Image display device, method for controlling image display device, and information storage medium

A method for controlling an image display device for displaying an image rendering a scene viewed from a viewpoint in a virtual space in a line of sight, the virtual space having at least one virtual object disposed therein, the method for controlling an image display device comprising the steps of:

• performing at least one of a process of moving a position of the viewpoint and a process of changing the line of sight, according to a viewpoint moving operation performed by a user;
• calculating a position of a pitch angle change center point which exists a given distance away from the viewpoint on a straight line extending from the viewpoint in the line of sight;
• and
• rotating the viewpoint about the pitch angle change center point keeping the line of sight so that the line of sight is directed to the pitch angle change center point by changing a pitch angle of the viewpoint about the pitch angle change center point according to a pitch angle change operation performed by the user.

A non-transitory, computer-readable information storage medium storing a program for controlling a computer to function as an image display device for displaying an image rendering a scene viewed from a viewpoint in a virtual space in a line of sight, the virtual space having at least one virtual object disposed therein, the computer-readable information storage medium storing the program for controlling the computer to carry out actions, comprising:

• performing at least one of a process of moving a position of the viewpoint and a process of changing the line of sight, according to a viewpoint moving operation performed by a user;
• calculating a position of a pitch angle change center point which exists a given distance away from the viewpoint on a straight line extending from the viewpoint in the line of sight;
• and
• rotating the viewpoint about the pitch angle change center point keeping the line of sight so that the line of sight is directed to the pitch angle change center point by changing a pitch angle of the viewpoint about the pitch angle change center point according to a pitch angle change operation performed by the user.

An image display device for displaying an image rendering a scene depicting a view field region determined based on a viewpoint and a line of sight in a virtual space having a virtual object disposed therein, the image display device comprising:

• allowable range calculation unit configured to calculate an allowable range for moving a position of the viewpoint and/or an allowable range for changing the line of sight, based on a size of a region where the view field region overlaps with a closed region occupied by the virtual object;
• and
• viewpoint moving unit configured to perform a process of moving the position of the viewpoint and/or a process of changing the line of sight within the allowable range, according to a viewpoint moving operation performed by a user,
• wherein the allowable range calculation unit calculates the position of the viewpoint and/or the line of sight when the line of sight is equivalent to a tangent line direction with respect to the closed region, as a boundary between an inside and an outside of the allowable range.

A method for controlling an image display device for displaying an image rendering a scene depicting a view field region which is defined based on a viewpoint and a line of sight in a virtual space having a virtual object disposed therein, the method for controlling an image display device, comprising the steps of:

• calculating an allowable range for moving a position of the viewpoint and/or an allowable range for changing the line of sight, based on a size of a region where the view field region overlaps with a closed region occupied by the virtual object;
• and
• performing a process of moving the position of the viewpoint and/or a process of changing the line of sight within the allowable range, according to a viewpoint moving operation performed by a user,
• wherein, in calculating the allowable range, calculating the position of the viewpoint and/or the line of sight when the line of sight is equivalent to a tangent line direction with respect to the closed region, as a boundary between an inside and an outside of the allowable range.

A non-transitory, computer-readable information storage medium storing a program for controlling a computer to function as an image display device for displaying an image rendering a scene depicting a view field region which is defined based on a viewpoint and a line of sight in a virtual space having a virtual object disposed therein, the computer-readable information storage medium storing the program for controlling the computer to carry out actions, comprising:

• calculating an allowable range for moving a position of the viewpoint and/or an allowable range for changing the line of sight, based on a size of a region where the view field region overlaps with a closed region occupied by the virtual object;
• and
• performing a process of moving the position of the viewpoint and/or a process of changing the line of sight within the allowable range, according to a viewpoint moving operation performed by a user,
• wherein the calculating action includes calculating the position of the viewpoint and/or the line of sight when the line of sight is equivalent to a tangent line direction with respect to the closed region, as a boundary between an inside and an outside of the allowable range.