JPS6310287A - Graphic display system - Google Patents

Abstract

PURPOSE:To display a 3-dimensional form containing a cavity and a new form obtained after shift of another form by providing plural sheets of depth buffers having two distance parameters and luminance for each pixel to a display memory. CONSTITUTION:In a graphic display system for a 3-dimensional form to a 2-dimensional display device, plural depth buffers are provided to a display memory part 11. Each depth buffer has two distance parameters and luminance for each pixel. A display arithmetic part 12 reads the contents of depth buffers out of the part 11 and performs calculation among those depth buffers for the sum, difference, product and shift respectively to write them to the depth buffers. A display processing part 13 reads the contents of the indicated one of those depth buffers of the part 11 and transfers them to a display monitor. Thus it is possible to perform the time simulation of the form cutting or the flow of an object and the display of an internal 3-dimensional form at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a system for displaying three-dimensional images on a two-dimensional display device, such as a raster display screen of a graphic display device.

[Prior art]

K for displaying three-dimensional images on a two-dimensional display device
It is necessary to erase the hidden surface of the image and detect and display the visible surface (visible surface) ``Ik''.

The conventional hidden surface removal method stores distance parameters and brightness of a three-dimensional shape in the depth direction in a memory called a depth buffer, and converts each pixel of the surface constituting the three-dimensional shape into a depth buffer by projection conversion. Some devices detect and display visible surfaces by mapping and writing only the brightness of the surface closest to the viewpoint into a buffer.

[Problem that the invention seeks to solve]

In the method using a depth buffer consisting of only one distance parameter, a cavity is created inside the shape due to the combination of sum, difference, product, etc., and when the previously invisible part becomes visible, the displayed content becomes completely different. There is a drawback. Furthermore, there is also the drawback that the distance parameter in the depth buffer needs to be created again for movement of the shape when viewed from one direction (J).

[Means for solving problems]

The graphic display method of the present invention is a graphic display method of a three-dimensional shape on a two-dimensional display device, and includes a display memory section having a plurality of depth buffers each having two values, a distance parameter and a luminance, for each pixel; a display calculation unit that reads the contents of the depth buffer from the display memory unit, performs calculations between the buffers such as sum, difference, product, and movement, and writes them to the depth buffer;
It has a display processing section that reads and transfers the contents of the depth buffer to a display monitor for display, and is realized by having a plurality of depth buffers each having two distance parameters.

[Effect]

By having the above means, one of the two distance parameters is given the distance from the viewpoint of the point on the shape that is closest to the viewpoint, similar to a conventional depth buffer, and the other is given the distance on the shape that is farthest from the viewpoint. give the distance from the viewpoint of
By adding the results of calculations such as sum, difference, and product to the depth buffer, it is possible to improve the depth of the display of shapes with cavities or new shapes after shape movement, which were problems with previous methods. This can be done by buffer operations.

〔Example〕

Hereinafter, a graphic display method according to the present invention will be explained with reference to the drawings.

FIG. 1 is a functional block diagram showing one embodiment of the present invention. In the figure, the display memory unit 11 has a plurality of depth buffers F1...Fnl), and each depth buffer has two distance parameters d1 and dz and brightness d3 for each pixel. The display calculation unit 12 uses a depth buffer γF.
1... Calculate 0pt for Fn' i and F j K
- Execute and return result to t-Fk. Here, Fi, Fj, F
k and Op are Op (F i, [)j,)Fk(,dx,
It is specified in advance in the format of dy, dz)) and means each operation of sum, difference, product, and movement. Here, sum, difference,
Multiplication refers to an operation in which a union set, a difference set, and a common set of shapes stored in the depth buffer are performed on the depth buffer 7. Further, movement refers to an operation in which one depth buffer is moved by specified distances dx%dy and dz in the "+'/*" direction, respectively. Note that the display calculation section 12 performs all or one or more of the calculations for one food item. The contents of each of these calculations are listed in FIG. 8 (al and tb).

The display processing section 13 reads out the contents of a specified buffer from the depth buffer of the display memory section 11 and displays the contents.

Next, the processing of the display calculation section 12 will be explained using an example. Assume now that the contents of depth buffer γF1 and F2 represent the pictures shown in FIGS. 2(a) and 2(b). In reality, the buffer does not hold a picture like this, but two distance parameters representing the brightness and depth for each pixel. Furthermore, the picture itself is not a line drawing, but is displayed in colors corresponding to the brightness of each pixel. At this time, the results of the sum, difference, and product operations are shown in FIG. 3, respectively. For example, here pixel (i
, j), from the distance parameter of pixel (i, j) of depth buffer F1 and the distance parameter of pixel (trj) of depth buffer γF2, The results shown in Figure 4 are obtained. If these results are summarized for all pixels, the result is shown in Figure 3. Also, a movement operation (F2') is applied to the depth buffer γF2, and the further steps are the same as in the following. When the difference calculation (lI"1-F2') is performed, a result as shown in FIG. 5 is obtained.

Also, FIGS. 6(a), (b), (c), and (d)
) The four depth buffers Fl, F2, F3 shown in
, for F4, (Fl-F2)+F3 and (F'1-F4
) - (F2 - F4) + F3 are shown in Figure 7 (al and (bl). For the former operation, first, for the difference operation between Fl and F2 and the sum operation of F3 for the result, Since the shape indicated by Fl is outside the shape indicated by other depth buffers, the display is exactly the same as 1. On the other hand,
In the latter example, a difference calculation is performed for each of F1 and F2 with the shape indicated by F4, and a cut 1 of the portion of shape F1 and F2 close to the viewpoint is performed. Further, by the union with F3, F3, which was hidden behind Fl, can be displayed.

All of these processes described above are shown in Figure 8 (al and (b)
This is performed by the calculation shown in l.

〔Effect of the invention〕

As described above, according to the graphic display method of the present invention, each pixel of the depth buffer has two distance parameters, and depth buffer operations that perform sum, difference, product, and movement using these distance parameters solve problems that have not been possible until now. Since the shape can be expressed using a depth buffer, which was previously possible, the cutting of the shape, the temporal simulation of the flow of objects, and the display of the internal shape of a three-dimensional shape can be performed at high speed using depth buffer calculations.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing the contents of the depth buffer for explaining the present invention in detail. FIG. 3 is a diagram showing sum, difference, and product operations for the buffer shown in FIG. 2. FIG. 4 is a diagram showing pixel-by-pixel processing of the calculation in FIG. 3. FIG. 5 is a diagram showing movement calculation. FIG. 6 is a diagram showing the contents of a rounding depth buffer to explain calculations of more complicated shapes. FIG. 7 is a diagram showing an example in which sum and difference operations are combined with the contents shown in FIG. 6. FIG. 8 is a diagram showing processing of sum, difference, product, and movement calculations in the display calculation section. 11... Display memory section, 12... Display calculation section, 13
...Display processing section. Agent Patent Attorney Susumu Uchihara\-1〆Figure 1Figure 2 (see) (1)) FI F2 (6L) (b) (C) JFO operation difference z -i calculation 1”l
+F2 Fl -F2 F
l
<d>Figure 7 (see) (b) (F+ -F2) 10F3
(F Blind - F4) - (F2-F4) 10F3 Fig. 8 (Slope

Claims (1)

[Scope of Claim] A method for displaying a three-dimensional shape on a two-dimensional display device, comprising: a display memory section having a plurality of depth buffers each having two values, a distance parameter and a brightness, for each pixel; and the display memory. Read the contents of the depth buffer from
It has a display calculation section that performs calculations between buffers such as sum, difference, product, and movement and writes them to the depth buffer, and a display processing section that reads and transfers the contents of the depth buffer to the display monitor for display. A graphic display method characterized by having multiple depth buffers each having parameters.