A photon accurate model of individual cones in the human eye perceiving images on digital display devices is presented. Playback of streams of pixel video data is modeled as individual photon emission events from within the physical substructure of each display pixel. The thus generated electromagnetic wavefronts are refracted through a four surface model of the human cornea and lens, and diffracted at the pupil. The position, size, shape, and orientation of each of the five million photoreceptor cones in the retina are individually modeled by a new synthetic retina model. Photon absorption events map the collapsing wavefront to photon detection events in a particular cone, resulting in images of the photon counts in the retinal cone array. The custom rendering systems used to generate sequences of these images takes a number of optical and physical properties of the image formation into account, including wavelength dependent absorption in the tissues of the eye, and the motion blur caused by slight movement of the eye during a frame of viewing. The creation of this new model is part of a larger framework for understanding how changes to computer graphics rendering algorithms and changes in image display devices are related to artifacts visible to human viewers.

This article describes HoloSketch, a virtual reality-based 3D geometry creation and manipulation tool. HoloSketch is aimed at providing nonprogrammers with an easy-to-use 3D “What-You-See-Is-What-You-Get” environment. Using head-tracked stereo shutter glasses and a desktop CRT display configuration, virtual objects can be created with a 3D wand manipulator directly in front of the user, at very high accuracy and much more rapidly than with traditional 3D drawing systems. HoloSketch also supports simple animation and audio control for virtual objects. This article describes the functions of the HoloSketch system, as well as our experience so far with more-general issues of head-tracked stereo 3D user interface design.

FBRAM, a new form of dynamic random access memory that greatly accelerates the rendering of Z-buffered primitives, is presented. Two key concepts make this acceleration possible. The first is to convert the read-modify-write Z-buffer compare and RGBα blend into a single write only operation. The second is to support two levels of rectangularly shaped pixel caches internal to the memory chip. The result is a 10 megabit part that, for 3D graphics, performs read-modify-write cycles ten times faster than conventional 60 ns VRAMs. A four-way interleaved 100MHz FBRAM frame buffer can Z-buffer up to 400 million pixels per second. Working FBRAM prototypes have been fabricated.

A physically compact, low cost, high performance 3D graphics accelerator is presented. It supports shaded rendering of triangles and antialiased lines into a double-buffered 24-bit true color frame buffer with a 24-bit Z-buffer. Nearly the only chips used besides standard memory parts are 11 ASICs (of four types). Special geometry data reformatting hardware on one ASIC greatly speeds and simplifies the data input pipeline. Floating-point performance is enhanced by another ASIC: a custom graphics microprocessor, with specialized graphics instructions and features. Screen primitive rasterization is carried out in parallel by five drawing ASICs, employing a new partitioning of the back-end rendering task. For typical rendering cases, the only system performance bottleneck is that intrinsically imposed by VRAM.