Julien Guertault

Graphics Programmer

I love light, I want to put my programming skills and sense of aesthetics at work to create beautiful images.

Tokyo based

French nationality

38 years old




  • Master's degree (2004) in computer science, over a decade of software engineering experience
  • Computer graphics : OpenGL, OpenGL ES, GLSL
  • Applications : C, C++, C#
  • Scripting : Bourne shell, Lua
  • Environments : emacs, Visual Studio, XCode, Subversion, Unreal Engine 4, Unity, Oculus, Vive

Communication and leadership

  • Lead programmer at Gameloft Tokyo for 2 years
  • Fluent in English, Japanese and Spanish; native French speaker
  • Composed public speaker1 (list of talks)
  • Organizer of the Tokyo Demo Fest2 demoparty for 6 years
  • Organizer of the Prologin programming contest for 8 years


  • Master's degree (2005) in Human Computer Interaction
  • Award winning demoscener3 (productions)
  • Amateur photographer4 (portfolio)
  • Visual enthusiast5 (blog)


Graphics engineer at Square-Enix

VR narrative experience, Tokyo, Japan


Graphics engineer on the VR manga project, Hikari, from early prototype to first public release. Design, implementation and optimization of NPR features and materials for the artists. Supervision of the continuous integration, in particular the workflow to upgrade UE4 while retaining extended modifications to its rendering source code. Presentation of the rendering technique at SIGGRAPH Asia 2018.
Environment : Unreal Engine 4, Blueprint and C++ on Windows, Oculus Rift and HTC Vive.

Lead programmer at Gameloft Tokyo

iOS and Android games, Tokyo, Japan


Technical lead of Magna Memoria6, from early prototypes to release on the market ; management of a team of 10 programmers, mentoring, set up of tools (automated builds, issue tracking) and policies (code reviews, unit testing).
Environment : C++ on Windows and iOS, Unity for prototyping and authoring.

Graphics and Tool Programmer at Silicon Studio

Middleware for the video game industry, Tokyo, Japan


Tool development, including implementation of a mesh importer, profiling of an existing rendering on a new platform, specification of a bug reporting library, maintenance of a particles effect editor, implementation and unit testing of a shader editor.
Environment : mostly C++ and C# on Windows.

iOS Programmer at Visuamobile

iPhone and iPad applications, Paris, France


Implementation of applications7 (example) from A to Z within teams of two or three programmers; products include a videos browsing app, a front-end for an image signing app, an e-book reader, a learning app for small kids (with drawing recognition), a showcase for a car.
Environment : Obj-C and C++ on iOS.

Game Developer at F4

PC video games, Paris, France


Tool development, specification and implementation of the NPC interface and avatar customization interface in a persistent world game, specification and implementation of an automatic camera system in a multiplayer car racing game. The most significant projects were MMO games8 (Exalight, Empire of Sports).
Environment : C++, MEL and Lua on Windows.

Graphics Programmer Intern at Alsim

Professional flights trainers, Nantes, France


Geographic data processing, implementation of new features for the rendering engine, especially weather effects like fog or volumetric clouds9 (screenshot on Flipcode).
Environment : C++ and DirectX 8 on Windows.


Master of Science, in Human Computer Interaction

South Brittany University, with Honours


Courses included ergonomics, machine learning, natural language processing, computer graphics, and a four months research internship.

Master of Science, in Computer Software Engineering



Courses included Unix system programming, compiler theory and object-oriented modelling. Numerous assignments, including writing a complete Bourne compatible shell and a toy compiler.

Classes préparatoires aux grandes écoles


Two years of intensive undergraduate courses majoring in mathematics, physics and mechatronics.


  1. Examples of talks about shading, lighting, or post-processing:
  2. Tokyo Demo Fest:
  3. Notable demoscene productions:
  4. Examples of photography:
  5. Blog on image and rendering:
  6. Magna Memoria:
  7. ABC rigolo Grandes lettres:
  8. Examples of games at F4:
  9. Short summary and screenshot on Flipcode: