Graphics plotting apparatus and method

• US 5,664,071 A
• Filed: 12/15/1994
• Issued: 09/02/1997
• Est. Priority Date: 12/21/1993
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nagashima, Ichiro
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): LEGREE, TRACY MICHELLE
• Application Number:
  US08/356,736
• Time in Patent Office: 992 Days
• Field of Search: 395/109, 395/101, 395/103, 395/123, 395/128, 395/124, 395/125, 395/141, 395/139, 395/127, 364/518
• US Class Current: 358/1.3
• CPC Class Codes: G06T 17/20 Finite element generation, e.g. wire-frame surface description, tesselation

Abstract

A graphics plotting apparatus has a decision unit for determining whether or not a polygon is smaller than a predetermined size, for example, the size of a pixel on a display screen or the size of a pixel on a texture pattern according to data of the vertexes of the polygon, a divider for dividing the polygon into small polygons if the polygon is not smaller than the predetermined size, and a plotting unit for plotting pixels corresponding to the polygon if the polygon is smaller than the predetermined size. This apparatus is capable of plotting perspective three-dimensional graphics with smooth shading and texture mapping at a high speed in real time.

Claims

1. A graphics plotting apparatus for writing a three-dimensional polygon defined by vertexes to an image memory to plot the polygon, comprising:

(a) storing means having registers for storing data of the vertexes of the polygon;

(b) stack means for storing data of the vertexes of polygons;

(c) decision means for determining whether or not the polygon stored in the storage means is smaller than a predetermined size;

(d) plotting means for writing pixels corresponding to the polygon to the image memory if said decision means determines that the polygon is smaller than the predetermined size; and

(e) division means for dividing the polygon into small polygons if said decision means determines that the polygon is not smaller than the predetermined size, writing data of the vertexes of one of the small polygons to the registers of said storage means, and writing data of the vertexes of the other small polygons to said stack means,

wherein the three-dimensional polygon is also defined by a depth of each vertex thereof, and said division means divides the polygon into small polygons according to a ratio of the depth of a vertex at one end to the depth of a vertex at the other end of each edge of the polygon.

2. A graphics plotting apparatus for writing a three-dimensional polygon defined by vertexes to an image memory to plot the polygon, comprising:

(a) storing means having registers for storing data of the vertexes of the polygon;

(b) stack means for storing data of the vertexes of polygons;

(c) decision means for determining whether or not the polygon stored in the storage means is smaller than a predetermined size;

(d) plotting means for writing pixels corresponding to the polygon to the image memory if said decision means determines that the polygon is smaller than the predetermined size; and

(e) division means for dividing the polygon into small polygons if said decision means determines that the polygon is not smaller than the predetermined size, writing data of the vertexes of one of the small polygons to the registers of said storage means, and writing data of the vertexes of the other small polygons to said stack means,

wherein the three-dimensional polygon is also defined by a depth of each vertex thereof, and said division means defines the coordinates of each vertex of each small polygon by averaging the depths of vertexes at both ends of each edge of the polygon to be divided into the small polygons.

3. A graphics plotting apparatus for writing a three-dimensional polygon defined by vertexes to an image memory to plot the polygon, comprising:

(a) storing means having registers for storing data of the vertexes of the polygon;

(b) stack means for storing data of the vertexes of polygons;

(c) decision means for determining whether or not the polygon stored in the storage means is smaller than a predetermined size;

(d) plotting means for writing pixels corresponding to the polygon to the image memory if said decision means determines that the polygon is smaller than the predetermined size; and

(e) division means for dividing the polygon into small polygons if said decision means determines that the polygon is not smaller than the predetermined size, writing data of the vertexes of one of the small polygons to the registers of said storage means, and writing data of the vertexes of the other small polygons to said stack means,

wherein the three-dimensional polygon is also defined by a luminance of each vertex thereof, and said division means determines the luminance of each vertex of each small polygon by averaging the luminance of vertexes at both ends of each edge of the polygon to be divided into the small polygons.

4. A graphics plotting apparatus for writing a three-dimensional polygon defined by vertexes to an image memory to plot the polygon, comprising:

(a) registers for storing data of the vertexes of the polygon;

(b) edge dividers connected to the registers for dividing the polygon into small polygons;

(c) a decision unit connected to the registers and the edge dividers for determining whether or not the polygon stored in the registers is smaller than a predetermined size;

(d) a stack connected to the registers, the edge dividers and the decision unit for storing data of the vertexes of polygons;

(e) an adder connected to the edge dividers, the registers and the stack for averaging data by the edge dividers; and

(f) a plotting unit connected to the decision unit for writing pixels corresponding to the polygon to the image memory if the decision unit determines that the polygon is smaller than the predetermined size,

wherein the three-dimensional polygon is also defined by a depth of each vertex thereof, and said edge dividers divide the polygon into small polygons according to a ratio of the depth of a vertex at one end to the depth of a vertex at the other end of each edge of the polygon.

5. A graphics plotting apparatus for writing a three-dimensional polygon defined by vertexes to an image memory to plot the polygon, comprising:

(a) registers for storing data of the vertexes of the polygon;

(b) edge dividers connected to the registers for dividing the polygon into small polygons;

(c) a decision unit connected to the registers and the edge dividers for determining whether or not the polygon stored in the registers is smaller than a predetermined size;

(d) a stack connected to the registers, the edge dividers and the decision unit for storing data of the vertexes of polygons;

(e) an adder connected to the edge dividers, the registers and the stack for averaging data by the edge dividers; and

(f) a plotting unit connected to the decision unit for writing pixels corresponding to the polygon to the image memory if the decision unit determines that the polygon is smaller than the predetermined size,

wherein the three-dimensional polygon is also defined by a depth of each vertex thereof, and said edge dividers define the coordinates of each vertex of each small polygon by averaging the depths of vertexes at both ends of each edge of the polygon to be divided into the small polygons.

6. A graphics plotting apparatus for writing a three-dimensional polygon defined by vertexes to an image memory to plot the polygon, comprising:

(a) registers for storing data of the vertexes of the polygon;

(b) edge dividers connected to the registers for dividing the polygon into small polygons;

(c) a decision unit connected to the registers and the edge dividers for determining whether or not the polygon stored in the registers is smaller than a predetermined size;

(d) a stack connected to the registers, the edge dividers and the decision unit for storing data of the vertexes of polygons;

(e) an adder connected to the edge dividers, the registers and the stack for averaging data by the edge dividers; and

(f) a plotting unit connected to the decision unit for writing pixels corresponding to the polygon to the image memory if the decision unit determines that the polygon is smaller than the predetermined size,

wherein the three-dimensional polygon is also defined by a luminance of each vertex thereof, and said edge dividers determine the luminance of each vertex of each small polygon by averaging the luminance of vertexes at both ends of each edge of the polygon to be divided into the small polygons.