c++ openGL picking problems - c++

Question

I'm working on a little example, where I have loaded an object from a wavefront file - and am trying to get my picking right, I've gone over this and a few tutorials about 10 times... but must be missing something. Was wondering if anyone could provide an extra set of eyes.
I've used a saved list to draw the object, which appears fine on the screen... At the moment, when gl_select(x, y) runs, I get a hit no matter what, and if I enable the translate/rotate code (which is currently commented out) - I get no hits what-so-ever.
Relevant code blocks:
// gl_select, is called when the mouse is clicked, with its x and y coords
void gl_select(int x, int y)
{
GLuint buff[256];
GLint hits;
GLint view[4];
//Buffer to store selection data
glSelectBuffer(256, buff);
//Viewport information
glGetIntegerv(GL_VIEWPORT, view);
//Switch to select mode
glRenderMode(GL_SELECT);
//Clear the name stack!
glInitNames();
//Fill the stack with one element
glPushName(0);
//Restric viewing volume
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
//Restrict draw area
gluPickMatrix(x, y, 1.0, 1.0, view);
gluPerspective(60, 1, 0.0001, 1000.0);
//Draw the objects onto the screen
glMatrixMode(GL_MODELVIEW);
//Draw only the names in the stack
glutSwapBuffers();
DrawSavedObject();
//Back into projection mode to push the matrix
glMatrixMode(GL_PROJECTION);
glPopMatrix();
hits = glRenderMode(GL_RENDER);
cout << hits;
//Back to modelview mode
glMatrixMode(GL_MODELVIEW);
}
And the draw functions:
void DrawSavedObject()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glColor3f(1.0,0.0,0.0);
//translate and rotate
//glRotated(rotation,0.0,0.0,1.0);
//glTranslated(7.0, 7.0, 0.0);
//Draw the saved object
glLoadName(7);
glCallList(list_object);
glutSwapBuffers();
}
And where the list is saved:
void SaveDisplayList(){
glNewList(list_object, GL_COMPILE);
glVertexPointer(3, GL_DOUBLE, 3*sizeof(GLdouble), vertices);
glEnableClientState(GL_VERTEX_ARRAY);
glDrawElements(GL_TRIANGLES, verticesSize ,GL_UNSIGNED_INT, triangles);
glDisableClientState(GL_VERTEX_ARRAY);
glEndList();
}
Sorry again for the chunkiness of the code blocks.

Answer 1

A few things to consider here:
OpenGL selection mode is deprecated and never was HW accelerated, except on a few SGI boxes and 3DLabs GPUs.
DisplayLists don't mix with Vertex Arrays.
Why do you call glutSwapBuffers right before drawing your list of saved objects? Makes absolutely no sense at all.

Answer 2

I'm not sure if it's relevant but you're not supposed to store things like glVertexPointer in display lists. From the spec http://www.opengl.org/sdk/docs/man/xhtml/glNewList.xml:
Certain commands are not compiled into the display list but are
executed immediately, regardless of the display-list mode. These
commands are glAreTexturesResident, glColorPointer, glDeleteLists,
glDeleteTextures, glDisableClientState, glEdgeFlagPointer,
glEnableClientState, glFeedbackBuffer, glFinish, glFlush, glGenLists,
glGenTextures, glIndexPointer, glInterleavedArrays, glIsEnabled,
glIsList, glIsTexture, glNormalPointer, glPopClientAttrib,
glPixelStore, glPushClientAttrib, glReadPixels, glRenderMode,
glSelectBuffer, glTexCoordPointer, glVertexPointer, and all of the
glGet commands.
This could be what's causing your problem.