Computer graphics processing and selective visual display system – Computer graphics processing – Three-dimension
Reexamination Certificate
2000-11-21
2003-07-22
Zimmerman, Mark (Department: 2671)
Computer graphics processing and selective visual display system
Computer graphics processing
Three-dimension
C345S421000, C345S426000, C345S427000
Reexamination Certificate
active
06597356
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to graphics processors and, more particularly, to graphics pipeline systems including tessellation, transform, lighting and rasterization modules.
BACKGROUND OF THE INVENTION
Three dimensional graphics are central to many applications. For example, computer aided design (CAD) has spurred growth in many industries where computer terminals, cursors, CRT's and graphics terminals are replacing pencil and paper, and computer disks and tapes are replacing drawing vaults. Most, if not all, of these industries have a great need to manipulate and display three-dimensional objects. This has lead to widespread interest and research into methods of modeling, rendering, and displaying three-dimensional objects on a computer screen or other display device. The amount of computations needed to realistically render and display a three-dimensional graphical object, however, remains quite large and true realistic display of three-dimensional objects have largely been limited to high end systems. There is, however, an ever-increasing need for inexpensive systems that can quickly and realistically render and display three dimensional objects.
One industry that has seen a tremendous amount of growth in the last few years is the computer game industry. The current generation of computer games is moving to three-dimensional graphics in an ever increasing fashion. At the same time, the speed of play is being driven faster and faster. This combination has fueled a genuine need for the rapid rendering of three-dimensional graphics in relatively inexpensive systems. In addition to gaming, this need is also fueled by e-commerce applications, which demand increased multimedia capabilities.
Rendering and displaying three-dimensional graphics typically involves many calculations and computations. For example, to render a three dimensional object, a set of coordinate points or vertices that define the object to be rendered must be formed. Vertices can be joined to form polygons that define the surface of the object to be rendered and displayed. Once the vertices that define an object are formed, the vertices must be transformed from an object or model frame of reference to a world frame of reference and finally to two-dimensional coordinates that can be displayed on a flat display device. Along the way, vertices may be rotated, scaled, eliminated or clipped because they fall outside the viewable area, lit by various lighting schemes, colorized, and so forth. Thus the process of rendering and displaying a three-dimensional object can be computationally intensive and may involve a large number of vertices.
A general system that implements such a pipelined system is illustrated in Prior Art FIG.
1
. In this system, a data source
10
generates a stream of expanded vertices, often interpreted as triangles. The data source may also produce higher level descriptions such as spheres, cylinders, or general curved surfaces. These higher level primitives/descriptions may be approximated by a plurality of triangles before processing by the remainder of the graphics pipeline.
Initially, the vertices are tessellated by a tessellation module
9
. Tessellation refers to the process of decomposing a complex surface such as a sphere into simpler primitives such as triangles or quadrilaterals. These tessellated vertices are then passed through a pipelined graphic system
12
via vertex memory
13
. Thereafter, the * vertices are transformed and lit by a transformation module
14
and a lighting module
16
, respectively, and further clipped and set-up for rendering by a rasterizer
18
, thus generating rendered primitives that are displayed on a display device
20
.
During operation, the tessellation module
9
is adapted to use patches or other higher level descriptions to calculate vertices and form triangles. The transform module
14
may be used to perform scaling, rotation, and projection of a set of three dimensional vertices from their local or model coordinates to the two dimensional window that will be used to display the rendered object. The lighting module
16
sets the color and appearance of a vertex based on various lighting schemes, light locations, ambient light levels, materials, and so forth. The rasterization module
18
rasterizes or renders vertices that have previously been transformed and/or lit. The rasterization module
18
renders the object to a rendering target which can be a display device or intermediate hardware or software structure that in turn outputs the rendered data.
When manufacturing graphics processing systems, there is a general need to increase the speed of the various graphics processing components, while minimizing costs. In general, integration is often employed to increase the speed of a system. Integration refers to the incorporation of different processing modules on a single integrated circuit. With such processing modules communicating in a microscopic semiconductor environment, as opposed to external buses, speed is vastly increased.
Such increase in speed can contribute to overcoming many shortcomings in current graphic pipeline implementations. For example, the quality of computer graphics is currently limited by the ability of the graphic pipeline to execute transform operations. In particular, transform performance dictates how finely software developers may tessellate three-dimensional objects created, how many objects are put in a scene, and how sophisticated the three-dimensional world itself can be. This creates a classic performance-versus-quality trade-off for the software developer because finer tessellation will result in more polygons and slower performance, but with the reward of higher quality.
Integration is often limited, however, by a cost of implementing and manufacturing multiple processing modules on a single chip. In the realm of graphics processing, any attempt to integrate the various modules for increased speed would be cost prohibitive. The reason for this increase in cost is that the required integrated circuit would be of a size that is simply too expensive to be feasible.
This size increase is due mainly to the complexity of the various engines. High performance transform and lighting engines alone are very intricate and are thus expensive to implement on-chip, let alone implement with any additional functionality. Further, conventional rasterizers are multifaceted with the tasks of clipping, rendering, etc. making any cost-effective attempt to combine such module with the transform and lighting modules nearly impossible.
There is therefore a need for tessellation, transform, lighting, and rasterization modules having a design that allows cost-effective integration.
DISCLOSURE OF THE INVENTION
An integrated graphics pipeline system is provided for graphics processing. Such system includes a tessellation module that is positioned on a single semiconductor platform for receiving data for tessellation purposes. Tessellation refers to the process of decomposing either a complex surface such as a sphere or surface patch into simpler primitives such as triangles or quadrilaterals, or a triangle into multiple smaller triangles. Further included on the single semiconductor platform is a transform module adapted to transform the tessellated data from a first space to a second space. Coupled to the transform module is a lighting module which is also positioned on the single semiconductor platform for performing lighting operations on the data received from the transform module. Also included is a rasterizer coupled to the lighting module and positioned on the single semiconductor platform for rendering the data received from the lighting module.
With the foregoing integration, improved performance is achieved thus overcoming many of the shortcomings of non-integrated systems. For example, the combined tessellation and transform integration affords improved quality by way of finer tessellations. Applications can thus take advantage of this and other capabilities by invoking the correspondi
Legakis Justin
Moreton Henry P.
Rogers Douglas H.
Cooley & Godward LLP
Nguyen Kimbinh T.
Nvidia Corporation
Zimmerman Mark
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