The ASC visualization group is working in conjunction with several
collaborators to provide a scalable, parallel rendering interface that
supports portable visualization applications. We are working with teams
from Stanford, Red Hat, Tungsten Graphics, IBM, HP and other DOE labs to
develop an Open Source software stack that can be scaled to large
parallel systems and provides a series of conceptual abstraction layers.
The basic software stack is illustrated below:
Parallel applications may or may not sit on top of higher level
toolkits such as VTK.
Other layers include:
- Chromium provides an OpenGL abstraction which includes a parallel
interface and a generalized stream processing layer.
- Distributed Multi-headed X (DMX) provides a distributed X11 server
implementation that aggregates a number of X11 servers into a single
- Parallel Image Compositing API (PICA) provides a standard API
abstraction for hardware and software compositing systems.
- MIDAS provides indirect rendering and digital image delivery
mechanisms that allow for the separation of 3D rendering from image
- Merlot provides a flexible image transport service that allows
distributed applications to leverage existing image compression and
- Telepath provides visualization scheduling, session and resource
Interaction with a NIF simulation on a PowerWall, rendered using
VisIt via DMX and Chromium (movie)
The core technology components are packaged so that unmodified
applications can use them without knowledge and see basic performance
gains or added flexibility. "Aware" applications can also be written to
exploit the parallel performance features of the various components.
Each of these components is being built as a separate project and as
such they each provide a scalable interface that applications can be
coded to. For example, a pure X11 application that does not need 3D
rendering can use the scalable rendering hooks in DMX to render in a
scalable fashion to a tiled display. However, all of these projects are
being developed together with many developers serving on multiple
projects. As a result, they are all designed to be interconnected to
provide a consistent, fully functional parallel rendering API that can
be easily ported to any new host system. The various subs-systems
include mechanisms that allow hardware vendors to contribute as well
while protecting their intellectual property via binary modules. Much
of the core infrastructure software is available for immediate download
via OpenSource channels such as SourceForge.
DMX Distributed X11 Server Providing a Single, Continuous Desktop
Over Six XFree86 Servers