glm.c

学习c++必备

}

/* 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.  
 */
GLvoid
glmWriteOBJ(GLMmodel* model, char* filename, GLuint mode)
{
  GLuint    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: [e-mail]\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);
}

/* glmDraw: Renders the model to the current OpenGL context using the
 * mode specified.
 *
 * model    - initialized GLMmodel structure
 * 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
glmDraw(GLMmodel* model, GLuint mode)
{
  GLuint i;
  GLMgroup* group;

  assert(model);
  assert(model->vertices);

  /* do a bit of warning */
  if (mode & GLM_FLAT && !model->facetnorms) {
    printf("glmDraw() warning: flat render mode requested "
	   "with no facet normals defined.\n");
    mode &= ~GLM_FLAT;
  }
  if (mode & GLM_SMOOTH && !model->normals) {
    printf("glmDraw() warning: smooth render mode requested "
	   "with no normals defined.\n");
    mode &= ~GLM_SMOOTH;
  }
  if (mode & GLM_TEXTURE && !model->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 && !model->materials) {
    printf("glmDraw() warning: color render mode requested "
	   "with no materials defined.\n");
    mode &= ~GLM_COLOR;
  }
  if (mode & GLM_MATERIAL && !model->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(model->position[0], model->position[1], model->position[2]);

  glBegin(GL_TRIANGLES);
  group = model->groups;
  while (group) {
    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);
    }

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

  glPopMatrix();
}

/* glmList: Generates and returns a display list for the model using
 * the mode specified.
 *
 * model    - initialized GLMmodel structure
 * 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
glmList(GLMmodel* model, GLuint mode)
{
  GLuint list;

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

  return list;
}

/* 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)
 *
 */
GLvoid
glmWeld(GLMmodel* model, GLfloat epsilon)
{
  GLfloat* vectors;
  GLfloat* copies;
  GLuint   numvectors;
  GLuint   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] = (GLuint)vectors[3 * T(i).vindices[0] + 0];
    T(i).vindices[1] = (GLuint)vectors[3 * T(i).vindices[1] + 0];
    T(i).vindices[2] = (GLuint)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 = (GLfloat*)malloc(sizeof(GLfloat) * 
				     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);
}


#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] = (GLuint)vectors[3 * T(i).nindices[0] + 0];
    T(i).nindices[1] = (GLuint)vectors[3 * T(i).nindices[1] + 0];
    T(i).nindices[2] = (GLuint)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 = (GLfloat*)malloc(sizeof(GLfloat) * 
				    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] = (GLuint)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 = (GLfloat*)malloc(sizeof(GLfloat) * 
				      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