// Filename: displayRegionDrawCallbackData.cxx
// Created by:  drose (13Mar09)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) Carnegie Mellon University.  All rights reserved.
//
// All use of this software is subject to the terms of the revised BSD
// license.  You should have received a copy of this license along
// with this source code in a file named "LICENSE."
//
////////////////////////////////////////////////////////////////////

#include "displayRegionDrawCallbackData.h"

#include "config_display.h"
#include "cullResult.h"
#include "displayRegion.h"
#include "graphicsOutput.h"
#include "graphicsStateGuardian.h"
#include "sceneSetup.h"

TypeHandle DisplayRegionDrawCallbackData::_type_handle;


////////////////////////////////////////////////////////////////////
//     Function: DisplayRegionDrawCallbackData::Constructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
DisplayRegionDrawCallbackData::
DisplayRegionDrawCallbackData(CullResult *cull_result, SceneSetup *scene_setup) :
  _cull_result(cull_result),
  _scene_setup(scene_setup)
{
}

////////////////////////////////////////////////////////////////////
//     Function: DisplayRegionDrawCallbackData::output
//       Access: Published, Virtual
//  Description:
////////////////////////////////////////////////////////////////////
void DisplayRegionDrawCallbackData::
output(ostream &out) const {
  out << get_type() << "(" << (void *)_cull_result << ", " 
      << (void *)_scene_setup << ")";
}

////////////////////////////////////////////////////////////////////
//     Function: DisplayRegionDrawCallbackData::upcall
//       Access: Published, Virtual
//  Description: You should make this call during the callback if you
//               want to continue the normal rendering function that
//               would have been done in the absence of a callback.
//
//               Specifically, this method will draw all of the
//               objects in the CullResult list that have been built
//               up for the DisplayRegion during the cull traversal.
////////////////////////////////////////////////////////////////////
void DisplayRegionDrawCallbackData::
upcall() {
  Thread *current_thread = Thread::get_current_thread();
  DisplayRegion *dr = _scene_setup->get_display_region();
  GraphicsStateGuardian *gsg = dr->get_window()->get_gsg();

  if (_cull_result == NULL || _scene_setup == NULL) {
    // Nothing to see here.

  } else if (dr->is_stereo()) {
    // We don't actually draw the stereo DisplayRegions.  These are
    // just placeholders; we draw the individual left and right eyes
    // instead.  (We might still clear the stereo DisplayRegions,
    // though, since it's probably faster to clear right and left
    // channels in one pass, than to clear them in two separate
    // passes.)

  } else if (!gsg->set_scene(_scene_setup)) {
    // The scene or lens is inappropriate somehow.
    display_cat.error()
      << gsg->get_type() << " cannot render scene with specified lens.\n";

  } else {
    // Tell the GSG to forget its state.
    gsg->clear_state_and_transform();

    if (gsg->begin_scene()) {
      _cull_result->draw(current_thread);
      gsg->end_scene();
    }
  }
}