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Viewpoint specification is fundamental to traditional computer
graphics rendering. Both the transformation of a
scene to eye space in the traditional graphics pipeline and
the origination of viewing rays in a ray-casting system depend
on the viewpoint. Moreover, many subsequent rendering
steps are also impacted by the choice of viewpoint, including
clipping, projection, illumination calculations,
shading, and visibility determination. As a result, changing
the viewpoint frequently gates the entire process of interactive
rendering, as each rendered frame is initiated with the
specification of a viewpoint, followed by the scene description,
and culminating with the final displayed image.
There are many potential advantages to decoupling
viewpoint specification from rendering. One advantage results from beginning the rendering
process before the viewing position is resolved, thereby reducing
latency. However, the ultimate advantage of separating rendering
from viewpoint selection is that it becomes possible to
render the same scene for multiple eyes. Possible applications
include shared virtual environments (stereo viewing
by many participants of a computer-generated scene). In
the future, view-independent graphics rendering hardware
will also be essential to support the multitude of viewpoints
required for real-time autostereoscopic and holographic
display devices.
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PixelView: A View-Independent Graphics Rendering Architecture
We present a new computer graphics rendering architecture that allows "all possible views" to be extracted
from a single traversal of a scene description. It supports a wide range of rendering primitives, including polygonal
meshes, higher-order surface primitives (e.g. spheres, cylinders, and parametric patches), point-based
models, and image-based representations. To demonstrate our concept, we have implemented a hardware prototype
that includes a 4D, z-buffered frame-buffer supporting dynamic view selection at the time of raster scan-out.
As a result, our implementation supports extremely low display-update latency. The PixelView architecture also
supports rendering of the same scene for multiple eyes, which provides immediate benefits for stereo viewing
methods like those used in today’s virtual environments, particularly when there are multiple participants. In the
future, view-independent graphics rendering hardware will also be essential to support the multitude of viewpoints
required for real-time autostereoscopic and holographic display devices.
Publications: GH04 Paper
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