JP4018291B2 - Display control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention uses the computer graphics (hereinafter referred to as "CG"), various objects that are specific shape relates Table示制control apparatus you with shading.
Table示制control apparatus of the present invention is applied, for example, in-vehicle navigation device and a driving simulator such as a map display device that is used to, personal computer display apparatus for performing the navigation software, such as in a portable computer display device to perform a walking navigation software can do.
[0002]
[Prior art]
When it is desired to display various objects whose shapes are specified in a three-dimensional manner, it is effective to add a shadow to give a three-dimensional effect. Various methods of shading can be considered. In any of these methods, the angle with the normal vector of the object surface is calculated by assuming a light vector, and the darkness corresponding to this angle is calculated. Add shading.
[0003]
When an object is shaded and displayed as an image, the relative angular relationship between the light source and each surface (hereinafter referred to as “polygon”) constituting the object and the relative angular relationship between the viewpoint and the polygon must be considered separately.
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. That's it.
[0004]
In addition, if the relative angle between the viewpoint and the polygon varies and the relative angle between the light source and the polygon, that is, the angle between the ray vector and the polygon normal vector changes by one frame, the angle calculation is performed. The shading calculation must be done in real time for each frame.
[0005]
[Problems to be solved by the invention]
However, even if the relative angle between the viewpoint and the polygon fluctuates, the angle between the ray vector and the normal vector of the polygon does not fluctuate, or even if fluctuates, the fluctuation time is much longer than one frame of the image. Has a long picture.
For example, in the case of an image in which a landscape is seen while driving, the angular relationship between the landscape and the sun hardly changes even if the position of the line of sight changes.
[0006]
When such an image is displayed, if angle calculation and shading calculation are performed in real time for each frame, a large amount of computer and memory are required, which is extremely inefficient.
Therefore, an image in which the relative angle between the viewpoint and the polygon varies with time, and the image in which the relative angle between the light source and the polygon does not vary with time, or even if it varies, the variation time is longer than one frame of the image. much longer image, when displaying by the shading on the object surface, and the capacity of the memory, the computational burden of calculation is already free Table示制control device with a minimum has been demanded.
[0009]
[Means for Solving the Problems]
(1) The display control apparatus of the present invention includes a shape storage unit that stores the shape of an object, a viewpoint setting unit that sets the direction or position of the viewpoint for each screen update period, and the direction or position of the light source is shaded. Based on the shape of the object stored in the light source setting / updating means and the shape storage means set for each update period, the direction of each surface constituting the object is read, and this direction is set by the light source setting / updating means. A shadow setting means for setting the shadow of each surface based on the direction or position of the light source for each shadow update period of the light source setting / updating means; a shadow storage means for storing the shadow set by the shadow setting means; Screen creation means for creating a screen viewed from the direction or position of the viewpoint set in the viewpoint setting means based on the shadow stored by the storage means, and the shadow update period of the light source setting / update means includes the The value is longer than the screen update cycle by the viewpoint setting means.
[0010]
In this display control apparatus, since the direction or the position of the light source is fluctuated, the shadows that can be produced also fluctuate. The cycle of updating the direction or position of the light source is set longer than the screen update cycle (one frame time). As a result, the shadow can be updated at a period longer than the screen update period, the calculation load of the shadow setting means can be reduced, and the capacity of the shadow storage means can be reduced.
[0011]
The light source setting and updating means may be also of the updating direction or position of the light source at predetermined time intervals. For example, it is effective when the position of the light source varies with time like the sun.
(2) The viewpoint setting means may set the viewpoint direction or position based on the position of the moving body.
[0012]
For example, in the case of an in-vehicle navigation device, the viewpoint direction or position is set based on the driver's eye height or a predetermined height in the sky like a bird's-eye view and the traveling direction of the vehicle at the detected current position of the vehicle. Also good. The user may arbitrarily set the position and direction. The display control device further includes a map data storage unit and a route calculation unit that automatically calculates a route on the map, and the viewpoint setting unit is based on the position of the moving object along the calculated route. but it may also be used to set the direction or position of the viewpoint Te.
[0013]
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 eyes of the driver, or may be a predetermined height in the sky as shown in a bird's-eye view.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiment of the present invention, the “object” is assumed to be a polyhedron, and the “polygon” means each surface constituting the object that is a polyhedron.
-Reference embodiment-
In the embodiment of the present invention, the direction of the light is fixed and the shadow is set off-line.
[0015]
FIG. 1 is a functional block diagram of the shadow setting apparatus. The shadow setting apparatus includes a database 3 that stores light source vectors, a shape database 4 that stores polygon data, a computer 1 that performs shading on polygon data stored in the shape database 4, and a man-machine. And an interface 2 (for example, a combination of a screen and a pointing device such as a keyboard and a mouse).
[0016]
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, DVD-RAM, CD-ROM, MD, hard disk, floppy disk, MO, DAT, etc.
[0017]
The shape data is composed of data of file size, polygon table size, vertex table size, data of the number of polygons constituting the object, data of the number of vertices, polygon data, and vertex data.
The breakdown of polygon data is the number of vertices, color, texture data, α value, and pointer to each vertex for each polygon. Here, the number of vertices is 5, for example, a pentagon. The color may be represented only by brightness, may be represented by RGB values, may be represented by an XYZ color system, a Munsell color system, or may be represented by a color sample number. The texture data is data of surface patterns of polygonal surfaces such as bricks, stone walls, granite, brick walls with windows, stone walls with windows. The α value is a parameter indicating how much weight the upper color is added to the lower color when a polygon is overlaid on the lower polygon. That is, if the weight is α (0 ≦ α ≦ 1), the RGB value of the lower color is (R1, G1, B1), and the RGB value of the upper color is (R2, G2, B2) The final RGB value of
(R, G, B) = α (R2, G2, B2) + (1-α) (R1, G1, B1),
It is expressed. Α = 1 for an opaque color, 0 <α <1 for a translucent color, and α = 0 for a colorless and transparent color.
[0018]
Vertex data is data that determines the position of each vertex.
FIG. 3 is a flowchart showing a process of applying a shading process to each polygon in the polygon data and storing it. First, when the light source vector is fixed (step S1), the computer 1 sequentially processes the 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).
[0019]
FIG. 4 is a flowchart showing details of shading processing for one polygon. First, the normal vector N of the polygon is calculated (step S51), the angle θ formed by both vectors is calculated by taking the inner product with the light source vector d (step S52), and the attenuation rate is calculated according to the angle θ. (Step S53). The formula for calculating this attenuation factor is
I (θ) / I = [(1-cos θ) (1-k)] / 2 + k
It is. Here, I is the maximum brightness, I (θ) is the brightness at the angle θ, k is I (0) when the angle θ formed by both vectors is 0 (when the polygon faces the light source). / I.
[0020]
FIG. 5 is a graph plotting the attenuation rate I (θ) / I with respect to the angle θ when k is 0.75.
The shading process described above is called the Lambert model, but other than this, von shading, Brin shading, smooth shading, etc. can be employed.
[0021]
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 respectively multiplied by an attenuation factor.
Unless R = G = B, the color of the polygon is converted to HSI (hue, saturation, brightness) (step S56), the lightness I is attenuated (step S57), and returned to R, G, B. (Step S58).
[0022]
- First Embodiment -
Here, an embodiment will be described in the case where the light source needs to be moved, such as when simulating the movement of the sun during the day. In this embodiment, it is assumed that a route is set on a road map, such as a drive simulator, and a driver's viewpoint and scenery viewed from the sky are reproduced with CG. However, the present invention is not limited to this. The viewpoint position and direction may be set using a machine interface.
[0023]
Even if the light source is not moved every display cycle, natural light can be realized by calculating the position of the sun and setting the light source vector automatically, for example, every 10 minutes or 1 hour.
FIG. 6 is an overall configuration diagram of the display control apparatus. The display control apparatus includes a viewpoint position database 6 that stores the viewpoint of the driver traveling along the route set by the route setting unit 5 and the position / direction of the sky. A man-machine interface 2, a shape database 4 storing polygon data, a computer 1 for shading the polygon data stored in the shape database 4, a display device 8, and a clock 7 I have.
[0024]
As shown in FIG. 6, the computer 1 includes a viewpoint position setting unit 11 that sets a viewpoint position based on data stored in the viewpoint position database 6 or data set by the man-machine interface 2, and a shadow update cycle. It has a 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.
[0025]
The shadow update cycle monitoring unit 15 monitors the cycle (for example, 1 hour) of updating the light source vector. The display cycle monitoring unit 16 monitors a cycle (for example, 1/30 second) for updating the viewpoint position.
FIG. 7 is a flowchart illustrating the shading process of the computer 1 described above.
[0026]
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 acquired from the clock 7 (step T3), and when the display update time comes (step T4), the viewpoint position is updated (step T5). . Then, the display target polygon is read (step T6), and known three-dimensional computer graphics processing such as rotation, enlargement / reduction, and parallel movement is performed on the display target polygon (for example, Japanese Patent Laid-Open No. 6-83937 and Japanese Patent Laid-Open No. No. 5-203457), and CG creation / display is performed (step T13).
[0027]
When the shadow update cycle comes (Yes in step T7), the computer 1 updates the light source vector from the viewpoint position and the clock (step T8), and processes the polygons in order (step T9). A polygon color is read from the polygon table (step T11), and shading processing is performed (step T12). Then, CG creation / display is performed on the display target polygon (step T13).
[0028]
As described above, CG creation / display is performed every time the display update time comes, and the light source vector is updated every shadow update cycle longer than the display update cycle.
- Second Embodiment -
In this embodiment, it is assumed that the scenery seen is reproduced with CG when the viewpoint of the driver or the viewpoint from the sky actually moves, such as an in-vehicle navigation device.
[0029]
FIG. 8 is an overall configuration diagram. The in-vehicle navigation device 21 stores a position detection unit 19 that detects the position of a vehicle based on signals from a sensor 17 such as a vehicle speedometer and a gyro, and map data including polygon data. Map database 20, route calculation unit 18, shadow update cycle monitoring unit 15, light source vector setting unit 12, and polygon shading unit 13 that shades polygon data stored in map database 20. And a display cycle monitoring unit 16 and a CG creation / display unit 14. Further, a display device 8 and a clock 7 are attached.
[0030]
The route calculation unit 18 reads link data for route calculation from the map database 20 based on the current vehicle position data calculated by the position detection unit 19, and calculates the shortest route from the current position to the destination. The obtained shortest route is sent to the CG creation / display unit 14 (see, for example, Japanese Patent Application Laid-Open No. 58-2223017 for a route calculation method).
[0031]
The in-vehicle navigation device 21 may further include a GPS receiver (not shown) that receives a signal from a GPS satellite and detects an absolute position and direction, and includes a beacon antenna, a leaky coaxial cable, and FM multiplex broadcasting. A receiver (not shown) that receives data such as location information, road information, and facility information (congestion information, accident information, intersection name, destination guidance) transmitted from aircraft, communication satellites, broadcast satellites, mobile phones, car phones, etc. May be provided.
[0032]
Further, the position detector 19 is based on a comparison between the position data of the vehicle and the road pattern stored in the map database 20 (so-called map matching method; see, for example, JP-A-61-56910). 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 that 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.
[0033]
The road map data is composed of combination data of nodes representing intersections or turning points of roads (express highway national highways, automobile exclusive roads, general national highways, prefectural roads, etc.) and links (representing roads) connecting the nodes. .
Here, the “node” is a coordinate position for specifying an intersection or a turning point on the road. A node representing the intersection is referred to as an intersection node, and a node representing a bending point other than the intersection is referred to as an interpolation point node. A line with direction connecting each node is a link, and link data includes a link number, a pointer to a node constituting the link, a link length, a link direction, a travel time in that direction, and a road such as a national road. Contains type data.
[0034]
Polygon data is data for specifying a three-dimensional shape of a facility. Basically, as shown in FIG. 2, data such as color, texture data, and α value are stored in the form of a polygon table. Yes. In addition to those shown in FIG. 2, the identification number of each facility and the attribute number (eg, private house, office building, park, school, etc.) of each facility may be added to the data.
[0035]
The vertex data is stored as relative coordinates of the vertices in the map mesh. Here, “relative coordinates” refers to coordinates measured from the end of the mesh.
The operation of the in-vehicle navigation device 21 will be described with reference to FIG. 7, but is basically the same as that described with reference to the flowchart of FIG. However, the point of view and the direction in which the map is viewed are different in that they are input from the position detector 19 as the vehicle travels.
[0036]
That is, when the display update time comes, the display target polygon is read based on the viewpoint position at that time, and CG creation / display from the viewpoint of the driver or the sky is performed on the display target polygon.
When the shadow update cycle arrives, the light source vector is updated from the viewpoint position and the clock, and the polygon is shaded to create a three-dimensional landscape map.
[0037]
9 and 10 show display examples of the created landscape map.
FIG. 9 is a landscape view showing a 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), but when turning around an intersection, the direction of the shade apparently changes as the vehicle rotates (see FIG. 10). However, if it is assumed that the shadow update period has not elapsed before and after turning at the intersection, the direction of the shadow viewed with respect to the sun and the ground is unchanged.
[0038]
If the shadow update cycle elapses, the position of the sun changes, so the direction of the shadow changes. FIG. 11 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, and 33 are shaded on a new polygonal surface as compared with FIG.
The shadow update period does not have to be every fixed time, and the length thereof may be changed according to time or time zone. FIG. 12 shows an example in which the shadow update periods t0, t1, t2, t3,. In this example, the shadow 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.
[0039]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.
[0041]
【The invention's effect】
As described above, according to the first aspect of the present invention, even when the relative angle between the light source and the object fluctuates with time, the screen is updated when the fluctuation time is much longer than one frame of the image. The shadow can be updated at a period longer than the period, 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 third or fourth aspect of the present invention, it is most suitable for in-vehicle navigation and a driving simulation apparatus.
[Brief description of the drawings]
FIG. 1 is a block diagram of a display control apparatus according to a reference embodiment.
FIG. 2 is a diagram showing a storage form of shape data.
FIG. 3 is a flowchart showing a process of performing a shading process on each polygon in polygon data and storing it.
FIG. 4 is a flowchart showing details of shading processing.
FIG. 5 is a graph plotting attenuation rate I (θ) / I with respect to angle θ when k is 0.75.
FIG. 6 is a block diagram of a display control apparatus according to an embodiment of the first 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 apparatus according to an embodiment of the second invention.
FIG. 9 is a diagram showing a display example of a landscape map created by the display control process 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 created by the display control process of the present invention and having different time zones.
FIG. 12 is a graph showing an example in which a shadow update period is changed according to a time zone.
[Explanation of symbols]
1 Computer It is a figure which shows the example of a display of the landscape map produced by the display control process of this invention.
2 Man-machine interface 3 Database 4 Shape database 5 Path setting unit 6 View position database 7 Clock 8 Display device 11 View position setting unit 12 Light source vector setting unit 13 Polygon shading unit 14 CG creation / display unit 15 Shadow update cycle monitoring unit 16 Display cycle monitoring unit 18 Route calculation unit 19 Position detection unit 20 Map database 21 Car-mounted navigation device

Claims (4)

A display control device that shades and displays various objects whose shapes are specified using computer graphics,
Shape storage means for storing the shape of the object, viewpoint setting means for setting the direction or position of the viewpoint for each screen update cycle, and light source setting / updating means for setting the direction or position of the light source for each shadow update cycle The direction of each surface constituting the object is read based on the shape of the object stored in the shape storage unit, and each surface is determined based on this direction and the direction or position of the light source set by the light source setting / updating unit. Based on the shadow stored by the shadow storage means, a shadow storage means for storing the shadow set by the shadow setting means, a shadow storage means for setting the shadow of the light source for each shadow update period of the light source setting / update means , Screen creation means for creating a screen viewed from the direction or position of the viewpoint set in the viewpoint setting means,
The display control apparatus according to claim 1, wherein a shadow update period of the light source setting / updating means is longer than a screen update period of the viewpoint setting means.   The display control device according to claim 1, wherein the light source setting / updating unit updates a direction or a position of the light source at regular intervals.   The display control apparatus according to claim 1, wherein the viewpoint setting unit sets a viewpoint direction or position based on a position of a moving body.   Map data storage means and route calculation means for automatically calculating a route on the map, wherein the viewpoint setting means is based on the position or position of the viewpoint based on the position of the moving object along the calculated route. The display control device according to claim 3, wherein the display control device is set.

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