JPH0234069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to an image processing device that implements shading and texture mapping using hardware incorporated within a graphic display.

<Prior art> Conventionally, in order to achieve shading and mapping, a general-purpose computer was used and the processing was performed using software. This is the computer (host)
Find the brightness of each point on the surface of the three-dimensional shape in
Because data was sent pixel by pixel to the graphic display, it took an enormous amount of time to display it.

<Objective of the Invention> The present invention provides an image processing apparatus that is equipped with a function for realizing mapping as well as shading on the graphic display side, and can perform shading and mapping in a short time.

<Example> An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of an image processing apparatus according to the present invention. 1 is a shape storage buffer that stores a polyhedral shape composed of square patches inputted from the outside (host computer) via an interface; 2 is a plurality of input devices or a single input device such as a TV camera 2a or a scanner 2b; Reference numeral 3 denotes a mapping data area for storing texture data such as two-dimensional patterns read by these. Further, 4 is a processor that performs shading and mapping, 5 is a Z buffer that performs hidden surface processing, and 6 is a color monitor.

A shape to be shaded is inputted from the outside as a collection of square patches into a shape storage buffer 1, and if mapping is also required, a two-dimensional pattern or figure is read from an input device 2 and stored in a mapping data area 3. Data read from the input device 2 can be displayed on the color monitor 6. Then, when the brightness, position, and viewpoint position of one or more light sources are given to the processor 4, the processor 4 performs shading and mapping processing, and the Z buffer 5 performs processing that does not display invisible parts, and the color monitor 6 to be displayed.

FIGS. 2 and 3 show structural diagrams of the shape storage buffer 1 and the mapping data area 3.

A three-dimensional shape consisting of one or more curved surfaces is stored in a shape storage buffer 1. For example, as shown in FIG. 4, one curved surface 11 consists of one or more square patches 12a, 12b, . . . , 12f, which are stored in the shape storage buffer 1 in one curved surface data unit. The head area 21 of one curved surface data unit contains information such as: ● the number of square patches that make up one curved surface ● the unique name of the curved surface unit ● the size of the data (in the shape storage buffer 1, the square patches that make up the curved surface are ● Color of the curved surface (in R, G, B units) ● Diffuse reflection coefficient ● Specular reflection coefficient ● Number of divisions of the curved surface in the U direction and V direction (see Figure 4; in the example shown, 3 in the U direction, 3 in the V direction) (divided into direction 2).

The square patch area 22 stores unique square patch numbers and pointers 1, 2, 3, and 4 to each vertex, which correspond to the square patches 12a, 12b, . . . , 12f, etc. in FIG.

The vertex information area 23 of the square patch contains: - Values of vertex coordinates X, Y, Z - Values of U, V in the U, V coordinate system (0.0≦U≦1.0,
0.0≦V≦1.0) ●Memorize the normal vector of the vertex (calculated from the average value of the normal vectors of the square patches that share the vertex).

The first area 24 is an area that commonly stores the brightness value of the surface due to diffused light for one polyhedron shape.

The mapping data area 3 stores two-dimensional data (texture mapping data) 25 read from the input device 2 in units of pixels in U and V coordinates. U=a, V of this mapping data 25
=b pixel data of the above-mentioned curved surface U=a,
If this is made to correspond to one point where V=b and this is done for all mapping data, the mapping process will be realized and the two-dimensional pattern will be attached to the surface of the three-dimensional shape.

The operation of this apparatus will be described in detail with reference to the flowchart shown in FIG.

First, in step _S1 , square patches constituting a three-dimensional shape are input and stored in the shape storage buffer 1. Next, in step _S2 , the luminance value of the light source,
Enter the position and viewpoint position. Step S ₃ is
Follow the operating instructions from the mapping switch, etc.
This is a step to determine whether or not to perform mapping processing. If mapping processing is not to be performed, the process jumps to step _S5 . Steps when mapping
Proceeding to _S4 , two-dimensional texture data is read from the input device 2 and stored in the mapping data area 3.

In step _S5 , the normal vector of the surface of the square patch is determined from the coordinates of each vertex of the square patch, and the normal vector of the vertex is determined by the average of the surface normal vectors of the square patches that share the vertex. The normal vector of the vertex is stored in the vertex information area 23 (see FIG. 2) of the shape storage buffer 1 as described above. Then, in step _S6 , the normal vector at any one point within the square patch is determined by linear interpolation of the normal vectors at each vertex.

Shading basically uses Phong's method. This is the brightness I of one point on the curved surface, I=Ia+Kd・_j=n 〓 ^j=1 (N→・L→j) +Ks・_j=n 〓 ^j=1 (N→・L→j′) ⁿ ...(1). Here, m is the number of light sources, Kd is the diffuse reflection coefficient, Ks is the specular reflection coefficient, Ia is the brightness due to diffused light, N→ is the unit normal vector of the surface, L→ is the unit normal vector in the direction of the light source, L→ ' is a unit vector in the direction bisecting the pect in the line-of-sight direction and the unit vector of the light source. In step _S7 , the brightness of any one point on the square patch is determined using the above equation (1).

At this time, if there is mapping data, add the color of the pixel that has the U, V coordinates of the mapping data that corresponds to the U, V coordinates of the surface of that point, R,
Calculate equation (1) for G and B units. In this way, the two-dimensional pattern or the like is pasted onto the surface of the three-dimensional shape.

In step _S8 , this calculated data is sent to the Z buffer 5 to perform hidden surface processing.

Hidden surface processing is performed using screen coordinates, and Z information corresponding to the coordinates of each pixel on the display is held. And add 3 new objects
The Z coordinate of a pixel obtained by converting the coordinates of one point in the dimensional shape into screen coordinates is compared with the Z coordinate of the old pixel, and if it is in the foreground, the information of the pixel is replaced with the new one. Figure 6 is an explanatory diagram of hidden surface processing. As shown in the figure, there is Z ₂ at the beginning,
When the new conversion result is Z ₁ , Z ₁
is compared with Z ₂ , and Z ₁ which is in front in the viewing direction
is retained as a new pixel.

Step _S9 determines whether all surfaces have been processed, and if not, returns to step _S6 . That is, step S ₆ for each point,
The operations S ₇ and S ₈ are repeated for all three-dimensional shapes made up of square patches.

When all points have been processed, the process proceeds from step _S9 to step _S10 , and the shape subjected to hidden surface processing is displayed on the color monitor 6 in parallel perspective or single point perspective.

<Effects of the Invention> As explained above, according to the present invention, the graphic display is provided with the shape storage buffer, the input device, the mapping data area, and the processor, so that the data sent from the host computer is
Instead of sending screen coordinates pixel by pixel after shaded and mapped processing, it is sufficient to send information in square patches, which reduces the amount of data sent through the interface, and allows shaded and mapped information to be processed by the hardware on the graphics display side. This has the advantage that the load on the host computer is small and the display speed is very fast. The ability to display processing results quickly is an important element in the CAD field, which emphasizes interactivity. Furthermore, the graphic display has an input device such as a TV camera or scanner for inputting texture data such as patterns, and has the advantage that it can be read in real time and displayed on the monitor at the same time.

Further, the present invention can provide an image processing device that is useful in a wide range of applications, such as the exterior design of products and packages, the CAD field of apparel design such as fabrics, and the field of real-time animation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the device configuration in an embodiment of the present invention, FIG. 2 is a structural diagram of the shape storage buffer shown in FIG. 1, FIG. 3 is a structural diagram of the mapping data area, and FIG. FIG. 5 is a flowchart explaining the operation, and FIG. 6 is an illustration of hidden surface processing. 1...Shape storage buffer, 2...Input device, 3...Mapping data area, 4...Processor, 5...Z
Buffer, 6...Color monitor, 21...Head area, 22...Square patch area, 23...Vertex information area, 24...Brightness area, 25...Texture mapping data.

Claims (1)

[Scope of Claims] 1. An image processing device having a host computer and a graphic display, comprising a shape storage for storing shape information obtained by dividing a polyhedron to be shaded sent from the host computer. a buffer, an input device for reading patterns and figures, a mapping data area for storing texture data of the patterns and figures input by the input device, and a light source sent from the host computer. information regarding the number, position, brightness, and position of the viewpoint, the texture data stored in the mapping data area, and the shape information stored in the shape storage buffer. An image processing apparatus characterized in that the graphic display includes a processor for calculating the brightness of one point.