10-06-2017, 06:56 AM
Introduction
Developers of 3D graphics applications have always had difficulty creating realistic computer generated characters, objects and environments that can be interacted with in real time. The limitation has been a lack of available processing power combined with the restricted flexibility afforded by existing graphics hardware. There has always been a trade-off between performing operations on the CPU, which allows more flexibility due to its general and programmable nature, and the graphics processor, which allows better performance due to its hard- wired and heavily optimized architecture. While the rapidly increasing speed of graphics processors has enabled a significant amount of progress, and while they have been steadily taking over many of the tasks formerly handled by the CPU, there are many interesting and useful graphical techniques that have remained out of reach because they require a combination of speed and flexibility that neither existing CPUs or graphics processors could adequately provide. What is needed is a technology that combines the speed and optimizations of a dedicated graphics processor with the flexibility and programmability of a CPU, allowing a virtually infinite range of visual effects at interactive frame rates. The first attempts at introducing this kind of technology were successful in increasing the number of effects available to developers, but still suffered from a number of limitations in terms of both versatility and performance. SMARTSHADER technology, developed by ATI, removes these limitations to free developers imaginations. SMARTSHADER Technology SMARTSHADER technology brings a new level of graphical effects to personal computers. It allows software developers to use techniques that, until recently, were only available to the creators of non-interactive computer generated movies and special effects, and bring them to interactive computer games, the world wide web, and digital content creation applications. ATI s SMARTSHADER technology represents a new generation of programmable, hardware-accelerated graphics pipelines. The technology was developed with a keen eye toward maximizing efficiency and minimizing common performance bottlenecks, especially memory bandwidth. SMARTSHADER technology is an extension of the Vertex Shader and Pixel Shader programming languages first introduced by Microsoft in DirectX 8.0. While these shader languages were a good first attempt at bringing programmability to graphics hardware, experimentation revealed that they had a number of limitations that offered many opportunities for improvement. Incorporating suggestions from leading 3D application developers and researchers, ATI worked closely with Microsoft to improve the flexibility, efficiency, and usability of the DirectX 8.0 shader languages. The results are being made available to developers for the first time with the release of DirectX 8.1, which reveals the full capabilities of SMARTSHADER technology. For developers that prefer to work with OpenGL, the full SMARTSHADER feature set is also accessible using custom extensions provided by ATI. The key improvements offered by ATI s SMARTSHADER technology over existing hardware vertex and pixel shader implementations are: Support for up to six textures in a single rendering pass, allowing more complex effects to be achieved without the heavy memory bandwidth requirements and severe performance impact of multi-pass rendering A simplified yet more powerful instruction set that lets developers design a much wider range of graphical effects with fewer operations Pixel shaders up to 22 instructions in length (compared to 12 instructions in DirectX 8.0 Pixel Shaders) allow more accurate simulation of the visual properties of materials Ability to perform mathematical operations on texture addresses as well as color values, enabling new types and combinations of lighting and texturing effects that were previously impossible
read http://ati.amdproducts/pdf/smartshader.pdf