//This example program is created by thecplusplusuy for demonstration purposes. It's a simple Wavefront (.obj) loader:
//http://www.youtube.com/user/thecplusplusguy
//Free source, modify if you want, LGPL licence (I guess), I would be happy, if you would not delete the link
//so other people can see the tutorial
//compile under Linux:
//g++ objloader.cpp -lSDL -lGL -lGLU
//under Windows, set the libraries as I showed you in the tutorial 0
#include <windows.h>
#include <SDL/SDL.h> //check your include folder, it may be just SDL.h
#include <GL/gl.h>
#include <GL/glu.h>
#include <cstdlib>
#include <vector>
#include <string>
#include <algorithm>
#include <fstream>
#include <cstdio>
#include <iostream>
struct coordinate{
float x,y,z;
coordinate(float a,float b,float c) : x(a),y(b),z(c) {};
};
//for faces, it can contain triangles and quads as well, the four variable contain which is that
struct face{
int facenum;
bool four;
int faces[4];
face(int facen,int f1,int f2,int f3) : facenum(facen){ //constructor for triangle
faces[0]=f1;
faces[1]=f2;
faces[2]=f3;
four=false;
}
face(int facen,int f1,int f2,int f3,int f4) : facenum(facen){ //overloaded constructor for quad
faces[0]=f1;
faces[1]=f2;
faces[2]=f3;
faces[3]=f4;
four=true;
}
};
float angle=0.0; //we rotate or object with angle degrees
int loadObject(const char* filename)
{
std::vector<std::string*> coord; //read every single line of the obj file as a string
std::vector<coordinate*> vertex;
std::vector<face*> faces;
std::vector<coordinate*> normals; //normal vectors for every face
std::ifstream in(filename); //open the .obj file
if(!in.is_open()) //if not opened, exit with -1
{
std::cout << "Nor oepened" << std::endl;
return -1;
}
char buf[256];
//read in every line to coord
while(!in.eof())
{
in.getline(buf,256);
coord.push_back(new std::string(buf));
}
//go through all of the elements of coord, and decide what kind of element is that
for(int i=0;i<coord.size();i++)
{
if(coord[i]->c_str()[0]=='#') //if it is a comment (the first character is #)
continue; //we don't care about that
else if(coord[i]->c_str()[0]=='v' && coord[i]->c_str()[1]==' ') //if vector
{
float tmpx,tmpy,tmpz;
sscanf(coord[i]->c_str(),"v %f %f %f",&tmpx,&tmpy,&tmpz); //read in the 3 float coordinate to tmpx,tmpy,tmpz
vertex.push_back(new coordinate(tmpx,tmpy,tmpz)); //and then add it to the end of our vertex list
}else if(coord[i]->c_str()[0]=='v' && coord[i]->c_str()[1]=='n') //if normal vector
{
float tmpx,tmpy,tmpz; //do the same thing
sscanf(coord[i]->c_str(),"vn %f %f %f",&tmpx,&tmpy,&tmpz);
normals.push_back(new coordinate(tmpx,tmpy,tmpz));
}else if(coord[i]->c_str()[0]=='f') //if face
{
int a,b,c,d,e;
if(count(coord[i]->begin(),coord[i]->end(),' ')==3) //if it is a triangle (it has 3 space in it)
{
sscanf(coord[i]->c_str(),"f %d//%d %d//%d %d//%d",&a,&b,&c,&b,&d,&b);
faces.push_back(new face(b,a,c,d)); //read in, and add to the end of the face list
}else{
sscanf(coord[i]->c_str(),"f %d//%d %d//%d %d//%d %d//%d",&a,&b,&c,&b,&d,&b,&e,&b);
faces.push_back(new face(b,a,c,d,e)); //do the same, except we call another constructor, and we use different pattern
}
}
}
//raw
int num; //the id for the list
num=glGenLists(1); //generate a uniqe
glNewList(num,GL_COMPILE); //and create it
for(int i=0;i<faces.size();i++)
{
if(faces[i]->four) //if it's a quad draw a quad
{
glBegin(GL_QUADS);
//basically all I do here, is use the facenum (so the number of the face) as an index for the normal, so the 1st normal owe to the first face
//I subtract 1 because the index start from 0 in C++
glNormal3f(normals[faces[i]->facenum-1]->x,normals[faces[i]->facenum-1]->y,normals[faces[i]->facenum-1]->z);
//draw the faces
glVertex3f(vertex[faces[i]->faces[0]-1]->x,vertex[faces[i]->faces[0]-1]->y,vertex[faces[i]->faces[0]-1]->z);
glVertex3f(vertex[faces[i]->faces[1]-1]->x,vertex[faces[i]->faces[1]-1]->y,vertex[faces[i]->faces[1]-1]->z);
glVertex3f(vertex[faces[i]->faces[2]-1]->x,vertex[faces[i]->faces[2]-1]->y,vertex[faces[i]->faces[2]-1]->z);
glVertex3f(vertex[faces[i]->faces[3]-1]->x,vertex[faces[i]->faces[3]-1]->y,vertex[faces[i]->faces[3]-1]->z);
glEnd();
}else{
glBegin(GL_TRIANGLES);
glNormal3f(normals[faces[i]->facenum-1]->x,normals[faces[i]->facenum-1]->y,normals[faces[i]->facenum-1]->z);
glVertex3f(vertex[faces[i]->faces[0]-1]->x,vertex[faces[i]->faces[0]-1]->y,vertex[faces[i]->faces[0]-1]->z);
glVertex3f(vertex[faces[i]->faces[1]-1]->x,vertex[faces[i]->faces[1]-1]->y,vertex[faces[i]->faces[1]-1]->z);
glVertex3f(vertex[faces[i]->faces[2]-1]->x,vertex[faces[i]->faces[2]-1]->y,vertex[faces[i]->faces[2]-1]->z);
glEnd();
}
}
glEndList();
//delete everything to avoid memory leaks
for(int i=0;i<coord.size();i++)
delete coord[i];
for(int i=0;i<faces.size();i++)
delete faces[i];
for(int i=0;i<normals.size();i++)
delete normals[i];
for(int i=0;i<vertex.size();i++)
delete vertex[i];
return num; //return with the id
}
int cube;
void init()
{
glClearColor(0.0,0.0,0.0,1.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45,640.0/480.0,1.0,500.0);
glMatrixMode(GL_MODELVIEW);
glEnable(GL_DEPTH_TEST);
cube=loadObject("test.obj"); //load the test.obj file
glEnable(GL_LIGHTING); //we enable lighting, to make the 3D object to 3D
glEnable(GL_LIGHT0);
float col[]={1.0,1.0,1.0,1.0}; //light color is white
glLightfv(GL_LIGHT0,GL_DIFFUSE,col);
}
void display()
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
float pos[]={-1.0,1.0,-2.0,1.0}; //set the position
glLightfv(GL_LIGHT0,GL_POSITION,pos);
glTranslatef(0.0,0.0,-5.0);
glRotatef(angle,0.0,0.0,1.0);
glCallList(cube); //draw the 3D mesh
}
int main(int argc,char** argv)
{
SDL_Init(SDL_INIT_EVERYTHING);
SDL_Surface* screen=SDL_SetVideoMode(640,480,32,SDL_SWSURFACE|SDL_OPENGL);
bool running=true;
Uint32 start;
SDL_Event event;
init();
while(running)
{
start=SDL_GetTicks();
while(SDL_PollEvent(&event))
{
switch(event.type)
{
case SDL_QUIT:
running=false;
break;
}
}
display();
SDL_GL_SwapBuffers();
angle+=0.5;
if(angle>360)
angle-=360;
if(1000/30>(SDL_GetTicks()-start))
SDL_Delay(1000/30-(SDL_GetTicks()-start));
}
SDL_Quit();
return 0;
}
