OpenGL 小游戏 贪吃蛇1(2D)

#include "stdafx.h"

#include <GL/glut.h> #include <stdlib.h>

#pragma comment(linker, "/subsystem:"windows" /entry:"mainCRTStartup"")

#include<vector>
#include<cmath>
using namespace std;
vector<int> x;
vector<int> y;
int point_x, point_y;
int direction = GLUT_KEY_RIGHT;
int level = 150;

void restart()
{
 x.clear();
 y.clear();
 int i;
 for (i = 0; i < 30; i++)
 {
  x.push_back(30 - i);
  y.push_back(75);
 }
 direction = GLUT_KEY_RIGHT;
}

void menu(int input)
{
 level = input;
 glutPostRedisplay();
}

double random(double start, double end)
{
 return start + (end - start)*rand() / (RAND_MAX + 1.0);
}

void createpoint()
{
 int i;
 bool state = true;
 while (1)
 {
  point_x = random(0, 200);
  point_y = random(0, 150);
  for (i = 0; i < x.size(); i++)
  {
   if ((x[i] == point_x) && (y[i] == point_y))
   {
    state = false;
    break;
   }
  }
  if (state == true)
   break;
 }
}

void move()
{
 int i;
 for (i = x.size() - 1; i > 0; i--)
 {
  x[i] = x[i - 1];
  y[i] = y[i - 1];
 }
}

void special(int key, int x, int y)
{
 if ((key != direction) && (abs(key - direction) != 2))
  direction = key;
}

void init(void)
{
 glClearColor(0.0, 0.0, 0.0, 0.0);
 glMatrixMode(GL_PROJECTION);
 gluOrtho2D(0.0, 200.0, 0.0, 150.0);
}

void display(void)
{
 int i;
 if ((x[0] < 0) || (x[0] > 200) || (y[0] < 0) || (y[0] > 150))
  restart();
 for (i = 1; i < x.size(); i++)
 {
  if ((x[0] == x[i]) && (y[0] == y[i]))
  {
   restart();
   break;
  }
 }
 glClear(GL_COLOR_BUFFER_BIT);
 glColor3f(1.0, 1.0, 0.0);
 glPointSize(5);
 for (i = 0; i < x.size(); i++)
 {
  glBegin(GL_POINTS);
  glVertex2i(x[i], y[i]);
  glEnd();
 }
 if ((x[0] == point_x) && (y[0] == point_y))
 {
  x.push_back(x[0]);
  y.push_back(y[0]);
  createpoint();
 }
 glBegin(GL_POINTS);
 glVertex2i(point_x, point_y);
 glEnd();
 glFlush();
}

void timer(int i) {

 move();  switch (direction)  

{  

case GLUT_KEY_RIGHT: ::x[0]++; break;  

case GLUT_KEY_UP: ::y[0]++; break;

 case GLUT_KEY_LEFT: ::x[0]--; break;

 case GLUT_KEY_DOWN: ::y[0]--; break;

 }  

glutTimerFunc(level, timer, 1);

 glutPostRedisplay();

}

int main(int argc, char** argv)
{
 int i;
 for (i = 0; i < 30; i++)
 {
  x.push_back(30 - i);
  y.push_back(75);
 }
 glutInit(&argc, argv);
 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
 glutInitWindowPosition(50, 100);
 glutInitWindowSize(400, 300);
 glutCreateWindow("贪吃蛇");
 init();
 glutCreateMenu(menu);
 glutAddMenuEntry("低级", 150);
 glutAddMenuEntry("中级", 100);
 glutAddMenuEntry("高级", 50);
 glutAttachMenu(GLUT_RIGHT_BUTTON);
 createpoint();
 glutDisplayFunc(display);
 glutSpecialFunc(special);
 glutTimerFunc(level, timer, 1);
 glutMainLoop();
}