Add automatic aspect ratio support for camera in Scene3D

Change-Id: Ibb3378e2e1d495986f68902e368847e89d8fbdd6
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

2 files changed, 72 insertions, 2 deletions

diff --git a/src/quick3d/imports/scene3d/scene3ditem.cpp b/src/quick3d/imports/scene3d/scene3ditem.cpp
index 8f356bda4..552204ffd 100644
--- a/src/quick3d/imports/scene3d/scene3ditem.cpp
+++ b/src/quick3d/imports/scene3d/scene3ditem.cpp
@@ -42,6 +42,7 @@
 
 #include <Qt3DCore/QAspectEngine>
 #include <Qt3DCore/qentity.h>
+#include <Qt3DRender/qcamera.h>
 #include <Qt3DRender/QRenderAspect>
 #include <Qt3DRender/qframegraph.h>
 #include <Qt3DRender/qrendersurfaceselector.h>
@@ -73,6 +74,7 @@ Scene3DItem::Scene3DItem(QQuickItem *parent)
     , m_renderer(Q_NULLPTR)
     , m_rendererCleaner(new Scene3DCleaner())
     , m_multisample(true)
+    , m_cameraAspectRatioMode(AutomaticAspectRatio)
 {
     setFlag(QQuickItem::ItemHasContents, true);
     setAcceptedMouseButtons(Qt::MouseButtonMask);
@@ -136,14 +138,43 @@ void Scene3DItem::setEntity(Qt3DCore::QEntity *entity)
     emit entityChanged();
 }
 
+void Scene3DItem::setCameraAspectRatioMode(CameraAspectRatioMode mode)
+{
+    if (m_cameraAspectRatioMode == mode)
+        return;
+
+    m_cameraAspectRatioMode = mode;
+    setCameraAspectModeHelper();
+    emit cameraAspectRatioModeChanged(mode);
+}
+
+Scene3DItem::CameraAspectRatioMode Scene3DItem::cameraAspectRatioMode() const
+{
+    return m_cameraAspectRatioMode;
+}
+
 void Scene3DItem::applyRootEntityChange()
 {
     if (m_aspectEngine->rootEntity() != m_entity) {
         m_aspectEngine->setRootEntity(m_entity);
 
         // Set the render surface
-        if (m_entity)
-            setWindowSurface(m_entity);
+        if (!m_entity)
+            return;
+
+        setWindowSurface(m_entity);
+
+        if (m_cameraAspectRatioMode == AutomaticAspectRatio) {
+            // Set aspect ratio of first camera to match the window
+            QList<Qt3DRender::QCamera *> cameras
+                = m_entity->findChildren<Qt3DRender::QCamera *>();
+            if (cameras.isEmpty()) {
+                qWarning() << "No camera found and automatic aspect ratio requested";
+            } else {
+                m_camera = cameras.first();
+                setCameraAspectModeHelper();
+            }
+        }
     }
 }
 
@@ -174,6 +205,28 @@ void Scene3DItem::setWindowSurface(QObject *rootObject)
     surfaceSelector->setWindow(this->window());
 }
 
+void Scene3DItem::setCameraAspectModeHelper()
+{
+    switch (m_cameraAspectRatioMode) {
+    case AutomaticAspectRatio:
+        connect(this, &Scene3DItem::widthChanged, this, &Scene3DItem::updateCameraAspectRatio);
+        connect(this, &Scene3DItem::heightChanged, this, &Scene3DItem::updateCameraAspectRatio);
+        break;
+    case UserAspectRatio:
+        disconnect(this, &Scene3DItem::widthChanged, this, &Scene3DItem::updateCameraAspectRatio);
+        disconnect(this, &Scene3DItem::heightChanged, this, &Scene3DItem::updateCameraAspectRatio);
+        break;
+    }
+}
+
+void Scene3DItem::updateCameraAspectRatio()
+{
+    if (m_camera) {
+        m_camera->setAspectRatio(static_cast<float>(width()) /
+                                 static_cast<float>(height()));
+    }
+}
+
 /*!
     \return \c true if a multisample renderbuffer is in use.
  */
diff --git a/src/quick3d/imports/scene3d/scene3ditem_p.h b/src/quick3d/imports/scene3d/scene3ditem_p.h
index bb078d6b8..f3379a7e9 100644
--- a/src/quick3d/imports/scene3d/scene3ditem_p.h
+++ b/src/quick3d/imports/scene3d/scene3ditem_p.h
@@ -49,6 +49,7 @@
 //
 
 #include <QQuickItem>
+#include <QtCore/qpointer.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -59,6 +60,7 @@ class QEntity;
 
 namespace Qt3DRender {
 
+class QCamera;
 class QRenderAspect;
 class Scene3DRenderer;
 class Scene3DCleaner;
@@ -69,6 +71,7 @@ class Scene3DItem : public QQuickItem
     Q_PROPERTY(Qt3DCore::QEntity* entity READ entity WRITE setEntity NOTIFY entityChanged)
     Q_PROPERTY(QStringList aspects READ aspects WRITE setAspects NOTIFY aspectsChanged)
     Q_PROPERTY(bool multisample READ multisample WRITE setMultisample NOTIFY multisampleChanged)
+    Q_PROPERTY(CameraAspectRatioMode cameraAspectRatioMode READ cameraAspectRatioMode WRITE setCameraAspectRatioMode NOTIFY cameraAspectRatioModeChanged)
     Q_CLASSINFO("DefaultProperty", "entity")
 public:
     explicit Scene3DItem(QQuickItem *parent = 0);
@@ -80,14 +83,23 @@ public:
     bool multisample() const;
     void setMultisample(bool enable);
 
+    enum CameraAspectRatioMode {
+        AutomaticAspectRatio,
+        UserAspectRatio
+    };
+    Q_ENUM(CameraAspectRatioMode);
+    CameraAspectRatioMode cameraAspectRatioMode() const;
+
 public Q_SLOTS:
     void setAspects(const QStringList &aspects);
     void setEntity(Qt3DCore::QEntity *entity);
+    void setCameraAspectRatioMode(CameraAspectRatioMode mode);
 
 Q_SIGNALS:
     void aspectsChanged();
     void entityChanged();
     void multisampleChanged();
+    void cameraAspectRatioModeChanged(CameraAspectRatioMode mode);
 
 private Q_SLOTS:
     void applyRootEntityChange();
@@ -95,6 +107,8 @@ private Q_SLOTS:
 private:
     QSGNode *updatePaintNode(QSGNode *node, UpdatePaintNodeData *nodeData) Q_DECL_OVERRIDE;
     void setWindowSurface(QObject *rootObject);
+    void setCameraAspectModeHelper();
+    void updateCameraAspectRatio();
 
     QStringList m_aspects;
     Qt3DCore::QEntity *m_entity;
@@ -105,6 +119,9 @@ private:
     Scene3DCleaner *m_rendererCleaner;
 
     bool m_multisample;
+
+    QPointer<Qt3DRender::QCamera> m_camera;
+    CameraAspectRatioMode m_cameraAspectRatioMode;
 };
 
 } // Qt3DRender