Hardware-Assisted Visibility Ordering for Point-Based and Volume Rendering

Abstract

Abstract

Object‐Space Visibility Ordering for Point‐Based and Volume Rendering

“…We have included it here as a reference to demonstrate how our hardware implementation also improves the axis‐aligned rendering technique. Also, as stated before, our graphics hardware implementation is at least one order of magnitude faster than the work presented in [HM05].…”

“…Our technique can also handle larger, non-sparse, volumes, and our approach does not need a proxy geometry, which makes it faster and more general. Our pointsprite implementation achieved a speedup of 12 with respect to what was presented in [HM05].…”

“…For all scenes , h = 0.85 . (a) point‐based rendering [ HM05 ] (b) light‐field rendering using coloured point clouds ‐ hyperline rendering (c) image‐based rendering of range data with estimated depth uncertainty; (d) volume rendering.…”

“… If this decision is made per frame, as in [WES89], based on the viewing ray at the image center, the whole image may appear to pop at the frame that switches to a new sorting order. In a perspective view, the decision can also be made per pixel ray, using clipping. This was first introduced in [HNM*04] and it is generalized in [HM05] for any point‐based and volume rendering data. However, in this case there is a moving set of transition lines across which the order changes with the changing view, creating smaller, but still visible artifacts, as the switching region becomes 1D in image space but also 1D in time.…”

“…These artifacts are the result of the discrete nature of the algorithm. There is a discontinuity at the borders of the regions. In this paper, we review a third method (also presented in [HM05]), which effectively blends the sorting order in a region near these transition lines, so that the artifacts are much less noticeable. We have extended the work in [HM05] by implementing most of the algorithm in graphics hardware, taking advantage of current state‐of‐the‐art GPUs, and using point sprites.…”