Computer graphics processing and selective visual display system – Computer graphics processing – Three-dimension
Reexamination Certificate
1998-11-09
2001-02-06
Zimmerman, Mark (Department: 2772)
Computer graphics processing and selective visual display system
Computer graphics processing
Three-dimension
C345S420000, C345S421000, C345S427000
Reexamination Certificate
active
06184890
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of computer graphics, including graphical user interfaces. More specifically, the present invention relates to a method and apparatus for rendering objects in a computer display with added realism.
2. Background
In a 3-D graphics computer system having a 2-D raster display, realistic 3-D effects are typically achieved by rendering objects on the 2-D raster display using perspective algorithms. A perspective algorithm well known in the art is the “z-divide” algorithm. Under this approach, every point of every object to be rendered has a triplet of coordinates (x, y, z) associated with it. Before the objects are rendered, the x and y coordinates of all points of all objects, are divided by their corresponding z values. The objects are then rendered by rendering all points in accordance with the computed x/z and y/z values. An example of such 3-D graphics computer systems is the Sparcstation®, manufactured by Sun Microsystems Inc., of Mountain View, Calif., embodied with the Programmer's Hierarchical Interactive Graphics System (PHIGS) (Sparcstation is a registered trademark of Sun Microsystems). The 3-D effects are realistically achieved, because the z-divides are performed for all points of all objects to be rendered, and the amount of computations, and therefore the resources in terms of CPU time and storage required, are substantial. As a result, 3-D graphics computer systems tend to be more costly than other non-three dimensional display systems.
In 2-D graphics computer systems, objects are rendered on the 2-D raster display through parallel projections. The user's eye is set at infinity. Using this approach, every object to be rendered has a pair of coordinates (x, y) associated with it. Beyond the x and y coordinates, only a “depth” order is provided for determining which object gets displayed when two objects overlap.
Particular examples of such 2-D graphics computer systems include the Macintosh® computer systems, manufactured by Apple Computer, Inc. of Cupertino, California, and various personal computers based on the X'86 microprocessor of Intel, Inc., of Santa Clara, Calif., manufactured by IBM of Armonk, N.Y., and other vendors, embodied with the Window™ system of Microsoft, Inc. of Redmond, Wash. (Macintosh is a registered trademark of Apple Computer and Window is a trademark of Microsoft). Since there are no z-divides to be performed for every point of every object to be rendered, the amount of computations, and therefore the resources required, are substantially less. As a result, 2-D graphics computer systems tend to be relatively less expensive than their three dimensional counterparts.
However, the 3-D effects are not realistically achieved on these 2-D graphics computer systems. For example, as the user's viewpoint (location) changes, objects at different depths will move the same distance. This is not what happens in the real world, where the user will see the effect of parallax. That is, objects closer to the user will appear to move more in distance, while objects further away from the user will appear to move a little bit, if at all.
Thus, it is desirable to be able to render objects on a 2-D raster display of a 2-D graphics computer system with added realism, without requiring the amount of computations and the resources of a 3-D graphics computer system. More specifically, it is desirable to be able to introduce the parallax effect to objects rendered in a less costly manner. As will be disclosed, the present invention provides for such a method and apparatus which advantageously achieves the desired results.
SUMMARY OF THE INVENTION
Under the present invention, the desired results are advantageously achieved by having the graphics applications of a 2-D graphics computer system provide each object to be rendered on a 2-D raster display of the computer system with a pair of rendering reference coordinates (x and y), and a relative depth value (z). The x and y rendering reference coordinates and the relative depth value z of an object describe the geometric location of the object relative to the users eye, which is set at a predetermined location.
Additionally, the 2-D graphics computer system is provided with a library of predetermined 2-D images and a number of graphics toolkit routines. The library comprises at least one predetermined 2-D image for each object to be rendered on the 2-D raster display. Each of the at least one predetermined 2-D image is the image of the object to be rendered in a display sector of the 2-D raster display. Each predetermined 2-D image has a first and a second rendering control value for controlling the rendering of the particular predetermined 2-D image in the corresponding display sector. The graphics toolkit routines cooperate with the graphic applications and the library to introduce the parallax effect to the objects being rendered.
As the user “moves” relative to the objects rendered, the graphics toolkit routines recompute the x and y rendering reference coordinates and the relative depth value z of the objects. Then the graphics toolkit routines divide the x and y rendering reference coordinates of each object by its relative depth value z. Next, the graphics toolkit routines select, for each object, a predetermined 2-D image from each object's at least one predetermined 2-D image, using the object's x/z and y/z values. Finally, the graphics toolkit routines cause the selected pre-determined 2-D images of the objects to be rendered using the objects' x/z and y/z values as the rendering controlling values.
As a result, the objects that are further away from the user will appear to move slower than the objects that are closer to the user, thereby introducing the effect of parallax and added realism to the 2-D graphics computer system. However, because the graphics toolkit routines perform the z-divides only once per object, rather than as many times as the number of points in an object to be rendered, the number of computations, and therefore the resources required, are substantially less than a 3-D graphics computer system. Thus, the added realism is achieved at a substantially lower cost.
In the presently preferred embodiment, the 2-D graphics computer system further includes a pair of stereo speakers. The library further comprises predetermined sounds for a subset of the objects. Each of these objects is provided with at least one predetermined stereo sound pair. Each of the at least one predetermined stereo sound pair describes the characteristics of the predetermined sound to be rendered in the speakers, and has a pair of left and right rendering control values.
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Bantz And Evangelisti “Device For Creating 3D Video Effect By Parallax” *the whole document*.
Frank Edward H.
Naughton Patrick J.
Finnegan Henderson Farabow Garrett and Dunner, LLP
Nguyen Kimbinh T.
Sun Microsystems Inc.
Zimmerman Mark
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