Patent
1992-08-14
1993-11-09
Harkcom, Gary V.
395119, G06F 1572
Patent
active
052610292
ABSTRACT:
A method and apparatus for determining a uniform step size with respect to pre-transformation derivative bounds for tessellation of a graphic primitive wherein the step size results in triangles which meet post-transformation thresholds. To maximize the efficiency of rendering curved surfaces while ensuring that the tessellation criteria is met, a maximum scale value for the non-linear transformation between device coordinate (DC) and lighting coordinate (LC) space is determined and utilized to translate the tessellation threshold in DC space to a tessellation threshold value in LC space. Information regarding the curved surface to be rendered is transformed to the LC space from the model coordinate (MC) space. The derivative bounds of the curved surface, and the tessellation threshold value are utilized to determine the uniform step size to tessellate triangles representative of the curved surface. Accurate lighting computations are then performed and the shaded triangles are transformed to DC space, converted to pixel data and actuated on the display device to produce the graphic image representative of the graphic image on the display.
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Abi-Ezzi Salim S.
Shirman Leon A.
Ba Huynh
Harkcom Gary V.
Sun Microsystems Inc.
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