GLTF Export QCamera properly

QCamera position, upVector, and viewCenter properties were not properly
preserved when doing GLTF export/import.

Change-Id: I6d81633cf29d6e347935c56605b46923d3e1aa03
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>
Reviewed-by: Antti Määttä <antti.maatta@qt.io>

5 files changed, 47 insertions, 9 deletions

diff --git a/src/plugins/sceneparsers/gltf/gltfimporter.cpp b/src/plugins/sceneparsers/gltf/gltfimporter.cpp
index e5434da3f..c026594bf 100644
--- a/src/plugins/sceneparsers/gltf/gltfimporter.cpp
+++ b/src/plugins/sceneparsers/gltf/gltfimporter.cpp
@@ -213,6 +213,9 @@
 #define KEY_EFFECT              QLatin1String("effect")
 #define KEY_EFFECTS             QLatin1String("effects")
 #define KEY_PROPERTIES          QLatin1String("properties")
+#define KEY_POSITION            QLatin1String("position")
+#define KEY_UPVECTOR            QLatin1String("upVector")
+#define KEY_VIEW_CENTER         QLatin1String("viewCenter")
 
 QT_BEGIN_NAMESPACE
 
@@ -380,7 +383,8 @@ Qt3DCore::QEntity* GLTFImporter::node(const QString &id)
     const auto translation = jsonObj.value(KEY_TRANSLATION);
     const auto scale = jsonObj.value(KEY_SCALE);
     Qt3DCore::QTransform *trans = nullptr;
-    QCameraLens* cameraLens = nullptr;
+    QCameraLens *cameraLens = nullptr;
+    QCamera *cameraEntity = nullptr;
 
     // If the node contains no meshes, results will still be null here.
     // If the node has camera and transform, promote it to QCamera, as that makes it more
@@ -389,10 +393,10 @@ Qt3DCore::QEntity* GLTFImporter::node(const QString &id)
         if (!cameraVal.isUndefined()
                 && (!matrix.isUndefined() || !rotation.isUndefined() || !translation.isUndefined()
                     || !scale.isUndefined())) {
-            auto camera = new QCamera;
-            trans = camera->transform();
-            cameraLens = camera->lens();
-            result = camera;
+            cameraEntity = new QCamera;
+            trans = cameraEntity->transform();
+            cameraLens = cameraEntity->lens();
+            result = cameraEntity;
         } else {
             result = new QEntity;
         }
@@ -460,7 +464,7 @@ Qt3DCore::QEntity* GLTFImporter::node(const QString &id)
         const bool newLens = cameraLens == nullptr;
         if (newLens)
             cameraLens = new QCameraLens;
-        if (!fillCameraLens(*cameraLens, cameraVal.toString())) {
+        if (!fillCamera(*cameraLens, cameraEntity, cameraVal.toString())) {
             qCWarning(GLTFImporterLog, "failed to build camera: %ls on node %ls",
                       qUtf16PrintableImpl(cameraVal.toString()), qUtf16PrintableImpl(id));
         } else if (newLens) {
@@ -925,7 +929,7 @@ QMaterial* GLTFImporter::material(const QString &id)
     return mat;
 }
 
-bool GLTFImporter::fillCameraLens(QCameraLens &lens, const QString &id) const
+bool GLTFImporter::fillCamera(QCameraLens &lens, QCamera *cameraEntity, const QString &id) const
 {
     const auto jsonVal = m_json.object().value(KEY_CAMERAS).toObject().value(id);
     if (Q_UNLIKELY(jsonVal.isUndefined())) {
@@ -973,6 +977,14 @@ bool GLTFImporter::fillCameraLens(QCameraLens &lens, const QString &id) const
                   qUtf16PrintableImpl(id), qUtf16PrintableImpl(camTy));
         return false;
     }
+    if (cameraEntity) {
+        if (jsonObj.contains(KEY_POSITION))
+            cameraEntity->setPosition(jsonArrToVec3(jsonObj.value(KEY_POSITION).toArray()));
+        if (jsonObj.contains(KEY_UPVECTOR))
+            cameraEntity->setUpVector(jsonArrToVec3(jsonObj.value(KEY_UPVECTOR).toArray()));
+        if (jsonObj.contains(KEY_VIEW_CENTER))
+            cameraEntity->setViewCenter(jsonArrToVec3(jsonObj.value(KEY_VIEW_CENTER).toArray()));
+    }
     renameFromJson(jsonObj, &lens);
     return true;
 }
diff --git a/src/plugins/sceneparsers/gltf/gltfimporter.h b/src/plugins/sceneparsers/gltf/gltfimporter.h
index 8f6b9b356..e97148600 100644
--- a/src/plugins/sceneparsers/gltf/gltfimporter.h
+++ b/src/plugins/sceneparsers/gltf/gltfimporter.h
@@ -147,7 +147,7 @@ private:
 
     Qt3DCore::QEntity *defaultScene();
     QMaterial *material(const QString &id);
-    bool fillCameraLens(QCameraLens &lens, const QString &id) const;
+    bool fillCamera(QCameraLens &lens, QCamera *cameraEntity, const QString &id) const;
 
     void parse();
     void cleanup();
diff --git a/src/plugins/sceneparsers/gltfexport/gltfexporter.cpp b/src/plugins/sceneparsers/gltfexport/gltfexporter.cpp
index befe7770d..7332fa6b5 100644
--- a/src/plugins/sceneparsers/gltfexport/gltfexporter.cpp
+++ b/src/plugins/sceneparsers/gltfexport/gltfexporter.cpp
@@ -961,6 +961,7 @@ void GLTFExporter::parseCameras()
 {
     qCDebug(GLTFExporterLog, "Parsing cameras...");
     int cameraCount = 0;
+
     for (auto it = m_cameraMap.constBegin(); it != m_cameraMap.constEnd(); ++it) {
         QCameraLens *camera = it.value();
         CameraInfo c;
@@ -984,7 +985,12 @@ void GLTFExporter::parseCameras()
         c.zfar = camera->farPlane();
 
         // GLTF cameras point in -Z by default, the rest is in the
-        // node matrix, so no separate look-at params given here.
+        // node matrix, so no separate look-at params given here, unless it's actually QCamera.
+        QCamera *cameraEntity = nullptr;
+        const QVector<QEntity *> entities = camera->entities();
+        if (entities.size() == 1)
+            cameraEntity = qobject_cast<QCamera *>(entities.at(0));
+        c.cameraEntity = cameraEntity;
 
         m_cameraInfo.insert(camera, c);
         if (GLTFExporterLog().isDebugEnabled()) {
@@ -1259,6 +1265,11 @@ bool GLTFExporter::saveScene()
             camera["type"] = QStringLiteral("orthographic");
             camera["orthographic"] = proj;
         }
+        if (camInfo.cameraEntity) {
+            camera["position"] = vec2jsvec(camInfo.cameraEntity->position());
+            camera["upVector"] = vec2jsvec(camInfo.cameraEntity->upVector());
+            camera["viewCenter"] = vec2jsvec(camInfo.cameraEntity->viewCenter());
+        }
         camera["name"] = camInfo.originalName;
         cameras[camInfo.name] = camera;
     }
diff --git a/src/plugins/sceneparsers/gltfexport/gltfexporter.h b/src/plugins/sceneparsers/gltfexport/gltfexporter.h
index e43bfe29c..07d852fd4 100644
--- a/src/plugins/sceneparsers/gltfexport/gltfexporter.h
+++ b/src/plugins/sceneparsers/gltfexport/gltfexporter.h
@@ -72,6 +72,7 @@ class QTransform;
 
 namespace Qt3DRender {
 
+class QCamera;
 class QCameraLens;
 class QMaterial;
 class QGeometryRenderer;
@@ -196,6 +197,8 @@ private:
         // Orthographic properties
         float xmag;
         float ymag;
+
+        QCamera *cameraEntity;
     };
 
     struct LightInfo {
diff --git a/tests/auto/render/gltfplugins/tst_gltfplugins.cpp b/tests/auto/render/gltfplugins/tst_gltfplugins.cpp
index 3ab10f17a..a800fc1fa 100644
--- a/tests/auto/render/gltfplugins/tst_gltfplugins.cpp
+++ b/tests/auto/render/gltfplugins/tst_gltfplugins.cpp
@@ -241,6 +241,7 @@ void tst_gltfPlugins::createTestScene()
         camera->lens()->setObjectName(QStringLiteral("Main camera lens"));
         camera->setFieldOfView(30.0f);
         camera->setAspectRatio(1.0f);
+        m_entityMap.insert(camera->objectName(), camera);
     }
     // Ortho camera
     {
@@ -263,6 +264,7 @@ void tst_gltfPlugins::createTestScene()
         lens->setObjectName(QStringLiteral("Ortho camera lens"));
         camera->addComponent(lens);
 
+        m_entityMap.insert(camera->objectName(), camera);
 #ifdef VISUAL_CHECK
         m_view1->defaultFrameGraph()->setCamera(camera);
 #endif
@@ -1208,6 +1210,16 @@ void tst_gltfPlugins::exportAndImport()
                               meshComponent(importedEntity));
             compareComponents(materialComponent(exportedEntity),
                               materialComponent(importedEntity));
+            Qt3DRender::QCamera *exportedCamera =
+                    qobject_cast<Qt3DRender::QCamera *>(exportedEntity);
+            if (exportedCamera) {
+                Qt3DRender::QCamera *importedCamera =
+                        qobject_cast<Qt3DRender::QCamera *>(importedEntity);
+                QVERIFY(importedCamera != nullptr);
+                QCOMPARE(exportedCamera->position(), importedCamera->position());
+                QCOMPARE(exportedCamera->upVector(), importedCamera->upVector());
+                QCOMPARE(exportedCamera->viewCenter(), importedCamera->viewCenter());
+            }
         }
     }