dithering when use LOB Group Test example

[yanzixiang]

I just change the waypoints as this,

  sim->addWaypoint(simUtil::Waypoint(27.74211689579827, 120.51018425777667, 20000, 1.0));
  sim->addWaypoint(simUtil::Waypoint(27.711827791596537, 120.60347651555334, 20000, 1.0));
  sim->addWaypoint(simUtil::Waypoint(27.681538687394806, 120.69676877333, 20000, 1.0));
  sim->addWaypoint(simUtil::Waypoint(27.651249583193074, 120.79006103110667, 20000, 1.0));
  sim->addWaypoint(simUtil::Waypoint(27.620960478991343, 120.88335328888334, 20000, 1.0));

and i got this

it seems that, the function here, https://github.com/USNavalResearchLaboratory/simdissdk/blob/0124ce7c6ce36327e9e51b9d28a86ef7c3486b05/SDK/simUtil/PlatformSimulator.cpp#L67

int PlatformSimulator::updatePlatform(double time, simData::PlatformUpdate *update) select two point at the start,

  // our 2 waypoints.
  Waypoint wp0 = waypoints_.front();
  Waypoint wp1 = waypoints_.size() > 1 ? *(waypoints_.begin() + 1) : wp0;

https://github.com/USNavalResearchLaboratory/simdissdk/blob/0124ce7c6ce36327e9e51b9d28a86ef7c3486b05/SDK/simUtil/PlatformSimulator.cpp#L161

    double by = sin(new_dlon_rad)*cos(lat1_rad);
    double bx = cos(lat_rad)*sin(lat1_rad) - sin(lat_rad)*cos(lat1_rad)*cos(new_dlon_rad);
    double bearing_rad = atan2(by, bx);
    if (overrideYaw_)
      bearing_rad = overrideYawValue_;

if wp0 == wp1, will casue bearing_rad be set to 90, maybe, wp0 should be selected by a previous point, or, bearing_rad shold be recorded.

the full code is here

/* -*- mode: c++ -*- */
/****************************************************************************
 *****                                                                  *****
 *****                   Classification: UNCLASSIFIED                   *****
 *****                    Classified By:                                *****
 *****                    Declassify On:                                *****
 *****                                                                  *****
 ****************************************************************************
 *
 *
 * Developed by: Naval Research Laboratory, Tactical Electronic Warfare Div.
 *               EW Modeling & Simulation, Code 5773
 *               4555 Overlook Ave.
 *               Washington, D.C. 20375-5339
 *
 * License for source code is in accompanying LICENSE.txt file. If you did
 * not receive a LICENSE.txt with this code, email simdis@nrl.navy.mil.
 *
 * The U.S. Government retains all rights to use, duplicate, distribute,
 * disclose, or release this software.
 *
 */

/**
 * Demonstrates how to use the Line of Bearing object, which display multiple time
 * stamped lines emanating from a platform's history trail.
 */

/// the simulator provides time/space data for our platform
#include "simUtil/PlatformSimulator.h"
#include "simData/MemoryDataStore.h"
#include "simCore/Common/Version.h"
#include "simCore/Common/HighPerformanceGraphics.h"
#include "simCore/Calc/CoordinateConverter.h"

/// include definitions for objects of interest
#include "simVis/Platform.h"
#include "simVis/PlatformModel.h"
#include "simVis/Locator.h"
#include "simVis/Scenario.h"
#include "simVis/SceneManager.h"
#include "simVis/Utils.h"

/// some basic components (mouse hover popups, scenario, utilities, camera controls)
#include "simVis/Viewer.h"

/// Animated lines
#include "simVis/LobGroup.h"
#include "simVis/GOG/Annotation.h"

/// paths to models
#include "simUtil/ExampleResources.h"

//----------------------------------------------------------------------------

// first line, describe the program
static const std::string s_title = "LOB Group Test";

//----------------------------------------------------------------------------

// create a platform and add it to 'dataStore'
simData::ObjectId addPlatform(simData::DataStore& dataStore)
{
  // create the platform:
  simData::ObjectId platformId;
  {
    simData::DataStore::Transaction xaction;
    simData::PlatformProperties* props = dataStore.addPlatform(&xaction);
    platformId = props->id();
    xaction.complete(&props);
  }

  // now configure its preferences:
  {
    simData::DataStore::Transaction xaction;
    simData::PlatformPrefs* prefs = dataStore.mutable_platformPrefs(platformId, &xaction);
    prefs->set_icon(EXAMPLE_AIRPLANE_ICON);
    prefs->set_scale(3.0f);
    prefs->set_dynamicscale(true);
    prefs->mutable_commonprefs()->mutable_labelprefs()->set_draw(true);
    xaction.complete(&prefs);
  }

  return platformId;
}

//----------------------------------------------------------------------------

simData::ObjectId addLobGroup(simData::ObjectId p1, simData::DataStore& ds)
{
  simData::ObjectId lobID;

  // make a LOB group
  {
    simData::DataStore::Transaction xaction;
    simData::LobGroupProperties* props = ds.addLobGroup(&xaction);
    lobID = props->id();
    props->set_hostid(p1);
    xaction.complete(&props);
  }

  // initial prefs
  {
    simData::DataStore::Transaction xaction;
    simData::LobGroupPrefs* prefs = ds.mutable_lobGroupPrefs(lobID, &xaction);
    prefs->set_color1(0xFF0000FF);
    prefs->set_color2(0x00FF00FF);
    prefs->set_stipple1(0xFF00);
    prefs->set_stipple2(0x00FF);
    prefs->set_lobwidth(4);
    prefs->mutable_commonprefs()->set_datadraw(true);
    prefs->mutable_commonprefs()->set_draw(true);
    xaction.complete(&prefs);
  }

  return lobID;
}

//----------------------------------------------------------------------------

void simulatePlatform(simData::ObjectId id, simData::DataStore& ds, simVis::Viewer* viewer)
{
  // set up a simple simulation to move the platform.
  osg::ref_ptr<simUtil::PlatformSimulator> sim = new simUtil::PlatformSimulator(id);

  sim->addWaypoint(simUtil::Waypoint(27.74211689579827, 120.51018425777667, 20000, 1.0));
  sim->addWaypoint(simUtil::Waypoint(27.711827791596537, 120.60347651555334, 20000, 1.0));
  sim->addWaypoint(simUtil::Waypoint(27.681538687394806, 120.69676877333, 20000, 1.0));
  sim->addWaypoint(simUtil::Waypoint(27.651249583193074, 120.79006103110667, 20000, 1.0));
  sim->addWaypoint(simUtil::Waypoint(27.620960478991343, 120.88335328888334, 20000, 1.0));

  osg::ref_ptr<simUtil::PlatformSimulatorManager> simman = new simUtil::PlatformSimulatorManager(&ds);
  simman->addSimulator(sim.get());
  simman->simulate(0.0, 1.0 * 5, 30.0);

  osg::ref_ptr<simUtil::SimulatorEventHandler> simHandler = new simUtil::SimulatorEventHandler(simman.get(), 0.0, 1.0 * 5);
  viewer->addEventHandler(simHandler.get());
}

//----------------------------------------------------------------------------

void simulateLobGroup(simData::ObjectId lobID, simData::DataStore& ds)
{
  for (double i = 0.0; i <= 12.0; i += 1.0)
  {
    simData::DataStore::Transaction xaction;
    simData::LobGroupUpdate* update = ds.addLobGroupUpdate(lobID, &xaction);
    update->set_time(i*3.0);
    {
      simData::LobGroupUpdatePoint* p = update->add_datapoints();
      p->set_time(i*3.0);
      p->set_range(100000.0);
      p->set_azimuth(-1.57 + (3.14*i/12.0));
      p->set_elevation(-.39 + (0.78*i/12.0));
    }
    xaction.complete(&update);
  }

  // Color constants in RGBA format
  static const uint32_t RED = 0xff0000ff;
  static const uint32_t GREEN = 0x00ff00ff;
  static const uint32_t BLUE = 0x0000ffff;
  static const uint32_t WHITE = 0xffffffff;

  // Add color changes
  // First color change: red/white, alternating colors
  {
    simData::DataStore::Transaction xaction;
    simData::LobGroupCommand* cmd = ds.addLobGroupCommand(lobID, &xaction);

    cmd->set_time(12.0);
    cmd->mutable_updateprefs()->set_color1(RED);
    cmd->mutable_updateprefs()->set_color2(WHITE);
    cmd->mutable_updateprefs()->set_stipple1(0xff00);
    cmd->mutable_updateprefs()->set_stipple2(0x00ff);
    xaction.complete(&cmd);
  }

  // Second color change: Blue/green, with a gap in the middle
  {
    simData::DataStore::Transaction xaction;
    simData::LobGroupCommand* cmd = ds.addLobGroupCommand(lobID, &xaction);

    cmd->set_time(24.0);
    cmd->mutable_updateprefs()->set_color1(BLUE);
    cmd->mutable_updateprefs()->set_color2(GREEN);
    cmd->mutable_updateprefs()->set_stipple1(0xf00f);
    cmd->mutable_updateprefs()->set_stipple2(0x00f0);
    xaction.complete(&cmd);
  }
}

//----------------------------------------------------------------------------

int main(int argc, char **argv)
{
  // Set up the scene:
  simCore::checkVersionThrow();
  simExamples::configureSearchPaths();

  osg::ref_ptr<osgEarth::Map> map = simExamples::createDefaultExampleMap();
  osg::ref_ptr<simVis::Viewer> viewer = new simVis::Viewer();
  viewer->setMap(map.get());
  viewer->setNavigationMode(simVis::NAVMODE_ROTATEPAN);

  // Set up the data:
  osg::ref_ptr<simVis::SceneManager> scene = viewer->getSceneManager();
  simData::MemoryDataStore dataStore;
  scene->getScenario()->bind(&dataStore);

  // add sky node
  simExamples::addDefaultSkyNode(viewer.get());

  simData::ObjectId platform2 = addPlatform(dataStore);

  // put platform 2 in motion
  simulatePlatform(platform2, dataStore, viewer.get());

  // make some lobs
  simData::ObjectId lobID = addLobGroup(platform2, dataStore);
  simulateLobGroup(lobID, dataStore);

  // tick the sim
  dataStore.update(0);

  // zoom the camera
  viewer->getMainView()->tetherCamera(scene->getScenario()->find(platform2));
  viewer->getMainView()->setFocalOffsets(0, -45, 4e5);

  // add some stock OSG handlers and go
  viewer->installDebugHandlers();
  return viewer->run();
}

[emminizer]

Thank you for your reported issue. I do see bad behavior in the display as you indicate, with the included sample code.

simUtil::PlatformSimulator is a relatively small class and currently only used in SIMDIS SDK examples. It is fit for purpose in order to simply get platforms moving in a scenario. I'm not surprised by the bad behavior you uncovered, as we do not stress this particular code much beyond the examples.

At this time we do not have the spare time to address this issue. However, if you were to submit a pull request on a suggested improvement we'd be happy to take a look at merging it in.