Graphics processing

A method of using geometry data by a graphics processor when rendering a frame that represents a view of a scene using a ray tracing process,

• wherein the ray tracing process uses a ray tracing acceleration data structure indicative of the distribution of geometry for the scene to be rendered to determine geometry for the scene that may be intersected by a ray being used for a ray tracing operation, the geometry of the scene represented by graphics primitives, wherein the ray tracing acceleration data structure includes at least some end points representing sets of graphics primitives defined for the scene that occupy a volume within the scene that the end point corresponds to;
• the method comprising, when using a ray tracing acceleration data structure when rendering a frame that represents a view of a scene using a ray tracing process:
• fetching vertex data for a set of graphics primitives for an end point of the ray tracing acceleration data structure;
• and
• using the vertex data when testing rays for intersection with the ray tracing acceleration data structure to determine geometry for the scene to be rendered that may be intersected by the rays;
• wherein, when fewer instances of the vertex information have been stored for a vertex that is shared by at least two contiguous graphics primitives than the number of graphics primitives that share the vertex, using the vertex data when testing rays for intersection with the ray tracing acceleration data structure to determine geometry for the scene to be rendered that may be intersected by the rays comprises using the same instance of the vertex data that is stored for the end point for the shared vertex for more than one of the contiguous graphics primitives that share the vertex.

A system for storing geometry data for use by a graphics processor when rendering a frame that represents a view of a scene using a ray tracing process,

• wherein the ray tracing process uses a ray tracing acceleration data structure indicative of the distribution of geometry for the scene to be rendered to determine geometry for the scene that may be intersected by a ray being used for a ray tracing operation, the geometry of the scene represented by graphics primitives, wherein the ray tracing acceleration data structure includes at least some end points representing sets of graphics primitives defined for the scene that occupy a volume within the scene that the end point corresponds to;
• the system comprising a processing circuit that is configured to when preparing a ray tracing acceleration data structure for use when rendering a frame that represents a view of a scene using a ray tracing process:
• for a set of graphics primitives that an end point of the ray tracing acceleration structure represents:
• store vertex data for the set of graphics primitives for the end point, wherein the processing circuit is configured to, when storing vertex data for the set of graphics primitives for the end point:
• sort the set of graphics primitives that the end point represents into zero or more groups of contiguous graphics primitives;
• and
• where the set of graphics primitives for the end point has been sorted into one or more groups of contiguous graphics primitives, for a vertex of a group of contiguous graphics primitives that is shared by at least two graphics primitives of the group of contiguous graphics primitives, store fewer instances of the vertex data for the shared vertex than the number of graphics primitives in the group of contiguous graphics primitives that share the vertex.

A graphics processor that is operable to render a frame that represents a view of a scene using a ray tracing process,

• wherein the ray tracing process uses a ray tracing acceleration data structure indicative of the distribution of geometry for the scene to be rendered to determine geometry for the scene that may be intersected by a ray being used for a ray tracing operation, the geometry of the scene represented by graphics primitives, wherein the ray tracing acceleration data structure includes at least some end points representing sets of graphics primitives defined for the scene that occupy a volume within the scene that the end point corresponds to;
• wherein the graphics processor is configured to, when using a ray tracing acceleration data structure when rendering a frame that represents a view of a scene using a ray tracing process:
• fetch vertex data for a set of graphics primitives for an end point of the ray tracing acceleration data structure;
• and
• use the vertex data when testing rays for intersection with the ray tracing acceleration data structure to determine geometry for the scene to be rendered that may be intersected by the rays;
• wherein, when fewer instances of the vertex data have been stored for a vertex that is shared by at least two contiguous graphics primitives than the number of graphics primitives that share the vertex, using the vertex data when testing rays for intersection with the ray tracing acceleration data structure to determine geometry for the scene to be rendered that may be intersected by the rays comprises using the same instance of the vertex data that is stored for the end point for the shared vertex for more than one of the contiguous graphics primitives that share the vertex.