Claims
- 1. An apparatus for processing primitives in a computer graphics display system, the apparatus comprising:
a graphics device, the graphics device comprising an interface unit for receiving commands and data from a host computer, the data including clip coordinates generated by an algorithm being executed by the host computer, the graphics device comprising logic configured to perform perspective projection on the clip coordinates to transform the clip coordinates into window coordinates.
- 2. The apparatus of claim 1, wherein said logic is comprised by a setup unit, the setup unit being in communication with the interface unit, the setup unit receiving commands and data sent by the host computer to the interface unit, the interface unit delivering the clip coordinates to the setup unit, wherein the setup unit comprises a floating point unit, wherein the floating point unit comprised in the setup unit performs perspective projection on the clip coordinates to transform the clip coordinates into window coordinates.
- 3. The apparatus of claim 2, wherein the setup unit further comprises a control register, the control register containing a plurality of bits used by the floating point unit to control the operations of the floating point unit, wherein a perspective enable bit contained in the control register is utilized by the floating point unit to inform the floating point unit as to whether or not the floating point unit is to perform perspective projection on the clip coordinates received by the setup unit, wherein if the perspective enable bit is asserted, the floating point unit performs perspective projection on the clip coordinates and wherein if the perspective enable bit is not asserted, the floating point unit does not perform perspective projection on the clip coordinates.
- 4. The apparatus of claim 3, wherein if the perspective enable bit is asserted, the setup unit performs perspective projection on the clip coordinates to transform the clip coordinates into window coordinates and then performs vector and triangle setup, wherein the setup unit utilizes the window coordinates to perform vector and triangle setup.
- 5. The apparatus of claim 4, wherein the clip coordinates are window clip coordinates and wherein, if the perspective enable bit is asserted, the floating point unit performs perspective projection on the window clip coordinates to transform the window clip coordinates into window coordinates, and wherein the setup unit performs vector and triangle setup on the window coordinates.
- 6. A computer graphics display system for processing primitives and for rendering an image on a display device of the computer graphics display system, the computer graphics display system comprising:
a host computer, the host computer being programmed to execute a geometry processing pipeline program, the geometry processing pipeline program receiving object coordinates relating to a primitive being processed in the computer graphics display system, the geometry processing pipeline transforming the object coordinates into clip coordinates; and a graphics device in communication with the host computer, the graphics device receiving the clip coordinates generated by the host computer and performing perspective projection on the clip coordinates to transform the clip coordinates into window coordinates.
- 7. The computer graphics display system of claim 6, wherein the graphics device comprises an interface unit for receiving the clip coordinates from the host computer and a setup unit in communication with the interface unit for receiving the clip coordinates from the interface unit, the setup unit comprising a control register and a floating point unit, the control register comprising a plurality of bits utilized by the floating point unit to control the operations of the floating point unit, said control register containing a perspective enable bit, the perspective enable bit being utilized by the floating point unit to determine whether or not perspective projection is to be performed in the setup unit, wherein if the perspective enable bit is asserted, the floating point unit performs perspective projection on the clip coordinates to transform the clip coordinates into window coordinates.
- 8. The computer graphics display system of claim 7, wherein the geometry processing pipeline program being executed in the host computer transforms the object coordinates into clip coordinates by first transforming the object coordinates into eye coordinates and then by transforming the eye coordinates into clip coordinates, and wherein the graphics device performs perspective projection by transforming the clip coordinates into normalized device coordinates and then by transforming the normalized device coordinates into window coordinates.
- 9. The computer graphics display system of claim 7, wherein the clip coordinates received by the interface unit of the graphics device are window clip coordinates, wherein the geometry processing pipeline program being executed in the host computer transforms the object coordinates into window clip coordinates and wherein the interface unit delivers the window clip coordinates to the setup unit, and wherein when the perspective enable bit is asserted, the floating point unit performs perspective projection on the window clip coordinates to transform the window clip coordinates into window coordinates.
- 10. A method for performing perspective projection in a computer graphics display system, the method comprising the steps of:
receiving clip coordinates in a graphics device, the clip coordinates being sent to the graphics device by a host computer of the computer graphics display system, the host computer executing an algorithm that generates the clip coordinates; and performing perspective projection on the clip coordinates in the graphics device to transform the clip coordinates into window coordinates.
- 11. The method of claim 10, wherein the graphics device comprises an interface unit and a setup unit, the setup unit comprising a floating point unit, wherein the interface unit receives the clip coordinates sent from the host computer and delivers the clip coordinates to the setup unit, wherein the floating point unit of the setup unit performs perspective projection on the clip coordinates to transform the clip coordinates into window coordinates.
- 12. The method of claim 11, wherein the setup unit comprises a control register, the control register containing a plurality of bits used by the floating point unit to control the operations of the floating point unit, wherein a perspective enable bit contained in the control register is utilized by the floating point unit to inform the floating point unit as to whether or not the floating point unit is to perform perspective projection on the clip coordinates received by the setup unit, wherein if the perspective enable bit is asserted, the floating point unit performs perspective projection on the clip coordinates and wherein if the perspective enable bit is not asserted, the floating point unit does not perform perspective projection on the clip coordinates.
- 13. The method of claim 12, wherein if the perspective enable bit is asserted, the setup unit performs perspective projection on the clip coordinates to transform the clip coordinates into window coordinates and then performs vector and triangle setup, wherein the setup unit utilizes the window coordinates to perform vector and triangle setup.
- 14. The method of claim 13, wherein the clip coordinates are window clip coordinates and wherein, if the perspective enable bit is asserted, the floating point unit performs perspective projection on the window clip coordinates to transform the window clip coordinates into window coordinates, and wherein the setup unit performs vector and triangle setup on the window coordinates.
- 15. A method for performing perspective projection in computer graphics display system, the method comprising the steps of:
transforming the object coordinates into clip coordinates in a host computer of the computer graphics display system, the host computer executing a geometry processing pipeline program which transforms the object coordinates into clip coordinates; and receiving the clip coordinates in a graphics device in communication with the host computer, the graphics device performing perspective projection on the clip coordinates to transform the clip coordinates into window coordinates.
- 16. The method of claim 15, wherein the graphics device comprises an interface unit for receiving the clip coordinates from the host computer and a setup unit in communication with the interface unit for receiving the clip coordinates from the interface unit, the setup unit comprising a control register and a floating point unit, the control register comprising a plurality of bits utilized by the floating point unit to control the operations of the floating point unit, said control register containing a perspective enable bit, wherein the floating point unit utilizes the perspective enable bit to determine whether or not perspective projection is to be performed in the setup unit, wherein if the perspective enable bit is asserted, the floating point unit performs perspective projection on the clip coordinates to transform the clip coordinates into window coordinates.
- 17. The method of claim 16, wherein the geometry processing pipeline program being executed in the host computer transforms the object coordinates into clip coordinates by first transforming the object coordinates into eye coordinates and by transforming the eye coordinates into clip coordinates, and wherein the graphics device performs perspective projection by transforming the clip coordinates into normalized device coordinates and then by transforming the normalized device coordinates into window coordinates.
- 18. The method of claim 16, wherein the clip coordinates received by the graphics device are window clip coordinates, and wherein the geometry processing pipeline program being executed in the host computer transforms the object coordinates into window clip coordinates, and wherein the interface unit receives the window clip coordinates and delivers the window clip coordinates to the setup unit, and wherein when the perspective enable bit is asserted, the floating point unit performs perspective projection on the window clip coordinates to transform the window clip coordinates into window coordinates.
- 19. A computer program embodied on a computer-readable medium, the computer program corresponding to a geometry processing pipeline program being executed in a host computer of a computer graphics display system, the computer program comprising:
a first code segment for transforming object coordinates associated with a primitive being processed in a computer graphics display system into window clip coordinates; and a second code segment for delivering the window clip coordinates to a graphics device which will transform the window clip coordinates into window coordinates.
- 20. A computer program embodied on a computer-readable medium, the computer program corresponding to a geometry processing pipeline program being executed in a host computer of a computer graphics display system, the computer program comprising:
a first code segment for transforming object coordinates associated with a primitive being processed in a computer graphics display system into eye coordinates; a second code segment for transforming the eye coordinates into clip coordinates; and a third code segment for delivering the clip coordinates to a graphics device which will transform the clip coordinates into normalized device coordinates and transform the normalized device coordinates into window coordinates.
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of copending U.S. utility application entitled, “A METHOD AND APPARATUS FOR PERFORMING PERSPECIVE PROJECTION IN A COMPUTER GRAPHICS DISPLAY SYSTEM” having Ser. No.09/190,754, filed Nov. 12, 1998 which is entirely incorporated herein by reference.
Continuations (1)
|
Number |
Date |
Country |
Parent |
09190754 |
Nov 1998 |
US |
Child |
10241943 |
Sep 2002 |
US |