Abstract: Ray tracing systems have computation units (“RACs”) adapted to perform ray tracing operations (e.g. intersection testing). There are multiple RACs. A centralized packet unit controls the allocation and testing of rays by the RACs. This allows RACs to be implemented without Content Addressable Memories (CAMs) which are expensive to implement, but the functionality of CAMs can still be achieved by implemented them in the centralized controller.

Abstract: Ray tracing systems and computer-implemented methods are described for performing intersection testing on a bundle of rays with respect to a box. Silhouette edges of the box are identified from the perspective of the bundle of rays. For each of the identified silhouette edges, components of a vector providing a bound to the bundle of rays are obtained and it is determined whether the vector passes inside or outside of the silhouette edge. Results of determining, for each of the identified silhouette edges, whether the vector passes inside or outside of the silhouette edge, are used to determine an intersection testing result for the bundle of rays with respect to the box.

Abstract: Foveated rendering for rendering an image uses a ray tracing technique to process graphics data for a region of interest of the image, and a rasterisation technique is used to process graphics data for other regions of the image. A rendered image can be formed using the processed graphics data for the region of interest of the image and the processed graphics data for the other regions of the image. The region of interest may correspond to a foveal region of the image. Ray tracing naturally provides high detail and photo-realistic rendering, which human vision is particularly sensitive to in the foveal region; whereas rasterisation techniques are suited for providing temporal smoothing and anti-aliasing in a simple manner, and is therefore suited for use in the regions of the image that a user will see in the periphery of their vision.

Abstract: Graphics processing systems and methods provide soft shadowing effects into rendered images. This is achieved in a simple manner which can be implemented in real-time without incurring high processing costs so it is suitable for implementation in low-cost devices. Rays are cast from positions on visible surfaces corresponding to pixel positions towards the center of a light, and occlusions of the rays are determined. The results of these determinations are used to apply soft shadows to the rendered pixel values.

Abstract: Systems and methods of geometry processing, for rasterization and ray tracing processes provide for pre-processing of source geometry, such as by tessellating or other procedural modification of source geometry, to produce final geometry on which a rendering will be based. An acceleration structure (or portion thereof) for use during ray tracing is defined based on the final geometry. Only coarse-grained elements of the acceleration structure may be produced or retained, and a fine-grained structure within a particular coarse-grained element may be Produced in response to a collection of rays being ready for traversal within the coarse grained element. Final geometry can be recreated in response to demand from a rasterization engine, and from ray intersection units that require such geometry for intersection testing with primitives. Geometry at different resolutions can be generated to respond to demands from different rendering components.

Abstract: In some aspects, systems and methods provide for forming groupings of a plurality of independently-specified computation workloads, such as graphics processing workloads, and in a specific example, ray tracing workloads. The workloads include a scheduling key, which is one basis on which the groupings can be formed. Workloads grouped together can all execute from the same source of instructions, on one or more different private data elements. Such workloads can recursively instantiate other workloads that reference the same private data elements. In some examples, the scheduling key can be used to identify a data element to be used by all the workloads of a grouping. Memory conflicts to private data elements are handled through scheduling of non-conflicted workloads or specific instructions and/or deferring conflicted workloads instead of locking memory locations.

Abstract: A bounce light map for a scene is determined for use in rendering the scene in a graphics processing system. Initial lighting indications representing lighting within the scene are determined. For a texel position of the bounce light map, the initial lighting indications are sampled using an importance sampling technique to identify positions within the scene. Sampling rays are traced between a position in the scene corresponding to the texel position of the bounce light map and the respective identified positions with the scene. A lighting value is determined for the texel position of the bounce light map using results of the tracing of the sampling rays. By using the importance sampling method described herein, the rays which are traced are more likely to be directed towards more important regions of the scene which contribute more to the lighting of a texel.

Abstract: Systems and methods of geometry processing, for rasterization and ray tracing processes provide for pre-processing of source geometry, such as by tessellating or other procedural modification of source geometry, to produce final geometry on which a rendering will be based. An acceleration structure (or portion thereof) for use during ray tracing is defined based on the final geometry. Only coarse-grained elements of the acceleration structure may be produced or retained, and a fine-grained structure within a particular coarse-grained element may be Produced in response to a collection of rays being ready for traversal within the coarse grained element. Final geometry can be recreated in response to demand from a rasterization engine, and from ray intersection units that require such geometry for intersection testing with primitives. Geometry at different resolutions can be generated to respond to demands from different rendering components.

Abstract: Systems and methods for producing an acceleration structure provide for subdividing a 3-D scene into a plurality of volumetric portions, which have different sizes, each being addressable using a multipart address indicating a location and a relative size of each volumetric portion. A stream of primitives is processed by characterizing each according to one or more criteria, selecting a relative size of volumetric portions for use in bounding the primitive, and finding a set of volumetric portions of that relative size which bound the primitive. A primitive ID is stored in each location of a cache associated with each volumetric portion of the set of volumetric portions. A cache location is selected for eviction, responsive to each cache eviction decision made during the processing. An element of an acceleration structure according to the contents of the evicted cache location is generated, responsive to the evicted cache location.

Abstract: A bounce light map for a scene is determined for use in rendering the scene in a graphics processing system. Initial lighting indications representing lighting within the scene are determined. For a texel position of the bounce light map, the initial lighting indications are sampled using an importance sampling technique to identify positions within the scene. Sampling rays are traced between a position in the scene corresponding to the texel position of the bounce light map and the respective identified positions with the scene. A lighting value is determined for the texel position of the bounce light map using results of the tracing of the sampling rays. By using the importance sampling method described herein, the rays which are traced are more likely to be directed towards more important regions of the scene which contribute more to the lighting of a texel.

Abstract: Systems and methods for producing an acceleration structure provide for subdividing a 3-D scene into a plurality of volumetric portions, which have different sizes, each being addressable using a multipart address indicating a location and a relative size of each volumetric portion. A stream of primitives is processed by characterizing each according to one or more criteria, selecting a relative size of volumetric portions for use in bounding the primitive, and finding a set of volumetric portions of that relative size which bound the primitive. A primitive ID is stored in each location of a cache associated with each volumetric portion of the set of volumetric portions. A cache location is selected for eviction, responsive to each cache eviction decision made during the processing. An element of an acceleration structure according to the contents of the evicted cache location is generated, responsive to the evicted cache location.

Abstract: A hierarchy is a multi-level linked structure of nodes, wherein the hierarchy represents data relating to a set of one or more items to be processed. Where there are multiple input hierarchies, it may improve the efficiency of the processing of the items to merge the input hierarchies to form a merged hierarchy. The hierarchies are merged by identifying two or more sub-hierarchies within the input hierarchies which are to be merged, and determining one or more nodes of the merged hierarchy which reference nodes of the identified sub-hierarchies. The determined nodes of the merged hierarchy are stored and indications of the references between the determined nodes of the merged hierarchy and the referenced nodes of the identified sub-hierarchies are also stored. In this way, the merged hierarchy is formed for use in processing the items.

Abstract: In an aspect, an update unit can evaluate condition(s) in an update request and update one or more memory locations based on the condition evaluation. The update unit can operate atomically to determine whether to effect the update and to make the update. Updates can include one or more of incrementing and swapping values. An update request may specify one of a pre-determined set of update types. Some update types may be conditional and others unconditional. The update unit can be coupled to receive update requests from a plurality of computation units. The computation units may not have privileges to directly generate write requests to be effected on at least some of the locations in memory. The computation units can be fixed function circuitry operating on inputs received from programmable computation elements. The update unit may include a buffer to hold received update requests.

Abstract: Ray tracing systems and computer-implemented methods are described for performing intersection testing on a bundle of rays with respect to a box. Silhouette edges of the box are identified from the perspective of the bundle of rays. For each of the identified silhouette edges, components of a vector providing a bound to the bundle of rays are obtained and it is determined whether the vector passes inside or outside of the silhouette edge. Results of determining, for each of the identified silhouette edges, whether the vector passes inside or outside of the silhouette edge, are used to determine an intersection testing result for the bundle of rays with respect to the box.

Abstract: Ray tracing systems have computation units (“RACs”) adapted to perform ray tracing operations (e.g. intersection testing). There are multiple RACs. A centralized packet unit controls the allocation and testing of rays by the RACs. This allows RACs to be implemented without Content Addressable Memories (CAMs) which are expensive to implement, but the functionality of CAMs can still be achieved by implemented them in the centralized controller.

Abstract: Ray tracing systems and computer-implemented methods are described for performing intersection testing on a bundle of rays with respect to a box. Silhouette edges of the box are identified from the perspective of the bundle of rays. For each of the identified silhouette edges, components of a vector providing a bound to the bundle of rays are obtained and it is determined whether the vector passes inside or outside of the silhouette edge. Results of determining, for each of the identified silhouette edges, whether the vector passes inside or outside of the silhouette edge, are used to determine an intersection testing result for the bundle of rays with respect to the box.

Abstract: Systems can identify visible surfaces for pixels in an image (portion) to be rendered. A sampling pattern of ray directions is applied to the pixels, so that the sampling pattern of ray directions repeats, and with respect to any pixel, the same ray direction can be found in the same relative position, with respect to that pixel, as for other pixels. Rays are emitted from visible surfaces in the respective ray direction supplied from the sampling pattern. Ray intersections can cause shaders to execute and contribute results to a sample buffer. With respect to shading of a given pixel, ray results from a selected subset of the pixels are used; the subset is selected by identifying a set of pixels, collectively from which rays were traced for the ray directions in the pattern, and requiring that surfaces from which rays were traced for those pixels satisfy a similarity criteria.

Abstract: A hierarchy is a multi-level linked structure of nodes, wherein the hierarchy represents data relating to a set of one or more items to be processed. Where there are multiple input hierarchies, it may improve the efficiency of the processing of the items to merge the input hierarchies to form a merged hierarchy. The hierarchies are merged by identifying two or more sub-hierarchies within the input hierarchies which are to be merged, and determining one or more nodes of the merged hierarchy which reference nodes of the identified sub-hierarchies. The determined nodes of the merged hierarchy are stored and indications of the references between the determined nodes of the merged hierarchy and the referenced nodes of the identified sub-hierarchies are also stored. In this way, the merged hierarchy is formed for use in processing the items.

Abstract: Ray tracing systems and computer-implemented methods perform intersection testing on a bundle of rays with respect to a box. Silhouette edges of the box are identified from the perspective of the bundle of rays. For each of the identified silhouette edges, components of a vector providing a bound to the bundle of rays are obtained and it is determined whether the vector passes inside or outside of the silhouette edge. Results of determining, for each of the identified silhouette edges, whether the vector passes inside or outside of the silhouette edge, are used to determine an intersection testing result for the bundle of rays with respect to the box.

Abstract: Systems can identify visible surfaces for pixels in an image (portion) to be rendered. A sampling pattern of ray directions is applied to the pixels, so that the sampling pattern of ray directions repeats, and with respect to any pixel, the same ray direction can be found in the same relative position, with respect to that pixel, as for other pixels. Rays are emitted from visible surfaces in the respective ray direction supplied from the sampling pattern. Ray intersections can cause shaders to execute and contribute results to a sample buffer. With respect to shading of a given pixel, ray results from a selected subset of the pixels are used; the subset is selected by identifying a set of pixels, collectively from which rays were traced for the ray directions in the pattern, and requiring that surfaces from which rays were traced for those pixels satisfy a similarity criteria.