Mapping circuit of a CRT display device

• US 4,974,177 A
• Filed: 06/14/1989
• Issued: 11/27/1990
• Est. Priority Date: 10/04/1985
• Status: Expired due to Fees

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Nishiguchi, Takaya
• Primary Examiner(s): Shaw, Dale M.
• Assistant Examiner(s): Zimmerman, Mark K.
• Application Number:
  US07/366,322
• Time in Patent Office: 531 Days
• Field of Search: 364/518, 364/521, 364/522, 340/728, 340/747, 434/43
• US Class Current: 345/582
• CPC Class Codes: G06T 15/80 Shading

Abstract

In a mapping circuit of a CRT display device in accordance with the present invention, vertex calculating means (2 and 3) evaluates corresponding relations between vertexes of a three-dimensional polygon and vertexes of a two-dimensional polygon and inclination calculating means (4 and 5) calculates inclination of the line segments connecting the respective vertexes of the three-dimensional polygon and inclinations of the line segments connecting the vertexes of the two-dimensional polygon. Vertexes interpolating means (6 and 7) performs interpolation between the respective vertexes of the three-dimensional polygon and also performs interpolation between the respective vertexes of the two-dimensional polygon. Then, using the interpolated points as start points or end points, start and end points interpolating means (9, 10, 11 and 12) performs interpolation between the respective start points and end points. A picture pattern on the coordinates of each interpolated point is read out by a pixel array memory control portion (14) and using the coordinates of each interpolated point as an address, the picture pattern is written in a frame memory (17), so that the picture pattern is displayed on a CRT display (18). Consequently, a host computer does not need to perform coordinate transformation in pixel units.

Claims

1. A CRT display device, used to display a representation of a three-dimensional polygon defined by data received from a host computer, said CRT display device comprising:

picture pattern storing means for storing a picture pattern and reference information for a two-dimensional polygon in a plane defined by an axis u and an axis v,

a CRT display for displaying a two-dimensional representation of the three-dimensional polygon having vertexes with three-dimensional coordinates in a three-dimensional space defined by an axis x, an axis y and an axis z,

vertex calculating means for calculating two dimensional coordinates of vertexes of said two-dimensional polygon from the data defining said three-dimensional polygon and the reference information for the two-dimensional polygon,

inclination calculating means for calculating inclinations of line segments connecting adjacent vertexes of said three-dimensional polygon and inclinations of line segments connecting adjacent vertexes of said two-dimensional polygon, including;

first increment calculating means for calculating increments parallel to the axis x and the axis z on the line segments connecting the adjacent vertexes of said three-dimensional polygon in response to increments parallel to the axis y, and

second increment calculating means for calculating increments parallel to the axis u and the axis v on the line segments connecting the adjacent vertexes of said two-dimensional polygon, corresponding to the increments calculated by said first increment calculating means,

vertexes interpolating means for performing interpolation between the adjacent vertexes of said three-dimensional polygon based on the three-dimensional coordinates of the vertexes of said three-dimensional polygon and the inclinations of the line segments therebetween, to produce first interpolated points, and for performing interpolation between the adjacent vertexes of said two-dimensional polygon based on the two-dimensional coordinates of the vertexes of said two-dimensional polygon and the inclinations of the line segments therebetween, to produce second interpolated points,

start and end points interpolating means for performing interpolation between pairs of the first interpolated points on said three-dimensional polygon to produce third interpolated points and for performing interpolation between corresponding pairs of the second interpolated points on said two-dimensional polygon to produce fourth interpolated points, the first, second, third and fourth interpolated points having coordinates,

reading means for reading, from said picture pattern storing means, the picture pattern at the coordinates of the fourth interpolated points within said two-dimensional polygon, and

a frame memory, operatively connected to said reading means, said start and end points interpolating means and said CRT display, including storage areas corresponding to display areas of said CRT display for storing the picture pattern read out by said reading means using as addresses the coordinates of the third interpolated points.

2. A CRT display device in accordance with claim 1, wherein the reference data for said two-dimensional polygon and the data defining said three-dimensional polygon each include a reference point and a reference vector, and

wherein said vertex calculating means comprises:

matrix calculating means for calculating a transformation matrix for transforming the three-dimensional coordinates of said three-dimensional polygon into transformed coordinates where a normal vector of a planar surface bounded by said three-dimensional polygon is parallel to the axis z in the three-dimensional space, the reference point of said three-dimensional polygon coincides with the reference point of said two-dimensional polygon and the reference vector of said three-dimensional polygon coincides with the reference vector of said two-dimensional polygon, and

coordinate calculating means for multiplying the three-dimensional coordinates of each vertex of said three-dimensional polygon by the transformation matrix calculated by said matrix calculating means to calculate the two-dimensional coordinates of the vertexes of said two-dimensional polygon.

3. A CRT display device in accordance with claim 1, wherein

said vertexes interpolating means comprises:

first edge interpolating means for performing interpolation between the adjacent vertexes of said three-dimensional polygon based on the increments parallel to the axis x and the axis z calculated by said first increment calculating means and the three-dimensional coordinates of the vertexes of said three-dimensional polygon to produce the first interpolated points, and

second edge interpolating means for calculating the second interpolated points on said two-dimensional polygon corresponding to the first interpolated points between the vertexes of said three-dimensional polygon produced by said first edge interpolating means.

4. A CRT display device used to display a representation of a three-dimensional polygon defined by data received from a host computer, said CRT display device comprising:

picture pattern storing means for storing a picture pattern and reference information for a two-dimensional polygon in a plane defined by an axis u and an axis v,

a CRT display for displaying a three-dimensional polygon having vertexes with three-dimensional coordinates in a three-dimensional space defined by an axis x, an axis y and an axis z,

vertex calculating means for calculating a correspondence between the two-dimensional coordinates of vertexes of said two-dimensional polygon from the data defining said three-dimensional polygon and the reference information for the two-dimensional polygon,

inclination calculating means for calculating inclinations of line segments connecting adjacent vertexes of said three-dimensional polygon and inclinations of line segments connecting adjacent vertexes of said two-dimensional polygon,

vertexes interpolating means for performing interpolation between the adjacent vertexes of said three-dimensional polygon based on the three-dimensional coordinates of the vertexes of said three-dimensional polygon and the inclinations of the line segments therebetween, to produce first interpolated points, and for performing interpolation between the adjacent vertexes of said two-dimensional polygon based on the two-dimensional coordinates of the vertexes of said two-dimensional polygon and the inclinations of the line segments therebetween, to produce second interpolated points,

start and end points interpolating means for performing interpolation between pairs of the first interpolated points on said three-dimensional polygon to produce third interpolated points and for performing interpolation between corresponding pairs of the second interpolated points on said two-dimensional polygon to produce fourth interpolated points, the first, second, third and fourth interpolated points having coordinates, said start and end points interpolating means including

first inclination calculating means for calculating an inclination of a first vector formed by using as start and end points one of the pairs of the first interpolated points on the three-dimensional polygon produced by said vertexes interpolating means,

second inclination calculating means for calculating an inclination of a second vector formed by using as start and end points one of the pairs of the second interpolated points on the two-dimensional polygon produced by said vertexes interpolating means,

first vector interpolating means for performing interpolation between the start and end points of the first vector used in said first inclination calculating means, based on the coordinates of the start and end points of the first vector and the inclinations calculated by said first inclination calculating means, and

second vector interpolating means for performing interpolation between the start and end points of the second vector used in said second inclination calculating means, based on the coordinates of the start and end points of the second vector and the inclinations calculated by said second inclination calculating means,

reading means for reading, from said picture pattern storing means, the picture pattern at the coordinates of the fourth interpolated points within said two-dimensional polygon, and

a frame memory, operatively connected to said reading means, said start and end points interpolating means and said CRT display, including storage areas corresponding to display areas of said CRT display for storing the picture pattern read out by said reading means using as addresses the coordinates of the third interpolated points.

5. A CRT display device used to display a representation of a three-dimensional polygon defined by data received from a host computer, said CRT display device comprising:

picture pattern storing means for storing a picture pattern for a two-dimensional polygon having vertexes with coordinates in a plan e defined by an axis u and an axis v,

a CRT display for displaying a two-dimensional representation of said three-dimensional polygon having vertexes with coordinates in a three-dimensional space defined by an axis x, an axis y and an axis z,

first storing means for storing the coordinates of the vertexes of said three-dimensional polygon,

second storing means for storing the coordinates of the vertexes of said two-dimensional polygon,

inclination calculating means for calculating inclinations of line segments connecting adjacent vertexes of said three-dimensional polygon based on the coordinates of the vertexes stored in said first storing means and for calculating inclinations of line segments connecting adjacent vertexes of said two-dimensional polygon based on the coordinates of the vertexes stored in said second storing means, said inclination calculating means including

first increment calculating means for calculating increments parallel to the axis x and the axis z on the line segments connecting the adjacent vertexes of said three-dimensional polygon in response to increments parallel to the axis y, and

second increment calculating means for calculating increments parallel to the axis u and the axis v on the line segments connecting the adjacent vertexes of said two-dimensional polygon, corresponding to the increments calculated by said first increment calculating means,

vertexes interpolating means for performing interpolation between the adjacent vertexes of said three-dimensional polygon based on the coordinates of the vertexes of said three-dimensional polygon and the inclinations of the line segments therebetween, to produce first interpolated points and for performing interpolation between the adjacent vertexes of said two-dimensional polygon based on the coordinates of the vertexes of said two-dimensional polygon stored in said second storing means and the inclinations of the line segments therebetween, to produce second interpolated points,

start and end points interpolating means for performing interpolation between pairs of the first interpolated points on said three-dimensional polygon to produce third interpolated points and for performing interpolation between pairs of the second interpolated points on said two-dimensional polygon to produce fourth interpolated points, the first, second, third and fourth interpolated points having coordinates,

reading means for reading, from said picture pattern storing means, the picture pattern at the coordinates of each of the fourth interpolated points within said two-dimensional polygon, and

a frame memory, operatively connected to said reading means, said start and end points interpolating means and said CRT display, including storage areas corresponding to display areas of said CRT display for storing the picture pattern read out by said reading means using as addresses the coordinates of the third interpolated points.

6. A CRT display device in accordance with claim 5, wherein

said vertexes interpolating means comprises:

first edge interpolating means for performing interpolation between the adjacent vertexes of said three-dimensional polygon based on the increments parallel to the axis x and the axis z calculated by said first increment calculating means and the coordinates of the vertexes of said three-dimensional polygon to produce the first interpolated points, and

second edge interpolating means for calculating the second interpolated points on the two-dimensional polygon corresponding to the first interpolated points between the respective vertexes of the three-dimensional polygon produced by said first edge interpolating means.

7. A CRT display device used to display a representation of a three-dimensional polygon defined by data received from a host computer, said CRT display device comprising:

picture pattern storing means for storing a picture pattern for a two-dimensional polygon having vertexes with coordinates in a plane defined by an axis u and an axis v,

a CRT display for displaying a two-dimensional representation of said three-dimensional polygon having vertexes with coordinates in a three-dimensional space defined by an axis x, an axis y and an axis z,

first storing means for storing the coordinates of the vertexes of said three-dimensional polygon,

second storing means for storing the coordinates of the vertexes of said two-dimensional polygon,

inclination calculating means for calculating inclinations of line segments connecting adjacent vertexes of said three-dimensional polygon based on the coordinates of the vertexes stored in said first storing means and for calculating inclinations of line segments connecting adjacent vertexes of said two-dimensional polygon based on the coordinates of the vertexes stored in said second storing means,

vertexes interpolating means for performing interpolation between the adjacent vertexes of said three-dimensional polygon based on the coordinates of the vertexes of said three-dimensional polygon and the inclinations of the line segments therebetween, to produce first interpolated points and for performing interpolation between the adjacent vertexes of said two-dimensional polygon based on the coordinates of the vertexes of said two-dimensional polygon stored in said second storing means and the inclinations of the line segments therebetween, to produce second interpolated points,

start and end points interpolating means for performing interpolation between pairs of the first interpolated points on said three-dimensional polygon to produce third interpolated points and for performing interpolation between pairs of the second interpolated points on said two-dimensional polygon to produce fourth interpolated points, the first, second, third and fourth interpolated points having coordinates, said start and end points interpolating means including

first inclination calculating means for calculating an inclination of a first vector formed by using as start and end points one of the pairs of the first interpolated points on the three-dimensional polygon produced by said vertexes interpolating means,

second inclination calculating means for calculating an inclination of a second vector formed by using as start and end points one of the pairs of the second interpolated points on the two-dimensional polygon produced by said vertexes interpolating means,

first vector interpolating means for performing interpolation between the start and end points of the first vector used in said first inclination calculating means, based on the start and end points of the first vector and the inclinations calculated by said first inclination calculating means, and

second vector interpolating means for performing interpolation between the start and end points of the second vector used in said second inclination calculating means, based on the coordinates of the start and end points of the second vector and the inclinations calculated by said second inclinations calculating means,

reading means for reading, from said picture pattern storing means, the picture pattern at the coordinates of each of the fourth interpolated points within said two-dimensional polygon, and

a frame memory, operatively connected to said reading means, said start and end points interpolating means and said CRT display, including storage areas corresponding to display areas of said CRT display for storing the picture pattern read out by said reading means using as addresses the coordinates of the third interpolated points.

8. A mapping method used to display a representation of a three-dimensional polygon, defined by data from a host computer, on a CRT display device, comprising the steps of:

(a) storing a predetermined picture pattern for a two-dimensional polygon having vertexes with coordinates in a plan e defined by an axis u and an axis v,

(b) calculating a correspondence between the vertexes of said two-dimensional polygon and the vertexes of the three-dimensional polygon having vertexes with coordinates in a three-dimensional space defined by an axis x, and axis y and an axis z,

(c) calculating inclinations of line segments connecting adjacent vertexes of said three-dimensional polygon and inclinations of line segments connecting adjacent vertexes of said two-dimensional polygon in dependence upon the correspondence calculated in step (b), by calculating increments parallel to the axis x and the axis z on the line segments connecting the adjacent vertexes of said three-dimensional polygon in response to increments parallel to the axis v and calculating increments parallel to the axis u and the axis v on the line segments connecting the adjacent vertexes of said two-dimensional polygon, corresponding to the increments calculated by said first increment calculating means,

(d) performing interpolation between the adjacent vertexes of said three-dimensional polygon, based on the coordinates of the vertexes of said three-dimensional polygon and the inclinations of the line segments therebetween to produce first interpolated points,

(e) performing interpolation between the adjacent vertexes of said two-dimensional polygon, based on the coordinates of the vertexes of said two-dimensional polygon and the inclinations of the line segments connecting the adjacent vertexes of said two-dimensional polygon to produce second interpolated points,

(f) performing interpolation between pairs of the first interpolated points on said three-dimensional polygon to produce third interpolated points,

(g) performing interpolation between pairs of the second interpolated points on said two-dimensional polygon, corresponding to the pairs of the first interpolated points, to produce fourth interpolated points, the first, second, third and fourth interpolated points having coordinates,

(h) providing a display picture pattern at the coordinates of the fourth interpolated points within said two-dimensional polygon, and

(i) storing the display picture pattern using as addresses the coordinates of the third interpolated points.

9. A mapping method used to display a representation of a three-dimensional polygon, defined by data from a host computer, on a CRT device, comprising the steps of:

(a) storing a predetermined picture pattern for a two-dimensional polygon having vertexes with coordinates in a plane defined by an axis u and an axis v,

(b) storing coordinates of vertexes of a three-dimensional polygon having vertexes with coordinates of the three-dimensional space defined by an axis x, and axis y and axis z,

(c) storing the coordinates of the vertexes of said two-dimensional polygon,

(d) calculating inclinations of line segments connecting adjacent vertexes of said three-dimensional polygon, based on the coordinates of the vertexes of said three-dimensional polygon stored in step (b), by calculating increments parallel to the axis x and the axis z on the line segments connecting the adjacent vertexes of aid three-dimensional polygon in response to increments parallel to the axis y,

(e) calculating inclinations of line segments connecting adjacent vertexes of said two-dimensional polygon, based on the coordinates of the vertexes of said two-dimensional polygon stored in step (c), by calculating increments parallel to the axis u and the axis y on the line segments connecting the adjacent vertexes of said two-dimensional polygon, corresponding to the increments calculated by said first increment calculating means,

(f) performing interpolation between the adjacent vertexes of said three-dimensional polygon, based on the coordinates of the vertexes of said three-dimensional polygon and the inclinations of the line segments connecting the adjacent vertexes of said three-dimensional polygon to produce first interpolated points,

(g) performing interpolation between the adjacent vertexes of said two-dimensional polygon, based on the coordinates of the vertexes of said two-dimensional polygon and the inclinations of the line segments connecting the adjacent vertexes of said two-dimensional polygon to produce second interpolated points,

(h) performing interpolation between pairs of the first interpolated points on said three-dimensional polygon to produce third interpolated points,

(i) performing interpolation between pairs of the second interpolated points on said two-dimensional polygon, corresponding to the pairs of the first interpolated points to produce fourth interpolated points, the first, second third and fourth interpolated points having coordinates,

(j) providing a display picture pattern at the coordinates of the fourth interpolated points, within said two-dimensional polygon, and

(k) storing the display picture pattern using as addresses the coordinates of the third interpolated points.