Rendering device and rendering method

A rendering device that renders a virtual space video of a projected virtual space object varying in at least one of shape and position over a plurality of frame periods, and having a plurality of image objects pasted on a plurality of surfaces of the virtual space object in one-to-one correspondence, the rendering device comprising:

• a scenario processor configured to analyze a rendering scenario of the virtual space video to calculate a scale-down ratio with respect to each of a plurality of image objects for a target frame period included in the frame periods, the scale-down ratio being for fitting the image object to a region in the virtual space video corresponding to one of the plurality of surfaces of the virtual space object, the target frame period being a period in which the virtual space video is to be displayed;
• a plurality of acquiring units each configured to acquire an image object for the frame period;
• a plurality of first scalers configured to scale-down the acquired image objects;
• a memory configured to store therein the scaled-down image objects;
• a plurality of second scalers configured to, when the target frame period is a current frame period, read from the memory the scaled-down image objects and re-scale each of the scaled-down image objects to match a scale-down ratio calculated by the scenario processor for the current frame period;
• a composing unit configured to compose each of the re-scaled image objects on a region in the virtual space video corresponding to one of the surfaces of the virtual space object;
• and
• a plurality of third scalers that are in one-to-one correspondence with the first scalers and are each configured, when a scale-down ratio used by a corresponding first scaler on the acquired image object is smaller than a predetermined scale-down ratio, to create an additionally scaled-down image object, corresponding to the scaled-down image object, using a smaller scale-down ratio than the scale-down ratio used by the corresponding first scaler, and to store both the additionally scaled-down image object and the scaled-down image object in the memory, wherein
• each of the additionally scaled-down image objects stored in the memory is read from the memory and re-scaled by the second scalers to create a re-scaled image object, and
• each of the scaled-down image objects stored in the memory is only read from the memory and re-scaled by the second scalers to create a re-scaled image object when no additionally scaled-down image object corresponding to the scaled-down image object is stored in the memory.

A rendering device that renders a virtual space video of a projected virtual space object varying in at least one of shape and position over a plurality of frame periods, and having a plurality of image objects pasted on a plurality of surfaces of the virtual space object in one-to-one correspondence, the rendering device comprising:

• a scenario processor configured to analyze a rendering scenario of the virtual space video to calculate a scale-down ratio with respect to each of a plurality of image objects for a target frame period included in the frame periods, the scale-down ratio being for fitting the image object to a region in the virtual space video corresponding to one of the plurality of surfaces of the virtual space object, the target frame period being a period in which the virtual space video is to be displayed;
• a plurality of acquiring units each configured to acquire an image object for the frame period;
• a plurality of first scalers configured to scale-down the acquired image objects;
• a memory configured to store therein the scaled-down image objects;
• a plurality of second scalers configured to, when the target frame period is a current frame period, read from the memory the scaled-down image objects and re-scale each of the scaled-down image objects to match a scale-down ratio calculated by the scenario processor for the current frame period;
• and
• a composing unit configured to compose each of the re-scaled image objects on a region in the virtual space video corresponding to one of the surfaces of the virtual space object, wherein
• a delay equivalent to a frame period k occurs for combined actions of writing to and reading from the memory each of the scaled-down image objects, and
• when one of the acquired image objects is scaled-down by one of the first scalers using a scale-down ratio S1 at a frame period t-k temporally in the past, one of the second scalers reads from the memory the scaled-down image object scaled-down using the ratio S1 and re-scales the scaled-down image object for a current frame period t where the scale-down ratio calculated by the scenario processor is S2, by using a factor of S2/S1.

A method for controlling a rendering device that renders a virtual space video of a projected virtual space object varying in at least one of shape and position over a plurality of frame periods, and having a plurality of image objects pasted on a plurality of surfaces of the virtual space object in one-to-one correspondence, the method comprising:

• an analyzing step of analyzing a rendering scenario of the virtual space video to calculate a scale-down ratio with respect to each of a plurality of image objects for a target frame period included in the frame periods, the scale-down ratio being for fitting the image object to a region in the virtual space video corresponding to one of the plurality of surfaces of the virtual space object, the target frame period being a period in which the virtual space video is to be displayed;
• an acquiring step of acquiring a plurality of image objects for the frame period;
• a first scaling step of scaling-down the acquired image objects;
• a storing step of storing the scaled-down image objects in a memory of the rendering device;
• a second scaling step of, when the target frame period is a current frame period, reading the scaled-down image objects stored in the memory and re-scaling each of the scaled-down image objects to match a scale-down ratio calculated for the current frame period;
• and
• a composing step of composing each of the re-scaled image objects on a region in the virtual space video corresponding to one of the surfaces of the virtual space object, wherein
• after n predetermined frame periods have passed, the analyzing step displays each of the image objects at the scale-down ratio designated by an argument of a scaling function,
• from when a 1st frame period passes to when an n−1st frame period passes, the analyzing step changes the scale-down ratio in stages in accordance with the number of passed frame periods, and
• the target frame is one of frame periods to which the scale-down ratio which is changed in stages is allocated.