Abstract: Images are presented on a display to produce the perception of viewpoint motion in a three-dimensional workspace. The user can indicate a point of interest (POI) or other region on a surface in an image and request viewpoint motion. In response, another image is presented from a viewpoint that is displaced as requested. The user can request viewpoint motion radially toward or away from the POI, and can also request viewpoint motion laterally toward a normal of the surface at the POI. Radial and lateral viewpoint motion can be combined. The orientation of the viewpoint can be shifted during lateral motion to keep the POI in the field of view, and can also be shifted to bring the POI toward the center of the field of view. In a sequence of steps of viewpoint motion, the radial viewpoint displacement in each step can be a proportion of the distance to the POI so that the radial displacements follow a logarithmic function and define an asymptotic path that approaches but does not reach the POI.

Abstract: A pixel buffer separate from the frame buffer is provided to store selected pixel information, including XYZ values, sub-pixel coverage, and a color value for a graphic object. The frame buffer stores pixel information for each pixel on the screen, including sub-pixel coverage. During the rendering process, the pixel information for each graphic object is computed and stored in the frame buffer. However, as subsequent pixel information for the same XY pixel locations are computed, it may be impossible to combine the two separate sets of pixel information into a single set of pixel information while maintaining the pixel information required to combine the single set of pixel information with subsequent pixel information to be rendered to the same XY location. To maintain the pixel information needed, the first set of pixel information is stored in the frame buffer and the second set of pixel information is stored in the pixel buffer.