GSoC Ends – Project Summary

Hi everyone! Okay, so GSoC finally comes to an end, and I’m going to miss it a lot. Working for Marble has become an addiction, and I am going to keep contributing to it in the future. However, here is a brief summary of what all I have been able to implement in Marble in the duration of the project.

My project is about implementing interactive tours in Marble, a feature by which we would be able to take a virtual tour of the planet, by making the camera fly from location to location on the globe, waiting at certain points, playing some music in the background through certain time-durations, and also possibly showing/hiding placemarks as well at certain moments during the tour. Tours are kml files consist of a playlist with five basic elements:
1) FlyTo : contains the latitude, longitude, altitude, etc. of the locations to which the camera is supposed to fly to.
2) Wait : contains the durations for which the camera should wait (not move) at some instances during the tour.
3) TourControl : these can be used to play / pause the tour automatically during its playback
4) SoundCue : these are required to play some music in the background while the tour is playing.
5) AnimatedUpdate : for being able to show/hide, or also create/delete balloon popups (info-boxes) at different coordinates during the tour.

-> There was a Tour Widget which showed a list-view of the different elements present in the kml tour file that has been loaded. Now I added the functionality to be able to edit the elements directly from the widget itself, thus modifying the tour without having to make any manual changes to the kml file, and providing a nice user-interface while doing so. Please go through my blog post for some screenshots and a clearer explanation of the feature.

-> Refactored tour playback logic, so that the tour is represented by only one serial track, containing of FlyTo, Wait, and TourControl items, and several parallel tracks, each representing either a SoundCue item, or an AnimatedUpdate item, which could overlap with other tracks, both serial and parallel. This refactoring of design was required in order to make the tours look more dynamic, and so that it is easier to handle and work with them in our subsequent codes.

-> Implemented seek functionality for tour playbacks, with a progress bar in the tour widget, which can be dragged manually by the user, to bring it to any position of the tour. Also, while dragging itself (not only just before and after), the respective changes, that is, the movements in the camera, along with the balloon visibility, can be seen getting changed in the map while dragging the slider itself, both forward and backward.

-> Added basic interpolation of tours in Marble, so that the camera makes smooth turns (not sharp ones) when flying from one location to the other (when the Fly-to-mode has been set to smooth). Please go though my blog post to know more about this, and the previous two features mentioned above [Note: In the kml file of the tour in the video shown there, the FlyTo modes are mostly not set to “smooth” so the “smooth interpolation” feature is not quite visible in that video, but the videos which are following later on in this blog, have all its flyto’s modes set to smooth, so it will be visible there.]

-> Next, I implemented the feature of being able to create / delete placemarks, and also to show / hide the popup balloons of existing placemarks, during the playback of the tours. The showing / hiding of popup balloons can be understood more clearly if you go through this video of a tour on the moon of the various landing sites made in it in the recent past. The creation / deletion of placemarks, during the playback of tours, can be understood from this very short video.

-> Then comes viewing of routes as tours. I implemented the functionality to preview routes as tours and showing turn-type icons in waypoints during a route preview, while adjusting the speed and range of the tour according to the density of waypoints in the current visible region in the map. This can get more clear if you look at this video.

-> Finally, I implemented the functionality of being able to create videos from tours directly, without having to play and record them manually in order to get the video. So, I added a new Play button in the Routing widget, clicking on which, a dialog box would come up where we can choose the destination filename with path, along with the fps rate with which we want the video to be written. Clicking on Start would start video recording, showing the % progress in the progress-bar. We can cancel video-recording any time by clicking on Cancel. Below are two pictures showing how it would look like, before and after the the video has finished being written.

Video Export Ongoing  Video Export Complete


I would like to thank my mentor Dennis, for his awesome help in making me be able to complete this project. Without his motivation, I wouldn’t have been able to make it to the very end. I am going to miss GSoC like hell. But I’ll obviously keep contributing to Marble in the future. It has been a hell of a great experience for me. Thanks again! 🙂


KDE Sprint, Randa

Hi all, just wanted to say that I am going to the Randa Meetings that are going to be held in Randa, Switzerland from the 9th to 15th of August this year. These code sprints are pretty important because through these, developers can get to interact and plan out stuff, collaborate, and create amazing softwares in a very small span of time. As always, this sprint is going to help everyone who uses KDE softwares. But we need your help to make this event possible. As you know that KDE is a non-profit organisation, and just like any other type of meeting / event needs funds, so do we. So even if you are not attending this meeting, still you can help us by donating some amount to the fundraiser. We need your help and It is people like you who can make these meetings possible. Thank you! 🙂

GSoC: Weeks 2, 3, 4

Marble has got something called “Tours”. It can be used to take a virtual tour of the world by visiting different places according to a defined playlist. These tours, when they are played from the playlist that is contained in the kml file containing the tour, they follow an order shown as given below. That is, there are basically two types of items that are being played here, just like a “track” is played:

  • Serial Tracks: These consist of the FlyTo items, the TourControl Items, and the Wait items. These play serially one after the other according to the order in which they are present in the playlist, and run for its respective duration. No two of items can run parallely.
  • Parallel Tracks: These consist of the SoundCue items, and the AnimatedUpdate items. That is, as you can see below, these items can run parallely, which means, if a sound cue starts at some point, it can keep playing in the background at the same time when the camera hovers on to some location’s coordinates there in the map. In fact, more than one parallel tracks can also play at the same time.



So, we needed to refactor our existing code keeping in mind the above design of kml as our goal, so that any type of kml files could be played without any type exceptions. So, I created two new classes, SerialTrack, and ParallelTrack, and further created separate classes for each of the 5 types of items I mentioned above. And then, handled these accordingly in the *Track classes. So, the code looks much cleaner, and clearer (easier to understand) now.

As far as the user-interface is concerned, we made some changes in that as well. So, apart from the previously existing Tour Widget showing the details of the items in the playlist, with an Edit button against each, and a Play, a Pause and a Stop button below it, we added to it a horizontal progress bar as well, so that the user is able to understand how much of the tour has finished and how much remaining. Also, the Play and Pause buttons, instead of making them separate buttons, we fused them into one togglable button that will act as both Play and Pause. Not to mention, the progress bar has also been made seekable, so that, now you can actually drag the slider as desired, and be able to enjoy it from any point of the tour as you want. Here is how the slider looks like now, with the togglable Play/Pause button:


Also, in the tour playback, previously when the map’s focus shifted from one coordinate to another coordinate in the map (when proceeding from one FlyTo item to another in the playlist), the camera didn’t actually move along the path joining those two points. So this also had to be implemented. Also, not only should the camera just move, it should move in a way that is not a straight line, so that turnings are smooth. That is, there should not be any pointy edges in the virtual path that the camera should take. So, thanks to my mentor Dennis, with whose help we could be able to implement squad interpolation for smooth playback of tours in Marble, by using some sort of Spline interpolation of three or more points. You are free to go through my code here in case you want 🙂

I have embedded a very short video below, of how it looks like when the tour is played now. I just added a few cities in its playlist and tried to take them from as much around the globe as possible. There are 10 cities in it, each with a duration of 5 seconds, and a Wait element each of one second in between each of those ten FlyTo’s (to keep the tour uniform and unbiased):
(my embedded video is not showing up in Planet KDE, so if you’re reading this post from there, then please open this post separately instead, by clicking on its title, in order to be able to watch the embedded video (which is the main thing in this post really). Thank you!)

Thanks to Dennis Nienhüser, my mentor, without whose help, none of this would have been possible! Thanks again! 🙂

GSoC: Week – 1

So, my scheduled work according to the timeline, for the first week of the coding period, is over. Here are the few changes made to Marble:

Marble has got something called “Tours”. It can be used to take a virtual tour of the world by visiting different places according to a defined playlist. Now, this “timeline” consists of four type of items:

  • FlyTo – These are fixed locations somewhere on Earth, with some coordinates, denoting a definite point on Earth. These are the very locations to which the tours travel to one by one, when it is played.
  • TourControl – These items are used for controlling the tour. These can be either “Play” or “Pause”. With their usual meanings, i.e., “Pause” will pause the tour, and “Play” will resume it.
  • Wait – These items, when encountered in the playlist, the tour playback stops for a definite amount of time. Wait items contain a value in seconds, defining the amount of time the tour has to wait, when it encounters this item.
  • SoundCue – Last but not the least, there is the SoundCue item, which is used for playing background music during the playback of the tour. Generally they are given towards the beginning, but you can place them anywhere in the playlist, and the sound will start playing in the background parallelly, when the item is encountered.

There is a separate TourWidget present in Marble, which handles these tours. Although it did have the functionality to open existing tours, and view them in the playlist, along with removing a few FlyTo items, but it did not have the ability to edit each of the Tour items, from inside the TourWidget itself. So, this is exactly what I did in my first week: Adding functionality for editing Tour items from the TourWidget.

This is how the Tour’s playlist looks like, after a tour is loaded:

Tour Playlist Normally


Now, notice the small Edit buttons adjacent to each item. Those are the buttons which trigger the Edit-mode by which we can edit each item. That is the exact functionality which I implemented. So, here goes a preview of the TourWidget, with a few of the item’s Edit button clicked:

Tour Playlist Edit mode


Here, the 1st, 2nd, 3rd, and fifth items are in Edit mode, and the others are not. By looking at the preview itself, I guess you can get a feel for what and how the items get changed. Anyways, so after making the desired changes, you just got to click on the Save button adjacent to the item, and the value shows up in the Tour Playlist again, but this time, with the modifications made during Edit-mode.

So, one hurdle complete. More to come, in the coming weeks! 🙂

I’m a GSoC’er! :)

Well, the results for Google Summer of Code are out, and I am proud to say that I am finally a GSoC’er 🙂
My project is on implementing interactive tours in Marble. Tours are a set of related places in Marble with supporting media, visited in a defined timeline, which can be played back, and are useful for a range of tasks, like highlighting places of interest for sightseeing, or taking a trip of the highest skyscrapers of the world, or even showing historic events and political changes happening over decades. Even though the Marble library currently supports these use cases but the UI does not reveal all the features yet. My project is about making them possible.

Well, although I am already super-excited about starting off with my project right now, unfortunately my end-semester exams had to come in between all this, so I can’t start with it right away. My exams are going to end on the 5th of May, after which me and my mentors Dennis and Torsten are going to discuss a few organisational stuff in the beginning, and after that, it’s going to be hardcore coding all the way. Thanks to Lydia and all the mentors of KDE for selecting me in this program. I’m sure it’s gonna be a great summer for me ahead! Just can’t wait for it to start! 🙂

Marble Updates

Never blogged much these days. Just wanted to make a quick post about my few contributions to Marble recently:

  1. Added equality operators for GeoDataLatLonQuad, GeoDataLod and GeoDataRegion – Added operator== and operator!= functions to each of the classes mentioned above, and then extended tests/TestEquality by a new unit test method for each of the classes, which verifies the implementation for several instances of each class, and to check the working of the newly added methods.
  2. Added a KML tour for the moon which can be started from the legend – Created data/maps/moon/clementine/tour.kml using Marble’s Tour Widget. Added a link to the above tour inside the <legend> tag of data/maps/moon/clementine/clementine.dgml
  3. Added equality operators for overlay related classes – Added equality operators for the following classes: GeoDataViewVolume, GeoDataVec2, GeoDataScreenOverlay, GeoDataPhotoOverlay and GeoDataGroundOverlay. Also, added the definition for GeoDataGroundOverlay::setLatLonQuad(const GeoDataLatLonQuad& quad). Added a protected bool equals( const GeoDataOverlay &other ) const method to GeoDataOverlay which is called in operator== of GeoDataScreenOverlay, GeoDataPhotoOverlay and GeoDataGroundOverlay to avoid redundancy. Then extended the tests/TestEquality by a new unit test method for each of the classes (except of GeoDataOverlay) which verifies the implementation for several instances of each class.
  4. Finally, added equality operators for Schema and SimpleField – Added operator== and operator!= to the classes GeoDataSimpleField and GeoDataSchema. Extended TestEquality by a new unit test method for each class which verifies the implementation for several instances of each class.

Btw, I would just like to mention, that all of these tasks, wouldn’t have even existed in the first place, if it weren’t for Dennis, my mentor. I owe all my thanks to him for all his help and support 🙂