Thumb

Thumb is my real-time 3D graphics research codebase, presented in the form of a library. It provides a rendering engine with a highly-configurable shading system wrapping an ODE physical simulation with an in-engine world editor. A wide array of stereoscopic displays and virtual reality devices are supported, and a distributed synchronization mechanism enables cluster-parallel rendering.

Dependencies

Thumb depends upon a number of external libraries. Binary distributions of Thumb provide these. However, if Thumb is to be built from its source then they must already be installed.

• SDL2 enables platform independence.
• GLEW enables OpenGL portability.
• FreeType renders text.
• libpng reads PNG image files.
• zlib decompresses data.
• ODE performs physics simulation.
• zip helps embed static data.

Optionally,

• LibOVR enables Oculus Rift support.

Build

Linux and OS X

Linux and OS X builds are driven by Makefiles. Dependencies are managed by pkg-config. Simply run make to produce Release/libthumb.a:

make

To produce a debug build of the library Debug/libthumb.a:

make DEBUG=1

To produce a dynamically linkable library:

make DYNAMIC=1

Windows

The Windows build is driven by nmake files named Makefile.vc. These include some local configuration that must be set.

• LOCAL_INCLUDE gives the location of the dependency headers. Default: C:\Include

• LIBOVR gives the root of the LibOVR directory in the Oculus SDK. Default: C:\OculusSDK\LibOVR

• ZIP gives the path and options for the ZIP command. Default: C:\Bin\zip.exe -9

The build is activated using either the included Visual Studio project file or the developer's command prompt. On the command prompt, use nmake to produce Release/thumb.lib:

nmake /f Makefile.vc

To produce a debug build of the library Debug/thumb.lib

nmake /f Makefile.vc DEBUG=1

The current Windows build does not support dynamic linking.

File system

When distributing an application, it's convenient to distribute supporting assets (images, models, shaders, etc.) in a compact archival form. It's critical to ensure an archive is internally self-consistent and does not refer to assets through absolute references to the developer's file system. To support this, Thumb implements a virtual filesystem mechanism.

The virtual filesystem stores assets with relative path names, overlaying a list of data sources that may include user directories, ZIP archives, and statically-linked binaries. This overlay allows user-defined assets to override application assets freely. Of course, normal access to the root file system remains available along side the virtual file system.

File selection dialogs display the current directory in a text edit box at the top. The root file system is accessed for all absolute paths (directories begining with / or C:/), and the virtual file system is used for all relative paths. Thus, to view the root filesystem, simply change the directory to / and press enter. To view the virtual file system, clear the directory text edit box.