Special purpose graphics instructions are provided to facilitate hidden surface elimination. A Z-buffer check instruction performs multiple, simultaneous unsigned-integer (ordinal) comparisons of newly computed distance (Z) values with the contents of a Z-buffer. Distances of points to be drawn are compared with corresponding values in the Z-buffer, and appropriate bits of a pixel mask are then set to designate those pixels for which the points to be drawn are closer (smaller) than the Z-buffer values. Previously calculated bits of the pixel mask are shifted so that consecutive Z-buffer check instructions accumulate their results in the pixel mask register. A pixel store instruction utilizes the pixel mask to update only those pixel locations in a frame buffer which correspond to a point on a newly rendered surface closer than the surface represented by the current pixel value.

Rendered wireframe models of objects offered for sale can be downloaded and displayed as virtual objects in the context of the actual environment in which they will be actually used. The rendered models are located, scaled and oriented so that they appear exactly as a real object would appear when placed in the actual environment. A transparent display permits the environment to be viewed concurrently with display of the rendered wireframe model.

The present invention is an improved flight simulation system. The system organizes data based upon a predetermined number of object types. Each scenery file is divided to separate the data for each object type. Object data is sub-divided into latitude bands of a fixed range of latitude. The system selectively analyzes the latitude band data to locate objects to be processed. For each object type, the objects within a latitude band are sorted and analyzed from west to east. The present system also includes a seeded scenery system. Various levels of seeds, each seed size referring to the size of the area covered by each seed are used. The seeded scenery system provides background scenery only when no other scenery is available to overwrite it. The system also includes a dynamic overlay management system which, when it loads a routine into memory, rewrites the line of code which called the routine to be a call directly to the location of the routine which is now in memory.

The present invention provides an image processing apparatus for use with an image projector to allow the image projector to project a magnified image on a screen without a trapezoid distortion or a keystone distortion even when a normal line of the screen is declined to an optical axis of a projector lens of the projector. Digital image data from AD converter are stored in the image memory (6-9) through a selector (3). From the image memory, the image data of four pixels nearby a deformed coordinate position are read out through a selector (4). The image data of the deformed coordinate position is obtained by calculating an average of sum of arithmetic results obtained by giving a weight to each of image data of the four pixels. The weight given corresponds to a positional deviation value from the deformed coordinate position to the respective coordinate positions of the four pixels nearby the deformed coordinate position.

A slewable projection system of the type having a relatively high-resolution area-of-interest (AOI) scenic portion inset into and blended with a relatively low-resolution field-of-view (FOV) scenic portion of greater areal extent than the high-resolution portion, includes: at least one optical element for providing the low-resolution background image portion; at least one other optical element for providing the high-resolution AOI image portion; an optical combiner receiving the low-resolution and high-resolution image portions; optics for projecting the combined image onto a viewing area; and at least one fiber-optic cable having a multiplicity of fibers for interconnecting the combining element and at least one of the two image optics portions and the projecting optics. A fiber-optic element can mechanically decouple the combining and projecting elements, so that high projection slew rates and accelerations can be realized, while also eliminating hard optics associated with image de-rotation and/or focusing. Another fiber-optic element can provide moveable area-of-interest blending at any selected location over the entire area of the background scene, without movement of a projector or other high-pass subassembly. Use of yet another fiber-optic element can facilitate dynamic image merging.