By Mark Ward

Technology correspondent, BBC News website



The team produced ray traced versions of the video game Quake

At the tech-fair Cebit, a team from the university demonstrated a lighting technique, known as ray-tracing, using relatively low-powered processors.

Before now, many powerful computers were needed to generate the life-like images this technique can produce.

But the scientists have shown they can achieve the effect using custom-made chips or a high-end PC graphics card.

Graphics in computer games are typically rendered via a technique known as rasterisation which involves drawing all the elements of a scene using polygons.

The holy grail for game makers is to use ray-tracing to depict scenes far more realistically because it models the way rays of light bounce around a scene and are reflected off objects.

Cinema quality effects

However the computational power needed to keep track of the light has meant that it can only be done using large numbers of dedicated machines.

You can even do reflections on reflections on reflections

Daniel Pohl University of Saarland

Film studio Pixar uses ray-tracing to produce the images for its cartoons and Peter Jackson used the technique in the Lord of the Rings to make special effects look convincing.

But Professor Philipp Slusallek and co-workers from the University of Saarland have developed a series of ray-tracing algorithms that promise to make it much easier to use the technique.

Daniel Pohl, one of the researchers who has worked with Professor Slusallek, has used the algorithms to produce ray-traced versions of the Quake 3 and 4 video games.

"It gives much higher image quality in shadows and reflections," said Mr Pohl. "You can even do reflections on reflections on reflections."

This is something that would be impossible with traditional rendering techniques.

The algorithms are well-suited to the next generation of PC chips that have multiple processing cores inside them.

Separate cores could be used to model different rays to make good use of the available computer power, said Mr Pohl.

The algorithms are being made available to anyone to use via the Open RT project.