Flat BTF.pdf

Flat Bidirectional Texture Functions (BTFs) are a representation for highly-realistic materials in computer graphics. BTFs are 6D textures that store appearance parameters varying spatially and with viewing and lighting direction changes. However, they require huge amounts of data, making compression necessary. Existing compression schemes have limitations due to the uncorrelated combination of complex optical phenomena such as parallax effects, masking, shadow casting, and inter-reflections.

A new representation for BTFs is introduced, which isolates parallax effects by building a flattened BTF according to a global spatial parameterization of the underlying meso-geometry. View-dependent indirection maps are generated to encode parallax effects. This representation is analyzed on synthetic BTF data, showing benefits in view-dependent coherency and finding the best sampling strategy. It is also suitable for hardware acceleration on current GPUs.

Key aspects of the representation include:

Isolating parallax effects from other optical phenomena
Building a flattened BTF using a global spatial parameterization
Generating view-dependent indirection maps to encode parallax effects
Analyzing the representation on synthetic BTF data for benefits in view-dependent coherency
* Demonstrating suitability for hardware acceleration on current GPUs

The introduced representation addresses the challenges of existing BTF compression schemes, providing a more efficient and effective way to represent highly-realistic materials in computer graphics.