The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 20, 2000
Filed:
Jun. 01, 1998
Daniel Wong, North York, CA;
Milivoje Aleksic, Richmond Hill, CA;
ATI Technologies, Inc., Thornhill, CA;
Abstract
A method and apparatus for determining the level of detail for texture mapping applications in video graphic circuits begins by updating first and second linear components of a set of derivatives when rendering a pixel of an object in a given scan line. The first and second linear components are updated in a linear manner based on first and second increment values, respectively. The set of derivatives corresponds the changes of the texture coordinates with the changes of the physical coordinates of an object being rendered, the derivatives include .delta.s/.delta.x, .delta.t/.delta.x, .delta.s/.delta.y, and .delta.t/.delta.y--in general, the set of derivatives equals .delta.a/.delta.b=w.sup.2 *((1/w)*(.delta.(a/w)/.delta.b-(a/w)*(.delta.(1/w)/.delta.b))). When the object is being rendered on a new scan line, third and fourth linear components are updated in a linear manner based on third and fourth increment values, respectively. As the linear components are updated, their magnitudes are compared, and the one having the greatest magnitude is selected. The selected magnitude is then converted into a logarithmic scale to produce a logarithmic magnitude. The logarithmic magnitude of the linear component is then combined with a logarithmic representation of a non-linear component of a set of derivatives to obtain the level of detail for a given pixel.