InteractiveRayTracing----光线跟踪原理.docVIP

窗体顶端 Interactive Ray Tracing by Jacco Bikker Introduction See how advances such as Hyper-Threading Technology and dual-core processors affect ray tracing—allowing for three- to four-fold speed increases. Ever since the introduction of ray tracing it has been regarded mostly as an off-line process; a really expensive way to produce really pretty images. Recently, ray tracing has been made much more interactive, even using consumer hardware. As ray tracing begins to make optimal use of recent advances in processor technology, such as Hyper-Threading Technology and dual-core processors, we expect that it will become practical for both interactive and real time applications in the near future. This article shows how low-level optimizations targeted at this technology allow for a three- to four-fold speed increase compared to existing implementations.A ray tracer typically consists of the following parts: Ray generation Ray traversal Primitive intersection Shading After summarizing earlier work, the rest of this paper describes the implementation of these parts in a SIMD optimized packet ray tracer.The first section describes the generation of ray packets. This section also details when not to use ray packets, and how to handle this case. The second section describes the kd-tree structure and its use for fast location of primitives to be intersected with a ray. The third section discusses efficient ray packet / triangle intersection. The fourth section describes the shading model used in our ray tracer.Finally, we present performance figures, and areas of future research. Ray Tracing Ray tracing is a very intuitive way of visualizing data, as it mimics the flow of light from light sources, via surfaces, to a camera. Or, stated the other way around, light travels in straight lines, so it doesnt matter at which end we start. Starting at the camera is more practical, as only a small portion of light emitted by light sources actually reaches the camera.The fact