Three dimensional graphics processing apparatus processing ordinary and special objects

• US 5,828,378 A
• Filed: 05/31/1996
• Issued: 10/27/1998
• Est. Priority Date: 06/01/1995
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Shiraishi, Naoto
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US08/657,810
• Time in Patent Office: 879 Days
• Field of Search: 345/419-422, 345/426, 345/427, 345/429, 345/432, 345/433-435, 345/441
• US Class Current: 345/422
• CPC Class Codes: G06T 15/405 using Z-buffer

Abstract

A three-dimensional graphics processing apparatus according to the present invention is provided with a memory which stores objects including an ordinary object and a special object, each object composed of polygons. A coordinate conversion processing device places each object stored in the memory in a three-dimensional coordinate system, and converts the coordinates of the placed object into those of a screen coordinate system. A MIN/MAX buffer memory stores Z values of front polygons of the special object and Z values of rear polygons of the special object. A drawing processing device determines whether or not Z values of a polygon of the ordinary object are values between the Z values of the front polygons and the Z values of the rear polygons of the special object stored in the MIN/MAX buffer memory. The drawing processing device performs a predetermined special operation when it is determined that the Z values of the polygon of the ordinary object are values between the Z values of the front polygons and the Z values of the rear polygons of the special object.

Claims

1. A three-dimensional graphics processing apparatus, comprising:

first storing means for storing objects including an ordinary object and a special object, each object comprising polygons;

coordinate conversion means for placing each object stored in said first storing means in a three-dimensional coordinate system, and converting coordinates of the placed object into coordinates of a screen coordinate system;

second storing means for storing Z values of front polygons of said special object and Z values of rear polygons of said special object to define a predetermined volume, said second storing means having a capacity of storing a frame of data;

determination means for determining whether Z values of a polygon of said ordinary object are values within the predetermined volume, by determining whether said Z values of the polygon of said ordinary object are values between said Z values of said front polygons and said Z values of said rear polygons of said special object stored in said second storing means; and

performance means for performing a predetermined special operation when said determination means determines that said Z values of said polygon of said ordinary object are values between said Z values of said front polygons and said Z values of said rear polygons of said special object.

2. The three-dimensional graphics processing apparatus according to claim 1, wherein:

said special object comprises a shadow object; and

said predetermined special operation comprises shadowing for performing a predetermined shadow luminance calculation.

3. The three-dimensional graphics processing apparatus according to claim 1, wherein:

said special object comprises a light object; and

said predetermined special operation comprises lighting for performing a predetermined light luminance calculation.

4. The three-dimensional graphics processing apparatus according to claim 1, wherein:

said special object comprises a hit object; and

said predetermined special operation comprises a hit occurrence determination for performing a predetermined hit occurrence operation.

5. The three-dimensional graphics processing apparatus according to claim 1, further comprising:

Z-buffer memory means; and

hidden surface processing means for comparing Z values of said polygon of said ordinary object with Z values stored in said Z-buffer memory and performing a predetermined hidden surface processing.