[opengl]opengl加载maya的obj模型并显示

obj文件的理解请参考：http://foolog.net/?p=941

 

要注意一点，obj文件中面的保存，有的是按照三角形(也就是只有三个点)，有的是按照空间四边形保存(包含四个点)，这里是按照四个点来的，注释中已经给出。

 

#ifndef GLUT_DISABLE_ATEXIT_HACK
#define GLUT_DISABLE_ATEXIT_HACK
#endif #define GLEW_STATIC
#include <GL/glew.h>
#include <GL/wglew.h>
#include <GL/freeglut.h>
#include <vector>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp> //for matrices
#include <glm/gtc/type_ptr.hpp>
//undefine if u want to use the default bending constraint of pbd
#include<sstream>
#include <fstream>
#include<iostream>
using namespace std;

GLfloat rtx = 0.0f, rty = 0.0f, rtz = 0.0;
GLfloat step = 0.1;
//float exp1 = 1e-3;
const int GRID_SIZE = 10;
GLint viewport[4];
GLdouble PP[16];

int v_num; //记录点的数量
int vn_num;//记录法线的数量
int vt_num;//
int f_num; //记录面的数量
GLfloat **vArr; //存放点的二维数组
GLfloat **vnArr;//存放法线的二维数组
int **fvArr; //存放面顶点的二维数组
int **fnArr; //存放面法线的二维数组

int readfile(string addrstr) //将文件内容读到数组中去
{
    int i;
    string s1;
    float f2,f3,f4;
    vArr=new GLfloat*[v_num];
    for (i=0; i<v_num; i++)
    {
        vArr[i]=new GLfloat[3];
    }
    vnArr=new GLfloat*[vn_num];
    for (i=0; i<vn_num; i++)
    {
        vnArr[i]=new GLfloat[3];
    }
    fvArr=new int*[f_num];
    fnArr=new int*[f_num];
    for (i=0; i<f_num; i++)
    {
        fvArr[i]=new int[4];
        fnArr[i]=new int[3];
    }
    ifstream infile(addrstr.c_str());
    string sline;//每一行
    int ii=0,jj=0,kk=0;

    while(getline(infile,sline))
    {
        if(sline[0]=='v')
        {
            if(sline[1]=='n')//vn
            {
                istringstream sin(sline);
                sin>>s1>>f2>>f3>>f4;
                vnArr[ii][0]=f2;
                vnArr[ii][1]=f3;
                vnArr[ii][2]=f4;
                ii++;
            }
            else if(sline[1] == 't'){}
            else//v
            {
                istringstream sin(sline);
                sin>>s1>>f2>>f3>>f4;
                vArr[jj][0]=f2;
                vArr[jj][1]=f3;
                vArr[jj][2]=f4;
                jj++;
            }
        }
        if (sline[0]=='f') //读取面
        {
            istringstream in(sline);
            GLfloat a;

            in>>s1;//去掉前缀f
            int i,k;
//点数改这里
            for(i=0; i<4; i++)
            {
                in>>s1;
//                cout<<s1<<endl;
                printf("%s\n",s1.c_str());
                //取得顶点索引和法线索引
                a=0;
                for(k=0; s1[k]!='/'; k++)
                {
                    a=a*10+(s1[k]-48);
                }
                fvArr[kk][i]=a;

                a=0;
                for(k=k+2; s1[k]; k++)
                {
                    a=a*10+(s1[k]-48);;
                }
                fnArr[kk][i]=a;
            }
            kk++;
        }
    }
    return 0;
}

void getLineNum(string addrstr){   //获取点数以及面数
//    cout<<addrstr.c_str()<<endl;
    v_num = vn_num = f_num = vt_num = 0;
    ifstream infile(addrstr.c_str());
    string sline;//每一行
    while(getline(infile, sline)){
//        cout<<sline<<endl;
            printf("%s\n",sline.c_str());
        if(sline[0]=='v'){
            if(sline[1] == 'n'){
                vn_num ++;
            }else if(sline[1] =='t'){ //vt
                vt_num ++;
            }else{
                v_num ++;
            }
        }else{
            if(sline[0] == 'f'){
                f_num ++;
            }
        }
    }
}

string s1;
GLfloat f2,f3,f4;

void DrawGrid()
{
	glBegin(GL_LINES);
	glColor3f(0.5f, 0.5f, 0.5f);
	for(int i=-GRID_SIZE;i<=GRID_SIZE;i++)
	{
		glVertex3f((float)i,0,(float)-GRID_SIZE);
		glVertex3f((float)i,0,(float)GRID_SIZE);

		glVertex3f((float)-GRID_SIZE,0,(float)i);
		glVertex3f((float)GRID_SIZE,0,(float)i);
	}
	glEnd();
}

void draw(void)
{
    cout<<f_num;
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glTranslatef(0,0,-10);
    glRotatef(15,1,0,0);
    DrawGrid();

    glBegin(GL_LINES);
    glColor3f(1, 1, 1);
    for(int i = 0; i < f_num; i++){
        int a0,a1,a2,a3;
        a0 = fvArr[i][0]-1;
        a1 = fvArr[i][1]-1;
        a2 = fvArr[i][2]-1;
        //点数改这里
        a3 = fvArr[i][3]-1;
            glVertex3f(vArr[a0][0],vArr[a0][1],vArr[a0][2]);
            glVertex3f(vArr[a1][0],vArr[a1][1],vArr[a1][2]);
            cout<<vArr[a0][0]<<" line "<<vArr[a1][0]<<endl;
            glVertex3f(vArr[a1][0],vArr[a1][1],vArr[a1][2]);
            glVertex3f(vArr[a2][0],vArr[a2][1],vArr[a2][2]);
            cout<<vArr[a1][0]<<" line "<<vArr[a2][0]<<endl;
            glVertex3f(vArr[a2][0],vArr[a2][1],vArr[a2][2]);
            //点数改这里
            glVertex3f(vArr[a3][0],vArr[a3][1],vArr[a3][2]);
            glVertex3f(vArr[a3][0],vArr[a3][1],vArr[a3][2]);
            cout<<vArr[a2][0]<<" line "<<vArr[a0][0]<<endl;
            glVertex3f(vArr[a0][0],vArr[a0][1],vArr[a0][2]);

    }
    glEnd();
    glutSwapBuffers();
}

void OnReshape(int nw, int nh) {
    glViewport(0,0,nw, nh);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60, (GLfloat)nw / (GLfloat)nh, 1.f, 100.0f);

    glGetIntegerv(GL_VIEWPORT, viewport);
    glGetDoublev(GL_PROJECTION_MATRIX, PP);

    glMatrixMode(GL_MODELVIEW);
}
//float step = 0.001;

int main(int argc, char * argv[])
{
    getLineNum("yifu.obj");
    readfile("yifu.obj");
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
    glutInitWindowPosition(100, 100);
    glutInitWindowSize(1024, 1024);
    glutCreateWindow("Hello OpenGL");
//    init();
    glutDisplayFunc(draw);
//    glutIdleFunc(draw); //指定程序空闲时调用函数
    glutReshapeFunc(OnReshape); //指定窗口形状变化时的回调函数
    glEnable(GL_DEPTH_TEST);

    glutMainLoop();
    return 0;
}