关于OpenGL 鼠标拾取的问题，请大神帮忙

sannuo22 2016-08-17 05:13:31

就是用红宝书第七版第十三章选择那一章，改写一下，先在屏幕上用鼠标随机画了点，然后点右键，用线连接，再点下选取模式，用鼠标去选择那些线，但是怎么也选不中，以下是完整代码，其中Point3D 就是一个包括x.y.z三个坐标点的类。

求指点。困扰了好多天了，实在看不出问题在哪里~快哭了~~~~~~~~~~~

#include "StdAfx.h"

#include <Windows.h>

#include <gl/GL.h>

#include<gl/glu.h>

#include<gl/glut.h>

#include<time.h>

#include<iostream>  

#include<math.h>

#include<vector>



#include "Point3D.h"



using namespace std;

 

#define BUFSIZE 512



int screenWidth=340;

int screenHeight=280;

 



vector<Point3D> P;

 



 

static int pickUpModel=0; //1: mouse pickup work  0:close the function of mouse pick up



 void  drawSpere(float x, float y,float z);

 void drawLine2D(GLenum);

  void pickUp(int x, int y);

  void processHits (GLint hits, GLuint buffer[]);

void myInit(void) 

 

{ 

	glClear (GL_COLOR_BUFFER_BIT);

      glClearColor(1.0, 1.0, 1.0, 0.0);

     glShadeModel(GL_SMOOTH);   

   

  

}

void myDisplay(void)

{

		glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); 

   glClearColor(1.0, 1.0, 1.0, 0.0);

   glColor3f (0.0, 1.0, 1.0);

 

}

void myReshape (int w, int h)

{

 

   glViewport (0, 0, (GLsizei) w, (GLsizei) h); 

   glMatrixMode (GL_PROJECTION);

   glLoadIdentity ();

 //  gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);

   if(w<=h)

		  glOrtho(0,screenWidth*2, 0,  screenHeight*2*(GLfloat)h/w,-screenWidth,screenWidth);

	 else

		   glOrtho(0,screenWidth*2*(GLfloat)w/h,0,screenHeight*2,-screenWidth,screenWidth);

   glMatrixMode(GL_MODELVIEW);

  glLoadIdentity();

  gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

   

}

 

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

{

		

	Point3D X;

    if((state==GLUT_DOWN)&&(button==GLUT_LEFT_BUTTON)&&(pickUpModel==0))

    {

 

		         X.x=x;

			X.y=screenHeight*2-y; 

			X.z=0;

			P.push_back(X);   

			pointNum++;

			for(int i=0;i<pointNum;i++)

			   drawSpere(P[i].x, P[i].y, P[i].z);

		 

            

		   cout<<x<<"  "<<y<<endl;

	}

 

	 if((state==GLUT_DOWN)&&(button==GLUT_LEFT_BUTTON)&&(pickUpModel==1))

    {

		pickUp(x,y);

	 }

//	glutSwapBuffers();

	 glFlush();

}

 

void myMenu(int value){

   if(value==1)

   {

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); 

	 

	  P.clear();

	  pointNum=0;

	  idx=0;

	  glFlush();

		

   }

   if(value==2)  

   {

	  drawLine2D(GL_RENDER);

 

   }

   if(value==3)

   {  

   }

   if(value==4)

	   pickUpModel=1;

   if(value==5)

	   pickUpModel=0;

	 

}

 void  drawSpere(float x, float y,float z)

 {

     glPushMatrix();

		 

   glTranslatef (x, y, 0.0);

   glRotatef (5, 0.0, 1.0, 0.0);

   glutWireSphere(5, 100, 80);    /* draw smaller planet */

   glPopMatrix();

  

 

 }

 

 void drawLine2D(GLenum mode)

 {

    glLineWidth(5);

	 for(int i=0;i<pointNum;i++){

		 if(mode==GL_SELECT)

		  glPushName(i+1);

		 glBegin(GL_LINE_LOOP);

	           glVertex2f(P[i%pointNum].x, P[i%pointNum].y);

		    glVertex2f(P[(i+1)%pointNum].x, P[(i+1)%pointNum].y);

		 glEnd();

 }

	 	glFlush();

 }

 

 

 void pickUp(int x, int y)

{

   GLuint selectBuf[BUFSIZE];

   GLint hits;

   GLint viewport[4];

 



   glGetIntegerv (GL_VIEWPORT, viewport);

 

   glSelectBuffer (BUFSIZE, selectBuf);

   (void) glRenderMode (GL_SELECT);

 

   glInitNames();

   glPushName(0);

 

   glMatrixMode (GL_PROJECTION);

   glPushMatrix ();

   glLoadIdentity ();

/*  create 5x5 pixel picking region near cursor location	*/

   gluPickMatrix ((GLdouble) x, (GLdouble) (viewport[3] - y), 

                  5.0, 5.0, viewport);

   gluOrtho2D (0.0, screenWidth*2.0, 0.0, screenHeight*2.0);

 



    drawLine2D(GL_SELECT);

 

   glMatrixMode (GL_PROJECTION);

   glPopMatrix ();

   glFlush ();

 

   hits = glRenderMode(GL_RENDER);

   processHits (hits, selectBuf);

 



} 

 

void processHits (GLint hits, GLuint buffer[])

{

   unsigned int i, j;

   GLuint names, *ptr;

 

   printf ("hits = %d\n", hits);

   ptr = (GLuint *) buffer;

   for (i = 0; i < hits; i++) {	/*  for each hit  */

      names = *ptr;

      printf (" number of names for hit = %d\n", names); ptr++;

      printf("  z1 is %g;", (float) *ptr/0x7fffffff); ptr++;

      printf(" z2 is %g\n", (float) *ptr/0x7fffffff); ptr++;

      printf ("   the name is ");

      for (j = 0; j < names; j++) {	/*  for each name */

         printf ("%d ", *ptr); ptr++;

      }

      printf ("\n");

   }

}

 



 

int main(int argc, char** argv)

{

   glutInit(&argc, argv);

  // glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);

   glutInitDisplayMode (GLUT_SINGLE| GLUT_RGB);

   glutInitWindowSize (screenWidth*2, screenHeight*2); 

   glutInitWindowPosition (100, 100);

   glutCreateWindow (argv[0]);

   myInit();

   glutDisplayFunc(myDisplay); 

   glutReshapeFunc(myReshape);

    glutMouseFunc(myMouse);

		int id=glutCreateMenu(myMenu);

	glutAddMenuEntry("Clear Screen",1);

	glutAddMenuEntry("InitialDraw",2);

	glutAddMenuEntry("iter",3);

	glutAddMenuEntry("pickUpOpen",4);

	glutAddMenuEntry("pickUpClose",5);

		glutAttachMenu(GLUT_RIGHT_BUTTON); 

   glutMainLoop();

   return 0;