Isocube: Exploiting the Cubemap Hardware

Liang Wan, Tien-Tsin Wong and Chi-Sing Leung,
IEEE Transactions on Visualization and Computer Graphics,

Vol. 13, No. 4, pp. 720-731, 2007
　

Abstract

This paper proposes a novel six-face spherical map, isocube, that fully utilizes the cubemap hardware built in most GPUs. Unlike the cubemap, the proposed isocube uniformly samples the unit sphere (uniformly distributed) and all samples span the same solid angle (equally important). Its mapping computation contains only a small overhead. By feeding the cubemap hardware with the six-face isocube map, the isocube can exploit all built-in texturing operators tailored for the cubemap and achieve a very high frame rate. In addition, we develop an anisotropic filtering that compensates aliasing artifacts due to texture magnification. This filtering technique extends the existing hardware anisotropic filtering and can be applied to, not just the proposed isocube, but also other texture mapping applications.

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Visual Comparison

The table below compares properties between cubemap and isocube.

 

 

Sample distribution

Texel shape

Horizontal-cross format

Cubemap

 

 

  

Isocube

 

 

  

 

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