Backwards Memory Allocation and Improved OIT

Knowles, Pyarelal; Leach, Geoff; Zambetta, Fabio

Backwards Memory Allocation and Improved OIT

Files

059-064.pdf (1.1 MB)

Date

2013

Authors

Knowles, Pyarelal
Leach, Geoff
Zambetta, Fabio

Publisher

The Eurographics Association

Abstract

Order independent transparency (OIT) is a graphics technique which sorts surfaces per-pixel for correct alpha blending. The sorting stage requires relatively large amounts of temporary memory in shaders that is usually conservatively allocated at a maximum, which impacts occupancy and performance. To address this issue we introduce backwards memory allocation (BMA), a strategy which creates a set of shaders with varying static allocation size in lieu of dynamic allocation. Batches of threads are then executed directly with the appropriate shader. This also allows optimizations for each generated shader such as choosing the sorting algorithm based on allocation size with no additional overhead. BMA gives both a more flexible OIT (BMA-OIT) for dynamic scenes of varying depth complexity and up to a 3x speedup.

        @inproceedings{:10.2312/PE.PG.PG2013short.059-064
,
booktitle = {Pacific Graphics Short Papers
},
editor = {Bruno Levy and Xin Tong and KangKang Yin
},
title = {{Backwards Memory Allocation and Improved OIT
}},
author = {Knowles, Pyarelal and 
Leach, Geoff and 
Zambetta, Fabio
},
year = {2013
},
publisher = {The Eurographics Association
},
ISBN = {978-3-905674-50-7
},
DOI = {/10.2312/PE.PG.PG2013short.059-064
}
}