US 5,699,497 AGranted

Rendering global macro texture, for producing a dynamic image, as on computer generated terrain, seen from a moving viewpoint

AssigneeEvans & Sutherland Computer Corporation

InventorsAlan C. Erdahl, John A. Robinson

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Abstract

A dynamic terrain display is created from digitized grid post data as a height field, that is textured using maps embracing progressively larger areas with increasing remoteness from the viewpoint. A truncated pyramid is defined by map parts for each level that are maintained in active memory. The map parts or fragments are stored in rectangular configurations to be updated row-by-row or column-by-column, by overwriting obsolete data in a circular manner to reflect changes in the viewpoint. Levels of the map parts accordingly are paged independently of each other from database storage. Not all levels are required to have texture in that if a level is not available, a lower level can be employed. Theme cells also can be utilized.

Claims14

Dependent claims

A computer graphics system for producing a dynamic image of a continuous textured surface, as global terrain seen from a moving viewpoint, utilizing height field data or other two-dimensional terrain field representations and texture data comprising

terrain storage for storing said terrain field representation data;
texture storage for storing at least a first level and a second level of texture data, said first level providing a greater texture resolution of said terrain, said second level providing a lesser texture resolution of said terrain;
an active map memory system coupled to said texture storage for storing a first portion of said first level and a second portion of said second level, said first and second portions containing a common plurality of said texels, both arranged in rectangular arrays, said first portion and second portions relating to areas of said terrain having a common center corresponding to said viewpoint, but said first portion spanning a smaller surface area about said common center and said second portion spanning a larger surface area about said common center;
a paging structure coupled to said active map memory system for selectively paging fresh texture data from said texture storage to said active map memory system in accordance with said moving viewpoint, said paging structure paging in said texels from said first level to said first portion at a faster rate and paging in said texels from said second level to said second portion at a slower rate, while maintaining said common plurality of texels in each of said actively-stored portions;
an image system for processing said terrain representation data from said terrain storage and said selectively stored portions of texture data from said active map memory system to provide image data signals;
and
display means for providing said dynamic image in accordance with said image data signals wherein said active map memory system stores said actively-stored portions of said levels of texture as a truncated pyramid and said image system applies texture from said levels of texture data in accordance with ranges defined by annular rings relating projected pixel size to projected texel size.

4 more elements

A computer graphics system for producing a dynamic image of a continuous surface, as global terrain seen from a moving viewpoint utilizing height field data or other two-dimensional terrain field representations and texture data for said terrain, said image defined by a plurality of concentric circular ranges of different texture resolution, said system comprising:

terrain storage for storing said terrain field representation data;
texture storage for storing said two-dimensional texture data comprising a plurality of independent texture map levels having varying texture resolution for said terrain;
an active map memory system coupled to said texture storage for selectively storing a common plurality of selected texels from said texture map levels, said actively stored texels from said levels being commonly configured in N.times.M rectangular arrays with N rows and M columns, but said arrays for different levels having progressively lesser texture resolution for progressively greater rectangular surface areas relative to arrays of adjacent levels, said surface areas spanning increasing distances from a common center coinciding with said viewpoint;
a paging structure coupled to said active map memory system for selectively paging fresh texture data from said texture storage to said active map memory in accordance with said moving viewpoint, said paging structure independently accessing said different levels for paging in fresh rows or columns of texels to said respective N.times.M rectangular arrays at different rates for different levels while maintaining said arrays in said common plurality of texels said fresh rows or columns of lesser texture resolution being paged in slower than said fresh rows or columns of greater texture resolution;
an image system for processing said terrain representation data from said terrain storage and said selectively stored texel arrays from said active map memory system to provide image data signals, said image system texturing said circular ranges by blending between said arrays of appropriate adjacent levels corresponding to said circular ranges;
and
display means for providing said dynamic image in accordance with said image data signals wherein said active map memory system stores said actively-stored portions of said levels of texture as a truncated pyramid and said image system applies texture from said levels of texture data in accordance with ranges defined by annular rings relating projected pixel size to projected texel size.

4 more elements

A computer graphics system for producing a dynamic image of a continuous surface, as global terrain seen from a moving viewpoint, utilizing height field data or other terrain field representations and texture data for said terrain, comprising:

terrain storage for storing said terrain representation data;
texture storage for storing said texture data, said texture data configured in multiple independent levels of different texture resolution, said levels being continuous and directed to said terrain;
an active map memory system coupled to said texture storage for selectively storing portions of said levels of texture data with reference to said moving viewpoint, said actively-stored portions of said levels of texture data containing a common plurality of texels configured in rectangular arrays having rows and columns, said actively-stored portions of texels being of progressively reduced texture detail for progressively larger surface areas, said surface areas having a common point corresponding to said veiwpoint, but spanning progressively larger distances from said point;
a paging structure for independently refreshing said actively-stored portions with fresh texels at different rates for different levels while maintaining said actively-stored portions with said common plurality of texels;
an image system for processing said terrain representation data from said terrain storage and actively stored portions of said levels of texture from said active map memory system to provide image data signals;
and
display means for providing said dynamic image in accordance with said image data signals wherein said active map memory system stores said actively-stored portions of said levels of texture as a truncated pyramid and said image system applies texture from said levels of texture data in accordance with ranges defined by annular rings relating projected pixel size to projected texel size.

4 more elements

Dependencies are inferred from the claim text.