Simple Blurry Reflections with Environment Maps

Michael Ashikhmin and Abhijeet Ghosh
SUNY at Stony Brook

This paper appears in issue Volume 7, Number 4.
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Abstract

We present a technique which uses existing OpenGL capabilities to approximate the effect of blurry specular reflections and indirect diffuse illumination. It makes use of environment maps, mipmapping with level of detail control, and possibly texture borders. The method is extremely simple to implement, in some cases requiring just a single additional OpenGL statement.

Author Information

Michael Ashikhmin, SUNY at Stony Brook, Computer Science Department, Stony Brook, NY 11794 ash@cs.sunysb.edu

Abhijeet Ghosh, SUNY at Stony Brook, Computer Science Department, Stony Brook, NY 11794 abhijeet@cs.sunysb.edu

Figures

The images from the paper are reproduced here. Click on a thumbnail to view the full-resolution image.

[Thumbnail of Figure 1]

Figure 1. Illustration of the filtering procedure. For each of the faces of a cube EM, we unwrap the EM to create the image above and then use simple box filter to obtain higher mipmap levels. To complete the square, we use a simple strategy of filling in corner areas with faces of the original cube map. This leads to some noticeable seams in the result and a better filtering procedure might be needed to improve the results. Note that standard mipmap creation procedure using GLU library functions is insufficient since it does not filter across different faces.

[Thumbnail of Figure 6(a)] [Thumbnail of Figure 6(b)]
(a) (b)
[Thumbnail of Figure 6(c)] [Thumbnail of Figure 6(d)]
(c) (d)

Figure 6. Different material appearances, all obtained using the same EM with different material parameter. (a) uses the original EM Note aliasing in the reflection near the silhouette due to fast change of the surface normal. (b),(c) blurry reflections; (d) diffuse appearance.

BibTeX Entry

@article{AshikhminGhosh02,
  author = "Michael Ashikhmin and Abhijeet Ghosh",
  title = "Simple Blurry Reflections with Environment Maps",
  journal = "journal of graphics tools",
  volume = "7",
  number = "4",
  pages = "3-8",
  year = "2002",
}