Power-Aware 3D Computer Graphics Rendering

摘要

Real-time 3D Graphics rendering consumes significant power because of its very high computation and memory access rate. Due to variation in workload and perceptual tolerance, power-awareness can optimize this power consumption significantly, thus facilitating migration to future power-constrained devices such as personal digital assistants (PDAs), tablets, wearables, phones etc. This work proposes such a low power system based on Approximate Graphics Rendering (AGR). The AGR system supports various algorithms and incremental changes to the computational mechanism based on certain pre-specified parameters. The knowledge available apriori about the signal and noise models of graphic images and Human Visual Perception (HVP) are used to select the configuration that meets the quality needs at the lowest power consumption. The power savings using the AGR system are examined for two power hungry stages of the 3D graphics rendering system, namely shading and texture mapping. Besides supporting various algorithms, two novel parameterizable computation schemes are proposed. First, iterative Coordinate Rotation Digital Computer (CORDIC) algorithm based units are incorporated for certain computations. Second, a scheme for dynamically enhancing the perceived image spatial correlation for reduced computations is presented. A hardware synthesis and estimation methodology based on realistic graphics content from the well-known 3D graphics benchmarks and the game Quake2 is used for estimation of power savings. Significant power savings of 75.1%, 73.8% and 72% are demonstrated in the shading, texture mapping function blocks and CORDIC based 3D vector interpolator respectively.