编译一个OpenGL项目（C语言）

 

《交互式计算机图形学》书中附带的示例程序：polygon.c

/* polygon modeler */


#define MAX_POLYGONS 8

#define MAX_VERTICES 10


typedef int bool;

#define TRUE 1

#define FALSE 0


#include <stdlib.h>

#include <stdio.h>

//#include <GL/glut.h>
#ifdef __APPLE__

#include <GLUT/glut.h>

#else

#include <GL/glut.h>

#endif


void myMouse(int,int, int, int);

void myMotion(int, int);

void myDisplay();

void myReshape(int, int);

void color_menu(int);

void main_menu(int);

int pick_polygon(int x, int y);


void myinit();


/* globals */


/* polygon struct */


typedef struct polygon

{ 

     int color; /* color index */

     bool used; /* TRUE if polygon exists */

     int xmin, xmax, ymin, ymax; /* bounding box */

     float xc, yc; /* center of polygon */

     int nvertices; /* number of vertices */

     int x[MAX_VERTICES]; /* vertices */

     int y[MAX_VERTICES];

} polygon;


/* flags */


bool picking = FALSE; /* true while picking */

bool moving = FALSE; /* true while moving polygon */

int in_polygon = -1; /* not in any  polygon */

int present_color = 0; /* default color */


GLsizei wh = 500, ww = 500; /* initial window size */


int draw_mode = 0; /* drawing mode */


GLfloat colors[8][3]={{0.0, 0.0, 0.0}, {1.0, 0.0, 0.0},{0.0, 1.0, 0.0},

    {0.0, 0.0, 1.0}, {0.0, 1.0, 1.0}, {1.0, 0.0, 1.0}, {1.0, 1.0, 0.0},

    {1.0, 1.0, 1.0}};


polygon polygons[MAX_POLYGONS];



void myReshape(int w, int h)

{


        glMatrixMode(GL_PROJECTION);

        glLoadIdentity(); 

        gluOrtho2D(0.0, (GLdouble)w, 0.0, (GLdouble)h);

        glMatrixMode(GL_MODELVIEW);

        glLoadIdentity(); 


        glViewport(0,0,w,h);


        ww = w;

        wh = h; 

}


void myinit()

{

        int  i;


/* set clear color to grey */


        glClearColor(0.5, 0.5, 0.5, 1.0);


/* mark all polygons unused */


        for(i = 0; i<MAX_POLYGONS; i++) polygons[i].used = FALSE;

}




void myMouse(int btn, int state, int x, int y)

{

    int i,j;

    y = wh-y;

    if(btn==GLUT_LEFT_BUTTON && state==GLUT_DOWN &&!picking&&!moving)


    /* adding vertices */    


    {

        moving = FALSE;

        if(in_polygon>=0) 

        {

             if(polygons[in_polygon].nvertices == MAX_VERTICES)

             {

                 printf("exceeds maximum number vertices\n");

                 exit(0);

             }

             i = polygons[in_polygon].nvertices;

             polygons[in_polygon].x[i] = x;

             polygons[in_polygon].y[i] = y;

             polygons[in_polygon].nvertices++;

        }

    }

    if(btn==GLUT_LEFT_BUTTON && state==GLUT_DOWN &&picking&&!moving)

    {


    /* delete polygon */


        picking = FALSE;

        moving = FALSE;

        j = pick_polygon(x,y);

        if(j >= 0)

        {

                    polygons[j].used = FALSE;

                    in_polygon = -1;

                    glutPostRedisplay();

        }

    } 

}


int pick_polygon(int x, int y)

{


        /* find first polygon in which we are in bounding box */


        int i;

        for(i=0; i<MAX_POLYGONS; i++)

        {

             if(polygons[i].used)

                if((x>=polygons[i].xmin)&&(x<=polygons[i].xmax)&&(y>=polygons[i].ymin)&&(y<polygons[i].ymax))

                {

                    in_polygon = i;

                    moving = TRUE;

                    return(i);

                }

        printf("not in a polygon\n");

        return(-1);

        }

}


void myMotion(int x, int y)

{


   /* find if we are inside a polugon */


   float dx, dy;

   int i,j;

   if(moving)

   {

       y = wh - y;

       j = pick_polygon(x, y);

       if(j<0) 

          {

                printf("not in a polygon\n");

                return;

           }


       /* if inside then move polygon */


       dx = x - polygons[j].xc;

       dy = y - polygons[j].yc;

       for(i = 0; i< polygons[j].nvertices; i++)

       {

           polygons[j].x[i] += dx;

           polygons[j].y[i] += dy;

       }


      /* update bounding box */


       polygons[j].xc += dx;

       polygons[j].yc += dy;

       if(dx>0) polygons[j].xmax += dx;

         else polygons[j].xmin += dx;

       if(dy>0) polygons[j].ymax += dy;

         else polygons[j].ymin += dy;

       glutPostRedisplay();

    }

}


void color_menu(int index)

{

    present_color =  index;

    if(in_polygon>=0) polygons[in_polygon].color = index;

}


void main_menu(int index)

{

   int i;

   switch(index)

   {

      case(1):  /* create a new polygon */

    {


                moving = FALSE;

           for(i=0; i<MAX_POLYGONS; i++) if(polygons[i].used == FALSE) break;

            if(i == MAX_POLYGONS)

            {

                 printf("exceeeded maximum number of polygons\n");

                 exit(0);

            }

                polygons[i].color = present_color;

                polygons[i].used = TRUE;

            polygons[i].nvertices = 0;

            in_polygon = i;

                picking = FALSE;

                break;

         }

    case(2):   /* end polygon and find bounding box and center */

    {

                moving = FALSE;

                if(in_polygon>=0)

                {

                   polygons[in_polygon].xmax = polygons[in_polygon].xmin = polygons[in_polygon].x[0];

                   polygons[in_polygon].ymax = polygons[in_polygon].ymin = polygons[in_polygon].y[0];

                   polygons[in_polygon].xc = polygons[in_polygon].x[0];

                   polygons[in_polygon].yc = polygons[in_polygon].y[0];

                   for(i=1;i<polygons[in_polygon].nvertices;i++)

                   {

                     if(polygons[in_polygon].x[i]<polygons[in_polygon].xmin)

                              polygons[in_polygon].xmin = polygons[in_polygon].x[i];

                     else if(polygons[in_polygon].x[i]>polygons[in_polygon].xmax)

                              polygons[in_polygon].xmax = polygons[in_polygon].x[i];

                     if(polygons[in_polygon].y[i]<polygons[in_polygon].ymin)

                              polygons[in_polygon].ymin = polygons[in_polygon].y[i];

                     else if(polygons[in_polygon].y[i]>polygons[in_polygon].ymax)

                              polygons[in_polygon].ymax = polygons[in_polygon].y[i];

                     polygons[in_polygon].xc += polygons[in_polygon].x[i];

                     polygons[in_polygon].yc += polygons[in_polygon].y[i];

                   }

                   polygons[in_polygon].xc = polygons[in_polygon].xc/polygons[in_polygon].nvertices;

                   polygons[in_polygon].yc = polygons[in_polygon].yc/polygons[in_polygon].nvertices;

                }

        in_polygon = -1;

                glutPostRedisplay();

        break;

    }

    case(3):  /* set picking mode */

    {

                picking = TRUE;

                moving = FALSE;

        break;

    }

        case(4):  /* set moving mode */

        {

                moving = TRUE;

                break;

        }

    case(5):  /* exit */

    {

        exit(0);

        break;

    }

   }

}


void myDisplay()

{


    /* display all active polygons */


    int i, j;


    glClear(GL_COLOR_BUFFER_BIT);

    for(i=0; i<MAX_POLYGONS; i++)

    {

       if(polygons[i].used)

       {

           glColor3fv(colors[polygons[i].color]);

           glBegin(GL_POLYGON);

           for(j=0; j<polygons[i].nvertices; j++) glVertex2i(polygons[i].x[j], polygons[i].y[j]);

           glEnd();

       }

    }

    glFlush();

}



int main(int argc, char** argv)

{

    int c_menu;


    glutInit(&argc,argv);

    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);

    glutInitWindowSize(500, 500);

    glutCreateWindow("polygon modeler");

    glutDisplayFunc(myDisplay);

    myinit ();

    c_menu = glutCreateMenu(color_menu);

    glutAddMenuEntry("Black",0);

    glutAddMenuEntry("Red",1);

    glutAddMenuEntry("Green",2);

    glutAddMenuEntry("Blue",3);

    glutAddMenuEntry("Cyan",4);

    glutAddMenuEntry("Magenta",5);

    glutAddMenuEntry("Yellow",6);

    glutAddMenuEntry("White",7);


    glutCreateMenu(main_menu);

    glutAddMenuEntry("new polygon", 1);

    glutAddMenuEntry("end polygon", 2);

    glutAddMenuEntry("delete polygon", 3);

    glutAddMenuEntry("move polygon", 4);

    glutAddMenuEntry("quit",5);

    glutAddSubMenu("Colors", c_menu);

    glutAttachMenu(GLUT_MIDDLE_BUTTON);


    glutReshapeFunc (myReshape); 

    glutMouseFunc (myMouse);

    glutMotionFunc(myMotion);

    glutMainLoop();


}

首先新建了一个Win32控制台应用程序，空白项目，将该文件添加到资源文件。直接编译会出错，需要修改项目属性，如下设置：

1.工程属性->配置（设为‘所有配置’）->配置属性->C/C++->预处理器定义(设为‘GLUT_BUILDING_LIB’)

2.工程属性->配置（设为‘活动(Debug)’）->链接器->系统->子系统(设为‘控制台(/SUBSYSTEM:CONSOLE)’)——此处不必修改，本身是Win32控制台程序

3.链接器->输入->附加依赖项中添加

glu32.lib
glut32.lib
glut.lib
opengl32.lib
glaux.lib

确定。

4.属性->配置（设为‘所有配置’）->配置属性->C/C++->高级->编译为设置为默认值或编译为C语言

该项目介绍了拾取的相关知识，还要好好学习一下，鼠标中键点击弹出菜单。

http://www.cnblogs.com/cjyang/archive/2010/10/21/1855169.html