glm.c

OpenGL的大海量资料收集

    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\n");
    fprintf(file, "#  Nate Robins\n");
    fprintf(file, "#  [e-mail]\n");
    fprintf(file, "#  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 / 128.0 * 1000.0);
        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 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 */
    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);
#if SINGLE_STRING_GROUP_NAMES
                sscanf(buf, "%s", buf);
#else
                buf[strlen(buf)-1] = '\0';  /* nuke '\n' */
#endif
                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;
        }
  }
  
  /* 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;
  }
}

/* glmSecondPass: second pass at a Wavefront OBJ file that gets all
 * the data.
 *
 * model - properly initialized GLMmodel structure
 * file  - (fopen'd) file descriptor 
 */
static 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 */
    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 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 + 0], 
                    &vertices[3 * numvertices + 1], 
                    &vertices[3 * numvertices + 2]);
                numvertices++;
                break;
            case 'n':           /* normal */
                fscanf(file, "%f %f %f", 
                    &normals[3 * numnormals + 0],
                    &normals[3 * numnormals + 1], 
                    &normals[3 * numnormals + 2]);
                numnormals++;
                break;
            case 't':           /* texcoord */
                fscanf(file, "%f %f", 
                    &texcoords[2 * numtexcoords + 0],
                    &texcoords[2 * numtexcoords + 1]);
                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);
#if SINGLE_STRING_GROUP_NAMES
                sscanf(buf, "%s", buf);
#else
                buf[strlen(buf)-1] = '\0';  /* nuke '\n' */
#endif
                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 */