Image drawing system, image drawing server, image drawing method, and computer program

1. An image drawing server connected to a client terminal via a network for constructing a three-dimensional virtual world, comprising:

a reception unit for acquiring, from the client terminal, a position of an avatar of a user of said three-dimensional virtual world in said client terminal;

a three-dimensional object creation unit for providing a viewpoint in the vicinity of said avatar and for creating a three-dimensional object having substantially horizontal concentric polygons or concentric circles as cross sections thereof, wherein said concentric polygons or concentric circles are centered around said viewpoint;

a panoramic image creation unit for performing a perspective projection of a static object residing in a region of a plurality of regions in said three-dimensional virtual world by dividing said three-dimensional object by borders that correspond to said concentric polygons or concentric circles, wherein said perspective projection performed for said region with respect to an outer side face of a concentric polygon or concentric circle of the concentric polygons or concentric circles, while centering around said viewpoint, to create a 360 degree two-dimensional panoramic image, wherein said perspective projection is repeated for a different static object with respect to a different region of the plurality of regions to create at least one more 360 degree two-dimensional panoramic image that corresponds to an outer side face of a different concentric polygon or concentric circle of said concentric polygons or concentric circles, and said perspective projection has not already been performed for the different concentric polygon or concentric circle; and

a transmission unit for transmitting, to said client terminal, said 360 degree two-dimensional panoramic images and information on a dynamic object residing in a region of an outer object within the smallest concentric polygon or concentric circle of said concentric polygons or concentric circles created by said three-dimensional object creation unit;

wherein said panoramic image creation unit adds, to one of said 360 degree two-dimensional panoramic images, action information that one of said static objects has, and wherein said client terminal displays said action information such that a user can select an action that enables interaction with one of said static objects;

wherein said panoramic image creation unit adds a Z value to one of said 360 degree two-dimensional panoramic images residing in a region of said three-dimensional object within the closest vicinity from said viewpoint to which one of said static objects is projected, wherein said Z value represents a position of the one of said static objects in a depth direction thereof.

2. The image drawing server according to claim 1 , further comprising a resolution conversion unit for converting a resolution of said 360 degree two-dimensional panoramic images.

3. The image drawing server according to claim 1 , wherein said panoramic image creation unit adds, to said 360 degree two-dimensional panoramic images, data concerning a region in which said dynamic object cannot enter using said Z value.

4. The image drawing server according to claim 1 , wherein said three-dimensional object is a cylinder whose bottom face is one of the cross sections when said viewpoint is provided over an earth's surface.

5. The image drawing server according to claim 1 , wherein said three-dimensional object is a hemi-polyhedron or a hemisphere whose bottom face is one of the cross sections when said viewpoint is provided over an earth's surface.

6. The image drawing server according to claim 1 , wherein when said avatar moves closer to a side face of a closest vicinity three-dimensional object for said viewpoint, (i) said three-dimensional object creation unit creates a new closest vicinity three-dimensional object while setting a position in the vicinity of said avatar as a new viewpoint in response to a request from said client terminal, and (ii) said panoramic image creation unit creates a new 360 degree two-dimensional panoramic image corresponding to said new closest vicinity three-dimensional object and a second closest vicinity three-dimensional object, wherein said second closest vicinity three-dimensional object is second closest to said viewpoint that has been already created.

7. The image drawing server according to claim 1 , wherein said transmission unit transmits a dynamic object one by one.

8. An image drawing system in a three-dimensional virtual world configured by a client terminal and a server connected via a network, comprising:

a three-dimensional object creation unit for providing a viewpoint in the vicinity of an avatar of a user of said three-dimensional virtual world in said client terminal and for creating a three-dimensional object having substantially horizontal concentric polygons or concentric circles as cross sections thereof, wherein said three-dimensional object has polygonal pillars or cylinders nested within, said polygonal pillars or said cylinders are tubular space figures having substantially congruent two plane figures, and said concentric polygons or concentric circles are centered around said viewpoint;

a panoramic image creation unit for performing a perspective projection of a static object residing in a region of a plurality of regions in said three-dimensional virtual world by dividing said three-dimensional object by borders that correspond to said concentric polygon or concentric circles, wherein said perspective projection performed for said region with respect to an outer side face of a concentric polygon or concentric circle of the concentric polygons or concentric circles, while centering around said viewpoint, creates a 360 degree two-dimensional panoramic image, wherein said perspective projection is repeated for a different static object with respect to a different region of the plurality of regions to create at least one more 360 degree two-dimensional panoramic image that corresponds to an outer side face of a different concentric polygon or concentric circle of said concentric polygons or concentric circles, and said perspective projection has not already been performed for the different concentric polygon or concentric circle;

a drawing unit for overlaying said of 360 degree two-dimensional panoramic image, information on a dynamic object residing in a region of an outer object within the smallest concentric polygon or concentric circle of said concentric polygons or concentric circles created by said three-dimensional object creation unit, and an image of said avatar; and

a panoramic image storage unit for storing said 360 degree two-dimensional panoramic image;

wherein said panoramic image creation unit adds, to one of said 360 degree two-dimensional panoramic images, action information that one of said static objects has, and wherein said client terminal displays said action information such that a user can select an action that enables interaction with one of said static objects;

wherein said panoramic image creation unit adds a Z value to one of said 360 degree two-dimensional panoramic images residing in a region of said three-dimensional object within the closest vicinity from said viewpoint to which one of said static objects is projected, wherein said Z value represents a position of the one of said static objects in a depth direction thereof.

9. The image drawing system according to claim 8 , further comprising a resolution conversion unit for converting a resolution of said 360 degree two-dimensional panoramic images.

10. The image drawing system according to claim 8 , wherein when said avatar moves, said drawing unit expands or shrinks said image of said avatar in accordance with a distance from said viewpoint.

11. The image drawing system according to claim 8 , wherein when said avatar moves closer to a side face of a closest vicinity three-dimensional object for said viewpoint, said three-dimensional object creation unit creates a new closest vicinity three-dimensional object while setting a position in the vicinity of said avatar as a new viewpoint in response to a request from said client terminal,

the panoramic image creation unit creates new a 360 degree two-dimensional panoramic image corresponding to said new closest vicinity three-dimensional object and a second closest vicinity three-dimensional object, wherein said second closest vicinity three-dimensional object is second closest to said viewpoint that has been already created, and

the drawing unit redraws 360 degree two-dimensional panoramic images that have been already created corresponding to said closest vicinity three-dimensional object and said second closest vicinity three-dimensional object with said created new 360 degree two-dimensional panoramic images.

12. An image drawing method that draws an image in a three-dimensional virtual world configured by a client terminal and a server connected via a network, the method comprising the steps of:

providing a viewpoint in the vicinity of an avatar of a user of said three-dimensional virtual world in said client terminal and creating a three-dimensional object having substantially horizontal concentric polygons or concentric circles as cross sections thereof, wherein said concentric polygons or concentric circles are centered around said viewpoint;

performing a perspective projection of a static object residing in a region of a plurality of regions in said three-dimensional virtual world by dividing said three-dimensional object by borders that correspond to said concentric polygons or concentric circles, wherein said perspective projection performed for said region with respect to an outer side face of a concentric polygon or concentric circle of the concentric polygons or concentric circles, while centering around said viewpoint, to create a 360 degree two-dimensional panoramic image, wherein said perspective projection is repeated for a different static object with respect to a different region of the plurality of regions to create at least one more 360 degree two-dimensional panoramic image that corresponds to an outer side face of a different concentric polygon or concentric circle of said concentric polygons or concentric circles, and said perspective projection has not already been performed for the different concentric polygon or concentric circle;

overlaying said 360 degree two-dimensional panoramic images, information on a dynamic object residing in a region of an outer object within the smallest concentric polygon or concentric circles of said concentric polygons of concentric circles created by a three-dimensional object creation unit, and an image of said avatar; and

storing said 360 degree two-dimensional panoramic images;

wherein said panoramic image creation unit adds, to one of said 360 degree two-dimensional panoramic images, action information that one of said static objects has, and wherein said client terminal displays said action information such that a user can select an action that enables interaction with said one of static objects;

wherein said panoramic image creation unit adds a Z value to one of said 360 degree two-dimensional panoramic images residing in a region of said three-dimensional object within the closest vicinity from said viewpoint to which one of said static objects is projected, wherein said Z value represents a position of the one of said static objects in a depth direction thereof.

13. The image drawing method according to claim 12 , wherein said 360 degree two-dimensional panoramic images created based on said three-dimensional object in the closest vicinity of said viewpoint has data concerning a region in which said dynamic object cannot enter using said Z value.

14. The image drawing method according to claim 12 , further comprising the step of expanding or shrinking said image of said avatar in accordance with a distance from said viewpoint when said avatar moves.

15. The image drawing method according to claim 12 , further comprising the steps of:

when said avatar moves closer to a side face of a closest vicinity three-dimensional object for said viewpoint, creating a new closest vicinity three-dimensional object while setting a position in the vicinity of said avatar as a new viewpoint in response to a request from said client terminal;

creating a new 360 degree two-dimensional panoramic image corresponding to said new closest vicinity three-dimensional object and a second closest vicinity three-dimensional object, wherein said second closest vicinity three-dimensional object is second closest to said viewpoint that has been already created, and

redrawing 360 degree two-dimensional panoramic images that have been already created corresponding to said closest vicinity three-dimensional object and said second vicinity three-dimensional object with said created new 360 degree two-dimensional panoramic images.

16. A computer program product comprising a non-transitory computer readable medium and instructions of a method of drawing an image in a three-dimensional virtual world configured by a client terminal and a server connected to a network, which when implemented causes a computer to execute the steps of:

providing a viewpoint in the vicinity of an avatar of a user of said three-dimensional virtual world in said client terminal and creating a three-dimensional object having substantially horizontal concentric polygons or concentric circles as cross sections thereof, wherein said concentric polygons or concentric circles are centered around said viewpoint;

performing a perspective projection of a static object residing in a region in said three-dimensional virtual world by dividing said three-dimensional object by borders that correspond to said concentric polygons or concentric circles, wherein said perspective projection performed for said region with respect to an outer side face of a concentric polygon or concentric circle of the concentric polygons or concentric circles, while centering around said viewpoint, to create a 360 degree two-dimensional panoramic image, wherein said perspective projection is repeated for a different static object with respect to a different region of the plurality of regions to create at least one more 360 degree two-dimensional panoramic image that corresponds to an outer side face of a different concentric polygon or concentric circle of said concentric polygons or concentric circles, and said perspective projection has not already been performed for the different concentric polygon or concentric circle;

overlaying said 360 degree two-dimensional panoramic images, information on a dynamic object residing in a region of an outer object within the smallest concentric polygon or concentric circles of said concentric polygons of concentric circles created by a three-dimensional object creation unit, and an image of said avatar; and

storing said 360 degree two-dimensional panoramic images;

wherein said panoramic image creation unit adds, to one of said 360 degree two-dimensional panoramic images, action information that one of said static objects has, and wherein said client terminal displays said action information such that a user can select an action that enable interaction with one of said static objects;

wherein said panoramic image creation unit adds a Z value to one of said 360 degree two-dimensional panoramic images residing in a region of said three-dimensional object within the closest vicinity from said viewpoint to which one of said static objects is projected, wherein said Z value represents a position of the one of said static objects in a depth direction thereof.