JPH09319894A - Method and device for three-dimensional cg image using plural light sources - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the burden to a user owing to plural light sources at the time of generating a three-dimensional CG images, using plural light sources. SOLUTION: When a three-dimensional CG model consisting of plural light sources 220-1 and 220-2, arranged in a three-dimensional space and plural irradiated three-dimensional graphics 230-1, 230-2, 230-3, and 230-4 are displayed on an image, ranges in irradiation of individual light sources (light source clip volumes) 250-1 and 250-2 are designated on the picture, and only the light source 220-1 is taken into consideration to calculate a display color, with respect to irradiated three-dimensional graphics 230-1 and 230-2 included in the range 250-1, and only the light source 220-2 is taken into consideration to calculate a display color, with respect to irradiated three-dimensional graphics 230-3 and 230-4 included in the range 250-2. Since it is sufficient if ranges corresponding to light sources are designated on the image, the burden to he user is not increased, even if the number of light sources and the number of irradiated objects are increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for generating a three-dimensional CG image, and more particularly, to each object of a three-dimensional CG image composed of a combination of a plurality of light sources and a plurality of illuminated objects (objects). The present invention relates to a method and an apparatus for generating a three-dimensional CG image using a plurality of light sources suitable for easily determining a display color (object color) of an illuminated object.

[0002]

2. Description of the Related Art A three-dimensional CG model shown in FIG. 6 (two-dimensional display is shown for the sake of simplicity) is a general model in which a room is represented as a three-dimensional CG. There are two rooms on the wall 310 (340-1 and 340-
2), and a lighting fixture 320-1 (hereinafter referred to as light source 1) is provided on the ceiling of one room 340-1.
A desk 330-1 (hereinafter referred to as object 1) and a chair 330-2 (hereinafter referred to as object 2) are arranged in the room. On the ceiling of the other room 340-2, lighting equipment 320-
2 (hereinafter, light source 2) is provided, and a desk 330-3 is provided in the room.
(Hereinafter, referred to as object 3) and chair 330-4 (hereinafter referred to as object 4) are arranged.

When displaying such a three-dimensional CG model image on the screen, the computer calculates the display colors of the objects 1 to 4 in consideration of the light from the light sources 1 and 2. Since the wall 310 exists between the two rooms, it is necessary to instruct the computer not to consider the illumination light from the light source 2 in order to determine the display color of the object 1, for example.

Therefore, conventionally, as shown in FIG. 7, a table 410 having an identifier of an object illuminated by the light source 1 and a table 420 having an identifier of an object illuminated by the light source 2 are provided. The object 2 is registered, and the object 3 and the object 4 are registered in the table 420. In addition, this is an example in which there is only one light source.
As described in Japanese Unexamined Patent Publication No. 76074, a range not covered by light on a three-dimensional CG image is finely designated as a two-dimensional surface so that the entire display does not become unnatural.

[0005]

In the prior art in which the table shown in FIG. 7 is provided, the user grasps the positional relationship among the light sources, the illuminated objects, and the light blocking objects (walls in the example of FIG. 6) one by one. It is necessary to grasp this positional relationship,
You have to create each table. Also, if the position or shape of the illuminated object changes, re-registration processing in the table is required for the changed illuminated object, and re-registration in the table each time the position or shape of the illuminated object changes. Processing becomes necessary. Further, even if the position of the wall changes and the illuminated range of each light source changes, the re-registration process to the table must be executed. That is, there is a problem that the burden on the user is large. Further, even in the conventional technique described in Japanese Patent Laid-Open No. 6-76074, the user has to specify the shadowed area in detail, which imposes a heavy burden on the user. When the number of light sources increases, it is necessary to grasp the positional relationship between each light source and the light-shielding object and specify which light source has a shadow, and this further increases the burden on the user.

An object of the present invention is to provide a three-dimensional C using a plurality of light sources, which can reduce the burden on the user even if the number of light sources is increased.
It is to provide a method of generating a G image and an apparatus thereof.

[0007]

The above-mentioned object is to generate a three-dimensional CG image in which a three-dimensional CG model consisting of a plurality of light sources arranged in a three-dimensional space and a plurality of illuminated three-dimensional figures is displayed on a screen. This is achieved by causing each light source to specify a three-dimensional range illuminated by each light source on the screen, and obtaining the color of the illuminated three-dimensional figure in each three-dimensional designated range from the light source in the three-dimensional designated range. It

The above object is preferably achieved by defining the range as a region surrounded by a plurality of planes at a predetermined distance.

Preferably, the above-mentioned object is to calculate the color of only the portion within the range with respect to the illuminated three-dimensional figure straddling the boundary of the range by using only the light source corresponding to the range, To be achieved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a three-dimensional CG model for explaining an embodiment of the present invention on a display, which is the same model as the three-dimensional CG model shown in FIG. Each room 2 is different from the conventional technique described in FIG.
40-1 and 240-2 for each of the light sources 220-
1 and 220-2 range of light source clip volume 2
It is about to be designated as 50-1 and 250-2. The light source clip volume 250-1 (the range shown by the diagonal lines: includes the parts of the objects 1 and 2) is the room 240-.
1 is specified three-dimensionally on the screen so as to include the entire internal area of 1, for example, by dragging the mouse.
Light source clip volume 250-2 is designated to encompass the entire interior of room 240-2.

When the three-dimensional CG model of FIG. 1 is drawn, the object 1 is included in the light source 1 clip volume 250-1 which is a range illuminated by the light source 1, but the light source 2 clip which is a range illuminated by the light source 2 is clipped. Since it is not included in the volume 250-2, when calculating the object color of the object 1, the object color illuminated only by the light source 1 is calculated, and the object 1 is drawn using this object color. Similarly, the object 3 is not included in the light source 1 clip volume 250-1 which is the range illuminated by the light source 1, but is included in the light source 2 clip volume 250-2 which is the range illuminated by the light source 2, When calculating the object color, the object color illuminated only by the light source 2 is calculated, and the object 3 is drawn using this object color. The same applies to the objects 2 and 4. In this way, the user only has to specify the range for calculating the object color using the light source on the screen for each light source, and thus the burden on the user is reduced.

FIG. 2 is an explanatory diagram of the light source clip volume. Starting from the light source 100 corresponding to the clip volume arranged in the three-dimensional space, a plurality of light source clip surfaces 110-1 to 110-5 defined in the three-dimensional space, which are boundaries of the light source clip volumes in the three-dimensional space, are defined. The three-dimensional vectors that are the end points and are perpendicular to the respective light source clip planes are light source clip vectors 120-1 to 120-6. However, the light source clip plane corresponding to the light source clip vector 120-6 is omitted for convenience of expression in FIG.

Here, the light source clip volume is shown in FIG.
As shown in FIG. 3, it is defined as an area on the three-dimensional space that includes the light source and is surrounded by the light source clipping plane. Further, the number of light source clip surfaces is one or more, and the area surrounded by the plurality of light source clip surfaces becomes a closed space or an open space. Each of the light source clip planes 110-1 to 110-6 can be uniquely determined by the light source 100 and the light source clip vectors 120-1 to 120-6. Below, the light source clipping plane and the light source clipping volume are defined using the formulas.

The light source clip vector i (in the example of FIG. 2,
i is the vector 120-i, i) is a three-dimensional vector (VXi, VYi, VZi) whose length is greater than 0, and the position coordinates of the light source are three-dimensional coordinates (LX, LY, LZ). A formula expressing the clip plane i (i in the example of FIG. 2 is i of 110-i)

[0015]

[Formula 1] VXi · (x- (LX + VXi)) + VYi · (y- (LY + VYi)) + VZi · (z- (LZ + VZi)) = 0 (Formula 1) is defined.

Further, it is assumed that the light source clip volume is a region including a light source, the number of light source clip surfaces is n, and the equation 1 representing the light source clip surface i is used to obtain an expression representing the light source clip volume.

[0017]

[Formula 2] VXi ・ (x- (LX + VXi)) ＋ VYi ・ (y- (LY + VYi)) ＋ VZi ・ (z- (LZ + VZi)) ≦ 0… (Equation 2) n Is defined as a common area of the three-dimensional half space i (i = 1 to n).

An example of the light source clipping process will be described below with reference to the position coordinates and vector (see FIG. 3) on the XY plane of each element forming the three-dimensional CG model of FIG. 1, and the light source clip volume shown in FIG. The table for holding the data for determining the area of and the flow chart showing the procedure of the light source clipping processing of FIG. 5 will be described.

FIG. 3 shows set values in this embodiment for position coordinates and vectors of each element constituting the three-dimensional CG model shown in FIG. 1, and includes the light source 1 clip volume 510-1 and the light source. 2 clip volume 510-2, light source 520-1 (light source 1), and light source 5
20-2 (light source 2), object 540-1 (object 1),
Object 540-2 (object 2), vertex 550-1 which is one of the vertex coordinates of object 1, vertex 550-2 which is one of the vertex coordinates of object 3, and light source 1 clip volume 510
-1 light source clip vector 531-1 for determining the region
~ 534-1 and light source 2 clip volume 510-2
Light source clip vectors 531-2-5 that determine the region of
34-2 and the like. However, although each element forming the three-dimensional CG model in FIG. 1 is defined on the three-dimensional coordinate system, in order to briefly describe the embodiment described here,
In FIG. 3, the straight line along the wall 210 is the Y axis, and the room 2
40-1 and 240-2 X- with the boundary between the ground and the X-axis
It is shown as a view of the Y plane. For the same reason, the illuminated objects are limited to the objects 1 and 3 (the objects 2 and 4 are omitted), and the first vertex 550 is used as a representative to calculate the object color of each illuminated object. Each light source clip volume is an area surrounded by four light source clip surfaces.

FIG. 4 is a table group holding each position coordinate and vector value shown in FIG. 3, and the light source clip vector 53 for determining the area of the light source clip volume 510.
1 to 534, a table 630 holding the position coordinates of the light source 520, and the illuminated object 54.
Table 660 that holds the position coordinates of the vertices that make up 0
It is composed of

FIG. 5 is a flow chart showing a processing procedure when drawing the three-dimensional CG model shown in FIG. 1 using the table group shown in FIG. 4, which is a processing for drawing one illuminated object. Steps 720 to repeat steps 700 and 780 for repeating steps 710 to 770, step 710 to initialize the object color of the object i, and steps 730 to 750 to calculate the object color of the object i when the light source j is illuminated. , 760, and a step 730 of determining whether the object i is included in the light source clip volume of the light source j, and when it is determined by the step 730 that the object i is not completely included in the light source j clip volume, Step 740 of drawing only a part included in the light source clip volume with a figure illuminated by the light source j, and the light source j illuminates the object i. A step 750 of calculating the object color of Rutoki, consisting of steps 770 Metropolitan of drawing an object i in object color calculated in step 720-760.

Next, the processing operation when drawing the object 1 of the three-dimensional CG model shown in FIG. 1 will be described. When drawing the object 1 of FIG. 1, it is determined in step 730 of FIG. 5 whether the first vertex is included in each light source clip volume in order to calculate the color of the first vertex that determines the object color of the object 1. Find out. In step 730, the light source 1 clip vector 610 that determines the region of the clip volume of the light source 1, and
The position coordinates 640 of the light source 1, the table setting values of the position coordinates 670 of the first vertex of the object 1, and the definition formula (Formula 2) of the light source clip volume are used. According to the position coordinate 640 of the light source 1, the coordinate (LX, LY, LZ) of the light source 1 is (-5,7,0), and the vector 610 indicates the clip vector (VX1, VY) of the light source 1.
1, VZ1) to (VX4, VY4, VZ4) are (0,2,0), (0, -6,0), (-4,0,
0), (4,0,0), the half space defined by the light source clip surface 1 to the light source clip surface 4 of the light source 1 is y ≦ 9, y ≧ 1, x ≧ −9, x ≦ −1. Equation 3) Here, the position coordinates (x, y, z) of the first vertex of the object 1
Is (-4,2,0) according to the position coordinate 670, and this satisfies all the inequalities (Equation 3) indicating the four half spaces. Therefore, in step 730, the object 1 is included in the clip volume of the light source 1. It is determined that

Similarly, in this step 730, in order to check whether or not the object 1 is included in the light source clip volume of the light source 2, the light source 2 clip vector 620 for determining the area of the clip volume of the light source 2 and the position coordinate of the light source 2 are determined. 650, the table setting value of the position coordinate 670 of the first vertex of the object 1, and the definition formula (Formula 2) of the light source clip volume are used. In this case, the position coordinate 650 causes the light source 2
The coordinates (LX, LY, LZ) of (5,7,0) are (5,7,0), and the clip vector (VX1, VY1, VZ1) to (VX4,
VY4, VZ4) is (0,2,0), (0, -6,0), (-4,0,0), (4,0,0), so the light source clipping plane 1 of the light source 2 ~ Light source clip surface 4
The half space by is y ≦ 9, y ≧ 1, x ≧ 1, x ≦ 9 (Equation 4). Here, the position coordinates (x, y, z) of the first vertex of the object 1
Is (-4,2,0) according to the position coordinate 670, and this does not satisfy x ≧ 1 in the inequality (Equation 4) indicating the four half spaces, so that it is not included in the clip volume of the light source 2. to decide.

As described above, in steps 710 to 760 of calculating the object color of the object 1, the object color of the object 1 illuminated by only the light source 1 is calculated, and in step 770, the object 1 is displayed on the screen. Draw on top. Object 2,
Similarly for 3 and 4, it is drawn on the screen.

[0025]

According to the present invention, the user does not need to grasp the positional relationship between each light source, each illuminated object, and a light-shielding object (wall) that blocks light, and each light source uses the light source clip volume. The object color is calculated while the computer dynamically determines whether or not to illuminate, so even if the position or shape of the illuminated object changes or the range illuminated by the light source changes, the user's It is possible to generate a three-dimensional CG image without increasing the burden.

[Brief description of drawings]

FIG. 1 is a diagram showing a light source clip volume designated on an image of a three-dimensional CG model according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a light source clip volume.

FIG. 3 is an explanatory diagram showing the three-dimensional CG model shown in FIG. 1 on an XY plane.

FIG. 4 is a table diagram that holds position coordinates and vectors of respective elements that make up the three-dimensional CG model of FIG.

FIG. 5 is a flowchart showing a processing procedure for drawing a three-dimensional CG model using a light source clip volume.

FIG. 6 is a diagram showing an example of a three-dimensional CG model.

FIG. 7 is a diagram showing a table for holding an illumination relationship between a light source and an illuminated object used in the conventional technique.

[Explanation of symbols]

100 ... Light source, 110 ... Light source clipping plane, 120 ... Light source clipping vector, 210 ... Wall, 230 ... Illuminated object, 410 ... Table holding identifier of object illuminated by light source, 600 ... Table holding light source clipping vector, 630 ... A table that holds the position coordinates of the light source, 660 ... A table that holds the position coordinates of the vertices that make up the illuminated object, 730 ... A step for determining whether or not the light source clip volume of the object is included, 750 ... The object color 770, a step of drawing an object.

Claims (6)

[Claims] 1. A three-dimensional CG image generation method for displaying on a screen a three-dimensional CG model consisting of a plurality of light sources arranged in a three-dimensional space and a plurality of illuminated three-dimensional figures. A plurality of light sources characterized in that the range to be illuminated is designated on the screen, and the color of the illuminated three-dimensional figure included in the range is calculated for each range using only the light source corresponding to the range. A method for generating a three-dimensional CG image to be used. 2. The method for generating a three-dimensional CG image using a plurality of light sources according to claim 1, wherein the range is defined as a region surrounded by a plurality of planes at a predetermined distance. 3. The method according to claim 1, wherein for the illuminated three-dimensional figure extending over the boundary of the range, the color of only the portion within the range is calculated using only the light source corresponding to the range. A method for generating a three-dimensional CG image using a plurality of characteristic light sources. 4. A three-dimensional CG image generating apparatus for displaying on a screen a three-dimensional CG model consisting of a plurality of light sources arranged in a three-dimensional space and a plurality of illuminated three-dimensional figures. Light source clip volume designating means for designating the range to be illuminated on the screen, and computing means for calculating the color of the illuminated three-dimensional figure included in the range for each range using only the light source corresponding to the range. An apparatus for generating a three-dimensional CG image using a plurality of light sources, comprising: 5. The apparatus for generating a three-dimensional CG image using a plurality of light sources according to claim 4, further comprising means for defining the range as an area surrounded by a plurality of planes at a predetermined distance. 6. The calculation means according to claim 4, wherein, for the illuminated three-dimensional figure straddling the boundary of the range, only the light source corresponding to the range is used for the color of only the part within the range. An apparatus for generating a three-dimensional CG image using a plurality of light sources, which is characterized in that