int main(int ac, char **av)
{
QApplication app(ac, av);
Qt3DExtras::Qt3DWindow view;
view.defaultFrameGraph()->setClearColor(Qt::black);
// Root entity
Qt3DCore::QEntity *sceneRoot = new Qt3DCore::QEntity();
// Scene Camera
Qt3DRender::QCamera *camera = view.camera();
camera->setProjectionType(Qt3DRender::QCameraLens::PerspectiveProjection);
camera->setViewCenter(QVector3D(0.0f, 3.5f, 0.0f));
camera->setPosition(QVector3D(0.0f, 3.5f, 25.0f));
camera->setNearPlane(0.001f);
camera->setFarPlane(10000.0f);
// For camera controls
Qt3DExtras::QFirstPersonCameraController *camController = new Qt3DExtras::QFirstPersonCameraController(sceneRoot);
camController->setCamera(camera);
// Scene loader
Qt3DCore::QEntity *sceneLoaderEntity = new Qt3DCore::QEntity(sceneRoot);
Qt3DRender::QSceneLoader *sceneLoader = new Qt3DRender::QSceneLoader(sceneLoaderEntity);
SceneWalker sceneWalker(sceneLoader);
QObject::connect(sceneLoader, &Qt3DRender::QSceneLoader::statusChanged, &sceneWalker, &SceneWalker::onStatusChanged);
sceneLoaderEntity->addComponent(sceneLoader);
QStringList args = QCoreApplication::arguments();
QUrl sourceFileName;
if (args.count() <= 1) {
QWidget *container = new QWidget();
QFileDialog dialog;
dialog.setFileMode(QFileDialog::AnyFile);
sourceFileName = dialog.getOpenFileUrl(container, QStringLiteral("Open a scene file"));
} else {
sourceFileName = QUrl::fromLocalFile(args[1]);
}
if (sourceFileName.isEmpty())
return 0;
sceneLoader->setSource(sourceFileName);
view.setRootEntity(sceneRoot);
view.show();
return app.exec();
}
void checkSyncFrustumCullingExecution()
{
// GIVEN
Qt3DRender::QViewport *viewport = new Qt3DRender::QViewport();
Qt3DRender::QClearBuffers *clearBuffer = new Qt3DRender::QClearBuffers(viewport);
Qt3DRender::QFrustumCulling *frustumCulling = new Qt3DRender::QFrustumCulling(clearBuffer);
Qt3DRender::QCameraSelector *cameraSelector = new Qt3DRender::QCameraSelector(frustumCulling);
Qt3DRender::QCamera *camera = new Qt3DRender::QCamera();
cameraSelector->setCamera(camera);
Qt3DRender::TestAspect testAspect(buildSimpleScene(viewport));
// THEN
Qt3DRender::Render::FrameGraphNode *leafNode = testAspect.nodeManagers()->frameGraphManager()->lookupNode(cameraSelector->id());
QVERIFY(leafNode != nullptr);
// WHEN
Qt3DRender::Render::RenderViewBuilder renderViewBuilder(leafNode, 0, testAspect.renderer());
renderViewBuilder.prepareJobs();
renderViewBuilder.buildJobHierachy();
// THEN
QCOMPARE(renderViewBuilder.frustumCullingJob()->viewProjection(), QMatrix4x4());
// WHEN
renderViewBuilder.renderViewJob()->run();
renderViewBuilder.syncFrustumCullingJob()->run();
// THEN
QCOMPARE(renderViewBuilder.frustumCullingJob()->viewProjection(), camera->projectionMatrix() * camera->viewMatrix());
}
QgsChunkedEntity::SceneState _sceneState( QgsCameraController *cameraController )
{
Qt3DRender::QCamera *camera = cameraController->camera();
QgsChunkedEntity::SceneState state;
state.cameraFov = camera->fieldOfView();
state.cameraPos = camera->position();
QRect rect = cameraController->viewport();
state.screenSizePx = std::max( rect.width(), rect.height() ); // TODO: is this correct?
state.viewProjectionMatrix = camera->projectionMatrix() * camera->viewMatrix();
return state;
}
float Qgs3DMapScene::worldSpaceError( float epsilon, float distance )
{
Qt3DRender::QCamera *camera = mCameraController->camera();
float fov = camera->fieldOfView();
QRect rect = mCameraController->viewport();
float screenSizePx = std::max( rect.width(), rect.height() ); // TODO: is this correct?
// in qgschunkedentity_p.cpp there is inverse calculation (world space error to screen space error)
// with explanation of the math.
float frustumWidthAtDistance = 2 * distance * tan( fov / 2 );
float err = frustumWidthAtDistance * epsilon / screenSizePx;
return err;
}
int main(int argc, char* argv[])
{
QGuiApplication app(argc, argv);
Qt3DExtras::Qt3DWindow view;
ExampleScene *sceneRoot = new ExampleScene();
// Scene Camera
Qt3DRender::QCamera *basicCamera = view.camera();
basicCamera->setProjectionType(Qt3DRender::QCameraLens::PerspectiveProjection);
basicCamera->setAspectRatio(view.width() / view.height());
basicCamera->setUpVector(QVector3D(0.0f, 1.0f, 0.0f));
basicCamera->setViewCenter(QVector3D(0.0f, 3.5f, 0.0f));
basicCamera->setPosition(QVector3D(0.0f, 3.5f, 25.0f));
// For camera controls
Qt3DExtras::QFirstPersonCameraController *camController = new Qt3DExtras::QFirstPersonCameraController(sceneRoot);
camController->setCamera(basicCamera);
view.setRootEntity(sceneRoot);
view.show();
return app.exec();
}
bool Qgs3DMapScene::updateCameraNearFarPlanes()
{
// Update near and far plane from the terrain.
// this needs to be done with great care as we have kind of circular dependency here:
// active nodes are culled based on the current frustum (which involves near + far plane)
// and then based on active nodes we set near and far plane.
//
// All of this is just heuristics assuming that all other stuff is being rendered somewhere
// around the area where the terrain is.
//
// Near/far plane is setup in order to make best use of the depth buffer to avoid:
// 1. precision errors - if the range is too great
// 2. unwanted clipping of scene - if the range is too small
if ( mTerrain )
{
Qt3DRender::QCamera *camera = cameraController()->camera();
QMatrix4x4 viewMatrix = camera->viewMatrix();
float fnear = 1e9;
float ffar = 0;
QList<QgsChunkNode *> activeNodes = mTerrain->activeNodes();
// it could be that there are no active nodes - they could be all culled or because root node
// is not yet loaded - we still need at least something to understand bounds of our scene
// so lets use the root node
if ( activeNodes.isEmpty() )
activeNodes << mTerrain->rootNode();
Q_FOREACH ( QgsChunkNode *node, activeNodes )
{
// project each corner of bbox to camera coordinates
// and determine closest and farthest point.
QgsAABB bbox = node->bbox();
for ( int i = 0; i < 8; ++i )
{
QVector4D p( ( ( i >> 0 ) & 1 ) ? bbox.xMin : bbox.xMax,
( ( i >> 1 ) & 1 ) ? bbox.yMin : bbox.yMax,
( ( i >> 2 ) & 1 ) ? bbox.zMin : bbox.zMax, 1 );
QVector4D pc = viewMatrix * p;
float dst = -pc.z(); // in camera coordinates, x grows right, y grows down, z grows to the back
if ( dst < fnear )
fnear = dst;
if ( dst > ffar )
ffar = dst;
}
}
if ( fnear < 1 )
fnear = 1; // does not really make sense to use negative far plane (behind camera)
if ( fnear == 1e9 && ffar == 0 )
{
// the update didn't work out... this should not happen
// well at least temprarily use some conservative starting values
qDebug() << "oops... this should not happen! couldn't determine near/far plane. defaulting to 1...1e9";
fnear = 1;
ffar = 1e9;
}
// set near/far plane - with some tolerance in front/behind expected near/far planes
float newFar = ffar * 2;
float newNear = fnear / 2;
if ( !qgsFloatNear( newFar, camera->farPlane() ) || !qgsFloatNear( newNear, camera->nearPlane() ) )
{
camera->setFarPlane( newFar );
camera->setNearPlane( newNear );
return true;
}
}