JP2000285254A - Shade setting device and display control device - Google Patents

Abstract

(57) [Summary] An image in which the relative angle between a viewpoint and an object fluctuates with time, and in which the relative angle between a light source and an object does not fluctuate with time, is shaded on the object plane. When displaying, the memory capacity is saved and the computational burden on the computer is reduced. When the direction or position of a light source is fixed with respect to an object, the direction of each surface constituting the object is read from a shape database, and each surface is read based on this direction and the direction or position of the light source. , And stored in the shape database 4. [Effect] There is no need to perform shading calculation in real time for each frame, and shading can be set efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shading setting device and a display control device for shading various objects having a specified shape using computer graphics (hereinafter referred to as "CG"). The shade setting device and the display control device of the present invention are, for example, a map display device used for an in-vehicle navigation device or a driving simulator, a personal computer display device executing navigation software, and a mobile personal computer display device executing walking navigation software. And so on.

[0002]

2. Description of the Related Art When it is desired to three-dimensionally display various objects having a specified shape, shading is effective to give a three-dimensional effect. Various shading methods are conceivable, but in any case, the angle with the normal vector of the object plane is calculated assuming the vector of the light ray, and the density corresponding to this angle is calculated. Add shading.

In the case where an object is shaded and displayed as an image, the relative angle relationship between the light source and each surface (hereinafter, referred to as a "polygon") constituting the object and the relative angle relationship between the viewpoint and the polygon must be considered separately. No. If the relative angle between the viewpoint and the polygon is fixed and the relative angle between the light source and the polygon, that is, the angle between the ray vector and the normal vector of the polygon does not change, the shading calculation is performed once. You just need to.

In an image in which the relative angle between the viewpoint and the polygon fluctuates, the relative angle between the light source and the polygon, that is, the angle between the ray vector and the normal vector of the polygon is 1
For images that change frame by frame, the angle calculation and the shading calculation must be performed in real time for each frame.

[0005]

However, even for an image in which the relative angle between the viewpoint and the polygon fluctuates, an image in which the angle between the ray vector and the normal vector of the polygon does not fluctuate, or even when the image fluctuates, the angle fluctuates. There are images whose time is much longer than one frame of the image. For example, in the case of an image in which the scenery is viewed while driving, the angular relationship between the scenery and the sun hardly changes even if the position direction of the line of sight changes.

In the case of displaying such an image, if the angle calculation and the shading calculation are performed in real time for each frame, a large capacity of a computer and a memory is required, which is extremely inefficient. Therefore, an image in which the relative angle between the viewpoint and the polygon fluctuates with time, and the image in which the relative angle between the light source and the polygon does not fluctuate with time, or even if it fluctuates, the fluctuation time is longer than one frame of the image. When displaying a much longer image with shading on an object surface, a shading setting device and a display control device that requires a minimum amount of memory and a small computational load on a computer have been required.

[0007]

Means for Solving the Problems (1) A shadow setting device according to the present invention comprises: shape storage means for storing the shape of an object; viewpoint setting means for setting the direction or position of a viewpoint; Light source fixing means for fixing the position to the object, and the direction of each surface constituting the object is read based on the shape of the object stored in the shape storage means, and the direction and the light source fixed by the light source fixing means And a shadow storage means for storing the shadow set by the shadow setting means (claim 1).

In this shadow setting device, since the direction or position of the light source is fixed with respect to the object, the way of shading does not change even if the direction or position of the viewpoint changes.
Therefore, the shading of each surface does not change,
It is stored in the shadow storage means. Therefore, the angle calculation,
There is no need to perform shading calculations in real time for each frame, and shading can be set efficiently.

Then, based on the shadows stored by the shadow storage means, a screen viewed from the direction or position of the viewpoint can be created. (2) The display control device of the present invention includes a shape storage unit that stores the shape of the object, a viewpoint setting unit that sets the direction or position of the viewpoint, and a light source setting that sets or updates the direction or position of the light source. Update means, based on the shape of the object stored in the shape storage means, read the direction of each surface constituting the object, this direction and the direction of the light source set or updated by the light source setting / update means or A shadow setting unit that sets a shadow of each surface based on the position, a shadow storage unit that stores the shadow set by the shadow setting unit, and a viewpoint setting unit that is set based on the shadow stored by the shadow storage unit. Screen creation means for creating a screen viewed from the direction or position of the viewpoint, wherein an update cycle of the light source setting / update means is longer than an update cycle of the screen.

[0010] In this display control device, since the direction or position of the light source is presumed to fluctuate, the resulting shadow also fluctuates. The cycle of updating the direction or position of the light source is set longer than the cycle of updating the screen (time of one frame).
As a result, the shadow can be updated in a cycle longer than the screen update cycle, so that the calculation load of the shadow setting unit can be reduced and the capacity of the shadow storage unit can be reduced.

[0011] The light source setting / updating means may update the direction or position of the light source at fixed time intervals. For example, this is effective when the position of the light source fluctuates with time like the sun. (3) The viewpoint setting means may set a direction or a position of the viewpoint based on a position of the moving body (claim 4).

For example, in the case of an in-vehicle navigation device, the direction or position of the viewpoint is determined by the height of the driver's eyes or a predetermined height in the sky as in a bird's eye view and the traveling direction of the vehicle at the detected current position of the vehicle. May be set. The user may arbitrarily set the position and the direction.
The display control device further includes map data storage means, and route calculation means for automatically calculating a route on the map,
The viewpoint setting means may set a direction or a position of the viewpoint based on the calculated position of the moving body along the route (claim 5).

According to the present invention, the viewpoint is set at a predetermined height and direction along the optimum route. A landscape map along the optimal route can be created. Here, the “predetermined height” may be, for example, the height of the driver's eyes or a predetermined height in the sky as in a bird's eye view.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the embodiments of the present invention, an “object” is assumed to be a polyhedron, and a “polygon” refers to each surface constituting an object that is a polyhedron. -First Embodiment- In an embodiment of the present invention, a shadow is set offline by fixing the direction of a light beam.

FIG. 1 is a functional block diagram of the shadow setting device. The shading setting device includes a database 3 storing light source vectors, a shape database 4 storing polygon data, and a computer 1 for shading polygon data stored in the shape database 4.
And a man-machine interface 2 (for example, a combination of a screen and a pointing device such as a keyboard and a mouse).

The computer 1 has a light source vector setting unit 12 and a polygon shading unit 13. The shape data is data for specifying the shape of each object, and is stored in a form as shown in FIG.
The storage medium may be anything, for example, DVD-ROM, D
VD-RAM, CD-ROM, MD, hard disk,
Floppy disk, MO, DAT and the like.

The shape data includes file size, polygon table size, vertex table size data, data on the number of polygons constituting the object, data on the number of vertices,
It is composed of polygon data and vertex data. The details of the polygon data are, for each polygon, the number of vertices, color, texture data, α value, and pointer to each vertex. Here, the number of vertices is 5, for example, for a pentagon. The color may be represented only by lightness, RGB
It may be represented by a value, an XYZ color system, a Munsell color system, or a color sample number. The texture data is data of a surface pattern of a polygon surface such as a brick, a stone wall, a granite, a brick wall with a window, and a stone wall with a window. The α value is a parameter indicating what weight is applied to the upper color with respect to the lower color when a polygon is overlaid on the lower polygon. That is, the weight is α
(0 ≦ α ≦ 1), and the RGB values of the lower color are (R1, G1,
B1), the RGB value of the upper color is written as (R2, G2, B2), and the RGB value of the final color of the painted portion is (R, G, B) = α (R2, G2, B2) ) + (1-α)
(R1, G1, B1). Α = 1 for an opaque color, 0 <α <1 for a translucent color, and α = 0 for a colorless and transparent color.

The vertex data is data for determining the position of each vertex. FIG. 3 is a flowchart showing a process of performing shading processing and saving each polygon in the polygon data. First, when the light source vector is fixed,
(Step S1), the computer 1 sequentially processes polygons (Step S2). The polygon color is read from the polygon table (step S4), and shading processing is performed (step S5). After the processing, the polygon color is stored (step S6), and this processing is repeated for all the polygons.
(Step S3).

FIG. 4 is a flowchart showing details of the shading process for one polygon. First, a normal vector N of the polygon is calculated (step S51), and an inner product of the polygon and the light source vector d is calculated to calculate an angle θ between the two vectors (step S52), and an attenuation rate is calculated according to the angle θ. (Step S53). The formula for calculating this attenuation rate is I (θ) / I = [(1−cos θ) (1−k)] / 2 + k. Here, I is the maximum lightness, I (θ) is the lightness at the angle θ, and k is I (0) when the angle θ formed by both vectors is 0 (when the polygon is directly behind the light source).
/ I.

Attenuation rate I (θ) / I when k is 0.75
FIG. 5 is a graph in which is plotted against the angle θ. The above-described shading processing is called a Lambert model, but other than this, von shading, bling shading, smooth shading, and the like can be adopted.

In S54, it is determined whether R = G = B. If R = G = B, it means an achromatic color, and the process proceeds to step S5, where R, G, and B are multiplied by the respective attenuation rates. If R = G = B, the color of the polygon is HS
I is converted into I (hue, saturation, lightness) (step S56), the lightness I is multiplied by an attenuation rate (step S57), and the values are returned to R, G, B (step S58).

Second Embodiment Here, an embodiment in which the light source needs to be moved, such as when simulating the movement of the sun in a day, will be described. In this embodiment, it is assumed that a route is set on a road map such as a drive simulator, and a scene viewed from the driver's viewpoint or the sky is reproduced by CG. However, the present invention is not limited to this. The viewpoint position and direction may be set using a machine interface.

Even if the light source is not moved every display cycle,
For example, natural light can be realized by calculating the position of the sun every 10 minutes or 1 hour and automatically setting the light source vector. FIG. 6 is an overall configuration diagram of the display control device. The display control device includes a viewpoint position database 6 that stores a viewpoint and a position / direction of a driver traveling along the route set by the route setting unit 5. , A man-machine interface 2, a shape database 4 storing polygon data, and a computer 1 for shading the polygon data stored in the shape database 4
And a display device 8 and a clock 7.

As shown in FIG. 6, the computer 1 includes a viewpoint position setting unit 11 for setting a viewpoint position based on data stored in the viewpoint position database 6 or data set on the man-machine interface 2. It has a shading update cycle monitoring unit 15, a light source vector setting unit 12, a polygon shading unit 13, a display cycle monitoring unit 16, and a CG creation / display unit 14.

The shade update cycle monitor 15 monitors a cycle (for example, one hour) for updating the light source vector. The display cycle monitoring unit 16 updates the cycle of updating the viewpoint position (for example, 1/3
0 seconds). FIG. 7 is a flowchart illustrating the shading processing of the computer 1 described above.

A description will be given with reference to FIG. First, when the initial position and direction of the viewpoint are set (step T1), the time is obtained from the clock 7 (step T3). When the display update time comes (step T4), the viewpoint position is updated (step T4).
5). Then, the display target polygon is read (step T6), and the display target polygon is rotated, enlarged,
A known CG process such as reduction and translation is performed (for example, see JP-A-6-83937 and JP-A-5-203457) to create a CG.
Display is performed (step T13).

When the shadow update cycle comes (y in step T7)
es), the computer 1 updates the light source vector from the viewpoint position and the clock (step T8), and sequentially processes the polygons (step T9). The polygon color is read from the polygon table (step T11), and shading processing is performed (step T12). Then, a CG is created and displayed for the display target polygon (step T13).

Thus, every time the display update time comes,
CG creation and display are performed, and the feature is that the light source vector is updated in each shadow update cycle longer than the display update cycle. -Third Embodiment-In this embodiment, it is assumed that when a driver's viewpoint or a viewpoint from the sky actually moves, such as a vehicle-mounted navigation device, the viewed scene is reproduced by CG.

FIG. 8 is an overall configuration diagram. The on-vehicle navigation device 21 is a position detecting section 1 for detecting the position of the vehicle based on a signal from a sensor 17 such as a speedometer or a gyro.
9, a map database 20 storing map data including polygon data, a route calculation unit 18, a shadow update cycle monitoring unit 15, a light source vector setting unit 12, and polygon data stored in the map database 20. , A polygon shading unit 13 for shading, a display cycle monitoring unit 16, and a CG creation / display unit 14.
Further, a display device 8 and a clock 7 are attached.

The route calculation unit 18 reads link data for route calculation from the map database 20 based on the current position data of the vehicle calculated by the position detection unit 19, and calculates the shortest route from the current position to the destination. Do the calculation,
The obtained shortest route is sent to the CG creation / display unit 14 (for a route calculation method, see, for example,
No. 3017).

The in-vehicle navigation device 21 further includes:
A GPS receiver (not shown) for receiving a signal from a GPS satellite and detecting an absolute position and an azimuth may be provided.
Beacon antennas, leaky coaxial cables, FM multiplex broadcasters, communication satellites, broadcast satellites, mobile phones, car phones, location information and road information, facility information (traffic jam information, accident information, intersection names, destination guidance), etc. May be provided with a receiver (not shown) for receiving the data of FIG.

The position detector 19 compares the vehicle position data with the road pattern stored in the map database 20 (so-called map matching method; see, for example, Japanese Patent Application Laid-Open No. 61-56910). Based on this, a function of detecting a road and a vehicle position on the road in consideration of the existence probability of the vehicle may be provided. The map data is stored in units of meshes, which are rectangles or squares obtained by dividing the map at a certain latitude and longitude. The map data includes road map data and polygon data.

The road map data is a combination of nodes representing intersections or bends of roads (highway expressways, motorways, general national roads, prefectural roads, etc.) and links (representing roads) connecting the nodes. Consists of data. Here, the “node” is a coordinate position for specifying a road intersection or a bending point. A node representing an intersection is called an intersection node, and a node representing a bending point other than an intersection is called an interpolation point node. A line segment with a direction connecting each node is a link, and the link data includes a link number, a pointer to a node constituting the link, a link length, a link direction, a required traveling time in that direction, and a road such as a national road. Includes type data.

The polygon data is data for specifying the three-dimensional shape of the facility, etc. Basically, as shown in FIG. 2, data such as color, texture data, α value, etc.
It is stored in the form of a polygon table. In addition to the data shown in FIG. 2, an identification number of each facility and an attribute number of each facility (eg, a private house, an office building, a park, a school, etc.) may be added to the data.

The vertex data is stored as the relative coordinates of the vertices in the map mesh. Here, “relative coordinates” refer to coordinates measured from the edge of the mesh. The operation of the in-vehicle navigation device 21 described above will be described, but is basically the same as that described using the flowchart of FIG. The difference is that the viewpoint position and the direction of viewing the map are input from the position detection unit 19 as the vehicle travels.

That is, when the display update time comes, a display target polygon is read based on the viewpoint position at that time, and CG creation / display from the driver's viewpoint or the sky is performed on the display target polygon. When the shade update cycle comes,
The light source vector is updated from the viewpoint position and the clock, shading processing is performed on the polygon, and a three-dimensional landscape map is created.

FIGS. 9 and 10 show display examples of the created landscape map. FIG. 9 is a landscape view showing the screen before turning left at the intersection along the route 34, and FIG. 10 is a landscape view immediately after turning left at the intersection. The buildings 31, 32, and 33 are shaded by the sun 35 (see FIG. 9).
However, when the vehicle turns around the intersection, the direction of the shadow changes apparently as the vehicle rotates (see FIG. 10). However, assuming that the shadow update cycle has not elapsed before and after turning at the intersection, the direction of the shadow as viewed with respect to the sun and the earth is unchanged.

It should be noted that, after the elapse of the shadow update cycle, the position of the sun changes, so that the direction of the shadow changes. FIG.
It shows a landscape view when the position of the sun is further lowered. The position of the sun is indicated by 35a and the buildings 31, 32, 3
In FIG. 3, a shadow is added to a new polygon surface as compared with FIG. The shading update cycle does not need to be at regular time intervals, but may be changed in length depending on time or time zone. FIG. 12 shows a shadow update cycle t0, t1, t
An example in which 2, t3, ‥‥ is changed according to the time zone is shown. In this example, the shading is not updated from 18:00 to 6:00. This is because the shadow does not change at night even if the position of the sun changes.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.
Various changes can be made within the scope of the present invention.

[0040]

As described above, according to the first aspect of the present invention, an image in which the relative angle between the viewpoint and the object fluctuates with time, the relative angle between the light source and the object fluctuates with time. Since the object plane of the image not to be displayed can be displayed offline with a three-dimensional effect, the memory capacity can be saved and the computational burden on the computer can be minimized.

According to the second aspect of the present invention, even if the relative angle between the light source and the object fluctuates with time, if the fluctuation time is much longer than one frame of the image, the screen update cycle The shadow can be updated in a longer cycle, so that the calculation load of the shadow setting means can be reduced and the capacity of the shadow storage means can be reduced. According to the present invention described in claim 4 or claim 5, the present invention is most suitable for in-vehicle navigation and a driving simulation device.

[Brief description of the drawings]

FIG. 1 is a block diagram of a display control device according to an embodiment of the first invention.

FIG. 2 is a diagram showing a storage form of shape data.

FIG. 3 is a flowchart showing a process of applying a shading process to each polygon in polygon data and storing the result;

FIG. 4 is a flowchart illustrating details of shading processing.

FIG. 5 is a graph in which an attenuation rate I (θ) / I when k is 0.75 is plotted with respect to an angle θ.

FIG. 6 is a block diagram of a display control device according to an embodiment of the second invention.

FIG. 7 is a flowchart for explaining shading and display control processing of the computer 1;

FIG. 8 is a block diagram of a display control device according to an embodiment of the third invention.

FIG. 9 is a diagram showing a display example of a landscape map created by the display control processing of the present invention.

FIG. 10 is a diagram showing a display example of a landscape map created by the display control process of the present invention.

FIG. 11 is a diagram showing a display example of a landscape map with different time zones created by the display control process of the present invention.

FIG. 12 is a graph showing an example in which a shadow update cycle is changed according to a time zone.

[Explanation of symbols]

FIG. 1 is a diagram illustrating a display example of a landscape map created by the display control process of the present invention. 2 Man-machine interface 3 Database 4 Shape database 5 Route setting unit 6 Viewpoint position database 7 Clock 8 Display device 11 Viewpoint position setting unit 12 Light source vector setting unit 13 Polygon shading unit 14 CG creation / display unit 15 Shading update cycle monitoring unit 16 Display cycle monitoring unit 18 Route calculation unit 19 Position detection unit 20 Map database 21 In-vehicle navigation device

Claims (5)

[Claims] 1. A shading setting device for shading and displaying various objects whose shapes are specified by using computer graphics, comprising: shape storage means for storing the shapes of the objects; Viewpoint setting means for setting the direction or position of the viewpoint; light source fixing means for fixing the direction or position of the light source to the object; and each surface constituting the object based on the shape of the object stored in the shape storage means And a shade setting means for setting the shade of each surface based on the direction and the direction or position of the light source fixed by the light source fixing means, and a shading storage means for storing the shading set by the shading setting means. And a shadow setting device. 2. A display control apparatus for shading and displaying various objects having a specified shape using computer graphics, comprising: shape storage means for storing the shape of the object; Viewpoint setting means for setting the direction or position; light source setting / updating means for setting or updating the direction or position of the light source; and, based on the shape of the object stored in the shape storage means, A direction is read, a shadow setting means for setting a shadow of each surface based on the direction and the direction or position of the light source set or updated by the light source setting / update means, and a shadow set by the shadow setting means are stored. And a screen creating means for creating a screen viewed from the direction or position of the viewpoint set by the viewpoint setting means based on the shadow stored by the shadow storing means. A display control device, wherein an update cycle of the light source setting / updating means is longer than a screen update cycle. 3. The display control device according to claim 2, wherein said light source setting / updating means updates the direction or position of the light source at predetermined time intervals. 4. The viewpoint setting means sets a direction or a position of a viewpoint based on a position of a moving body.
Display control device. 5. A map data storage means, and a route calculation means for automatically calculating a route on a map, wherein the viewpoint setting means is based on the calculated position of the moving body on the route. The display control device according to claim 4, wherein the direction or the position of the viewpoint is set.