Adobe, Inc.

Creative Technology Corporation

William D Bilodeau

Stephen N Schiller

Paul A George

Paul C Chen

David R Lazarony, Jr

Matthew J Foley

Michael Songy

The invention renders a resolution independent object having a silhouette by rendering the object to a buffer, determining the silhouette of the object from the buffer, generating a clipped image of the silhouette, and rendering the clipped image on the graphical rendering system.

Rendering of objects on graphical rendering devices as clipped images

A method for real-time shadow rendering in a 3-D graphics scene uses an inverted z-test to mark a shadow area in a stencil buffer. Front and back facing shadow volume polygons are rendered subsequent to rendering the scene and corresponding stencil buffer entries are incremented for pixels viewing the back facing polygon when the new z-test is passed and decremented for pixels viewing the front facing polygons when the new z-test is passed. The new z-test is passed for pixels having depth (z) values greater than the corresponding depth value stored z-buffer.

Method for rendering shadows using a shadow volume and a stencil buffer

A method for defining a color gradient across a region in a display space that includes defining a bi-cubic patch enclosing the region. The bi-cubic patch includes four corners having a color associated therewith and four curves connecting pairs of the corners forming a closed loop. The four curves define the color gradient across the bi-cubic patch as a function of the four colors associated with the four corners of the bi-cubic patch. The method includes defining a unit square in parameter space including a mapping function from the unit square to the bi-cubic patch such that the corners of the bi-cubic patch map to the corners of the unit square. The color of every point in the unit square is a bi-cubic interpolation of the four colors associated with the four corners of the bi-cubic patch. The method includes clipping the bi-cubic patch for display of the region. In another aspect, the invention provides a method of accurately rendering color gradients across a bi-cubic patch that includes subdividing the bi-cubic patch into sub-patches until each side of a given sub-patch is a good approximation of a line and checking to determine if for all points inside of a given sub-patch the color associated with each point is sufficiently accurate. If not, the sub-patch is further subdivided until the color associated with each point inside a given sub-patch is sufficiently accurate. The method includes dividing the sub-patches into polygons and rendering the polygons.

Smooth shading of objects on display devices

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Boulder Creek, CA, United States of America

William D Bilodeau