Click on 3D object and PlaneNode

C++ coding using Panda3D
#1

Hi, it’s me again.

I’m still working on the same project and I’m now stuck with two problems. The first one concern PlaneNodes and the other one is about clicking on a 3D object.

  1. I wanted to use PlaneNode to create a sort of “base” on my scene by putting a texture on it. I tried this :
Planef plan(LPoint3f(0,0,0),LPoint3f(0,1,0),LPoint3f(1,0,0));
    PlaneNode* planenode = new PlaneNode("ground");
    planenode->set_plane(plan);

    Filename filename = Filename("Myfile.png");
    Texture * tex = TexturePool::load_texture(filename);
    NodePath nodepath(planenode);
    tex->set_wrap_u(Texture::WM_repeat);
    tex->set_wrap_v(Texture::WM_repeat);
    nodepath.set_texture(tex);
    nodepath.reparent_to(_win_fr->get_render());

But unfortunately, it doesn’t seems to work. Do you have any solution ?

  1. I’ve also been trying to “click” on 3D objects and I came up with this :
CollisionTraverser myTraverser = CollisionTraverser("ctraverser");
        CollisionNode* pickerNode = new CollisionNode("mouseRay");
        NodePath pickerNP = _win_fr->get_camera_group().attach_new_node(pickerNode);
        pickerNode->set_from_collide_mask(GeomNode::get_default_collide_mask());
        CollisionRay* pickerRay = new CollisionRay();
        pickerNode->add_solid(pickerRay);
        CollisionHandlerQueue* myHandler = new CollisionHandlerQueue();
        myTraverser.add_collider(pickerNP, myHandler);
        pickerRay->set_from_lens(_camera, x, y);

        myTraverser.traverse(_win_fr->get_render());

       if(myHandler->get_num_entries() > 0)
       {
            std::cout<<"it works"<<std::endl;
            myHandler->sort_entries();
            NodePath pickedObj = myHandler->get_entry(0)->get_into_node_path();
            return PandaEntity::get(pickedObj.node());
       }
       else{
            std::cout<<"nope"<<std::endl;
            return NULL;
       }

But again, it doesn’t work. Any suggestion ?

Thank you again,
Quentin.

#2

No one has even just a clue of how I could solve these problems ? I’ve been working on it the whole day and I diddn’t came up with anything.

#3

Hi

I don’t know about using the PlaneNode to create a ground plane to use as the base of your scene. I tried your code and can’t see anything.

Here is another method using card maker:

    CardMaker cm("ground");
    cm.set_frame(0.,512.,0.,512);
    PT(PandaNode) card = cm.generate();

    Filename filename = Filename("Myfile.png");
    Texture * tex = TexturePool::load_texture(filename);
    NodePath nodepath(card);
    nodepath.set_p(-90.);
    tex->set_wrap_u(Texture::WM_repeat);
    tex->set_wrap_v(Texture::WM_repeat);
    nodepath.set_texture(tex);
    nodepath.reparent_to(_win_fr->get_render());

I use GeoMipTerrain for my scene base and use the get_elevation function to find the z value on the terrain, but since you are making a flat world then maybe CardMaker is okay.

As for the picking, I don’t see how you set your x and y; but here is how I do it:

Viewer::Viewer(PandaFramework *fw, QtGUI *gui){
.
.
  mPickerRay = new CollisionRay(0., 0., 0., 0., 1., 0.);
  PT(CollisionNode) camGroundCol = new CollisionNode("mPickerRay");
  camGroundCol->add_solid(mPickerRay);
  camGroundCol->set_from_collide_mask(BitMask32::bit(0));
  camGroundCol->set_into_collide_mask(BitMask32::all_off());
  camGroundNode = mCameraNode.attach_new_node(camGroundCol);
  mCamGroundHandler = new CollisionHandlerQueue();
  mGroundTraverse.add_collider(camGroundNode,mCamGroundHandler);
.
.
}


bool Viewer::getPick(NodePath &hitNode,LPoint3f &hitPt,float &minDist){

  bool pickOk = false;
  float xsize =  (float)window->get_graphics_window()->get_x_size();
  float ysize =  (float)window->get_graphics_window()->get_y_size();

  mMouseX = window->get_graphics_window()->get_pointer(0).get_x();
  mMouseY = window->get_graphics_window()->get_pointer(0).get_y();

  int yy = ysize - mMouseY;

  float xp = 2.*(float)mMouseX/xsize - 1.;
  float yp = 2.*(float)yy/ysize - 1.;

  mPickerRay->set_from_lens(window->get_camera(0), xp, yp);
  mGroundTraverse.traverse(mRootNode);
  CollisionEntry *entry;
  
  if(mCamGroundHandler->get_num_entries()){
    pickOk = true;
    LVecBase3f pos = mCameraNode.get_pos();
    mCamGroundHandler->sort_entries();
    entry = mCamGroundHandler->get_entry(0);
    hitPt = entry->get_surface_point(mRootNode);
    hitNode = entry->get_into_node_path();
    minDist = (hitPt - pos).length();
    printf("hit node:%s  pt:%f %f %f\n",hitNode.get_name().c_str(),hitPt.get_x(),hitPt.get_y(),hitPt.get_z());
  }

  return(pickOk);

}

any model that you want to be pickable should have its collide mask set the same as the CollisionNode,
in my case I use model_node.set_collide_mask(BitMask32::bit(0));

#4

Note, for the record, that a PlaneNode is used to describe a plane as a mathematical concept; it is not normally visible and doesn’t work with setTexture() and whatnot. If you want to make a visible polygon for a floor plane, either load the intended polygon from an egg file, or use something like CardMaker to create a visible polygon.

David