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Summer of Code/Application/2015Summer of Code/Application/2015


Introduction & overview

This is the application of the ScummVM project for the Google Summer of Code. Let's start with a quick overview of the facts before turning to the more elaborate parts of this document.

Project: ScummVM
Participation in prior SoCs: Yes
Applications for prior SoCs: 2014, 2013, 2012, 2011, 2009, 2008, 2007
Organization administrator: strangerke
Organization co-administrator: sev
Backup administrator: wjpalenstijn
Project License: GPLv2
Ideas page: GSoC Ideas
IRC channel: #scummvm on
Development mailing list:
Backup Mentors:

Please address all items in RED ;-)

Application organized according to program FAQ

Description of the Organization

Since 2014, ScummVM is an GSoC umbrella for its sister project, ResidualVM.

ScummVM is a collection of Virtual Machines for playing classic graphical point-and-click adventure games on modern hardware.

Supported games include favorites such as Monkey Island, Simon the Sorcerer, Space Quest, and many more. To this end, the Virtual Machines (called Engines) are complete reimplementations in C++ of the engines used in the original games. The development team works either by reverse engineering game executables (usually with the permission of creators of the game), or by using the original source code of the games provided by the creators. The number of engines is constantly growing thanks to a very agile and diversified development team and ScummVM is able to run more than 200 games. The VM approach followed by ScummVM results in efficient code, which has been ported to numerous Operating Systems. Besides running on all mainstream desktop environments, namely Windows, Mac OS X and most Unix variants (Linux, *BSD, Solaris), ScummVM also runs on popular game consoles (Wii, Nintendo DS, PlayStation 2, PlayStation Portable, Dingoo and more), smart phones and PDAs (Android, WinCE, iPhone or Symbian based), and even on many not-so-mainstream systems (like BeOS, AmigaOS or OS/2). ScummVM has a highly productive team of about 45 currently active developers (out of an all-time pool of over 110), working together on a codebase of 2,300,000 lines of code. In addition ScummVM has many non-developer contributors, and a huge and highly active community. ScummVM is among the top ranking projects hosted on with over 100,000 monthly downloads and ~10 million project web hits per month. ScummVM has been regularly designated SourceForge project of the week in 2014, and was elected SourceForge project of the month February 2015.

ResidualVM is a sister project of ScummVM and was created in 2003. ResidualVM shares large blocks of common code with ScummVM, some developers and even a mentor.

ResidualVM is a cross-platform 3D game interpreter which allows you to play some 3D adventure games, such as Cyan's Myst 3 and LucasArts' Lua-based 3D adventures: Grim Fandango and Escape from Monkey Island, provided you already have their data files. ResidualVM just replaces the executables shipped with the games, allowing you to play them on systems for which they were never designed! To this end, the VM (called Engines) are complete reimplementations (in C++) of the engines used in the original games.

The VM approach followed by ResidualVM results in efficient code, which has been ported to several Operating Systems. ResidualVM runs on Windows, Mac OS X and most Unix variants (Linux, *BSD, Solaris), and there is even a port on AmigaOS (which is a big-endian system). Recent developments have also added a basic workable Android port, which is currently undergoing polishing.

ResidualVM has a productive team of about 20 currently active developers (out of an all-time pool of over 40), working together on a codebase of nearly 300,000 lines of code.

What Open Source Initiative approved license(s) does your project use?

GNU General Public License version 2.0 (GPL-2.0)

What is the URL for your Ideas list? **This is the most important part of your proposal. Please make sure we can access it and it is complete when you submit this proposal. “Placeholder” or inaccessible ideas pages will be grounds for an automatic rejection for participation in Google Summer of Code 2014.**

What is the main development mailing list for your organization?

  • scummvm-devel AT

What is the main IRC channel for your organization?

  • #scummvm on

Who will be your backup organization administrator?

  • wjpalenstijn

If you chose "veteran" in the checkbox, please summarize your involvement in Google Summer of Code and the successes and challenges of your participation. Please also list your pass/fail rate for each year.

We have participated in the GSoC program for the last eight years. From 2007-2014.

Below are details of the successes and challenges we have encountered grouped by year.

2014: 5 students mentored by 8 mentors and co-mentors.

All the students passed. Two of them were working on ScummVM tasks, three of them on the ResidualVM tasks. Two students are still active, and consider participating again in GSoC this year as a student. Merging the code early still shows benefits, so we'll keep this rule during our next GSoC.

2013: 4 students mentored by 6 team members. Each mentor was also co-mentor of another task.

All the students passed, and 2 students are still actively contributing the project and one student is still regularly on our IRC channel. One of the active students would also like to participate again in GSoC this year as a student. Merging code earlier gave excellent results and we'll do the same if possible this year in order to build on the great results of this year.

2012: 4 students mentored by 5 team members. Each mentor was also the co-mentor of another task.

3 students passed, and one failed at mid-term. One student is still actively contributing to the project and volunteered each year to be a mentor since GSoC 2013, which is really awesome. Based on discussion with other projects and our experience one of the key outcomes from this year was to look at merging student code earlier in the GSoC process and encouraging students to be much closer to mainline development. We modified our processes accordingly for the next year.

2011: 2 students mentored by 4 team members. Each mentor was also the co-mentor of another task.

1 student succeeded in objectifying the CruisE engine, which really needed it. The other student unfortunately gave up fairly quickly after starting work (although the work done was eventually merged into our main repository, after being worked on further by a team member). After stepping back to review our processes, we feel we can still consider them to be mature. Part of the problems which caused the student to quickly give up came from internal tensions, that we have since addressed by redefining the project management structure.

2010: 4 students mentored by 6 team members. Each mentor was also the co-mentor of another task.

All four passed the finals this time, and we merged in their code. One student still continues to contribute to the project. We addressed several long standing project needs and this was a very good year for the project.

2009: 5 students mentored by 6 team members. Some co-mentoring happened.

4 of our students passed, and one failed the finals. The year was a the success and all the students' code was merged within three months into the main development line. We considered this to be a good outcome.

2008: 6 students mentored by 7 mentors.

5 of our students were so successful that their code is included in the mainline of ScummVM, and we consider it a great achievement that 4 of the students continued to contribute to the project afterwards.

2007: 7 students mentored by 4 mentors.

5 of our students passed. Two of our students continued to become active, regular developers in the team after having their respective code contributions integrated in the codebase. Two of the students did not succeeded in their projects.

All in all, we maintain that we have been refining our method of student selection and balancing the workload and commitment required to achieve great outcomes in the past years and this refinement leads to generally better results each year.

The discussions, testimonials and proposed actions which the mentor summit has raised - and which we have participated in during our involvement with GSoC - have helped us a great deal. Our new wider management organization has also proven its efficiency during these last 3 years. Being an umbrella for ResidualVM made us work together more than ever before, and we hope to continue improving the experience for all parties in the future.

Summary pass/fail: 2014: 5/0 2013: 4/0 2012: 3/1 2011: 1/1 2010: 4/0 2009: 4/1 2008: 5/1 2007: 5/2

Why is your organization applying to participate in Google Summer of Code 2015? What do you hope to gain by participating?

Each year since 2007, the program gave us the opportunity to have talented and motivated students working with us. We also love the GSoC mentor summit where we have the opportunity to share our knowledge with mentors from other projects and to learn a lot from them. That's why we wait impatiently, each year, for the announcement of a new GSoC program!

As usual, what we hope to gain is valuable code contributions. In previous years, we've had students take up and complete tasks which had been marked as "to-do", but the main developers had no time to implement them. The students took these up as self-contained GSoC projects and realized them. But also, some students have come up with new functionality, proposing and finally implementing it. These have been our favorite.

In addition, we hope to gain new developers for the project. We hope that after their projects, students will stick around and improve them or work on other interesting tasks. We hope that GSoC brings the students in touch with open source and, in our case, brings them in touch with game development. We hope these students will add their piece of code to this project, but will also keep on contributing afterwards.

We've been successful in the past eight years, and we're really looking forward to great results from the program this year too.

How many potential mentors do you have for this year's program? What criteria did you use to select them?


  1. aquadran
  2. clone2727
  3. djwillis
  4. dreammaster
  5. joostp
  6. klusark (joelteichroeb)
  7. lordhoto</span>
  8. md5
  9. sev
  10. somaen
  11. strangerke

Backup Mentors

  1. botje (dharnie)
  2. fuzzie
  3. wjp


We have 14 potential (co) mentors or backup mentors this year.

We want our mentors to have the following qualities:

  1. Be able to commit to participating for the entire duration of the program. They first and foremost have to be available to their students and the mentor team.
  2. Have a considerable track record hacking on ScummVM or ResidualVM. They can help the students more effectively and in an immediate fashion this way.
  3. Have the patience and skills to explain to their respective students on how to tackle their tasks. Also, to be able to help the students out in sticky situations.
  4. Have a clear vision on how a task should proceed, both in broad strokes as well as in the technical details level. Allowing, of course, some freedom of movement to the students, where this is applicable.
  5. Be regularly present on our #scummvm-gsoc channel, where we continuously inform each others of the progresses and issues of the students

For this year, and this holds for our previous participations too, our mentors have volunteered to work with GSoC. This means that they primarily want to be involved in the program and that they are not dragged in to participate. Moreover, they have all been contributors to ScummVM and/or ResidualVM for several years. They feel comfortable around the current code and can guide students to perform their tasks. The majority of the mentors have also participated in past GSoCs so they know their way around the procedures and have also refined their mentoring style. Some of them have been GSoC students one of the previous years. Some of them are/have been part of academia, guiding real students. They have seen the student mentalité in-action and have experience helping people along. We are drawing the best available from our pool of developers to mentor GSoC students this year again.

What is your plan for dealing with disappearing students?

We know that the students can do that. We learned this the hard way the first time 'round the GSoC ride :-) The measures we set in place during the previous years almost eradicated this problem.

As in the last few years, we will again be sure to enforce certain rules at the program start; we will clearly explain that this work should be considered as full-time, and if that is in any doubt, we will not let the student enter the program.

We have also introduced the policy that students have to provide status to their mentors on a bi-daily basis at most. If a student disappears for more than 3 days without notifying his/her mentor, the student will fail the project. The students will be made immediately aware of this during their applications. We have positively identified that frequent and meaningful communication goes a long way in keeping the students engaged and interested.

Of course, comprehensive timelines will be required as usual, and we will accept only those of the students which will set realistic goals, thus minimizing the risk of getting intimidated. This factor too frequently leads to the student disappearing.

During the program, we will make sure that the students will feel comfortable with their tasks. Our mentors already have experience with that. Moreover, in difficult situations in the past there was not just a single person feeling responsible for a particular student, but rather the whole project was trying to help when needed. These reflexes on behalf of the mentor group but also on behalf of the active team members of ScummVM and ResidualVM have proven to be a pretty good "tool" and we are going to do our best this year too.

Based on our more negative experience several years ago, we will also make sure that internal project tensions stay internal and under control, since they were an identified cause of demotivation of our last disappearing student (in 2011). The current umbrella management structures should make sure that it will not as easily happen in the future.

What is your plan for dealing with disappearing mentors?

For the mentors, the risk is relatively low; our past experiences absolutely verify this claim. In order to be even more efficient this year, five of our mentors are project leaders, core team members or project administrators for ScummVM and/or ResidualVM and are reachable virtually 24/7 (in case of emergencies).

We all have exchanged sufficient contact information (including cell phone numbers etc.) to be able to discover our whereabouts. Should something really bad happen which precludes a mentor from fulfilling his duties (including personal reasons), we will attempt to shift students to new mentors among the existing mentors, or drawn from our backup pool of mentors. This will depend on the number of students we have to mentor.
We also defined for the last four years a co-mentoring system so the students have a primary and a secondary mentor, which comfort us in the idea that, in any case, the students will not be left hanging for any reason at all, no matter what happens.
On top of that, we have a specific #scummvm-gsoc channel on IRC where mentors (and only them) and org admins are connected all of the time. We use this channel to keep ourselves informed constantly of the situation of each task, each student and eventually each mentor. A mentor wouldn't disappear without being noticed very quickly by this mean too.

What steps will you take to encourage students to interact with your project's community before and during the program?

The development team actively uses the project resources, including forums, IRC, Wiki and the development mailing list during project development.

We consider our students to be special, but developers nonetheless. Each developer including our students is encouraged to take part in discussions, whatever the means these discussions occur. As a pragmatic fact, on IRC any student will be able to get support literally 24/7, as our developers are scattered all over the globe.

Support and feedback is not only a function provided by the mentors, but the entire development team and community, are encouraged to communicate constructively with the students. The students are marked with a special flag on our IRC channel (voice), so everyone knows who they are. We require the students to write introductory letters to our development list and their blog so everyone will have a sensible background about them, their skills and their assigned task (of course).
In order to help the students familiarize themselves with the project, we also have created several key pieces of documentation for them. In particular, we have an exhaustive 'developer central' on our Wiki where we describe the all-important internals of ScummVM and finding your way around the project. This is highly valuable as a quick reference as well as during the initial explorations of the codebase.

What will you do to encourage your accepted students to stick with the project after Google Summer of Code concludes?

The two previous years, we decided to require the GSoC student code be merged into our Master tree much earlier in the process, if possible. Our past experience was telling it should be very motivating for students to directly interact with our main repository and could potentially make some of them stay after the end of GSoC: it seems we were right as 2 students out of 4 are still actively contributing, while a 3rd one is still present from times to times. This is obviously for us a very positive sign and we plan to proceed the same way this year again.

Are you a new organization who has a Googler or other organization to vouch for you? If so, please list their name(s) here

Are you an established or larger organization who would like to vouch for a new organization applying this year? If so, please list their name(s) here

Is there anything else we should know or you'd like to tell us that doesn't fit anywhere else on the application?

We are very grateful for all the benefits we reaped over the previous years thanks to your program and we would like to thank you again


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