JP5089147B2 - Camera control method and CG game apparatus incorporating the camera control - Google Patents

Description

  The present invention relates to a camera control method capable of performing camera control for obtaining a line of sight according to terrain by control of a third-person camera in a CG (computer graphic) game, and a CG game apparatus incorporating the camera control. Here, the “third-person camera” is defined as a camera that is arranged in a predetermined positional relationship with respect to an arbitrary character appearing on the screen and captures a field of view including the character and displays it as a screen.

There has been proposed a game apparatus that controls a camera position that changes a third-person camera position with respect to a main character in a CG game or the like.
As one of them, a three-dimensional game device that controls the axis of a camera in accordance with the moving speed of a character is disclosed (Patent Document 1).
In this case, when a moving body is moved based on operation information in a three-dimensional game apparatus, a virtual camera is set at a position to follow and a view image viewed from the virtual camera is synthesized. The viewpoint setting unit of the camera uses at least one axis component in the X, Y, and Z directions with respect to the moving object as the viewpoint movement control direction, and uses the velocity component of the moving object in the viewpoint movement control direction as a control function. The movement of the viewpoint position is controlled.

In general camera control, for example, when going down a downhill, it is necessary to make the camera look a little lower than usual so that the camera control in Patent Document 1 can go down the hill. Since the camera moves downward, the camera axis can be directed downward. However, since there is no movement in the vertical direction until it starts to descend, the camera does not face downward. Although it is necessary to point the camera down at the point where it approaches the downhill slope, such control is not possible.
For example, when moving the camera position in the Z-axis direction following an auto-race bike, when the bike changes its speed in the horizontal direction (X-axis direction) by ΔX, the camera viewpoint position moves in the X-axis direction. The bike is moved in the direction of speed change from the center of the screen and displayed. In addition, when the speed is changed by ΔY in the upward direction (Y-axis direction) by jumping or the like, the camera viewpoint position is moved in the Y-axis direction and the motorcycle is moved upward from the center of the screen for display. However, as described above, it does not change the rotation of the pitch axis of the camera with respect to uphill or downhill.

Further, a method for changing the camera position according to the distance from the target to which the camera is directed is disclosed (Patent Document 2).
This is for the purpose of improving the visibility related to the positional relationship between the player character and other characters, and the line-of-sight direction is controlled so as to face an intermediate position between the player character PC and the target character TC, Control is performed so that the depression angle of the virtual camera increases as the line difference from the character TC increases.
The depression angle of the camera is controlled in accordance with the distance between the player character PC and the target character, but the player character PC and the target character are displayed on the screen so as to enter the screen well, and the character is related to the background image. It does not optimize the field of view to be advanced.
Japanese Patent Laid-Open No. 11-146978 JP 2006-87600 A

  Usually, since the player operates the main character appearing in the game to control movement in the background screen, it is required that the player can clearly display the distance to which the main character should travel.

  The present invention responds to the above request, and the purpose of the present invention is to obtain an angle position of the camera in accordance with the terrain of the screen, and to make it easy to see the feet on a composition that looks far away on uphill terrain, downhill, cliff, etc. It is an object of the present invention to provide a camera control method for controlling a shooting screen of a camera in a composition and a CG game apparatus incorporating the camera control.

Claim 1 of the present invention in order to achieve the object, relative to the character to move the screen, the CG screen control method for displaying the previous SL image obtained by photographing a character on the monitor screen, the position of the character from the operation unit If the operation of moving is made to move the character to a position corresponding to the operation amount, corresponding to the movement position of the character to set the camera to be placed additionally follow, connecting the camera installation position and character It is determined whether or not a line segment tip of a predetermined distance from the character intersects the terrain surface displayed on the screen, and if it does not intersect in the determination, the line segment tip is The position and optical axis of the camera are controlled to move and rotate with respect to the character so that the position substantially coincides with the terrain surface displayed on the screen .
Claim 2 of the present invention, the intersecting determined whether in the invention according to the first aspect is carried out at predetermined time intervals, to rotate the optical axis of a predetermined angle in a direction crossing if disjoint camera, This operation is repeated until the position substantially coincides with the topographic surface.
According to a third aspect of the present invention, in the second aspect of the present invention, the rotation control of the camera is repeated by the predetermined angle , and when the front end of the line segment intersects the topographic surface, the camera is returned to the rotation position before the intersection. Features.
Claim 4 of the present invention, to the character to move the screen, in the CG game device for displaying the previous SL image obtained by photographing a character on the monitor screen, and character moving means for moving the character in accordance with operation of the operation unit, Camera position setting means for capturing the character in the field of view according to the movement of the character, and an extended line segment connecting the camera position and the character, and a line segment tip at a predetermined distance from the character is displayed on the screen It is determined whether or not to intersect with the terrain surface, and if it does not intersect with the determination, the position and optical axis of the camera so that the tip of the line segment is substantially coincident with the terrain surface displayed on the screen. the and control means for controlling movement and rotation relative to the character, in response to changes in the movement and terrain of the character, view from the camera And displaying the empty part and terrain portion while including the character on the screen at a predetermined ratio.
According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the control means determines whether or not to intersect at a predetermined time interval, and if not intersects , the optical axis of the camera by a predetermined angle in the intersecting direction. , And this operation is repeated until the position substantially coincides with the terrain surface.
According to a sixth aspect of the present invention, in the invention according to the fifth aspect, the control means repeats the rotation control of the camera by a predetermined angle , and when the tip of the line segment intersects the topographic surface, the rotational position of the camera before the intersection It is characterized by returning to.

According to the above configuration, the terrain surface and the tip of the line of sight are hit-checked (check whether the tip at a predetermined distance on the extension line from the character intersects the terrain surface) and the camera angle (pitch angle) is determined. Since it is controlled, the camera angle can be obtained according to the terrain. For this reason, it is possible to see the field of view including the ground instead of the sky on the uphill, and the terrain display on the downhill, cliff, etc. makes it easier to see the feet.

First, a method for applying the camera control method according to the present invention will be described.
In the present invention a determination is made as to whether or intersects the position and the surface of such ground distance L from the player that an extension passing through the player from the camera position, when the intersect changing the angle of the camera to view on However, if it does not intersect, the angle is changed so as to lower the angle, but the hit check whether or not it intersects uses the following method.

1) First, input data is defined as follows.
The position information of the start point and end point of the straight line is (x, y, z) VECTOR start, end.
Let the array of face (triangles based on 3 vertex information) information be (x, y, z) VECTOR vertex [].
Here, VECTOR means a variable type having elements (x, y, z).
In the following, float means a general floating point type variable type.
vertex [] means an array of VECTOR type variables.
The reason why the surface is triangular according to the above definition is that generally the triangle has hit data in many cases. If it is a quadrangle, a curved surface may be formed, which may cause inconvenience.

2) Surface normal data is created from surface vertex information to obtain surface equations.
The equation of the surface is ax + by + cz + d = 0 (1).
Next, a vector of two lines constituting the surface is obtained from the vertex data of the surface.
VECTOR vec1 = vertex [1]-vertex [0] (2)
VECTOR vec2 = vertex [2]-vertex [0] (3)
Furthermore, normal data normal is obtained using the outer product.
VECTOR normal = vec1X vec2 (4)
The normal x, y, z in equation (4) corresponds to a, b, c in equation (1). X means outer product calculation. d is a constant.
Next, find d from the surface equation.
Since d =-(ax + by + cz) from equation (1),
d =-(vertex [0] .x * normal.x + vertex [0] .y * normal.y + vertex [0] .z * normal.z) (5)

3) From the straight line equation, find the intersection of the surface and straight line obtained in 2).
Since the straight line is represented by the initial position, the direction vector (vec), and the parameter (t), the parameter (t) where the surface and the line intersect is first obtained.
For this purpose, the value float q obtained by substituting each element (x, y, z) of the input data start into the x, y, z of the surface equation (1) is used as the vector VECTOR a of end-start. Divide by the result of the inner product of normal data normal in equation (4).
Substituting start.x, start.y, start.z and normal.x, normal.y, normal.z into equation (1)
float q = (start.x * normal.x + start.y * normal.y + start.z * normal.z + d) (6)
VECTOR a = (end-start) (7)
end-the inner product float b of the start vector and normal data normal
float b = a (normal) (8)
Therefore, the parameter (t) is
float t = q / b (9)
Note that (end-start) is a vector subtraction, and · means inner product calculation.
In the above calculation, when b = 0, it means that the surface and the straight line are parallel to each other, so that it is determined that they will not intersect.
Also, when t is not 0 <= t <= 1, it is also excluded from hits, for example, when the faces are face down or not intersecting .

Thus, after obtaining the parameter (t) from the equation (9), the intersection of the surface and the straight line is obtained from the straight line equation.
The intersection point p is
VECTOR p = a * t + start (10)
Here a * t means to multiply each element of VECTOR a by a parameter t.
Equation (10) is to obtain the intersection point p between the surface and the straight line when the size is infinite.

4) Next, it is examined whether the intersection point p obtained in 3) passes through the triangle surface or the outside.
The intersection point p of the equation (10) obtained in 3) is a point where the straight line intersects with an infinite surface and may not exist in the triangular surface to be actually checked. Therefore, it is checked whether or not it exists in the triangle.
For this purpose, an outer product is obtained using the intersection obtained in 3) and each vertex of the triangle.
・ The first vertex is
VECTOR vec1 = vertex [0]-p
VECTOR vec2 = vertex [1]-vertex [0]
VECTOR vec3 _- a 1 = vec1X vec2.

・ The second vertex is
VECTOR vec1 = vertex [1]-p
VECTOR vec2 = vertex [2]-vertex [1]
VECTOR vec3 _- a 2 = vec1X vec2.

・ The third vertex is
VECTOR vec1 = vertex [2]-p
VECTOR vec2 = vertex [0]-vertex [2]
VECTOR vec3 _- a 3 = vec1X vec2.

If all three vertices have the same orientation, the intersection obtained in 3) exists inside the triangle.
As a method of comparing the directions of the vertices, there is a method of calculating an inner product with the vector normal obtained in 2). This is because the vector to be obtained this time is a vector having the same direction as the vector normal obtained in 2) or a direction opposite to 180 °.
If the signs of the inner products with the vector normal obtained in 2) are compared, and the signs are all the same, the intersection point obtained in 3) exists inside the triangle.
The inner product with the vector normal obtained in 2) is as follows.
_{float nn1 = vec3 - 1 · normal} ··· (11)
_{float nn2 = vec3 - 2 · normal} ··· (12)
_{float nn3 = vec3 - 3 · normal} ··· (13)
Therefore, it is possible to determine whether or not the intersection point p exists inside the triangle by examining the signs of the above equations (11), (12), and (13).

Next, a determinant for obtaining the camera position from the position of the player and the camera angle will be described. The rotation determinant is used in the calculation for obtaining the camera position described later.
Here, a 3 × 3 matrix will be described. In the calculation of CG, a matrix of 4 rows and 4 columns is sometimes used. However, since this part affects the calculation of rotation, it is set to 3 rows and 3 columns.
The rotation of each axis when the rotation angle of the X axis is Rx, the rotation angle of the Y axis is Ry, and the rotation angle of the Z axis is Rz is as follows.

・・・（１４）

・Ｙ軸の回転

・・・（１５）
・Ｚ軸の回転

・・・（１６） ・ Rotation of X axis

(14)

・ Rotation of Y axis

... (15)
・ Z axis rotation

... (16)

・・・（１７）
? には各軸の記号を入れて表す。例えば、Ｘ軸の行列の要素は、Xm00,Xm01,Xm12,Xm10 ・・・
Ｙ軸の行列の要素は、Ym00,Ym01,Ym12,Ym10 ・・・といった様にである。 Multiply these to create a rotation matrix. The results differ greatly depending on the order of multiplication, but the order of multiplication varies depending on the system and library.
This time, the thing which multiplied in order of X, Y and Z is explained.
Since it will be difficult to see if the above equation using sin and cos is used, it will be explained in a simplified version.

Give a number to each element of the matrix.

... (17)
The symbol of each axis is put in? For example, the elements of the X-axis matrix are Xm00, Xm01, Xm12, Xm10.
The elements of the Y-axis matrix are Ym00, Ym01, Ym12, Ym10, and so on.

・・・（１８）
となる。この結果とＺ軸の回転行列を同様に掛け合わせることにより最終的な回転行列を得ることが出来る。 First, the X-axis rotation matrix and the Y-axis rotation matrix are multiplied.
Each element of the rotated rotation matrix XY is

XYm00 = Xm00 * Ym00 + Xm01 * Ym10 + Xm02 * Ym20
XYm01 = Xm00 * Ym01 + Xm01 * Ym11 + Xm02 * Ym21
XYm02 = Xm00 * Ym02 + Xm01 * Ym12 + Xm02 * Ym22
XYm10 = Xm10 * Ym00 + Xm11 * Ym10 + Xm12 * Ym20
XYm11 = Xm10 * Ym01 + Xm11 * Ym11 + Xm12 * Ym21
XYm12 = Xm10 * Ym02 + Xm11 * Ym12 + Xm12 * Ym22
XYm20 = Xm20 * Ym00 + Xm21 * Ym10 + Xm22 * Ym20
XYm21 = Xm20 * Ym01 + Xm21 * Ym11 + Xm22 * Ym21
XYm22 = Xm20 * Ym02 + Xm21 * Ym12 + Xm22 * Ym22

... (18)
It becomes. By multiplying this result and the Z-axis rotation matrix in the same manner, a final rotation matrix can be obtained.

Next, referring to FIG. 1A, a method of incorporating the above method with respect to the camera position, camera angle, player position, and gaze (attention) point check position will be described.
As shown in FIG. 1A, the camera position is (camera pos (x, y, z)), the camera angle is (camera angle (x, y, z)), the point you want to bring to the center of the screen, that is, the third person In the case of, the player character's head or a position slightly above the head (player pos (x, y, z)), a distance from the player pos of a straight line extending from the camera pos through the player pos in the camera angle direction A point in the length of L, that is, a gaze point check position is defined as (check pos (x, y, z)).

The position and angle of the camera are usually determined so that the player character can be accommodated in the screen.
The camera may change the angle so as to see the player character from this fixed position, or may move the position in accordance with the movement of the player character. In the CG game machine according to the present invention, the player can change the camera angle from the position fixed by the operation unit. Further, if the CG game machine is set so that the camera and the player character always have a predetermined positional relationship, the camera position moves as the player moves.
(i) First, the point to be determined is the player character position player pos. This is operated by an input from the operation unit of the player, and the position of the player character is determined as a result of calculation of the operation information.
(ii) Next, the camera angle camera angle is determined. There are a case where the angle of the camera is changed by a player operation or the like, and a case where the previous calculation result is used.

(iii) Next, the position of the camera is determined. The position of the camera is obtained from the position of the player character and the angle of the camera. The position separated from the player character by the distance Lp is defined as a camera position camera pos.
The camera position camera pos is multiplied by the camera X-axis, Y-axis, and Z-axis angles (Equations (14) and (15)) to form a rotation matrix XY, which is then rotated by the Z-axis rotation matrix (Equation (16)). ) To create a rotation matrix of the X axis, Y axis, and Z axis, and multiply this by Lp as a vector component.
(iv) Next, check point pos for performing a hit check of the terrain and the line of sight is obtained. Since this is an inverse vector from the position of the player character to the position of the camera, this can also be easily obtained.

(v) Next, a hit check is performed with the check pos to perform a hit check of the terrain surface and the line of sight.
This can be checked using the methods 1), 2), 3) and 4) above. At this time, player pos (x, y, z) is calculated corresponding to VECTOR start, and check pos (x, y, z) is calculated corresponding to VECTOR end. 3) Find the intersection of 4), and if the intersection is inside or outside of the triangle, if the line connecting check pos and player pos intersects the surface of the terrain, check pos enters the terrain So the camera angle is changed to look up.
If they don't meet, they are floating above the terrain, so the camera angle is changed to look down.
If this process is repeated as it is, it will change up and down every time on the terrain and the boundary line, so when entering the terrain or floating from the terrain, either one, again at the changed camera angle A hit check is performed, and if the result of the hit check changes, the process is performed so that the angle of the changed camera is not used and the angle of the camera before the change is returned.

Next, embodiments of the present invention will be described in detail.
FIG. 1B is a perspective view showing an external appearance of a CG game device using the camera control method according to the present invention. The CG game apparatus 1 is a home-use game machine, and a player moves a character on the screen displayed on the monitor 3 by operating each button, direction selection button, or the like of the pad 2, or performs various operations. Or let the game progress.
In this game, the hero character 4 is shown climbing up the slope 5, the camera position is controlled so that the slope 5 and the sky 6 are in the approximate center of the screen, and the player moves in front of the background image. I have a good view.

FIG. 2 is a circuit block diagram showing an embodiment of a circuit of a CG game device using the camera control method according to the present invention.
The home game machine 1 includes a CPU 10, an image processing circuit 11, a main bus 13, a memory circuit 14, an external storage device 16, a sound processing circuit 17, and a speaker 18.
The external storage device 16 is a storage unit in which a medium such as a CD-ROM, a card, or a DVD is mounted. The medium stores a game program and its data.
The game program includes a game start starting step for displaying a screen for starting a game, a game operation step for moving a character position in response to a moving operation from the player, and a camera from a character position to a predetermined position corresponding to the character position. A camera position setting step to be installed; a game progress processing step for performing a game process in accordance with a player's operation; and whether or not a line segment extending from the character and a predetermined distance intersects the surface of the terrain. In the collision check step for checking, and in the collision check, if the line segment of the predetermined distance and the surface of the terrain do not match (contact), a camera angle adjustment step for rotating the camera pitch in the matching direction is included.
The memory circuit 14 is used as a work area where the CPU 10 performs processing, and also includes a RAM that temporarily stores data such as calculation results, a control program that controls the entire apparatus, and a ROM that stores data related thereto. Is.

The image processing circuit 11 receives the image data calculated by the CPU 10 and converts it into image data to be displayed on the CRT 3.
The sound processing circuit 17 receives the sound data calculated by the CPU 10, converts it into analog sound, and outputs a sound such as background sound and sound from the speaker 18.
The CPU 10 has a function of reading a control program from the ROM and controlling the entire apparatus. When a CD-ROM, for example, is loaded in the external storage device 16, the CPU 10 reads the CD-ROM game program and first displays a game start screen on the CRT.
The CPU 10 realizes each function of the above steps by a game program read by the control program. That is, the functions of the game start / progress unit 10a, the game operation processing unit 10b, the camera position setting unit 10c, the collision check unit 10d, and the camera angle adjustment unit 10e are realized.

FIG. 3 is a diagram for explaining a camera control method when a screen including a character is captured and displayed from the camera viewpoint.
The player can move the character C on the screen by operating the input device (pad). In (a), a character C exists on a horizontal ground GO, the camera V is set at a predetermined distance behind the character C at a predetermined camera angle, and the length L is extended from the camera through the head of the character. This shows a state in which the position and pitch angle of the camera are adjusted so that these points substantially coincide with the ground.
As shown in (b), the camera is adjusted in position and pitch angle so that the boundary between the ground and the sky is arranged at approximately a half position with respect to the height h of the screen.

When the character C moves and approaches a downhill as shown by a two-dot chain line G1, if the pitch angle of the original camera is in the initial state, the background behind the character C is only empty as shown in FIG. It becomes. In order to avoid such a screen, when the inclination of the terrain is changed by the movement of the character C, the position and pitch angle of the camera V are moved and rotated little by little as shown in the drawing of (b). The control method is not corrected little by little, and the camera can be moved and rotated when the inclination of the terrain becomes very large.
Further, when approaching an uphill as shown by a two-dot chain line G2, if the original camera position and pitch angle are in the state, the background of the character C is only the topography as shown in ( d ). . In order to avoid such a screen, when the inclination of the terrain is changed by the movement of the character C, the position and pitch angle of the camera V are moved and rotated little by little as shown in the drawing of (b). The control method is not corrected little by little, but it is also possible to move and rotate the camera when the inclination of the terrain is considerably inclined.

FIG. 4 is a flowchart for explaining the flow of camera control in the game in the CG game device of FIG. 1B.
In the game, when the player operates the buttons of the input / output device (pad) 2, operation information is sent to the CPU 10. Based on the input operation information, the game operation processing unit 10b moves the character by the amount corresponding to the operation information, for example, if the character is moving, and the image is displayed on the CRT 3. The camera position setting unit 10c sets the camera so that it is at a distance Lp from the character (head position or slightly above the head position) and has a pitch angle θh with respect to the horizontal plane. As long as the character is moving on the horizontal ground surface, the camera position is moved so as to maintain the relative relationship between the camera position and the character position (step (hereinafter referred to as “S”) 001).

The collision check unit 10d performs a hit check of the tip (check position) of the length L of the line segment extended from the character. That checks do not intersect dolphin or no intersecting check position with respect to the ground (S002). This is performed, for example, at an interval of 1/60 seconds, and is performed using the arithmetic expression as described above. As a result of the check, when the leading ends of the line segment L cross and enter the ground as shown in FIG. 5A, the camera angle adjustment unit 10e corrects the angle upward by 2 ° (S003). Then, the angle of the camera is adjusted (S004). Accordingly, the camera position also becomes a position along the camera angle.

On the other hand, as a result of the check, when the tip of the line segment L does not intersect and is away from the ground as shown in FIG. 6A , the camera angle adjustment unit 10e corrects the angle downward by 2 ° in one check ( S004). Then, it is checked whether or not the gazing point intersects the ground (S005). Gazing point when being reached the position intersecting the ground, return to the front of the check position (S006), to adjust the camera to its angular position (S007). Accordingly, the camera position also becomes a position along the camera angle.
If the game is not over after such an operation, the process returns from S001 to S002 again, and the same operation is repeated. As a result, when the gazing point does not intersect with the ground, the camera pitch angle is controlled by 2 ° in 1/60 second intervals so as to intersect the ground , and an appropriate field of view is obtained as shown in FIG. Brought to the resulting position. In addition, when the gazing point is at a position where it intersects the ground , the camera pitch angle is controlled by 2 ° at 1/60 second intervals so that it does not intersect the ground, and an appropriate field of view as shown in FIG. 5B is obtained. Is brought to a position.

FIG. 7 is a flowchart for explaining a camera control method different from the flowchart of FIG. In the flowchart of FIG. 4, the case where the camera angle is changed by 2 ° has been described, but in this example, the camera angle is determined by one process.
S101 is the same process as S001, and the camera position is moved so that the relative relationship between the camera position and the character position is maintained .
The collision check unit 10d performs a hit check of the tip (check position) of the length L of the line segment extended from the character. That is, it is checked whether the check position intersects with the ground or does not intersect at all (S102).

As a result of the check, when the leading ends of the line segment L cross each other and enter the ground as shown in FIG. 5A, the camera angle adjustment unit 10e corrects the camera angle so as to look up (S103). Then, a hit check is performed again in S102, and if they intersect , the camera angle is continuously changed so as to look upward. As a result of the check, when the tip of the line segment L does not intersect and is away from the ground as shown in FIG. 6A , the camera angle adjustment unit 10e corrects the downward angle (S104). Then, it is checked whether or not the gazing point intersects the ground (S105), and if not, the angle position of the camera is changed to look downward (S105). In this way, the gazing point is the it reaches a position intersecting the ground, return to the front of the check position (S106), to adjust the camera to its angular position (S107). Accordingly, the camera position also becomes a position along the camera angle.

Although the above embodiment has been described with reference to an example applied to a home game machine, the present invention can be similarly applied to an arcade game machine, a portable game machine, an online game machine, and the like.
Further, although an example in which the gazing point check operation is performed at 1/60 second intervals has been described, it is also possible to check at other time intervals, for example, 1/30 seconds, 1/20 seconds, or the like. Although the pitch angle is corrected by 2 ° in one check, this angle may be corrected by another angle, for example, 1 ° or 3 °. As a correction method, correction can be performed in units of angles up to a position where the gazing point substantially coincides with the ground. For example, if you move from the horizontal plane to the edge of the cliff, it will take time to display the proper screen when standing on the cliff if you correct it in small angle units. It is necessary to correct the position.

  This GC game device can be applied to home game machines, arcade game machines, portable game machines, online game machines and the like, and incorporates camera control that obtains a line of sight according to the terrain and displays it on the screen.

It is a figure for demonstrating the taking-in method of the said method with respect to a camera position, a camera angle, a player position, and a gaze point check position. It is a perspective view which shows the external appearance of the CG game device using the camera control method by this invention. It is a circuit block diagram which shows embodiment of the circuit of the CG game device using the camera control method by this invention. It is a figure for demonstrating the control method of the camera at the time of imaging | photography displaying the screen containing a character from a camera viewpoint. It is a flowchart for demonstrating the flow of the camera control method of FIG. It is a figure for demonstrating the example which makes the visual field position of a camera favorable when a visual field is bad covering a screen. It is a figure for demonstrating the example which makes the visual field position of a camera favorable when a step cannot be seen but a visual field is bad. 5 is a flowchart for explaining a camera control method different from the flowchart of FIG. 4.

Explanation of symbols

1 CG game machine
2 Input device (pad)
3 Monitor (CRT)
10 CPU
11 Image processing circuit
13 Main bus 14 Memory circuit 16 External storage device 17 Sound processing circuit 18 Speaker

Claims (6)

To the character to move the screen, the CG screen control method for displaying the previous SL image obtained by photographing a character on the monitor screen,
When an operation for moving the position of the character is performed from the operation unit, the character is moved to a position corresponding to the operation amount,
In response to the movement position of the character to set the camera to be placed additionally slave,
It is a line segment on the extension connecting the camera installation position and the character, and it is determined whether or not the tip of the line segment at a predetermined distance from the character intersects the terrain surface displayed on the screen. In this case, the camera control is characterized in that the position and optical axis of the camera are controlled to move and rotate with respect to the character so that the end of the line segment is substantially coincident with the terrain surface displayed on the screen. Method. The determination of whether or not to cross each other is performed at a predetermined time interval. If not , the optical axis of the camera is rotated by a predetermined angle in the crossing direction, and this operation is repeated until the position substantially coincides with the topographic surface. The camera control method according to claim 1, wherein control is performed until The camera control method according to claim 2, wherein the rotation control of the camera is repeated by the predetermined angle , and when the tip of the line segment intersects the topographic surface, the camera is returned to the rotation position before the intersection . To the character to move the screen, in the CG game device for displaying the previous SL image obtained by photographing a character on the monitor screen,
Character moving means for moving the character according to the operation of the operation unit;
Camera position setting means for capturing the character in view according to the movement of the character;
A line segment on the extension connecting the camera position and the character, and it is determined whether or not the tip of the line segment at a predetermined distance from the character intersects the terrain surface displayed on the screen. , and control means for the segment tip is controlled to move and rotation relative to the character position and the optical axis of the camera so as to be substantially coincident position with respect to terrain surface displayed on the screen,
A CG game device, wherein the CG game device displays an empty portion and a terrain portion on a screen in a predetermined ratio while including the character, in view of the movement of the character and a change in terrain. The control means, it is determined whether intersect at predetermined time intervals, rotates the optical axis of a predetermined angle camera only in a direction intersecting if not intersect, substantially relative to the terrain surface by repeating this operation 5. The CG game apparatus according to claim 4, wherein control is performed until the positions coincide with each other. 6. The CG game apparatus according to claim 5, wherein the control means repeats the rotation control of the camera by a predetermined angle, and returns to the rotation position of the camera before the intersection when the end of the line segment intersects the terrain surface. .

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