Viewability testing in a computer-generated environment

A method of determining a value indicative of an extent to which an object in a computer-generated scene is visible when viewed from a perspective of a virtual camera, the method comprising:

• rendering the computer-generated scene from the perspective of the virtual camera, said rendering comprising storing, in a depth buffer, depth map data corresponding to a depth map of the computer-generated scene and comprising respective depth map values at pixel locations spanning a field of view of the virtual camera;
• generating a plurality of points distributed substantially evenly across a surface of the object;
• for each point of the plurality of points lying within the field of view of the virtual camera:
• determining a respective depth map value from the perspective of the virtual camera;
• and
• determining, using the depth map data stored in the depth buffer, whether the point is visible from the perspective of the virtual camera based on a comparison between the determined depth map value for the point and a corresponding one or more of the depth map values stored in the depth buffer;
• and
• in dependence on the comparison, writing data to a region of memory configured to record how many of the plurality of points are determined to be visible from the perspective of the virtual camera;
• and
• determining, based at least in part on based at least in part on how many of the plurality of points are determined to be visible as recorded in the region of memory, the value indicative of the extent to which the surface is visible when viewed from the perspective of the virtual camera.

A non-transient storage medium comprising computer-readable instructions which, when executed by a computing system, cause the computing system to perform a method of determining a value indicative of an extent to which an object in a computer-generated scene is visible when viewed from a perspective of a virtual camera, the method comprising:

• rendering the computer-generated scene from the perspective of the virtual camera, said rendering comprising storing, in a depth buffer, depth map data corresponding to a depth map of the computer-generated scene and comprising respective depth map values at pixel locations spanning a field of view of the virtual camera;
• generating a plurality of points distributed substantially evenly across the surface;
• for each point of the plurality of points lying within the field of view of the virtual camera:
• determining a respective depth map value from the perspective of the virtual camera;
• and
• determining whether the point is visible from the perspective of the virtual camera based on a comparison between the determined depth map value for the point and a corresponding one or more of the depth map values stored in the depth buffer;
• and
• in dependence on the comparison, writing data to a region of memory configured to record how many of the plurality of points are determined to be visible from the perspective of the virtual camera;
• and
• determining, based at least in part on how many of the plurality of points are determined to be visible as recorded in the region of memory, the value indicative of the extent to which the object is visible when viewed from the perspective of the virtual camera.