You might want to do this: Qt3DRender::QGeometryRenderer *mesh = ...
Qt3DRender::QGeometry *meshGeometry = mesh->geometry(); for (Qt3DRender::QAttribute *attribute : meshGeometry->attributes()) { Qt3DRender::QBuffer *buf = attribute->buffer(); if (buf) { if (buf->data().isEmpty()) buf->setData(buf->dataGenerator()->operator()()); buf->setSyncData(true); buf->setAccessType(Qt3DRender::QBuffer::AccessType::ReadWrite); } } On Mon, Mar 9, 2020 at 12:54 PM Federico Ferri <federico.ferri...@gmail.com> wrote: > I’m trying to access vertex data of QGeometry objects for computing the > bounding box of the object. > This works fine for QMesh, but for QCuboidMesh, QSphereMesh, etc… vertex > data seems invalid. > Is there some method to call to make vertex data actual? > > This is my code: > > QVector<qreal> entityBoundingBox(Qt3DCore::QEntity *entity) > { > for(const auto &comp : > entity->componentsOfType<Qt3DRender::QGeometryRenderer>()) > { > auto geom = comp->geometry(); > if(geom) > return geometryBoundingBox(geom); > } > return {}; > } > > QVector<qreal> geometryBoundingBox(Qt3DRender::QGeometry *geom) > { > QVector<qreal> ret; > auto attrs = geom->attributes(); > for(const auto &attr : attrs) > { > if(attr->name() != "vertexPosition") continue; > int n = attr->count(); > auto buf = attr->buffer(); > const QByteArray &data = buf->data(); > float vmin[3], vmax[3]; > for(int i = 0; i < n; i++) > { > int vertexOffset = i * attr->byteStride(); > int offset = vertexOffset + attr->byteOffset(); > const char *rawData = &(data.constData()[offset]); > auto value = reinterpret_cast<const float*>(rawData); > qDebug() << "geometryBoundingBox: scanning vertex" << value[0] << > value[1] << value[2]; > for(int j = 0; j < 3; j++) > { > vmin[j] = i ? qMin(vmin[j], value[j]) : value[j]; > vmax[j] = i ? qMax(vmax[j], value[j]) : value[j]; > } > } > ret.resize(6); > ret[0] = vmin[0]; ret[1] = vmin[1]; ret[2] = vmin[2]; > ret[3] = vmax[0]; ret[4] = vmax[1]; ret[5] = vmax[2]; > return ret; > } > return ret; > } > > > when working on the cuboid or sphere meshes I see vertex data such as: > > geometryBoundingBox: scanning vertex 1.2992e-08 5.50632e+11 1.29257e+19 > > geometryBoundingBox: scanning vertex 0 0 nan > > geometryBoundingBox: scanning vertex 9.40053e-33 1.4013e-45 9.40053e-33 > > geometryBoundingBox: scanning vertex 0 0 nan > > > _______________________________________________ > Interest mailing list > Interest@qt-project.org > https://lists.qt-project.org/listinfo/interest >
_______________________________________________ Interest mailing list Interest@qt-project.org https://lists.qt-project.org/listinfo/interest