Basser Seminar Series

Efficient Algorithms for Graphics Hardware

Speaker: Jacob Munkberg
PhD student, Lund University

Time: Wednesday 27 August 2008, 4:00-5:00pm

Location: The University of Sydney, School of IT Building, Lecture Theatre (Room 123), Level 1

Abstract

Texture Compression
A High Dynamic Range image storeS a full floating point value per color channel for every pixel, and can capture bright sunlight and dark shaded regions in one single image file. We present algorithms for fixed-rate compression of high dynamic range (HDR) textures at low bit-rates. The algorithm can be efficiently implemented in hardware, and supports textures with a dynamic range of over 1e9:1. At a fixed rate of 8 bits per pixel, we obtain results virtually indistinguishable from uncompressed HDR textures at 48 bits per pixel. This technique has also been extended to compress normal map textures, which are texture that store fine-scale surface details.

Graphics Hardware Culling
Culling techniques have always been a central part of computer graphics, but graphics hardware still lack efficient and flexible support for culling. We introduce programmable culling, which is as flexible as a shader program and capable of quickly culling entire blocks of fragments or geometry. Our approach builds on an algorithm that automatically computing tight positional and normal bounds on the fly for a geometric primitive. These bounds are derived from an arbitrary vertex shader program, which may include a curved surface evaluation and different types of displacements, for example. For highly tessellated scenes, we show that up to 80% of the vertex shader instructions can be avoided, which implies an ”instruction speedup” of 5 times.

Speaker's biography

Jacob Munkberg is a 3rd year Ph.D. Student in the Graphics Group at Lund University, Sweden, working with Dr. Tomas Akenine-Möller. This semester, he is an occupational trainee student at ViSLAB, University of Sydney, working with Dr. Masahiro Takatsuka. His main research interests are graphics hardware algorithms, texture compression, real-time ray tracing and HDR images.

Jacob Munkberg's website