GPU Pro 6

1

VII

Block-Wise Linear Binary Grids

for Fast Ray-Casting Operations

Holger Gruen

1.1 Introduction

Binary grids only contain one bit of information per cell. Even reasonably high

grid resolutions (e.g., 4096 × 4096 × 256 amount to 512 MB of memory) still fit

into GPU memory and are thus practical in real-time situations.

This chapter examines the benefits of a block-wise linear memory layout for

binary 3D grids. This memory layout allows mapping a number of volumetric

intersection algorithms to binary

AND operations. Bulk-testing a subportion of

the voxel grid against a volumetric stencil becomes possible. The number of

arithmetic operations and the amoun