Jablonski,Sz., Martyn,T.
Abstract:
In this paper, we present a novel approach to real-time,
continuous and symmetrical level of detail (LOD) management of a 3D object
represented by a sparse voxel octree (SVO). We propose a new method for
continuous and symmetrical transition between two detail levels. The method is based on a
SVO representation extended by redundant, helper nodes which
are used to achieve a proper interpolation of geometry and material data.
We extend redundant nodes with a transition direction
attribute. Additional memory requirements are
minimized by storing indices in a direction vector lookup table in object
space. The new method is applied for an accurate evaluation of the required
LOD. It uses an image-based evaluation function, i.e. the standard level
transition function based on camera distance is extended by the real-time
calculation of the current LOD pixel fill rate.
We extend typical level transition function based on distance with real-time calculation of the current
LOD pixel fill rate. Two different image based
methods of SVO node pixel fill
rate calculations using compute shaders or GPU queries and parallel reduce are presented.
The developed LOD management algorithm is applicable
for a raytracing and a rasterization-based rendering pipeline.
The LOD transition algorithm allows to perform a
dynamic and continues control of the SVO based
objects which have not been available in other works. Moreover, the proposed
fading algorithm based on the fade out direction and scaling allows for a LOD change without any graphical artifacts or loss of the virtual scene
immersion.