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 #ifdef HAVE_CONFIG_H
  18 #  include <config.h>
  19 #endif
  20
  21 #include "CameraGroup.hxx"
  22
  23 #include "globals.hxx"
  24 #include "renderer.hxx"
  25 #include "FGEventHandler.hxx"
  26 #include "WindowBuilder.hxx"
  27 #include "WindowSystemAdapter.hxx"
  28 #include <simgear/props/props.hxx>
  29 #include <simgear/structure/OSGUtils.hxx>
  30 #include <simgear/scene/material/EffectCullVisitor.hxx>
  31 #include <simgear/scene/util/RenderConstants.hxx>
  32
  33 #include <algorithm>
  34 #include <cstring>
  35 #include <string>
  36
  37 #include <osg/Camera>
  38 #include <osg/GraphicsContext>
  39 #include <osg/Math>
  40 #include <osg/Matrix>
  41 #include <osg/Quat>
  42 #include <osg/Vec3d>
  43 #include <osg/Viewport>
  44
  45 #include <osgUtil/IntersectionVisitor>
  46
  47 #include <osgViewer/GraphicsWindow>
  48 #include <osgViewer/Renderer>
  49
  50 namespace flightgear
  51 {
  52 using namespace osg;
  53
  54 using std::strcmp;
  55 using std::string;
  56
  57 ref_ptr<CameraGroup> CameraGroup::_defaultGroup;
  58
  59 CameraGroup::CameraGroup(osgViewer::Viewer* viewer) :
  60     _viewer(viewer)
  61 {
  62 }
  63
  64 }
  65
  66 namespace
  67 {
  68 using namespace osg;
  69
  70 // Given a projection matrix, return a new one with the same frustum
  71 // sides and new near / far values.
  72
  73 void makeNewProjMat(Matrixd& oldProj, double znear,
  74                                        double zfar, Matrixd& projection)
  75 {
  76     projection = oldProj;
  77     // Slightly inflate the near & far planes to avoid objects at the
  78     // extremes being clipped out.
  79     znear *= 0.999;
  80     zfar *= 1.001;
  81
  82     // Clamp the projection matrix z values to the range (near, far)
  83     double epsilon = 1.0e-6;
  84     if (fabs(projection(0,3)) < epsilon &&
  85         fabs(projection(1,3)) < epsilon &&
  86         fabs(projection(2,3)) < epsilon) {
  87         // Projection is Orthographic
  88         epsilon = -1.0/(zfar - znear); // Used as a temp variable
  89         projection(2,2) = 2.0*epsilon;
  90         projection(3,2) = (zfar + znear)*epsilon;
  91     } else {
  92         // Projection is Perspective
  93         double trans_near = (-znear*projection(2,2) + projection(3,2)) /
  94             (-znear*projection(2,3) + projection(3,3));
  95         double trans_far = (-zfar*projection(2,2) + projection(3,2)) /
  96             (-zfar*projection(2,3) + projection(3,3));
  97         double ratio = fabs(2.0/(trans_near - trans_far));
  98         double center = -0.5*(trans_near + trans_far);
  99
 100         projection.postMult(osg::Matrixd(1.0, 0.0, 0.0, 0.0,
 101                                          0.0, 1.0, 0.0, 0.0,
 102                                          0.0, 0.0, ratio, 0.0,
 103                                          0.0, 0.0, center*ratio, 1.0));
 104     }
 105 }
 106
 107 void installCullVisitor(Camera* camera)
 108 {
 109     osgViewer::Renderer* renderer
 110         = static_cast<osgViewer::Renderer*>(camera->getRenderer());
 111     for (int i = 0; i < 2; ++i) {
 112         osgUtil::SceneView* sceneView = renderer->getSceneView(i);
 113         sceneView->setCullVisitor(new simgear::EffectCullVisitor);
 114     }
 115 }
 116 }
 117
 118 namespace flightgear
 119 {
 120 void updateCameras(const CameraInfo* info)
 121 {
 122     if (info->camera.valid())
 123         info->camera->getViewport()->setViewport(info->x, info->y,
 124                                                  info->width, info->height);
 125     if (info->farCamera.valid())
 126         info->farCamera->getViewport()->setViewport(info->x, info->y,
 127                                                     info->width, info->height);
 128 }
 129
 130 CameraInfo* CameraGroup::addCamera(unsigned flags, Camera* camera,
 131                                    const Matrix& view,
 132                                    const Matrix& projection,
 133                                    bool useMasterSceneData)
 134 {
 135     CameraInfo* info = new CameraInfo(flags);
 136     // The camera group will always update the camera
 137     camera->setReferenceFrame(Transform::ABSOLUTE_RF);
 138
 139     Camera* farCamera = 0;
 140     if ((flags & (GUI | ORTHO)) == 0) {
 141         farCamera = new Camera;
 142         farCamera->setAllowEventFocus(camera->getAllowEventFocus());
 143         farCamera->setGraphicsContext(camera->getGraphicsContext());
 144         farCamera->setCullingMode(camera->getCullingMode());
 145         farCamera->setInheritanceMask(camera->getInheritanceMask());
 146         farCamera->setReferenceFrame(Transform::ABSOLUTE_RF);
 147         // Each camera's viewport is written when the window is
 148         // resized; if the the viewport isn't copied here, it gets updated
 149         // twice and ends up with the wrong value.
 150         farCamera->setViewport(simgear::clone(camera->getViewport()));
 151         _viewer->addSlave(farCamera, view, projection, useMasterSceneData);
 152         installCullVisitor(farCamera);
 153         info->farCamera = farCamera;
 154         info->farSlaveIndex = _viewer->getNumSlaves() - 1;
 155         farCamera->setRenderOrder(Camera::POST_RENDER, info->farSlaveIndex);
 156         camera->setCullMask(camera->getCullMask() & ~simgear::BACKGROUND_BIT);
 157         camera->setClearMask(GL_DEPTH_BUFFER_BIT);
 158     }
 159     _viewer->addSlave(camera, view, projection, useMasterSceneData);
 160     installCullVisitor(camera);
 161     info->camera = camera;
 162     info->slaveIndex = _viewer->getNumSlaves() - 1;
 163     camera->setRenderOrder(Camera::POST_RENDER, info->slaveIndex);
 164     _cameras.push_back(info);
 165     return info;
 166 }
 167
 168 void CameraGroup::update(const osg::Vec3d& position,
 169                          const osg::Quat& orientation)
 170 {
 171     const Matrix masterView(osg::Matrix::translate(-position)
 172                             * osg::Matrix::rotate(orientation.inverse()));
 173     _viewer->getCamera()->setViewMatrix(masterView);
 174     const Matrix& masterProj = _viewer->getCamera()->getProjectionMatrix();
 175     for (CameraList::iterator i = _cameras.begin(); i != _cameras.end(); ++i) {
 176         const CameraInfo* info = i->get();
 177         const View::Slave& slave = _viewer->getSlave(info->slaveIndex);
 178         // refreshes camera viewports (for now)
 179         updateCameras(info);
 180         Camera* camera = info->camera.get();
 181         Matrix viewMatrix;
 182         if ((info->flags & VIEW_ABSOLUTE) != 0)
 183             viewMatrix = slave._viewOffset;
 184         else
 185             viewMatrix = masterView * slave._viewOffset;
 186         camera->setViewMatrix(viewMatrix);
 187         Matrix projectionMatrix;
 188         if ((info->flags & PROJECTION_ABSOLUTE) != 0)
 189             projectionMatrix = slave._projectionOffset;
 190         else
 191             projectionMatrix = masterProj * slave._projectionOffset;
 192
 193         if (!info->farCamera.valid()) {
 194             camera->setProjectionMatrix(projectionMatrix);
 195         } else {
 196             Camera* farCamera = info->farCamera.get();
 197             farCamera->setViewMatrix(viewMatrix);
 198             double left, right, bottom, top, parentNear, parentFar;
 199             projectionMatrix.getFrustum(left, right, bottom, top,
 200                                         parentNear, parentFar);
 201             if (parentFar < _nearField || _nearField == 0.0f) {
 202                 camera->setProjectionMatrix(projectionMatrix);
 203                 camera->setCullMask(camera->getCullMask()
 204                                     | simgear::BACKGROUND_BIT);
 205                 camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 206                 farCamera->setNodeMask(0);
 207             } else {
 208                 Matrix nearProj, farProj;
 209                 makeNewProjMat(projectionMatrix, parentNear, _nearField,
 210                                nearProj);
 211                 makeNewProjMat(projectionMatrix, _nearField, parentFar,
 212                                farProj);
 213                 camera->setProjectionMatrix(nearProj);
 214                 camera->setCullMask(camera->getCullMask()
 215                                     & ~simgear::BACKGROUND_BIT);
 216                 camera->setClearMask(GL_DEPTH_BUFFER_BIT);
 217                 farCamera->setProjectionMatrix(farProj);
 218                 farCamera->setNodeMask(camera->getNodeMask());
 219             }
 220         }
 221     }
 222 }
 223
 224 void CameraGroup::setCameraParameters(float vfov, float aspectRatio)
 225 {
 226     if (vfov != 0.0f && aspectRatio != 0.0f)
 227         _viewer->getCamera()
 228             ->setProjectionMatrixAsPerspective(vfov,
 229                                                1.0f / aspectRatio,
 230                                                _zNear, _zFar);
 231 }
 232 }
 233
 234 namespace
 235 {
 236 // A raw value for property nodes that references a class member via
 237 // an osg::ref_ptr.
 238 template<class C, class T>
 239 class RefMember : public SGRawValue<T>
 240 {
 241 public:
 242     RefMember (C *obj, T C::*ptr)
 243         : _obj(obj), _ptr(ptr) {}
 244     virtual ~RefMember () {}
 245     virtual T getValue () const
 246     {
 247         return _obj.get()->*_ptr;
 248     }
 249     virtual bool setValue (T value)
 250     {
 251         _obj.get()->*_ptr = value;
 252         return true;
 253     }
 254     virtual SGRawValue<T> * clone () const
 255     {
 256         return new RefMember(_obj.get(), _ptr);
 257     }
 258 private:
 259     ref_ptr<C> _obj;
 260     T C::* const _ptr;
 261 };
 262
 263 template<typename C, typename T>
 264 RefMember<C, T> makeRefMember(C *obj, T C::*ptr)
 265 {
 266     return RefMember<C, T>(obj, ptr);
 267 }
 268
 269 template<typename C, typename T>
 270 void bindMemberToNode(SGPropertyNode* parent, const char* childName,
 271                       C* obj, T C::*ptr, T value)
 272 {
 273     SGPropertyNode* valNode = parent->getNode(childName);
 274     RefMember<C, T> refMember = makeRefMember(obj, ptr);
 275     if (!valNode) {
 276         valNode = parent->getNode(childName, true);
 277         valNode->tie(refMember, false);
 278         setValue(valNode, value);
 279     } else {
 280         valNode->tie(refMember, true);
 281     }
 282 }
 283
 284 void buildViewport(flightgear::CameraInfo* info, SGPropertyNode* viewportNode,
 285                    const osg::GraphicsContext::Traits *traits)
 286 {
 287     using namespace flightgear;
 288     bindMemberToNode(viewportNode, "x", info, &CameraInfo::x, 0.0);
 289     bindMemberToNode(viewportNode, "y", info, &CameraInfo::y, 0.0);
 290     bindMemberToNode(viewportNode, "width", info, &CameraInfo::width,
 291                      static_cast<double>(traits->width));
 292     bindMemberToNode(viewportNode, "height", info, &CameraInfo::height,
 293                      static_cast<double>(traits->height));
 294 }
 295 }
 296
 297 namespace flightgear
 298 {
 299
 300 CameraInfo* CameraGroup::buildCamera(SGPropertyNode* cameraNode)
 301 {
 302     WindowBuilder *wBuild = WindowBuilder::getWindowBuilder();
 303     const SGPropertyNode* windowNode = cameraNode->getNode("window");
 304     GraphicsWindow* window = 0;
 305     int cameraFlags = DO_INTERSECTION_TEST;
 306     if (windowNode) {
 307         // New style window declaration / definition
 308         window = wBuild->buildWindow(windowNode);
 309     } else {
 310         // Old style: suck window params out of camera block
 311         window = wBuild->buildWindow(cameraNode);
 312     }
 313     if (!window) {
 314         return 0;
 315     }
 316     Camera* camera = new Camera;
 317     camera->setAllowEventFocus(false);
 318     camera->setGraphicsContext(window->gc.get());
 319     camera->setViewport(new Viewport);
 320     camera->setCullingMode(CullSettings::SMALL_FEATURE_CULLING
 321                            | CullSettings::VIEW_FRUSTUM_CULLING);
 322     camera->setInheritanceMask(CullSettings::ALL_VARIABLES
 323                                & ~(CullSettings::CULL_MASK
 324                                    | CullSettings::CULLING_MODE
 325 #if defined(HAVE_CULLSETTINGS_CLEAR_MASK)
 326                                    | CullSettings::CLEAR_MASK
 327 #endif
 328                                    ));
 329
 330     osg::Matrix pOff;
 331     osg::Matrix vOff;
 332     const SGPropertyNode* viewNode = cameraNode->getNode("view");
 333     if (viewNode) {
 334         double heading = viewNode->getDoubleValue("heading-deg", 0.0);
 335         double pitch = viewNode->getDoubleValue("pitch-deg", 0.0);
 336         double roll = viewNode->getDoubleValue("roll-deg", 0.0);
 337         double x = viewNode->getDoubleValue("x", 0.0);
 338         double y = viewNode->getDoubleValue("y", 0.0);
 339         double z = viewNode->getDoubleValue("z", 0.0);
 340         // Build a view matrix, which is the inverse of a model
 341         // orientation matrix.
 342         vOff = (Matrix::translate(-x, -y, -z)
 343                 * Matrix::rotate(-DegreesToRadians(heading),
 344                                  Vec3d(0.0, 1.0, 0.0),
 345                                  -DegreesToRadians(pitch),
 346                                  Vec3d(1.0, 0.0, 0.0),
 347                                  -DegreesToRadians(roll),
 348                                  Vec3d(0.0, 0.0, 1.0)));
 349         if (viewNode->getBoolValue("absolute", false))
 350             cameraFlags |= VIEW_ABSOLUTE;
 351     } else {
 352         // Old heading parameter, works in the opposite direction
 353         double heading = cameraNode->getDoubleValue("heading-deg", 0.0);
 354         vOff.makeRotate(DegreesToRadians(heading), osg::Vec3(0, 1, 0));
 355     }
 356     const SGPropertyNode* projectionNode = 0;
 357     if ((projectionNode = cameraNode->getNode("perspective")) != 0) {
 358         double fovy = projectionNode->getDoubleValue("fovy-deg", 55.0);
 359         double aspectRatio = projectionNode->getDoubleValue("aspect-ratio",
 360                                                             1.0);
 361         double zNear = projectionNode->getDoubleValue("near", 0.0);
 362         double zFar = projectionNode->getDoubleValue("far", 0.0);
 363         double offsetX = projectionNode->getDoubleValue("offset-x", 0.0);
 364         double offsetY = projectionNode->getDoubleValue("offset-y", 0.0);
 365         double tan_fovy = tan(DegreesToRadians(fovy*0.5));
 366         double right = tan_fovy * aspectRatio * zNear + offsetX;
 367         double left = -tan_fovy * aspectRatio * zNear + offsetX;
 368         double top = tan_fovy * zNear + offsetY;
 369         double bottom = -tan_fovy * zNear + offsetY;
 370         pOff.makeFrustum(left, right, bottom, top, zNear, zFar);
 371         cameraFlags |= PROJECTION_ABSOLUTE;
 372     } else if ((projectionNode = cameraNode->getNode("frustum")) != 0
 373                || (projectionNode = cameraNode->getNode("ortho")) != 0) {
 374         double top = projectionNode->getDoubleValue("top", 0.0);
 375         double bottom = projectionNode->getDoubleValue("bottom", 0.0);
 376         double left = projectionNode->getDoubleValue("left", 0.0);
 377         double right = projectionNode->getDoubleValue("right", 0.0);
 378         double zNear = projectionNode->getDoubleValue("near", 0.0);
 379         double zFar = projectionNode->getDoubleValue("far", 0.0);
 380         if (cameraNode->getNode("frustum")) {
 381             pOff.makeFrustum(left, right, bottom, top, zNear, zFar);
 382             cameraFlags |= PROJECTION_ABSOLUTE;
 383         } else {
 384             pOff.makeOrtho(left, right, bottom, top, zNear, zFar);
 385             cameraFlags |= (PROJECTION_ABSOLUTE | ORTHO);
 386         }
 387     } else {
 388         // old style shear parameters
 389         double shearx = cameraNode->getDoubleValue("shear-x", 0);
 390         double sheary = cameraNode->getDoubleValue("shear-y", 0);
 391         pOff.makeTranslate(-shearx, -sheary, 0);
 392     }
 393     CameraInfo* info = addCamera(cameraFlags, camera, pOff, vOff);
 394     // If a viewport isn't set on the camera, then it's hard to dig it
 395     // out of the SceneView objects in the viewer, and the coordinates
 396     // of mouse events are somewhat bizzare.
 397     SGPropertyNode* viewportNode = cameraNode->getNode("viewport", true);
 398     buildViewport(info, viewportNode, window->gc->getTraits());
 399     updateCameras(info);
 400     return info;
 401 }
 402
 403 CameraInfo* CameraGroup::buildGUICamera(SGPropertyNode* cameraNode,
 404                                         GraphicsWindow* window)
 405 {
 406     WindowBuilder *wBuild = WindowBuilder::getWindowBuilder();
 407     const SGPropertyNode* windowNode = (cameraNode
 408                                         ? cameraNode->getNode("window")
 409                                         : 0);
 410     if (!window) {
 411         if (windowNode) {
 412             // New style window declaration / definition
 413             window = wBuild->buildWindow(windowNode);
 414
 415         } else {
 416             return 0;
 417         }
 418     }
 419     Camera* camera = new Camera;
 420     camera->setAllowEventFocus(false);
 421     camera->setGraphicsContext(window->gc.get());
 422     camera->setViewport(new Viewport);
 423     // XXX Camera needs to be drawn last; eventually the render order
 424     // should be assigned by a camera manager.
 425     camera->setRenderOrder(osg::Camera::POST_RENDER, 100);
 426         camera->setClearMask(0);
 427     camera->setInheritanceMask(CullSettings::ALL_VARIABLES
 428                                & ~(CullSettings::COMPUTE_NEAR_FAR_MODE
 429                                    | CullSettings::CULLING_MODE
 430 #if defined(HAVE_CULLSETTINGS_CLEAR_MASK)
 431                                    | CullSettings::CLEAR_MASK
 432 #endif
 433                                    ));
 434     camera->setComputeNearFarMode(osg::CullSettings::DO_NOT_COMPUTE_NEAR_FAR);
 435     camera->setCullingMode(osg::CullSettings::NO_CULLING);
 436     camera->setProjectionResizePolicy(Camera::FIXED);
 437     camera->setReferenceFrame(Transform::ABSOLUTE_RF);
 438     const int cameraFlags = GUI;
 439     CameraInfo* result = addCamera(cameraFlags, camera, Matrixd::identity(),
 440                                    Matrixd::identity(), false);
 441     SGPropertyNode* viewportNode = cameraNode->getNode("viewport", true);
 442     buildViewport(result, viewportNode, window->gc->getTraits());
 443
 444     // Disable statistics for the GUI camera.
 445     result->camera->setStats(0);
 446     updateCameras(result);
 447     return result;
 448 }
 449
 450 CameraGroup* CameraGroup::buildCameraGroup(osgViewer::Viewer* viewer,
 451                                            SGPropertyNode* gnode)
 452 {
 453     CameraGroup* cgroup = new CameraGroup(viewer);
 454     for (int i = 0; i < gnode->nChildren(); ++i) {
 455         SGPropertyNode* pNode = gnode->getChild(i);
 456         const char* name = pNode->getName();
 457         if (!strcmp(name, "camera")) {
 458             cgroup->buildCamera(pNode);
 459         } else if (!strcmp(name, "window")) {
 460             WindowBuilder::getWindowBuilder()->buildWindow(pNode);
 461         } else if (!strcmp(name, "gui")) {
 462             cgroup->buildGUICamera(pNode);
 463         }
 464     }
 465     bindMemberToNode(gnode, "znear", cgroup, &CameraGroup::_zNear, .1f);
 466     bindMemberToNode(gnode, "zfar", cgroup, &CameraGroup::_zFar, 120000.0f);
 467     bindMemberToNode(gnode, "near-field", cgroup, &CameraGroup::_nearField,
 468                      100.0f);
 469     return cgroup;
 470 }
 471
 472 void CameraGroup::setCameraCullMasks(Node::NodeMask nm)
 473 {
 474     for (CameraIterator i = camerasBegin(), e = camerasEnd(); i != e; ++i) {
 475         CameraInfo* info = i->get();
 476         if (info->flags & GUI)
 477             continue;
 478         if (info->farCamera.valid() && info->farCamera->getNodeMask() != 0) {
 479             info->camera->setCullMask(nm & ~simgear::BACKGROUND_BIT);
 480             info->camera->setCullMaskLeft(nm & ~simgear::BACKGROUND_BIT);
 481             info->camera->setCullMaskRight(nm & ~simgear::BACKGROUND_BIT);
 482             info->farCamera->setCullMask(nm);
 483             info->farCamera->setCullMaskLeft(nm);
 484             info->farCamera->setCullMaskRight(nm);
 485         } else {
 486             info->camera->setCullMask(nm);
 487             info->camera->setCullMaskLeft(nm);
 488             info->camera->setCullMaskRight(nm);
 489         }
 490     }
 491 }
 492
 493 void CameraGroup::resized()
 494 {
 495     for (CameraIterator i = camerasBegin(), e = camerasEnd(); i != e; ++i) {
 496         CameraInfo *info = i->get();
 497         const Viewport* viewport = info->camera->getViewport();
 498         info->x = viewport->x();
 499         info->y = viewport->y();
 500         info->width = viewport->width();
 501         info->height = viewport->height();
 502     }
 503 }
 504
 505 Camera* getGUICamera(CameraGroup* cgroup)
 506 {
 507     CameraGroup::CameraIterator end = cgroup->camerasEnd();
 508     CameraGroup::CameraIterator result
 509         = std::find_if(cgroup->camerasBegin(), end,
 510                        FlagTester<CameraInfo>(CameraGroup::GUI));
 511     if (result != end)
 512         return (*result)->camera.get();
 513     else
 514         return 0;
 515 }
 516
 517 bool computeIntersections(const CameraGroup* cgroup,
 518                           const osgGA::GUIEventAdapter* ea,
 519                           osgUtil::LineSegmentIntersector::Intersections& intersections)
 520 {
 521     using osgUtil::Intersector;
 522     using osgUtil::LineSegmentIntersector;
 523     double x, y;
 524     eventToWindowCoords(ea, x, y);
 525     // Find camera that contains event
 526     for (CameraGroup::ConstCameraIterator iter = cgroup->camerasBegin(),
 527              e = cgroup->camerasEnd();
 528          iter != e;
 529          ++iter) {
 530         const CameraInfo* cinfo = iter->get();
 531         if ((cinfo->flags & CameraGroup::DO_INTERSECTION_TEST) == 0)
 532             continue;
 533         const Camera* camera = cinfo->camera.get();
 534         if (camera->getGraphicsContext() != ea->getGraphicsContext())
 535             continue;
 536         const Viewport* viewport = camera->getViewport();
 537         double epsilon = 0.5;
 538         if (!(x >= viewport->x() - epsilon
 539               && x < viewport->x() + viewport->width() -1.0 + epsilon
 540               && y >= viewport->y() - epsilon
 541               && y < viewport->y() + viewport->height() -1.0 + epsilon))
 542             continue;
 543         Vec4d start(x, y, 0.0, 1.0);
 544         Vec4d end(x, y, 1.0, 1.0);
 545         Matrix windowMat = viewport->computeWindowMatrix();
 546         Matrix startPtMat = Matrix::inverse(camera->getProjectionMatrix()
 547                                             * windowMat);
 548         Matrix endPtMat;
 549         if (!cinfo->farCamera.valid() || cinfo->farCamera->getNodeMask() == 0)
 550             endPtMat = startPtMat;
 551         else
 552             endPtMat = Matrix::inverse(cinfo->farCamera->getProjectionMatrix()
 553                                        * windowMat);
 554         start = start * startPtMat;
 555         start /= start.w();
 556         end = end * endPtMat;
 557         end /= end.w();
 558         ref_ptr<LineSegmentIntersector> picker
 559             = new LineSegmentIntersector(Intersector::VIEW,
 560                                          Vec3d(start.x(), start.y(), start.z()),
 561                                          Vec3d(end.x(), end.y(), end.z()));
 562         osgUtil::IntersectionVisitor iv(picker.get());
 563         const_cast<Camera*>(camera)->accept(iv);
 564         if (picker->containsIntersections()) {
 565             intersections = picker->getIntersections();
 566             return true;
 567         } else {
 568             break;
 569         }
 570     }
 571     intersections.clear();
 572     return false;
 573 }
 574
 575 void warpGUIPointer(CameraGroup* cgroup, int x, int y)
 576 {
 577     using osgViewer::GraphicsWindow;
 578     Camera* guiCamera = getGUICamera(cgroup);
 579     if (!guiCamera)
 580         return;
 581     Viewport* vport = guiCamera->getViewport();
 582     GraphicsWindow* gw
 583         = dynamic_cast<GraphicsWindow*>(guiCamera->getGraphicsContext());
 584     if (!gw)
 585         return;
 586     globals->get_renderer()->getEventHandler()->setMouseWarped();
 587     // Translate the warp request into the viewport of the GUI camera,
 588     // send the request to the window, then transform the coordinates
 589     // for the Viewer's event queue.
 590     double wx = x + vport->x();
 591     double wyUp = vport->height() + vport->y() - y;
 592     double wy;
 593     const GraphicsContext::Traits* traits = gw->getTraits();
 594     if (gw->getEventQueue()->getCurrentEventState()->getMouseYOrientation()
 595         == osgGA::GUIEventAdapter::Y_INCREASING_DOWNWARDS) {
 596         wy = traits->height - wyUp;
 597     } else {
 598         wy = wyUp;
 599     }
 600     gw->getEventQueue()->mouseWarped(wx, wy);
 601     gw->requestWarpPointer(wx, wy);
 602     osgGA::GUIEventAdapter* eventState
 603         = cgroup->getViewer()->getEventQueue()->getCurrentEventState();
 604     double viewerX
 605         = (eventState->getXmin()
 606            + ((wx / double(traits->width))
 607               * (eventState->getXmax() - eventState->getXmin())));
 608     double viewerY
 609         = (eventState->getYmin()
 610            + ((wyUp / double(traits->height))
 611               * (eventState->getYmax() - eventState->getYmin())));
 612     cgroup->getViewer()->getEventQueue()->mouseWarped(viewerX, viewerY);
 613 }
 614 }