[置顶] OpenGL鼠标拾取的实现：终于搞定（包括细节问题）

void OpenGL::pickRects(){/*GetCursorPos(&mouse);ScreenToClient(hWnd,&mouse);GLuint pickBuffer [32];    GLint nPicks,vpArray[4];glRenderMode(GL_SELECT);glSelectBuffer(32,pickBuffer);glInitNames();//glPushName(-1);glMatrixMode(GL_PROJECTION);glPushMatrix();   //glLoadIdentity();glGetIntegerv(GL_VIEWPORT,vpArray);gluPickMatrix(GLdouble(mouse.x),GLdouble(vpArray[3]-mouse.y),5.0,5.0,vpArray);//glOrtho(0,1,0,1,0,1);//激活拾取区域。  //gluOrtho2D(0,0,Width,Height);rects(GL_SELECT);glMatrixMode(GL_PROJECTION);int j;glGetIntegerv(GL_NAME_STACK_DEPTH,&j);cout<<j<<endl;glPopMatrix();glFlush();    nPicks=glRenderMode(GL_RENDER);    processPicks(nPicks,pickBuffer);        //processPicks(nPicks,pickBuffer);*/   GetCursorPos(&mouse);   ScreenToClient(hWnd,&mouse);   GLuint selectBuf[32];   GLint hits;   GLint viewport[4];     glGetIntegerv(GL_VIEWPORT, viewport);   glSelectBuffer(32, selectBuf);   (void) glRenderMode(GL_SELECT);   glInitNames();   glPushName(0);   glMatrixMode(GL_PROJECTION);

//下面这段代码可有可无，只是为了确保点击测试和实际绘图用的是同一个投影阵。

 glLoadIdentity();// 重置当前指定的矩阵为单位矩阵   gluPerspective// 设置透视图( 53.0f,// 透视角设置为 90 度  (GLfloat)Width/(GLfloat)Height,// 窗口的宽与高比  0.1f,// 视野透视深度:近点1.0f  3000.0f// 视野透视深度:始点0.1f远点1000.0f);

   glPushMatrix();

下面的代码是最关键的地方，，注意：据测试：gluPickMatrix()意思并不是仅仅绘制一个拾取窗口。同时，

它也是一个投影矩阵变换！！～～～～如果使用第二个LoadIdentity()那么：前面的拾取矩阵就会失效！！

   glLoadIdentity();/*  create 5x5 pixel picking region near cursor location */   gluPickMatrix((GLdouble) mouse.x, (GLdouble) (viewport[3] - mouse.y),                 5.0, 5.0, viewport);

//这个会促使上面那个PickMatrix失效！！切记～～～～   //glLoadIdentity();// 重置当前指定的矩阵为单位矩阵   gluPerspective// 设置透视图( 53.0f,// 透视角设置为 90 度  (GLfloat)Width/(GLfloat)Height,// 窗口的宽与高比  0.1f,// 视野透视深度:近点1.0f  3000.0f// 视野透视深度:始点0.1f远点1000.0f);   rects(GL_SELECT);   glPopMatrix();   glFlush();   hits = glRenderMode(GL_RENDER);   processPicks(hits, selectBuf);   int j;   glGetIntegerv(GL_NAME_STACK_DEPTH,&j);   int m;}void OpenGL::rects(GLenum mode){if (mode == GL_SELECT)    glLoadName(30);    glPushMatrix();glTranslatef(-2,-1,-15);glColor3f(0.6f,0.2f,0.9f);//glRecti(0,0,100,100);Font->c3dtext("离开游戏",hFont,0.25f);glPopMatrix();  /* glBegin(GL_QUADS);   glColor3f(1.0, 1.0, 0.0);   glVertex3i(2, 0, 0);   glVertex3i(2, 6, 0);   glVertex3i(6, 6, 0);   glVertex3i(6, 0, 0);   glEnd();   */   if (mode == GL_SELECT)      glLoadName(20);   glPushMatrix();     glTranslatef(-2,1,-15);  glColor3f(0.6f,0.2f,0.9f);  Font->c3dtext("开始游戏",hFont,0.25f);   glPopMatrix();  /*glBegin(GL_QUADS);   glColor3f(0.0, 1.0, 1.0);   glVertex3i(3, 2, -1);   glVertex3i(3, 8, -1);   glVertex3i(8, 8, -1);   glVertex3i(8, 2, -1);   glEnd();   */   /*   if (mode == GL_SELECT)      glLoadName(3);   glBegin(GL_QUADS);   glColor3f(1.0, 0.0, 1.0);   glVertex3i(0, 2, -2);   glVertex3i(0, 7, -2);   glVertex3i(5, 7, -2);   glVertex3i(5, 2, -2);   glEnd();/*   if(mode==GL_SELECT)glPushName(1);  glPushMatrix();//glTranslatef(0,0,-Height);    glColor3f(0.0,1.0,0.0);//glPushName(20); glTranslatef(-2,-1,-15);//glColor3f(0.6f,0.2f,0.9f);//glRecti(0,0,100,100);Font->c3dtext("离开游戏",hFont,0.25f);/*glBegin(GL_QUADS);glTexCoord2f(0.0f, 0.0f); glVertex3f(-Width/2, -Height/2,  -0.0f);// 前glTexCoord2f(1.0f, 0.0f); glVertex3f( Width/2,-Height/2,  -0.0f);glTexCoord2f(1.0f, 1.0f); glVertex3f( Width/2,  Height/2,  -0.0f);glTexCoord2f(0.0f, 1.0f); glVertex3f(-Width/2,  Height/2,  -0.0f);    glEnd(); //   glColor3f(1.0,0.0,0.0);//glTranslatef(-2,1,-15);glColor3f(0.6f,0.2f,0.9f);//Font->c3dtext("开始游戏",hFont,0.25f);glPopMatrix();   if(mode==GL_SELECT)glPushName(2);   glPushMatrix();   // glTranslatef(0,0,-Height);//glColor3f(0.0,1.0,0.0);//glPushName(20); glTranslatef(-2,-1,-15);glColor3f(0.6f,0.2f,0.9f);//glRecti(0,0,100,100);Font->c3dtext("离开游戏",hFont,0.25f);glBegin(GL_QUADS);glTexCoord2f(0.0f, 0.0f); glVertex3f(-Width/2, -Height/2,  -0.0f);// 前glTexCoord2f(1.0f, 0.0f); glVertex3f( Width/2,-Height/2,  -0.0f);glTexCoord2f(1.0f, 1.0f); glVertex3f( Width/2,  Height/2,  -0.0f);glTexCoord2f(0.0f, 1.0f); glVertex3f(-Width/2,  Height/2,  -0.0f);    glEnd();glPopMatrix();*/}void OpenGL::processPicks(GLint hits,GLuint buffer[]){rects(GL_RENDER);cout<<hits<<endl; unsigned int i, j;   GLuint names, *ptr;   printf("hits = %d\n", hits);   ptr = (GLuint *) buffer;   for (i = 0; i < hits; i++) {        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++) {           printf("%d ", *ptr); ptr++;      }      printf("\n");   }}