我正在尝试创建一个3D机器人，当单击某些身体部位时，应该执行某些动作。我已经成功（有点）实现了拾取功能，即如果您单击任何x平面部分，则会注册命中，但其他地方不行。也就是说，它没有注册深度，并且如果您单击其正方形头部，只能通过单击头部前面（面向您）来注册命中。显然，我并不完全理解选取和选择，并且在试图将我对2D选择的了解转录到3D时很粗心大意（我的老师像一块石头一样有用），但我漏掉了某些内容或者没有改变与深度相关的某些内容。有人可以帮助我吗？以下是相关函数。
void processHits (GLint hits, GLuint buffer[])
{
unsigned int i, j;
GLint n, *ptr;
printf ("hits = %d\n", hits);
ptr = (GLint *) buffer;
//For each hit.
for (i = 0; i < hits; i++)
{
n = *ptr; //Number of names under current hit.
ptr+=3; //Bypass three integers: n, z1, z2.
printf ("hit %d has %d name(s)\n", i, n);
//For each name.
for (j = 0; j < n; j++)
{
if(*ptr==1) printf ("Body hit.\n");
else if(*ptr==2) printf ("Right shoulder hit.\n");
else if(*ptr==3) printf ("Left shoulder hit.\n");
else if(*ptr==4) printf ("Left arm hit.\n");
else if(*ptr==5) printf ("Right arm hit.\n");
else if(*ptr==6) printf ("Left leg hit.\n");
else if(*ptr==7) printf ("Right leg hit.\n");
else if(*ptr==8) printf ("Right foot hit.\n");
else if(*ptr==9) printf ("Left foot hit.\n");
else if(*ptr==10) printf ("Neck hit.\n");
else if(*ptr==11) printf ("Head hit.\n");
else printf ("Nothing hit.\n");
ptr++;
}
printf ("\n");
}
}
void selection(int mouse_x, int mouse_y)
{
GLuint buffer[512]; //Set up a selection buffer.
GLint hits; //The number of objects we selected.
GLint viewport[4]; //Viewport size. [0] Is <x>, [1] Is <y>, [2] Is <length>, [3] Is <width>.
glGetIntegerv(GL_VIEWPORT, viewport); //Sets the array <viewport> to size and location of screen relative to window.
glSelectBuffer(512, buffer); //Tell OpenGL to use our array for selection.
glRenderMode(GL_SELECT); //Puts OpenGL in selection mode. Nothing will be drawn. Object IDs and extents stored in buffer.
glInitNames(); //Initializes name stack.
glPushName(0); //Push an entry onto the stack.
glMatrixMode(GL_PROJECTION); //Selects the projection matrix.
glPushMatrix(); //Push the projection matrix.
glLoadIdentity(); //Resets matrix.
//This creates a matrix that will zoom up to a small portion of the screen, where the mouse is.
gluPickMatrix((GLdouble) mouse_x, (GLdouble) (viewport[3]-mouse_y), 0.01, 0.01, viewport);
gluPerspective(45.0f, (GLfloat) (viewport[2]-viewport[0])/(GLfloat) (viewport[3]-viewport[1]), 0.1f, 100.0f);
glMatrixMode(GL_MODELVIEW); //Select the modelview matrix.
drawObjects(GL_SELECT); //Render the targets to the selection buffer.
glMatrixMode(GL_PROJECTION); //Select the projection matrix.
glPopMatrix(); //Pop the projection matrix.
glMatrixMode(GL_MODELVIEW); //Select the modelview matrix.
hits = glRenderMode(GL_RENDER);
processHits (hits, buffer);
//printf("%d ", hits);
//Post redisplay message.
glutPostRedisplay();
}
void mouse(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
{
selection(x, y);
}
}