opengl 读取与显示obj文件

/* * 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> using namespace std; #include <stdio.h> #include <string.h> #include <stdlib.h> #include <assert.h> #include "glm.h" /* 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 */ /* global variables */ /* GLubyte *_teximage_new; static int _teximageWidth_new = 1, _teximageHeight_new = 1; */ #define MAX_TEXTURES 100 static GLuint textureArray[MAX_TEXTURES] = {0}; /* typedefs */ /* _GLMnode: general purpose node */ typedef struct _GLMnode { GLuint index; GLboolean 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 = (char*) malloc(strlen(string) + 1); if (copy == NULL) return NULL; strcpy(copy, string); return copy; } /* 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; } /* _glmFindGroup: Find a group in the model */ 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 */ 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 */ 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; } /* _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; } /* _glmReadBMP: read a BMP texture image file * * filename - filename of the BMP texture * * return * whether the BMP is read correctly */ /* int _glmReadBMP(GLuint textureArray[], char* filename, int textureID) { // Read the BMP int h = 0; int w = 0; GLubyte* _teximage = ReadBitmapRGB( STLstring2LPCTSTC( string(filename) ), w, h ); if ( !_teximage ) { printf("Cannot open the BMP texture!!\n"); return 0; } static int _teximageWidth=w; static int _teximageHeight=h; glGenTextures(1, &textureArray[textureID]); glPixelStorei (GL_UNPACK_ALIGNMENT, 1); glBindTexture(GL_TEXTURE_2D, textureArray[textureID]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); gluBuild2DMipmaps(GL_TEXTURE_2D, 3, w, h, GL_BGR, GL_UNSIGNED_BYTE, (GLvoid*)_teximage); printf("texture %d : %s is loaded\n", textureArray[textureID], filename); // delete [] _teximage; return 1; }*/ /* _glmReadPPM: read a PPM texture image file * * filename - filename of the PPM texture * * return: * whether the PPM is read correctly */ int _glmReadPPM(GLuint textureArray[], char* filename, int textureID) { int h, w, i; //int no_read; char buf[200], temp[80]; FILE *fp; static int _teximageWidth, _teximageHeight; GLubyte *_teximage; if ((fp = fopen(filename, "r"))==NULL) { printf("File cannot open!!\n"); return 0; /*exit(1);*/ } else { fscan