JP2002049932A - Method for displaying polygon model shadow - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display method capable of representing the shadow of a polygon model in a state abundant in reality by a relatively simple image processing. SOLUTION: This displaying method consists of a step in which the data of the front image (21) of a shadow (20) on the projected face (3) of the polygon model (2) to be an object are operated with a usual method and recorded, a step in which pseudo-image data representing at least one pseudo image (22 to 24) drawn with a similar contour while a slight interval is provided from the contour of the front image (21) of the shadow displayed by the front image data are operated and recorded, a step in which a shadow image data representing a shadow image (20) obtained by respectively giving appropriate transparency to each image and superimposing images by using image data representing the front image (21) and at least one pseudo image (22 to 24) are operated and recorded, and a step in which the shadow image data are reproduced together with the image data of a polygon model (2) and the image of the polygon model (2) and the shadow image (20) are displayed in a game field (1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for displaying a shadow of a polygon model displayed on a display screen of a computer game.

[0002]

2. Description of the Related Art In a computer game, as a method of adding a shadow to a character to be displayed on a display screen, a method of preparing a picture in which a shadow is projected in advance and displaying it in accordance with the position of the character is generally used. Used. Also, in a game using CG, if there is enough computing power, there is a method of creating a matrix for projecting the model data of the character on the floor and displaying a shadow obtained by projecting the model data itself. This determinant can be created in various ways, but the simplest method is to crush the Y component of the determinant created to display model data when projecting on a flat surface with the Y axis. There is a method of doing it. This is, for example, the following 4 lines 4
A matrix of columns will be described as an example.

[0003]

(Equation 1) Here, “a0 *” is an X-axis rotation component, and “a1 *” is Y
The axis rotation component, “a2 *” is the Z axis rotation component, and “a3
“*” Represents a component of movement.

In the above matrix, "a01", "a10", "a
By setting “11”, “a12”, and “a21” to 0, a shadow (orthogonal projection) in a state where light is applied from directly above can be created.

However, according to this method, the polygon CG that represents an object as a polygon has a drawback that the edge of the shadow becomes too sharp and sharp, and a problem arises in that the shadow cannot be expressed realistically. This is because the edge portion of a real shadow is usually blurred unless it receives a light beam from a point light source of extremely high luminance. As one method of drawing so that the edge portion of the shadow is blurred, a method of increasing the transparency of the edge portion at the time of drawing and applying a gradation of transparency from the inside to the outside can be considered. However, since it is difficult to specify an edge, this method has a problem that a huge processing time is required.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to form a shadow of a polygon model by using relatively simple image processing so that an edge portion of the polygon model has an edge portion. It is an object of the present invention to provide a display method that can be expressed in a state full of reality that makes the image look somewhat blurry.

[0007]

In order to achieve the above-mentioned object, according to the present invention, a plurality of shadow models whose transparency and size are changed in a stepwise manner are overwritten, thereby realizing a blurred and realistic edge portion. It is designed to express shadows. For example, when a shadow is configured in three stages, the first first stage shadow model draws a shadow that is slightly smaller than the reference size and has low transparency. The shadow model of the second stage draws a model whose size is a reference size and whose transparency is slightly higher than that of the first stage. The shadow model in the third stage is drawn slightly larger than the reference size and with considerably increased transparency.
By superimposing and displaying these three types of shadow models, it is possible to easily create a shadow that is darker at the center and blurred on the outside. Since the calculation for changing the size of the shadow can be performed by changing “a00” and “a22” of the determinant, the calculation cost can be extremely small.

More specifically, the present invention relates to a method of displaying a shadow of one polygon model projected on a solid model surface in a game field by a light ray from a specific point light source. Calculating and recording the normal image data representing the positive image of the shadow of the polygon model to be drawn, and drawing the image with a similar contour at a slight distance from the contour of the positive image of the shadow displayed by the normal image data Calculating and recording pseudo image data representing at least one pseudo image; and using the image data representing the positive image and at least one pseudo image to give appropriate transparency to each image and superimposing them. Calculating and recording shadow image data representing the obtained shadow image; reproducing the shadow image data together with the polygon model image data; A step of displaying Le image and the shadow image in the game field and is characterized in that it consists of.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is an explanatory diagram schematically showing a shadow display method according to the present invention, and FIG. 2 is a flowchart of processing steps when the shadow display method according to the present invention is implemented. In FIG. 1, 1 is a game field displayed and set on a display screen of a computer game machine, 2 is a polygon model, 3 is a surface (projection plane) of a predetermined solid model on which a shadow 20 of the polygon model 2 is projected, Reference numeral 4 denotes a point light source set at a predetermined position in the game field, and reference numeral 40 denotes a light beam from the point light source 4. The point light source 4 and the light beam 40 itself are not normally displayed on the screen.

A shadow (shadow image) 20 is obtained by superimposing one normal image 21 and three pseudo images 22 to 24 on each other, as shown by enlarging the edge portion in the circle in the lower half of FIG. It is constituted by displaying. In other words, the area closest to the outermost part of the shadow 20 is composed of only the normal image 21, and the area slightly inside the pseudo image 22 is configured by superimposing the pseudo image 22 slightly smaller than the normal image 21 on the normal image 21. Is configured by superimposing the pseudo images 22 and 23 on the normal image 21, and the innermost region is formed by superimposing the pseudo images 22 and 23 on the normal image 21.
And 24 are superimposed. Each image has a predetermined transparency. Therefore, the inner region where the number of superimposed images is larger is displayed darker (darker), and as a result, a realistic shadow image 20 with a gradation applied to the edge portion can be displayed.

In the present invention, the normal image 21
The calculation of the contours of the pseudo images 22 to 24 is performed as follows. That is, the contour data of the normal image 21 is obtained by performing an arithmetic operation according to a standard method based on data relating to the contour of the polygon model 2, the position of the point light source 4, and the arrangement of the projection plane 3. On the other hand, the contour data of the pseudo images 22 to 24 are
It is determined by calculating similar contours defined by parallel lines at predetermined intervals with respect to the contour lines of the normal image 21. To do so, for example, it is only necessary to change “a00” and “a22” in the determinant as described above. Therefore, the calculation cost for calculating the contour data of the normal image 21 and the contour data of the pseudo images 22 to 24 similar thereto is very small. In the above description, 21 is a positive image and 22 to 24 are pseudo images. However, any one of the positive images and any of the pseudo images is arbitrary. It is also possible to make 22 and 24 pseudo images. The calculation process in that case can be easily performed similarly to the above case. In addition, the number of pseudo images is usually set to about 1 to 3, but may be more.

FIG. 2 is a flowchart showing the processing steps as described above. As shown in the drawing, the transparency of each of the positive image and the pseudo image may be set at the same time in the step of calculating the outline of each image. However, when the images are superimposed and displayed, the transparency of each image is simultaneously set. You may make it.

[0013]

Since the present invention is constructed as described above, according to the present invention, the shadow of the polygon model is rich in the reality that the edge part thereof looks somewhat blurry by relatively simple image processing. It is possible to provide a display method that can be expressed in a state where the display is in a state of being undone. It should be noted that the present invention is not limited to the above embodiments, but encompasses all modified embodiments that can be easily conceived by those skilled in the art from the above description within the scope of the object.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing a shadow display method according to the present invention.

FIG. 2 is a flowchart of processing steps when implementing the shadow display method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Game field 2 Polygon model 3 Projection surface 4 Point light source 20 Shadow image 21 Normal image 22-24 Pseudo image

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuo Tsumori 2-3-3 Hirakawacho, Chiyoda-ku, Tokyo F-term in Taito Corporation (reference) 2C001 BC00 BC05 BC06 BC10 CB01 CC02 5B080 AA13 BA07 FA08 FA17

Claims (1)

[Claims] 1. A shadow (20) of one polygon model (2) projected on a solid model surface (3) in a game field (1) by a light ray (40) from a specific point light source (4). A normal image data representing a normal image (21) of a shadow (20) on a projection plane (3) of a target polygon model (2) is calculated and recorded, and Calculate and record pseudo image data representing at least one pseudo image (22 to 24) drawn with a similar outline at a slight distance from the outline of the shadow normal image (21) displayed by the normal image data. Step; the positive image (21) and at least one pseudo image (22).
-24) giving appropriate transparency to each image using image data representing the same, calculating and recording shadow image data representing a shadow image (20) obtained by superimposing them, and converting the shadow image data into polygons. Reproducing the image with the image data of the model (2) and displaying the image of the polygon model (2) and its shadow image (20) in the game field (1). How to display shadows.