Send view scaling over parallel connection

include/openspace/interaction/keyframenavigator.h

@@ -41,6 +41,7 @@ public:
         glm::dvec3 position;
         glm::quat rotation;
         std::string focusNode;
+        float scale;
         bool followFocusNodeRotation;
     };
 

include/openspace/network/messagestructures.h

@@ -49,6 +49,7 @@ struct CameraKeyframe {
     glm::dquat _rotation;
     bool _followNodeRotation;
     std::string _focusNode;
+    float _scale;
 
     double _timestamp;
 
@@ -88,6 +89,12 @@ struct CameraKeyframe {
             _focusNode.data() + nodeNameLength
         );
 
+        buffer.insert(
+            buffer.end(),
+            reinterpret_cast<char*>(&_scale),
+            reinterpret_cast<char*>(&_scale) + sizeof(_scale)
+        );
+
         // Add timestamp
         buffer.insert(
             buffer.end(),
@@ -124,6 +131,11 @@ struct CameraKeyframe {
         _focusNode = std::string(buffer.data() + offset, buffer.data() + offset + size);
         offset += size;
 
+        // Scale
+        size = sizeof(_scale);
+        memcpy(&_scale, buffer.data() + offset, size);
+        offset += size;
+
         // Timestamp
         size = sizeof(_timestamp);
         memcpy(&_timestamp, buffer.data() + offset, size);

src/interaction/keyframenavigator.cpp

@@ -116,6 +116,14 @@ void KeyframeNavigator::updateCamera(Camera& camera) {
     camera.setRotation(
         glm::slerp(prevKeyframeCameraRotation, nextKeyframeCameraRotation, t)
     );
+
+    // We want to affect view scaling, such that we achieve
+    // logarithmic interpolation of distance to an imagined focus node.
+    // To do this, we interpolate the scale reciprocal logarithmically.
+    const float prevInvScaleExp = glm::log(1.0 / prevPose.scale);
+    const float nextInvScaleExp = glm::log(1.0 / nextPose.scale);
+    const float interpolatedInvScaleExp = prevInvScaleExp * (1 - t) + nextInvScaleExp * t;
+    camera.setScaling(1.0 / glm::exp(interpolatedInvScaleExp));
 }
 
 Timeline<KeyframeNavigator::CameraPose>& KeyframeNavigator::timeline() {

src/network/parallelconnection.cpp

@@ -27,7 +27,7 @@
 #include <cstdint>
 
 namespace {
-const uint32_t ProtocolVersion = 3;
+const uint32_t ProtocolVersion = 4;
 const char* _loggerCat = "ParallelConnection";
 } // namespace
 

src/network/parallelpeer.cpp

@@ -287,6 +287,7 @@ void ParallelPeer::dataMessageReceived(const std::vector<char>& messageContent)
         pose.focusNode = kf._focusNode;
         pose.position = kf._position;
         pose.rotation = kf._rotation;
+        pose.scale = kf._scale;
         pose.followFocusNodeRotation = kf._followNodeRotation;
 
         OsEng.navigationHandler().keyframeNavigator().addKeyframe(kf._timestamp, pose);
@@ -539,6 +540,7 @@ void ParallelPeer::sendCameraKeyframe() {
     }
 
     kf._focusNode = focusNode->identifier();
+    kf._scale = OsEng.navigationHandler().camera()->scaling();
 
     // Timestamp as current runtime of OpenSpace instance
     kf._timestamp = OsEng.windowWrapper().applicationTime();