Linux 下编译c++ opengl的小程序

Question

完整的代码如下

 #include <GL/glut.h>
#include <cmath>
#include <utility>
#include <vector>

using std::vector;
using std::pair;

vector<pair<int, int> > my_points(4);
vector<pair<int, int> > current_point(4);

my_points.push_back(make_pair(0, 0));
my_points.push_back(make_pair(50, 0));
my_points.push_back(make_pair(100, 0));
my_points.push_back(make_pair(150, 0));
current_point = my_points;
struct Degree {
  Degree(int a, int b, int c) {
    first = a;
    second = b;
    third = c;
  }
  int first;
  int second;
  int third;
};

map<int, Degree> position(4);

position[0] = position(0, 0, 0);
position[1] = position(90, 0, 0);
position[2] = position(45, -45, 45);
position[3] = position(-90, 0, 0);
void init();
void display();
void draw_axis();
void reshape(int w, int h);
void draw_frame(void);
void translate(Degree& posi);
void keyboard(unsigned char key, int x, int y);
float matrix_rotat[3][3] = {  // 旋转矩阵
  {0.0, -1.0, 0.0},
  {1.0, 0.0, 0.0},
  {0.0, 0.0, 1.0}
};

int main(int argc, char* argv[]) {
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
  glutInitWindowSize(500, 500);
  glutInitWindowPosition(0, 0);
  glutCreateWindow(argv[0]);
  init();
  glutDisplayFunc(display);
  glutReshapeFunc(reshape);
    glutKeyboardFunc(keyboard);
  glutMainLoop();
}
void init(void) {
  glClearColor(0.1, 0.2, 0.4, 0.0);
  glShadeModel (GL_SMOOTH);
}
void reshape (int w, int h) {
  glViewport (0, 0, (GLsizei) w, (GLsizei) h);
  glMatrixMode (GL_PROJECTION);
  glLoadIdentity ();
  if (w <= h)
    gluOrtho2D(-200.0, 250.0, -100.0*(GLfloat)h/(GLfloat)w,
                200.0*(GLfloat)h/(GLfloat)w);
  else
    gluOrtho2D(-200.0*(GLfloat)w/(GLfloat)h,
                250.0*(GLfloat)w/(GLfloat)h, -50.0, 200.0);
  glColor3f(1, 0.5, 0.4);
  glMatrixMode(GL_MODELVIEW);
}
void display() {
  glClear(GL_COLOR_BUFFER_BIT);
  glColor3f(1, 0.5, 0.4);
  draw_axis();
  glLoadIdentity();
  //  draw_frame();
  glFlush ();
}
void draw_frame() {
  glShadeModel(GL_SMOOTH);
  glBegin (GL_LINE_STRIP);//draw frame
  for (int i = 0; i < 4; i++) {
    glColor3f(1.0, 0.0, 0.0);
    glVertex2f(current_point[i].first, current_point[i].second);
  }
  glEnd();
}
void draw_axis() {
  // draw coordinate axis
  glBegin(GL_LINES);
  glColor3f(1.0, 1.0, 1.0);  // x axis
  glVertex2f(-500.0, 40.0);
  glVertex2f(500.0, 40.0);
  glColor3f(1.0, 1.0, 1.0);  // y axis
  glVertex2f(0.0, 400.0);  
  glVertex2f(0.0, -400.0);
  glEnd();
  // draw scale
  glBegin(GL_LINES);
  for (int i = -50; i <= 50; i++) {  // x axis
    glColor3f(1.0, 1.0, 1.0);
    glVertex2f(10.0*i, 40.0);
    glVertex2f(10.0*i, 44.0);
  }
  for (int i = -40; i <= 40; i++) {  // y axis
    glColor3f(1.0, 1.0, 1.0);
    glVertex2f(0.0, 10.0*i);
    glVertex2f(4.0, 10.0*i);
  }
  glEnd();
}
void translate(Degree& posi) {
  /////   changed into matrix later
  vector<vector<double> > trans_matrix(2);
  for (int i = 0; i < 2; i++)
    for (int j = 0; j < 2; j++)
      trans_matrix[i].push_back(0);
  double num1[] = {cos(posi.first), -sin(posi.first)};
  //initialize the transform matrix
  for (int i = 0; i < 2; i++)
    trans_matrix[0][i] = num1[i];
  double num2 = {sin(posi.first), cos(posi.first)};
  for (int i = 0; i < 2; i++)
    trans_matrix[1][i] = num2[i];
  current_point[0].first = current_point[0].second = 0;
  for (int i = 0; i < 2; i++) {
    current_point[0].first += (trans_matrix[i][0]*my_points[0].first
                         + trans_matrix[i][1]*my_points[1].second);
    current_point[0].second += (trans_matrix[i][0]*my_points[0].first
                          + trans_matrix[i][1]*my_points[0].second);
  }
  glBegin (GL_LINES);//draw frame
  glColor3f(1.0, 0.0, 0.0);
  glVertex2f(0, 0);
  glVertex2f(current_point[0].first, current_point[0].second);
  glEnd();
}
/*
void rotate_frame(void) {
  float (*tmp_frame)[7] = new float[3][7];
  memset(tmp_frame, 0.0, sizeof(tmp_frame));
  frame = tmp_frame;
  glLoadIdentity();
  draw_frame(); // draw the frame after transformation
  glFlush();
}
*/
void keyboard(unsigned char key, int x, int y) {
  switch (key) {
    case 'Q':
    case 'q':
      translate(position[0]);
      break;
    case 'W':
    case 'w':
      translate(position[1]);
      break;
    case 'E':
    case 'e':
      translate(position[2]);
      break;
    case 'R':
    case 'r':
      translate(position[3]);
      break;
  }
}

编译器报错＞
arm.cpp:12:1: error: ‘my_points’ does not name a type
my_points.push_back(make_pair(0, 0));
^
arm.cpp:13:1: error: ‘my_points’ does not name a type
my_points.push_back(make_pair(50, 0));
^
arm.cpp:14:1: error: ‘my_points’ does not name a type
my_points.push_back(make_pair(100, 0));
^
arm.cpp:15:1: error: ‘my_points’ does not name a type
my_points.push_back(make_pair(150, 0));
^
arm.cpp:16:1: error: ‘current_point’ does not name a type
current_point = my_points;
^
arm.cpp:28:1: error: ‘map’ does not name a type
map position(4);
^
arm.cpp:30:1: error: ‘position’ does not name a type
position[0] = position(0, 0, 0);
^
arm.cpp:31:1: error: ‘position’ does not name a type
position[1] = position(90, 0, 0);
^
arm.cpp:32:1: error: ‘position’ does not name a type
position[2] = position(45, -45, 45);
^
arm.cpp:33:1: error: ‘position’ does not name a type
position[3] = position(-90, 0, 0);
^
不知道这里是什么问题，STL为什么不能用，是编译选项的问题吗？
编译命令g++ arm.cpp -o arm -lGL -lglut -lGLU

Answer 1

不用麻烦各位了，找到问题了
是因为　vector.push_back()不能在非函数内部使用
要把这些全局变量的初始话放到一个函数里面
void init_value() {
my_points.push_back(make_pair(0, 0));
my_points.push_back(make_pair(50, 0));
my_points.push_back(make_pair(100, 0));
my_points.push_back(make_pair(150, 0));
current_point = my_points;
position.push_back(Degree(0, 0, 0));
position.push_back(Degree(90, 0, 0));
position.push_back(Degree(45, -45, 45));
position.push_back(Degree(-90, 0, 0));
}