src/Main/CameraGroup.cxx

   1 // Copyright (C) 2008  Tim Moore
   2 //
   3 // This program is free software; you can redistribute it and/or
   4 // modify it under the terms of the GNU General Public License as
   5 // published by the Free Software Foundation; either version 2 of the
   6 // License, or (at your option) any later version.
   7 //
   8 // This program is distributed in the hope that it will be useful, but
   9 // WITHOUT ANY WARRANTY; without even the implied warranty of
  10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 // General Public License for more details.
  12 //
  13 // You should have received a copy of the GNU General Public License
  14 // along with this program; if not, write to the Free Software
  15 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  16
  17 #include "CameraGroup.hxx"
  18
  19 #include "globals.hxx"
  20 #include "renderer.hxx"
  21 #include "FGEventHandler.hxx"
  22 #include "WindowBuilder.hxx"
  23 #include "WindowSystemAdapter.hxx"
  24 #include <simgear/props/props.hxx>
  25 #include <simgear/structure/OSGUtils.hxx>
  26 #include <simgear/scene/material/EffectCullVisitor.hxx>
  27 #include <simgear/scene/util/RenderConstants.hxx>
  28
  29 #include <algorithm>
  30 #include <cstring>
  31 #include <string>
  32
  33 #include <osg/Camera>
  34 #include <osg/GraphicsContext>
  35 #include <osg/Math>
  36 #include <osg/Matrix>
  37 #include <osg/Quat>
  38 #include <osg/Vec3d>
  39 #include <osg/Viewport>
  40
  41 #include <osgUtil/IntersectionVisitor>
  42
  43 #include <osgViewer/GraphicsWindow>
  44 #include <osgViewer/Renderer>
  45
  46 namespace flightgear
  47 {
  48 using namespace osg;
  49
  50 using std::strcmp;
  51 using std::string;
  52
  53 ref_ptr<CameraGroup> CameraGroup::_defaultGroup;
  54
  55 CameraGroup::CameraGroup(osgViewer::Viewer* viewer) :
  56     _viewer(viewer)
  57 {
  58 }
  59
  60 }
  61
  62 namespace
  63 {
  64 using namespace osg;
  65
  66 // Given a projection matrix, return a new one with the same frustum
  67 // sides and new near / far values.
  68
  69 void makeNewProjMat(Matrixd& oldProj, double znear,
  70                                        double zfar, Matrixd& projection)
  71 {
  72     projection = oldProj;
  73     // Slightly inflate the near & far planes to avoid objects at the
  74     // extremes being clipped out.
  75     znear *= 0.999;
  76     zfar *= 1.001;
  77
  78     // Clamp the projection matrix z values to the range (near, far)
  79     double epsilon = 1.0e-6;
  80     if (fabs(projection(0,3)) < epsilon &&
  81         fabs(projection(1,3)) < epsilon &&
  82         fabs(projection(2,3)) < epsilon) {
  83         // Projection is Orthographic
  84         epsilon = -1.0/(zfar - znear); // Used as a temp variable
  85         projection(2,2) = 2.0*epsilon;
  86         projection(3,2) = (zfar + znear)*epsilon;
  87     } else {
  88         // Projection is Perspective
  89         double trans_near = (-znear*projection(2,2) + projection(3,2)) /
  90             (-znear*projection(2,3) + projection(3,3));
  91         double trans_far = (-zfar*projection(2,2) + projection(3,2)) /
  92             (-zfar*projection(2,3) + projection(3,3));
  93         double ratio = fabs(2.0/(trans_near - trans_far));
  94         double center = -0.5*(trans_near + trans_far);
  95
  96         projection.postMult(osg::Matrixd(1.0, 0.0, 0.0, 0.0,
  97                                          0.0, 1.0, 0.0, 0.0,
  98                                          0.0, 0.0, ratio, 0.0,
  99                                          0.0, 0.0, center*ratio, 1.0));
 100     }
 101 }
 102
 103 void installCullVisitor(Camera* camera)
 104 {
 105     osgViewer::Renderer* renderer
 106         = static_cast<osgViewer::Renderer*>(camera->getRenderer());
 107     for (int i = 0; i < 2; ++i) {
 108         osgUtil::SceneView* sceneView = renderer->getSceneView(i);
 109         sceneView->setCullVisitor(new simgear::EffectCullVisitor);
 110     }
 111 }
 112 }
 113
 114 namespace flightgear
 115 {
 116 void updateCameras(const CameraInfo* info)
 117 {
 118     if (info->camera.valid())
 119         info->camera->getViewport()->setViewport(info->x, info->y,
 120                                                  info->width, info->height);
 121     if (info->farCamera.valid())
 122         info->farCamera->getViewport()->setViewport(info->x, info->y,
 123                                                     info->width, info->height);
 124 }
 125
 126 CameraInfo* CameraGroup::addCamera(unsigned flags, Camera* camera,
 127                                    const Matrix& view,
 128                                    const Matrix& projection,
 129                                    bool useMasterSceneData)
 130 {
 131     CameraInfo* info = new CameraInfo(flags);
 132     // The camera group will always update the camera
 133     camera->setReferenceFrame(Transform::ABSOLUTE_RF);
 134
 135     Camera* farCamera = 0;
 136     if ((flags & (GUI | ORTHO)) == 0) {
 137         farCamera = new Camera;
 138         farCamera->setAllowEventFocus(camera->getAllowEventFocus());
 139         farCamera->setGraphicsContext(camera->getGraphicsContext());
 140         farCamera->setCullingMode(camera->getCullingMode());
 141         farCamera->setInheritanceMask(camera->getInheritanceMask());
 142         farCamera->setReferenceFrame(Transform::ABSOLUTE_RF);
 143         // Each camera's viewport is written when the window is
 144         // resized; if the the viewport isn't copied here, it gets updated
 145         // twice and ends up with the wrong value.
 146         farCamera->setViewport(simgear::clone(camera->getViewport()));
 147         _viewer->addSlave(farCamera, view, projection, useMasterSceneData);
 148         installCullVisitor(farCamera);
 149         info->farCamera = farCamera;
 150         info->farSlaveIndex = _viewer->getNumSlaves() - 1;
 151         farCamera->setRenderOrder(Camera::POST_RENDER, info->farSlaveIndex);
 152         camera->setCullMask(camera->getCullMask() & ~simgear::BACKGROUND_BIT);
 153         camera->setClearMask(GL_DEPTH_BUFFER_BIT);
 154     }
 155     _viewer->addSlave(camera, view, projection, useMasterSceneData);
 156     installCullVisitor(camera);
 157     info->camera = camera;
 158     info->slaveIndex = _viewer->getNumSlaves() - 1;
 159     camera->setRenderOrder(Camera::POST_RENDER, info->slaveIndex);
 160     _cameras.push_back(info);
 161     return info;
 162 }
 163
 164 void CameraGroup::update(const osg::Vec3d& position,
 165                          const osg::Quat& orientation)
 166 {
 167     const Matrix masterView(osg::Matrix::translate(-position)
 168                             * osg::Matrix::rotate(orientation.inverse()));
 169     _viewer->getCamera()->setViewMatrix(masterView);
 170     const Matrix& masterProj = _viewer->getCamera()->getProjectionMatrix();
 171     for (CameraList::iterator i = _cameras.begin(); i != _cameras.end(); ++i) {
 172         const CameraInfo* info = i->get();
 173         const View::Slave& slave = _viewer->getSlave(info->slaveIndex);
 174         // refreshes camera viewports (for now)
 175         updateCameras(info);
 176         Camera* camera = info->camera.get();
 177         Matrix viewMatrix;
 178         if ((info->flags & VIEW_ABSOLUTE) != 0)
 179             viewMatrix = slave._viewOffset;
 180         else
 181             viewMatrix = masterView * slave._viewOffset;
 182         camera->setViewMatrix(viewMatrix);
 183         Matrix projectionMatrix;
 184         if ((info->flags & PROJECTION_ABSOLUTE) != 0)
 185             projectionMatrix = slave._projectionOffset;
 186         else
 187             projectionMatrix = masterProj * slave._projectionOffset;
 188
 189         if (!info->farCamera.valid()) {
 190             camera->setProjectionMatrix(projectionMatrix);
 191         } else {
 192             Camera* farCamera = info->farCamera.get();
 193             farCamera->setViewMatrix(viewMatrix);
 194             double left, right, bottom, top, parentNear, parentFar;
 195             projectionMatrix.getFrustum(left, right, bottom, top,
 196                                         parentNear, parentFar);
 197             if (parentFar < _nearField || _nearField == 0.0f) {
 198                 camera->setProjectionMatrix(projectionMatrix);
 199                 camera->setCullMask(camera->getCullMask()
 200                                     | simgear::BACKGROUND_BIT);
 201                 camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 202                 farCamera->setNodeMask(0);
 203             } else {
 204                 Matrix nearProj, farProj;
 205                 makeNewProjMat(projectionMatrix, parentNear, _nearField,
 206                                nearProj);
 207                 makeNewProjMat(projectionMatrix, _nearField, parentFar,
 208                                farProj);
 209                 camera->setProjectionMatrix(nearProj);
 210                 camera->setCullMask(camera->getCullMask()
 211                                     & ~simgear::BACKGROUND_BIT);
 212                 camera->setClearMask(GL_DEPTH_BUFFER_BIT);
 213                 farCamera->setProjectionMatrix(farProj);
 214                 farCamera->setNodeMask(camera->getNodeMask());
 215             }
 216         }
 217     }
 218 }
 219
 220 void CameraGroup::setCameraParameters(float vfov, float aspectRatio)
 221 {
 222     if (vfov != 0.0f && aspectRatio != 0.0f)
 223         _viewer->getCamera()
 224             ->setProjectionMatrixAsPerspective(vfov,
 225                                                1.0f / aspectRatio,
 226                                                _zNear, _zFar);
 227 }
 228 }
 229
 230 namespace
 231 {
 232 // A raw value for property nodes that references a class member via
 233 // an osg::ref_ptr.
 234 template<class C, class T>
 235 class RefMember : public SGRawValue<T>
 236 {
 237 public:
 238     RefMember (C *obj, T C::*ptr)
 239         : _obj(obj), _ptr(ptr) {}
 240     virtual ~RefMember () {}
 241     virtual T getValue () const
 242     {
 243         return _obj.get()->*_ptr;
 244     }
 245     virtual bool setValue (T value)
 246     {
 247         _obj.get()->*_ptr = value;
 248         return true;
 249     }
 250     virtual SGRawValue<T> * clone () const
 251     {
 252         return new RefMember(_obj.get(), _ptr);
 253     }
 254 private:
 255     ref_ptr<C> _obj;
 256     T C::* const _ptr;
 257 };
 258
 259 template<typename C, typename T>
 260 RefMember<C, T> makeRefMember(C *obj, T C::*ptr)
 261 {
 262     return RefMember<C, T>(obj, ptr);
 263 }
 264
 265 template<typename C, typename T>
 266 void bindMemberToNode(SGPropertyNode* parent, const char* childName,
 267                       C* obj, T C::*ptr, T value)
 268 {
 269     SGPropertyNode* valNode = parent->getNode(childName);
 270     RefMember<C, T> refMember = makeRefMember(obj, ptr);
 271     if (!valNode) {
 272         valNode = parent->getNode(childName, true);
 273         valNode->tie(refMember, false);
 274         setValue(valNode, value);
 275     } else {
 276         valNode->tie(refMember, true);
 277     }
 278 }
 279
 280 void buildViewport(flightgear::CameraInfo* info, SGPropertyNode* viewportNode,
 281                    const osg::GraphicsContext::Traits *traits)
 282 {
 283     using namespace flightgear;
 284     bindMemberToNode(viewportNode, "x", info, &CameraInfo::x, 0.0);
 285     bindMemberToNode(viewportNode, "y", info, &CameraInfo::y, 0.0);
 286     bindMemberToNode(viewportNode, "width", info, &CameraInfo::width,
 287                      static_cast<double>(traits->width));
 288     bindMemberToNode(viewportNode, "height", info, &CameraInfo::height,
 289                      static_cast<double>(traits->height));
 290 }
 291 }
 292
 293 namespace flightgear
 294 {
 295
 296 CameraInfo* CameraGroup::buildCamera(SGPropertyNode* cameraNode)
 297 {
 298     WindowBuilder *wBuild = WindowBuilder::getWindowBuilder();
 299     const SGPropertyNode* windowNode = cameraNode->getNode("window");
 300     GraphicsWindow* window = 0;
 301     int cameraFlags = DO_INTERSECTION_TEST;
 302     if (windowNode) {
 303         // New style window declaration / definition
 304         window = wBuild->buildWindow(windowNode);
 305     } else {
 306         // Old style: suck window params out of camera block
 307         window = wBuild->buildWindow(cameraNode);
 308     }
 309     if (!window) {
 310         return 0;
 311     }
 312     Camera* camera = new Camera;
 313     camera->setAllowEventFocus(false);
 314     camera->setGraphicsContext(window->gc.get());
 315     camera->setViewport(new Viewport);
 316     camera->setCullingMode(CullSettings::SMALL_FEATURE_CULLING
 317                            | CullSettings::VIEW_FRUSTUM_CULLING);
 318     camera->setInheritanceMask(CullSettings::ALL_VARIABLES
 319                                & ~(CullSettings::CULL_MASK
 320                                    | CullSettings::CULLING_MODE
 321                                    | CullSettings::CLEAR_MASK));
 322
 323     osg::Matrix pOff;
 324     osg::Matrix vOff;
 325     const SGPropertyNode* viewNode = cameraNode->getNode("view");
 326     if (viewNode) {
 327         double heading = viewNode->getDoubleValue("heading-deg", 0.0);
 328         double pitch = viewNode->getDoubleValue("pitch-deg", 0.0);
 329         double roll = viewNode->getDoubleValue("roll-deg", 0.0);
 330         double x = viewNode->getDoubleValue("x", 0.0);
 331         double y = viewNode->getDoubleValue("y", 0.0);
 332         double z = viewNode->getDoubleValue("z", 0.0);
 333         // Build a view matrix, which is the inverse of a model
 334         // orientation matrix.
 335         vOff = (Matrix::translate(-x, -y, -z)
 336                 * Matrix::rotate(-DegreesToRadians(heading),
 337                                  Vec3d(0.0, 1.0, 0.0),
 338                                  -DegreesToRadians(pitch),
 339                                  Vec3d(1.0, 0.0, 0.0),
 340                                  -DegreesToRadians(roll),
 341                                  Vec3d(0.0, 0.0, 1.0)));
 342         if (viewNode->getBoolValue("absolute", false))
 343             cameraFlags |= VIEW_ABSOLUTE;
 344     } else {
 345         // Old heading parameter, works in the opposite direction
 346         double heading = cameraNode->getDoubleValue("heading-deg", 0.0);
 347         vOff.makeRotate(DegreesToRadians(heading), osg::Vec3(0, 1, 0));
 348     }
 349     const SGPropertyNode* projectionNode = 0;
 350     if ((projectionNode = cameraNode->getNode("perspective")) != 0) {
 351         double fovy = projectionNode->getDoubleValue("fovy-deg", 55.0);
 352         double aspectRatio = projectionNode->getDoubleValue("aspect-ratio",
 353                                                             1.0);
 354         double zNear = projectionNode->getDoubleValue("near", 0.0);
 355         double zFar = projectionNode->getDoubleValue("far", 0.0);
 356         double offsetX = projectionNode->getDoubleValue("offset-x", 0.0);
 357         double offsetY = projectionNode->getDoubleValue("offset-y", 0.0);
 358         double tan_fovy = tan(DegreesToRadians(fovy*0.5));
 359         double right = tan_fovy * aspectRatio * zNear + offsetX;
 360         double left = -tan_fovy * aspectRatio * zNear + offsetX;
 361         double top = tan_fovy * zNear + offsetY;
 362         double bottom = -tan_fovy * zNear + offsetY;
 363         pOff.makeFrustum(left, right, bottom, top, zNear, zFar);
 364         cameraFlags |= PROJECTION_ABSOLUTE;
 365     } else if ((projectionNode = cameraNode->getNode("frustum")) != 0
 366                || (projectionNode = cameraNode->getNode("ortho")) != 0) {
 367         double top = projectionNode->getDoubleValue("top", 0.0);
 368         double bottom = projectionNode->getDoubleValue("bottom", 0.0);
 369         double left = projectionNode->getDoubleValue("left", 0.0);
 370         double right = projectionNode->getDoubleValue("right", 0.0);
 371         double zNear = projectionNode->getDoubleValue("near", 0.0);
 372         double zFar = projectionNode->getDoubleValue("far", 0.0);
 373         if (cameraNode->getNode("frustum")) {
 374             pOff.makeFrustum(left, right, bottom, top, zNear, zFar);
 375             cameraFlags |= PROJECTION_ABSOLUTE;
 376         } else {
 377             pOff.makeOrtho(left, right, bottom, top, zNear, zFar);
 378             cameraFlags |= (PROJECTION_ABSOLUTE | ORTHO);
 379         }
 380     } else {
 381         // old style shear parameters
 382         double shearx = cameraNode->getDoubleValue("shear-x", 0);
 383         double sheary = cameraNode->getDoubleValue("shear-y", 0);
 384         pOff.makeTranslate(-shearx, -sheary, 0);
 385     }
 386     CameraInfo* info = addCamera(cameraFlags, camera, pOff, vOff);
 387     // If a viewport isn't set on the camera, then it's hard to dig it
 388     // out of the SceneView objects in the viewer, and the coordinates
 389     // of mouse events are somewhat bizzare.
 390     SGPropertyNode* viewportNode = cameraNode->getNode("viewport", true);
 391     buildViewport(info, viewportNode, window->gc->getTraits());
 392     updateCameras(info);
 393     return info;
 394 }
 395
 396 CameraInfo* CameraGroup::buildGUICamera(SGPropertyNode* cameraNode,
 397                                         GraphicsWindow* window)
 398 {
 399     WindowBuilder *wBuild = WindowBuilder::getWindowBuilder();
 400     const SGPropertyNode* windowNode = (cameraNode
 401                                         ? cameraNode->getNode("window")
 402                                         : 0);
 403     if (!window) {
 404         if (windowNode) {
 405             // New style window declaration / definition
 406             window = wBuild->buildWindow(windowNode);
 407
 408         } else {
 409             return 0;
 410         }
 411     }
 412     Camera* camera = new Camera;
 413     camera->setAllowEventFocus(false);
 414     camera->setGraphicsContext(window->gc.get());
 415     camera->setViewport(new Viewport);
 416     // XXX Camera needs to be drawn last; eventually the render order
 417     // should be assigned by a camera manager.
 418     camera->setRenderOrder(osg::Camera::POST_RENDER, 100);
 419         camera->setClearMask(0);
 420     camera->setInheritanceMask(CullSettings::ALL_VARIABLES
 421                                & ~(CullSettings::COMPUTE_NEAR_FAR_MODE
 422                                    | CullSettings::CULLING_MODE
 423                                    | CullSettings::CLEAR_MASK));
 424     camera->setComputeNearFarMode(osg::CullSettings::DO_NOT_COMPUTE_NEAR_FAR);
 425     camera->setCullingMode(osg::CullSettings::NO_CULLING);
 426     camera->setProjectionResizePolicy(Camera::FIXED);
 427     camera->setReferenceFrame(Transform::ABSOLUTE_RF);
 428     const int cameraFlags = GUI;
 429     CameraInfo* result = addCamera(cameraFlags, camera, Matrixd::identity(),
 430                                    Matrixd::identity(), false);
 431     SGPropertyNode* viewportNode = cameraNode->getNode("viewport", true);
 432     buildViewport(result, viewportNode, window->gc->getTraits());
 433
 434     // Disable statistics for the GUI camera.
 435     result->camera->setStats(0);
 436     updateCameras(result);
 437     return result;
 438 }
 439
 440 CameraGroup* CameraGroup::buildCameraGroup(osgViewer::Viewer* viewer,
 441                                            SGPropertyNode* gnode)
 442 {
 443     CameraGroup* cgroup = new CameraGroup(viewer);
 444     for (int i = 0; i < gnode->nChildren(); ++i) {
 445         SGPropertyNode* pNode = gnode->getChild(i);
 446         const char* name = pNode->getName();
 447         if (!strcmp(name, "camera")) {
 448             cgroup->buildCamera(pNode);
 449         } else if (!strcmp(name, "window")) {
 450             WindowBuilder::getWindowBuilder()->buildWindow(pNode);
 451         } else if (!strcmp(name, "gui")) {
 452             cgroup->buildGUICamera(pNode);
 453         }
 454     }
 455     bindMemberToNode(gnode, "znear", cgroup, &CameraGroup::_zNear, .1f);
 456     bindMemberToNode(gnode, "zfar", cgroup, &CameraGroup::_zFar, 120000.0f);
 457     bindMemberToNode(gnode, "near-field", cgroup, &CameraGroup::_nearField,
 458                      100.0f);
 459     return cgroup;
 460 }
 461
 462 void CameraGroup::setCameraCullMasks(Node::NodeMask nm)
 463 {
 464     for (CameraIterator i = camerasBegin(), e = camerasEnd(); i != e; ++i) {
 465         CameraInfo* info = i->get();
 466         if (info->flags & GUI)
 467             continue;
 468         if (info->farCamera.valid() && info->farCamera->getNodeMask() != 0) {
 469             info->camera->setCullMask(nm & ~simgear::BACKGROUND_BIT);
 470             info->farCamera->setCullMask(nm);
 471         } else {
 472             info->camera->setCullMask(nm);
 473         }
 474     }
 475 }
 476
 477 void CameraGroup::resized()
 478 {
 479     for (CameraIterator i = camerasBegin(), e = camerasEnd(); i != e; ++i) {
 480         CameraInfo *info = i->get();
 481         const Viewport* viewport = info->camera->getViewport();
 482         info->x = viewport->x();
 483         info->y = viewport->y();
 484         info->width = viewport->width();
 485         info->height = viewport->height();
 486     }
 487 }
 488
 489 Camera* getGUICamera(CameraGroup* cgroup)
 490 {
 491     CameraGroup::CameraIterator end = cgroup->camerasEnd();
 492     CameraGroup::CameraIterator result
 493         = std::find_if(cgroup->camerasBegin(), end,
 494                        FlagTester<CameraInfo>(CameraGroup::GUI));
 495     if (result != end)
 496         return (*result)->camera.get();
 497     else
 498         return 0;
 499 }
 500
 501 bool computeIntersections(const CameraGroup* cgroup,
 502                           const osgGA::GUIEventAdapter* ea,
 503                           osgUtil::LineSegmentIntersector::Intersections& intersections)
 504 {
 505     using osgUtil::Intersector;
 506     using osgUtil::LineSegmentIntersector;
 507     double x, y;
 508     eventToWindowCoords(ea, x, y);
 509     // Find camera that contains event
 510     for (CameraGroup::ConstCameraIterator iter = cgroup->camerasBegin(),
 511              e = cgroup->camerasEnd();
 512          iter != e;
 513          ++iter) {
 514         const CameraInfo* cinfo = iter->get();
 515         if ((cinfo->flags & CameraGroup::DO_INTERSECTION_TEST) == 0)
 516             continue;
 517         const Camera* camera = cinfo->camera.get();
 518         if (camera->getGraphicsContext() != ea->getGraphicsContext())
 519             continue;
 520         const Viewport* viewport = camera->getViewport();
 521         double epsilon = 0.5;
 522         if (!(x >= viewport->x() - epsilon
 523               && x < viewport->x() + viewport->width() -1.0 + epsilon
 524               && y >= viewport->y() - epsilon
 525               && y < viewport->y() + viewport->height() -1.0 + epsilon))
 526             continue;
 527         Vec4d start(x, y, 0.0, 1.0);
 528         Vec4d end(x, y, 1.0, 1.0);
 529         Matrix windowMat = viewport->computeWindowMatrix();
 530         Matrix startPtMat = Matrix::inverse(camera->getProjectionMatrix()
 531                                             * windowMat);
 532         Matrix endPtMat;
 533         if (!cinfo->farCamera.valid() || cinfo->farCamera->getNodeMask() == 0)
 534             endPtMat = startPtMat;
 535         else
 536             endPtMat = Matrix::inverse(cinfo->farCamera->getProjectionMatrix()
 537                                        * windowMat);
 538         start = start * startPtMat;
 539         start /= start.w();
 540         end = end * endPtMat;
 541         end /= end.w();
 542         ref_ptr<LineSegmentIntersector> picker
 543             = new LineSegmentIntersector(Intersector::VIEW,
 544                                          Vec3d(start.x(), start.y(), start.z()),
 545                                          Vec3d(end.x(), end.y(), end.z()));
 546         osgUtil::IntersectionVisitor iv(picker.get());
 547         const_cast<Camera*>(camera)->accept(iv);
 548         if (picker->containsIntersections()) {
 549             intersections = picker->getIntersections();
 550             return true;
 551         } else {
 552             break;
 553         }
 554     }
 555     intersections.clear();
 556     return false;
 557 }
 558
 559 void warpGUIPointer(CameraGroup* cgroup, int x, int y)
 560 {
 561     using osgViewer::GraphicsWindow;
 562     Camera* guiCamera = getGUICamera(cgroup);
 563     if (!guiCamera)
 564         return;
 565     Viewport* vport = guiCamera->getViewport();
 566     GraphicsWindow* gw
 567         = dynamic_cast<GraphicsWindow*>(guiCamera->getGraphicsContext());
 568     if (!gw)
 569         return;
 570     globals->get_renderer()->getEventHandler()->setMouseWarped();
 571     // Translate the warp request into the viewport of the GUI camera,
 572     // send the request to the window, then transform the coordinates
 573     // for the Viewer's event queue.
 574     double wx = x + vport->x();
 575     double wyUp = vport->height() + vport->y() - y;
 576     double wy;
 577     const GraphicsContext::Traits* traits = gw->getTraits();
 578     if (gw->getEventQueue()->getCurrentEventState()->getMouseYOrientation()
 579         == osgGA::GUIEventAdapter::Y_INCREASING_DOWNWARDS) {
 580         wy = traits->height - wyUp;
 581     } else {
 582         wy = wyUp;
 583     }
 584     gw->getEventQueue()->mouseWarped(wx, wy);
 585     gw->requestWarpPointer(wx, wy);
 586     osgGA::GUIEventAdapter* eventState
 587         = cgroup->getViewer()->getEventQueue()->getCurrentEventState();
 588     double viewerX
 589         = (eventState->getXmin()
 590            + ((wx / double(traits->width))
 591               * (eventState->getXmax() - eventState->getXmin())));
 592     double viewerY
 593         = (eventState->getYmin()
 594            + ((wyUp / double(traits->height))
 595               * (eventState->getYmax() - eventState->getYmin())));
 596     cgroup->getViewer()->getEventQueue()->mouseWarped(viewerX, viewerY);
 597 }
 598 }