dxOcclusionQueryContext9.cxx

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/**
 * 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."
 *
 * @file dxOcclusionQueryContext9.cxx
 * @author drose
 * @date 2007-06-04
 */

#include "dxOcclusionQueryContext9.h"
#include "dxGraphicsStateGuardian9.h"
#include "pnotify.h"
#include "dcast.h"
#include "pStatTimer.h"

TypeHandle DXOcclusionQueryContext9::_type_handle;

/**
 *
 */
DXOcclusionQueryContext9::
~DXOcclusionQueryContext9() {
  _query->Release();
  _query = nullptr;
}

/**
 * Returns true if the query's answer is ready, false otherwise.  If this
 * returns false, the application must continue to poll until it returns true.
 *
 * It is only valid to call this from the draw thread.
 */
bool DXOcclusionQueryContext9::
is_answer_ready() const {
  DWORD result;
  HRESULT hr = _query->GetData(&result, sizeof(result), 0);
  return (hr != S_FALSE);
}

/**
 * Requests the graphics engine to expedite the pending answer--the
 * application is now waiting until the answer is ready.
 *
 * It is only valid to call this from the draw thread.
 */
void DXOcclusionQueryContext9::
waiting_for_answer() {
  get_num_fragments();
}

/**
 * Returns the number of fragments (pixels) of the specified geometry that
 * passed the depth test.  If is_answer_ready() did not return true, this
 * function may block before it returns.
 *
 * It is only valid to call this from the draw thread.
 */
int DXOcclusionQueryContext9::
get_num_fragments() const {
  DWORD result;
  HRESULT hr = _query->GetData(&result, sizeof(result), 0);
  if (hr == S_OK) {
    // The answer is ready now.
    return result;
  }

  {
    // The answer is not ready; this call will block.
    PStatTimer timer(DXGraphicsStateGuardian9::_wait_occlusion_pcollector);
    while (hr == S_FALSE) {
      hr = _query->GetData(&result, sizeof(result), D3DGETDATA_FLUSH);
    }
  }

  if (FAILED(hr)) {
    // Some failure, e.g.  devicelost.  Return a nonzero value as a worst-case
    // answer.
    dxgsg9_cat.info()
      << "occlusion query failed " << D3DERRORSTRING(hr);
    return 1;
  }

  return result;
}