c++ - glDrawElements() draw my .obj models wrong -

i'm having problem "gldrawelements" function in opengl. when drawing model function i'm seeing artifacts:

 

i didn't add light or texture.

i wrote class c++:

//the obj-catcher.h //just ignore chinese in code.... #include <gl\glut.h> #include <gl\glaux.h> #include"stdlib.h" #include"string.h" #include"cstdio" #include"math.h" #include"time.h" #define max_line_length 1024 //å­ç¬¦ä¸²å¤å¶æ大é¿åº¦  aux_rgbimagerec *loadbmp(char *filename)                // loads bitmap image {     file *file=null;                                    // file handle      if (!filename)                                      // make sure filename given     {         return null;                                    // if not return null     }     file=fopen(filename,"r");                           // check see if file exists     if (file)                                           // file exist?     {         fclose(file);                                   // close handle         return auxdibimageload(filename);               // load bitmap , return pointer     }      return null;                                        // if load failed return null } int loadgltextures(int num,char *dir,unsigned int * texture)                    // load bitmaps , convert textures å è½½çå¾ååªè½æ¯2çå¹ {     int status=false;                                   // status indicator     aux_rgbimagerec *textureimage[1];                   // create storage space texture     memset(textureimage,0,sizeof(textureimage));        // set pointer null     // load bitmap, check errors, if bitmap's not found quit     if (textureimage[0]=loadbmp(dir))     {         status=true;                                    // set status true         glgentextures(1, &texture[num]);                // create texture         // typical texture generation using data bitmap         glbindtexture(gl_texture_2d, texture[num]);         glteximage2d(gl_texture_2d, 0, 3, textureimage[0]->sizex, textureimage[0]->sizey, 0, gl_rgb, gl_unsigned_byte, textureimage[0]->data);         gltexparameteri(gl_texture_2d,gl_texture_min_filter,gl_linear);         gltexparameteri(gl_texture_2d,gl_texture_mag_filter,gl_nearest);     }     if (textureimage[0])                                    // if texture exists     {         if (textureimage[0]->data)                          // if texture image exists             free(textureimage[0]->data);                    // free texture image memory         free(textureimage[0]);                              // free image structure     }     return status;                                      // return status } typedef struct vertex {     glfloat pos[3];//ä¾æ¬¡æ¯x,y,z }vertex; typedef struct vertexnormals {     glfloat io[3]; }vertexnormals; typedef struct texturecoords {     glfloat io[3]; }texturecoords; typedef struct vertexindex {     unsigned int vertex[3]; }vertexindex; bool fco(file *file) {     if(fclose(file)!=0)     {         perror("fclose");         exit(exit_failure);     }     return true; } bool getsurface(char *src,vertexindex &vindex)//get surface {     if(src[0]!='f'||src[1]!=' ') return false;     int i;     int result=0;     for(i=1;i==' ';i++);i++;     for(;;i++)     {         if(src[i]==' ') break;         if(src[i]=='/')             break;         else         {             result*=10;             result+=src[i]-48;         }     }     vindex.vertex[0]=result-1;     for(;;i++) if(src[i]==' ') break;     for(;i==' ';i++);i++;     result=0;     for(;;i++)     {         if(src[i]==' ') break;         if(src[i]=='/') break;         else         {             result*=10;             result+=src[i]-48;         }     }     vindex.vertex[1]=result-1;     for(;;i++) if(src[i]==' ') break;     for(;i==' ';i++);i++;     result=0;     for(;;i++)     {         if(src[i]==' '||src[i]=='\0'||src[i]=='\n') break;         if(src[i]=='/')             break;         else         {             result*=10;             result+=src[i]-48;         }     }     vindex.vertex[2]=result-1;     return true; } bool getvertex(char *src,vertex &dir)//some shit in here|add:->the shit done {      int i;     bool flag[3];     bool pc[3];     double result=0;     int db=0;     bool floa;     memset(flag,0,sizeof(flag));//æ¥åç¹åæ å®æ度å¤æ­     memset(pc,0,sizeof(pc));//æ­£è´å¤æ­     if(src[0]!='v'||src[1]!=' ')         return false;     else     {         floa=false;         for(i=1;src[i+1]==' ';i++);i++;//æ¾å°vä¹å第ä¸ä¸ªæ°æ®ä½ç½®         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') return false;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[0]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[0]) result=-result;          dir.pos[0]=result;          for(;src[i+1]==' ';i++);i++;//æ¾å°ç¬¬ä¸ä¸ªæ°æ®ä¹å第äºä¸ªæ°æ®ä½ç½®         floa=false;         db=0;         result=0;         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') return false;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[1]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[1]) result=-result;          dir.pos[1]=result;          for(;src[i+1]==' ';i++);i++;//æ¾å°ç¬¬ä¸ä¸ªæ°æ®ä¹å第äºä¸ªæ°æ®ä½ç½®         floa=false;         db=0;         result=0;         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') break;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[2]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[2]) result=-result;          dir.pos[2]=result;          return true;     } } bool getvertexnormals(char *src,vertexnormals &dir) {     int i;     bool flag[2];     bool pc[3];     double result=0;     int db=0;     bool floa;     memset(flag,0,sizeof(flag));     memset(pc,0,sizeof(pc));     if(!(src[0]=='v'&&src[1]=='n'&&src[2]==' '))     {         return false;     }     else     {         floa=false;         for(i=1;src[i+1]==' ';i++);i++;//æ¾å°vä¹å第ä¸ä¸ªæ°æ®ä½ç½®         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') return false;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[0]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[0]) result=-result;          dir.io[0]=result;          for(;src[i+1]==' ';i++);i++;//æ¾å°ç¬¬ä¸ä¸ªæ°æ®ä¹å第äºä¸ªæ°æ®ä½ç½®         floa=false;         db=0;         result=0;         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') return false;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[1]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[1]) result=-result;          dir.io[1]=result;          for(;src[i+1]==' ';i++);i++;//æ¾å°ç¬¬ä¸ä¸ªæ°æ®ä¹å第äºä¸ªæ°æ®ä½ç½®         floa=false;         db=0;         result=0;         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') break;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[2]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[2]) result=-result;          dir.io[2]=result;          return true;     } } bool gettexturecoords(char *src,texturecoords &dir) {     int i;     bool flag[2];     bool pc[3];     double result=0;     int db=0;     bool floa;     memset(flag,0,sizeof(flag));     memset(pc,0,sizeof(pc));     if(!(src[0]=='v'&&src[1]=='t'&&src[2]==' '))     {         return false;     }     else     {         floa=false;         for(i=1;src[i+1]==' ';i++);i++;//æ¾å°vä¹å第ä¸ä¸ªæ°æ®ä½ç½®         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') return false;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[0]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[0]) result=-result;          dir.io[0]=result;          for(;src[i+1]==' ';i++);i++;//æ¾å°ç¬¬ä¸ä¸ªæ°æ®ä¹å第äºä¸ªæ°æ®ä½ç½®         floa=false;         db=0;         result=0;         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') return false;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[1]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[1]) result=-result;          dir.io[1]=result;          for(;src[i+1]==' ';i++);i++;//æ¾å°ç¬¬ä¸ä¸ªæ°æ®ä¹å第äºä¸ªæ°æ®ä½ç½®         floa=false;         db=0;         result=0;         for(;;i++)         {             if(src[i]=='\n'||src[i]=='\0') break;             if(src[i]==' ')                 break;             if(src[i]=='-')                 pc[2]=true;             if(src[i]<=57&&src[i]>=48)             {                 if(!floa)                 {                     result*=10;                     result+=src[i]-48;                 }                 else                 {                     result+=(src[i]-48)*pow(10.0,--db);                 }             }             else             {                 if(src[i]=='.') floa=true;             }         }         if(pc[2]) result=-result;          dir.io[2]=result;          return true;     } } bool getdir(char * dir,char * tem) {     int i,m=strlen(tem),num=0,j;     for(i=0;i<m;i++)     {         if(dir[i]=='\\')             num++;     }     for(i=0,j=0;i<m;i++)     {         tem[i]=dir[i];         if(dir[i]=='\\')             j++;         if(j==num)             break;     }     tem[i+1]='\0';     return true; } bool getmtl(char *src,file *fp,char * dir) {     int i,m=strlen(src),n;     char  temp[100];     if(m<6) return false;     if(!(src[0]=='m'&&src[1]=='t'&&src[2]=='l'&&src[3]=='l'&&src[4]=='i'&&src[5]=='b'&&src[6]==' ')) return false;     src[m-1]='\0';     getdir(dir,temp);     n=strlen(temp);     for(i=n;i<m;i++)         temp[i]=src[i-n+7];     fp=fopen(temp,"r");     if(fp==null)     {         perror(temp);         return false;     }     else         printf("导å¥æè´¨åºæå :%s\n",temp);     return true; } class container { public:     container(char *fp)//使ç¨æ¶å¿é¡»ä¿è¯obj中æ¯è¡åªæä¸æ¡æ令     {         int t1,t2;         t1=clock();         int cur=0;         int i[8]={0,0,0,0,0,0,0,0};         int vcur=0;         int tcur=0;         mtlfnum=0;         vertexnumber=0;         trianglenumber=0;         vertexnormals=0;         texturecoords=0;         if((file=fopen(fp,"r"))==null)         {             perror(fp);             exit(1);         }         printf("第ä¸æ¬¡éåæ件é¢å¤ç中...\n");         while(fgets(buffer,max_line_length,file)!=null)         {             cur++;             if(buffer[0]=='#')                 continue;             if(buffer[0]=='m'&&buffer[1]=='t'&&buffer[2]=='l'&&buffer[3]=='l'&&buffer[4]=='i'&&buffer[5]=='b'&&buffer[6]==' ')//ç±äº&&符å·çç­è·¯æåºæ以ä¸ä¼éæ³è®¿é®åå­                 mtlfnum++;             if(buffer[0]=='v'&&buffer[1]==' ')                 vertexnumber++;             if(buffer[0]=='f')                 trianglenumber++;             if(buffer[0]=='v'&&buffer[1]=='n')                 vertexnormals++;             if(buffer[0]=='v'&&buffer[1]=='t')                 texturecoords++;         }         printf("第ä¸æ¬¡é¢å¤çå·²ç»æ\nåå¾ä¿¡æ¯:æè´¨åºæ°:%d 顶ç¹æ°ï¼%d é¢æ°:%d æ³çº¿æ°ï¼%d 纹çåæ æ°:%d\n",mtlfnum,vertexnumber,trianglenumber,vertexnormals,texturecoords);         v=new vertex [vertexnumber];         vn=new vertexnormals[vertexnormals];         vt=new texturecoords[texturecoords];         vindex=new vertexindex[trianglenumber];         mtl=new file * [mtlfnum];         fco(file);         if((file=fopen(fp,"r"))==null)         {             perror(fp);             exit(1);         }         cur=0;         printf("æ­£å¨è¯»å¥æ¨¡åæ°æ®...\n");         while(fgets(buffer,max_line_length,file)!=null)         {             cur++;             if(i[0]<=vertexnumber)                 if(getvertex(buffer,v[i[0]]))                     i[0]++;             if(i[1]<=trianglenumber)                 if(getsurface(buffer,vindex[i[1]]))                     i[1]++;             if(i[2]<=vertexnormals)                 if(getvertexnormals(buffer,vn[i[2]]))                     i[2]++;             if(i[3]<=texturecoords)                 if(gettexturecoords(buffer,vt[i[3]]))                     i[3]++;             if(i[4]<=mtlfnum)                 if(getmtl(buffer,mtl[i[4]],fp))                     i[4]++;         }         t2=clock();         printf("读å¥æ¨¡åæåï¼\nç¨æ¶%5d(ms)\n",t2-t1);     }     ~container()     {         fco(file);         if(v)         {             delete(v);             v=null;         }         if(vt)         {             delete(vt);             vt=null;         }         if(vn)         {             delete(vn);             vn=null;         }         if(mtl)         {             for(int i=0;i<mtlfnum;i++)                 fco(mtl[i]);             delete mtl;             mtl=null;         }     }     inline int get_tnum(){return trianglenumber;}     inline int get_vnum(){return vertexnumber;}     inline int get_vnnum(){return vertexnormals;}     inline int get_vtnum(){return texturecoords;}     inline vertex *             get_v() {return v;      }     inline vertexnormals*       get_vn(){return vn;     }     inline texturecoords*       get_vt(){return vt;     }     inline vertexindex*         get_vi(){return vindex; } private:     file *file;     int vertexnumber;     int trianglenumber;     int vertexnormals;     int mtlfnum;     int texturecoords;     char buffer[max_line_length];     file **mtl;     vertexindex *vindex;     vertex *v;     texturecoords *vt;     vertexnormals *vn; }; 

and

#include <gl\glut.h> #include <math.h> #include"obj-catcher.h" #include"stdlib.h" container a("models\\scar.obj"); #define gl_pi 3.1415926f #define bcull 1 #define bdepth 1 #define boutline 1 double xrot=0.0f,yrot=0.0f,x=0.0f,y=0.0f,dx=0.8f,dy=1.0f; glfloat nrange=50.0f; static glfloat aspe; unsigned int te[37]; gluint sample=1; void setuprc() {     glclearcolor(0.0f,0.0f,0.0f,1.0f);     glcolor3f(0.0f,1.0f,0.0f);     glshademodel(gl_flat);//单调着色     glenableclientstate(gl_vertex_array);     glvertexpointer(3,gl_float,0,(float *)a.get_v());     glnewlist(sample,gl_compile);         gldrawelements(gl_triangles,a.get_tnum()*3,gl_unsigned_int,a.get_vi());     glendlist(); } void changesize(glsizei w,glsizei h) {     if(h==0)         h=1;     glviewport(0,0,w,h);     glmatrixmode(gl_projection);     glloadidentity();     if(w<=h)     {         aspe=h/w;         glortho(-nrange,nrange,-nrange*h/w,nrange*h/w,-nrange,nrange);     }     else     {         aspe=w/h;         glortho(-nrange*w/h,nrange*w/h,-nrange,nrange,-nrange,nrange);     }     glmatrixmode(gl_modelview);     glloadidentity();     glutswapbuffers(); } void renderscene(void) {     glclear(gl_color_buffer_bit|gl_depth_buffer_bit);     glcolor3f(1.0,1.0,1.0);     glpushmatrix(); //  yrot++;     if(yrot>360) yrot=0;     glrotatef(xrot,1.0f,0.0f,0.0f);     glrotatef(yrot,0.0f,1.0f,0.0f);     glcalllist(sample);     glpopmatrix();     glutswapbuffers();   } void processspecialkeys(int key,int x,int y)//键位控制 {     if(key==glut_key_up)         xrot--;     if(key==glut_key_down)         xrot++;     if(key==glut_key_right)         yrot++;     if(key==glut_key_left)         yrot--;     if(key==27)         exit(1); } void timerfunction(int value) {     glutpostredisplay();     gluttimerfunc(1,timerfunction,1); } int main(int argc,char*argv[]) {     glutinit( &argc , argv );     glutinitdisplaymode(glut_double|glut_rgb);     glutinitwindowsize(400,400);     glutcreatewindow("caption");     glutreshapefunc(changesize);     glutdisplayfunc(renderscene);     glutspecialfunc(processspecialkeys);     gluttimerfunc(1,timerfunction,1);     setuprc();     glutmainloop();     return 0; } 

can give me advise solve problem?

looks either elements data or vertex data not correct or miss-aligned between them. have seen similar problems when don't specify correctly stride or offset on vertex data. post code here how setup elements , vertex arrays before calling gldrawelements.

tip: start small, example quad o cube, move complex mesh, add texturing , lighting.