in the data this pass */
  rewind(file);

  _glmSecondPass(this, file);

  /* close the file */
  fclose(file);
}

/* Writes a model description in Wavefront .OBJ format to file.
 *
 * 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.  
 */
GLvoid GLMmodel::writeOBJ (const string & filename, GLuint mode)
{
  GLuint    i;
  FILE*     file;
  GLMmodel::GLMgroup* group;

  /* do a bit of warning */
  if (mode & GLM_FLAT && !facetnorms) {
    printf("glmWriteOBJ() warning: flat normal output requested "
	   "with no facet normals defined.\n");
    mode &= ~GLM_FLAT;
  }
  if (mode & GLM_SMOOTH && !normals) {
    printf("glmWriteOBJ() warning: smooth normal output requested "
	   "with no normals defined.\n");
    mode &= ~GLM_SMOOTH;
  }
  if (mode & GLM_TEXTURE && !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.c_str(), "w");
  if (!file) {
    fprintf(stderr, "glmWriteOBJ() failed: can't open file \"%s\" to write.\n",
	    filename.c_str());
    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: ndr@pobox.com\n");
  fprintf(file, "#  www:   http://www.pobox.com/~ndr\n");
  fprintf(file, "#  \n");

  if (mode & GLM_MATERIAL && mtllibname) {
    fprintf(file, "\nmtllib %s\n\n", mtllibname);
    _glmWriteMTL(this, filename.c_str(), mtllibname);
  }

  /* spit out the vertices */
  fprintf(file, "\n");
  fprintf(file, "# %d vertices\n", numvertices);
  for (i = 1; i <= numvertices; i++) {
    fprintf(file, "v %f %f %f\n", 
	    vertices[3 * i + 0],
	    vertices[3 * i + 1],
	    vertices[3 * i + 2]);
  }

  /* spit out the smooth/flat normals */
  if (mode & GLM_SMOOTH) {
    fprintf(file, "\n");
    fprintf(file, "# %d normals\n", numnormals);
    for (i = 1; i <= numnormals; i++) {
      fprintf(file, "vn %f %f %f\n", 
	      normals[3 * i + 0],
	      normals[3 * i + 1],
	      normals[3 * i + 2]);
    }
  } else if (mode & GLM_FLAT) {
    fprintf(file, "\n");
    fprintf(file, "# %d normals\n", numfacetnorms);
    for (i = 1; i <= numnormals; i++) {
      fprintf(file, "vn %f %f %f\n", 
	      facetnorms[3 * i + 0],
	      facetnorms[3 * i + 1],
	      facetnorms[3 * i + 2]);
    }
  }

  /* spit out the texture coordinates */
  if (mode & GLM_TEXTURE) {
    fprintf(file, "\n");
    fprintf(file, "# %d texcoords\n", numtexcoords);
    for (i = 1; i <= numtexcoords; i++) {
      fprintf(file, "vt %f %f\n", 
	      texcoords[2 * i + 0],
	      texcoords[2 * i + 1]);
    }
  }

  fprintf(file, "\n");
  fprintf(file, "# %d groups\n", numgroups);
  fprintf(file, "# %d faces (triangles)\n", numtriangles);
  fprintf(file, "\n");

  group = groups;
  while(group) {
    fprintf(file, "g %s\n", group->name);
    if (mode & GLM_MATERIAL)
      fprintf(file, "usemtl %s\n", 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",
		triangles[group->triangles[i]].vindices[0], 
		triangles[group->triangles[i]].nindices[0], 
		triangles[group->triangles[i]].tindices[0],
		triangles[group->triangles[i]].vindices[1],
		triangles[group->triangles[i]].nindices[1],
		triangles[group->triangles[i]].tindices[1],
		triangles[group->triangles[i]].vindices[2],
		triangles[group->triangles[i]].nindices[2],
		triangles[group->triangles[i]].tindices[2]);
      } else if (mode & GLM_FLAT && mode & GLM_TEXTURE) {
	fprintf(file, "f %d/%d %d/%d %d/%d\n",
		triangles[group->triangles[i]].vindices[0],
		triangles[group->triangles[i]].findex,
		triangles[group->triangles[i]].vindices[1],
		triangles[group->triangles[i]].findex,
		triangles[group->triangles[i]].vindices[2],
		triangles[group->triangles[i]].findex);
      } else if (mode & GLM_TEXTURE) {
	fprintf(file, "f %d/%d %d/%d %d/%d\n",
		triangles[group->triangles[i]].vindices[0],
		triangles[group->triangles[i]].tindices[0],
		triangles[group->triangles[i]].vindices[1],
		triangles[group->triangles[i]].tindices[1],
		triangles[group->triangles[i]].vindices[2],
		triangles[group->triangles[i]].tindices[2]);
      } else if (mode & GLM_SMOOTH) {
	fprintf(file, "f %d//%d %d//%d %d//%d\n",
		triangles[group->triangles[i]].vindices[0],
		triangles[group->triangles[i]].nindices[0],
		triangles[group->triangles[i]].vindices[1],
		triangles[group->triangles[i]].nindices[1],
		triangles[group->triangles[i]].vindices[2], 
		triangles[group->triangles[i]].nindices[2]);
      } else if (mode & GLM_FLAT) {
	fprintf(file, "f %d//%d %d//%d %d//%d\n",
		triangles[group->triangles[i]].vindices[0], 
		triangles[group->triangles[i]].findex,
		triangles[group->triangles[i]].vindices[1],
		triangles[group->triangles[i]].findex,
		triangles[group->triangles[i]].vindices[2],
		triangles[group->triangles[i]].findex);
      } else {
	fprintf(file, "f %d %d %d\n",
		triangles[group->triangles[i]].vindices[0],
		triangles[group->triangles[i]].vindices[1],
		triangles[group->triangles[i]].vindices[2]);
      }
    }
    fprintf(file, "\n");
    group = group->next;
  }

  fclose(file);
}

/* Renders the model to the current OpenGL context using specified mode.
 *
 * mode     - a bitwise OR of values describing what is to be rendered.
 *            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.  
 */
GLvoid GLMmodel::draw (GLuint mode)
{
  GLuint i;
  GLMmodel::GLMgroup* group;

  /* do a bit of warning */
  if (mode & GLM_FLAT && !facetnorms) {
//    printf("glmDraw() warning: flat render mode requested "
//	   "with no facet normals defined.\n");
    mode &= ~GLM_FLAT;
  }
  if (mode & GLM_SMOOTH && !normals) {
//    printf("glmDraw() warning: smooth render mode requested "
//	   "with no normals defined.\n");
    mode &= ~GLM_SMOOTH;
  }
  if (mode & GLM_TEXTURE && !texcoords) {
//    printf("glmDraw() warning: texture render mode requested "
//	   "with no texture coordinates defined.\n");
    mode &= ~GLM_TEXTURE;
  }
  if (mode & GLM_FLAT && mode & GLM_SMOOTH) {
//    printf("glmDraw() warning: flat render mode requested "
//	   "and smooth render mode requested (using smooth).\n");
    mode &= ~GLM_FLAT;
  }
  if (mode & GLM_COLOR && !materials) {
//    printf("glmDraw() warning: color render mode requested "
//	   "with no materials defined.\n");
    mode &= ~GLM_COLOR;
  }
  if (mode & GLM_MATERIAL && !materials) {
//    printf("glmDraw() warning: material render mode requested "
//	   "with no materials defined.\n");
    mode &= ~GLM_MATERIAL;
  }
  if (mode & GLM_COLOR && mode & GLM_MATERIAL) {
//    printf("glmDraw() warning: color and material render mode requested "
//	   "using only material mode\n");
    mode &= ~GLM_COLOR;
  }
  if (mode & GLM_COLOR)
    glEnable(GL_COLOR_MATERIAL);
  if (mode & GLM_MATERIAL)
    glDisable(GL_COLOR_MATERIAL);

  glPushMatrix();
  glTranslatef(position[0], position[1], position[2]);

  glBegin(GL_TRIANGLES);
  group = groups;
  while (group) {
    if (mode & GLM_MATERIAL) {
      glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, 
		   materials[group->material].ambient);
      glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, 
		   materials[group->material].diffuse);
      glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, 
		   materials[group->material].specular);
       glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 
  		  materials[group->material].shininess);
    }

    if (mode & GLM_COLOR) {
      glColor3fv(materials[group->material].diffuse);
    }

    for (i = 0; i < group->numtriangles; i++) {
      if (mode & GLM_FLAT)
	glNormal3fv(&facetnorms[3 * triangles[group->triangles[i]].findex]);
      
      if (mode & GLM_SMOOTH)
	glNormal3fv(&normals[3 * triangles[group->triangles[i]].nindices[0]]);
      if (mode & GLM_TEXTURE)
	glTexCoord2fv(&texcoords[2*triangles[group->triangles[i]].tindices[0]]);
      glVertex3fv(&vertices[3 * triangles[group->triangles[i]].vindices[0]]);
#if 0
      printf("%f %f %f\n", 
	     vertices[3 * triangles[group->triangles[i]].vindices[0] + X],
	     vertices[3 * triangles[group->triangles[i]].vindices[0] + Y],
	     vertices[3 * triangles[group->triangles[i]].vindices[0] + Z]);
#endif
      
      if (mode & GLM_SMOOTH)
	glNormal3fv(&normals[3 * triangles[group->triangles[i]].nindices[1]]);
      if (mode & GLM_TEXTURE)
	glTexCoord2fv(&texcoords[2*triangles[group->triangles[i]].tindices[1]]);
      glVertex3fv(&vertices[3 * triangles[group->triangles[i]].vindices[1]]);
#if 0
      printf("%f %f %f\n", 
	     vertices[3 * triangles[group->triangles[i]].vindices[1] + X],
	     vertices[3 * triangles[group->triangles[i]].vindices[1] + Y],
	     vertices[3 * triangles[group->triangles[i]].vindices[1] + Z]);
#endif
      
      if (mode & GLM_SMOOTH)
	glNormal3fv(&normals[3 * triangles[group->triangles[i]].nindices[2]]);
      if (mode & GLM_TEXTURE)
	glTexCoord2fv(&texcoords[2*triangles[group->triangles[i]].tindices[2]]);
      glVertex3fv(&vertices[3 * triangles[group->triangles[i]].vindices[2]]);
#if 0
      printf("%f %f %f\n", 
	     vertices[3 * triangles[group->triangles[i]].vindices[2] + X],
	     vertices[3 * triangles[group->triangles[i]].vindices[2] + Y],
	     vertices[3 * triangles[group->triangles[i]].vindices[2] + Z]);
#endif
    }
    
    group = group->next;
  }
  glEnd();

  glPopMatrix();
}

/* Generates and returns a display list for the model using specified mode.
 *
 * mode     - a bitwise OR of values describing what is to be rendered.
 *            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.  
 */
GLuint GLMmodel::compile (GLuint mode)
{
  GLuint list;

  list = glGenLists(1);
  glNewList(list, GL_COMPILE);
  draw(mode);
  glEndList();

  return list;
}

/* Eliminate (weld) vectors that are within an epsilon of each other.
 *
 * epsilon    - maximum difference between vertices
 */
GLvoid GLMmodel::weld (GLfloat epsilon)
{
  GLfloat* vectors;
  GLfloat* copies;
  GLuint   numvectors;
  GLuint   i;

  /* vertices */
  numvectors = numvertices;
  vectors    = vertices;
  copies = _glmWeldVectors(vectors, &numvectors, epsilon);

  printf("glmWeld(): %d redundant vertices.\n", 
	 numvertices - numvectors - 1);

  for (i = 0; i < numtriangles; i++) {
    triangles[i].vindices[0] = (GLuint)vectors[3 * triangles[i].vindices[0] + 0];
    triangles[i].vindices[1] = (GLuint)vectors[3 * triangles[i].vindices[1] + 0];
    triangles[i].vindices[2] = (GLuint)vectors[3 * triangles[i].vindices[2] + 0];
  }

  /* free space for old vertices */
  free(vectors);

  /* allocate space for the new vertices */
  numvertices = numvectors;
  vertices = (GLfloat*)malloc(sizeof(GLfloat) * 
				     3 * (numvertices + 1));

  /* copy the optimized vertices into the actual vertex list */
  for (i = 1; i <= numvertices; i++) {
    vertices[3 * i + 0] = copies[3 * i + 0];
    vertices[3 * i + 1] = copies[3 * i + 1];
    vertices[3 * i + 2] = copies[3 * i + 2];
  }

  free(copies);
}


#if 0
  /* normals */
  if (numnormals) {
  numvectors = numnormals;
  vectors    = normals;
  copies = _glmOptimizeVectors(vectors, &numvectors);

  printf("glmOptimize(): %d redundant normals.\n", 
	 numnormals - numvectors);

  for (i = 0; i < numtriangles; i++) {
    triangles[i].nindices[0] = (GLuint)vectors[3 * triangles[i].nindices[0] + 0];
    triangles[i].nindices[1] = (GLuint)vectors[3 * triangles[i].nindices[1] + 0];
    triangles[i].nindices[2] = (GLuint)vectors[3 * triangles[i].nindices[2] + 0];
  }

  /* free space for old normals */
  free(vectors);

  /* allocate space for the new normals */
  numnormals = numvectors;
  normals = (GLfloat*)malloc(sizeof(GLfloat) * 
				    3 * (numnormals + 1));

  /* copy the optimized vertices into the actual vertex list */
  for (i = 1; i <= numnormals; i++) {
    normals[3 * i + 0] = copies[3 * i + 0];
    normals[3 * i + 1] = copies[3 * i + 1];
    normals[3 * i + 2] = copies[3 * i + 2];
  }

  free(copies);
  }

  /* texcoords */
  if (numtexcoords) {
  numvectors = numtexcoords;
  vectors    = texcoords;
  copies = _glmOptimizeVectors(vectors, &numvectors);

  printf("glmOptimize(): %d redundant texcoords.\n", 
	 numtexcoords - numvectors);

  for (i = 0; i < numtriangles; i++) {
    for (j = 0; j < 3; j++) {
      triangles[i].tindices[j] = (GLuint)vectors[3 * triangles[i].tindices[j] + 0];
    }
  }

  /* free space for old texcoords */
  free(vectors);

  /* allocate space for the new texcoords */
  numtexcoords = numvectors;
  texcoords = (GLfloat*)malloc(sizeof(GLfloat) * 
				      2 * (numtexcoords + 1));

  /* copy the optimized vertices into the actual vertex list */
  for (i = 1; i <= numtexcoords; i++) {
    texcoords[2 * i + 0] = copies[2 * i + 0];
    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 <= numvertices; i++) {
    for (j = 0; j < numtriangles; i++) {
      if (T(j).vindices[0] == i || 
	  T(j).vindices[1] == i || 
	  T(j).vindices[1] == i)
	break;
    }
  }
#endif
