Abstract: A method and an intersection testing module for performing intersection testing in a ray tracing system determines a first offset intersection distance which is equal to a sum of an intersection distance at which a ray intersects a first primitive and a first offset which is dependent upon the orientation of the first primitive. A second offset intersection distance is determined which is equal to a sum of an intersection distance at which the ray intersects a second primitive and a second offset which is dependent upon the orientation of the second primitive. The determined first and second offset intersection distances are compared to select the intersection of the ray with one of the first and second primitives.

Abstract: A ray-tracing system for performing intersection testing includes a tester module for testing rays for intersection with a volume, the tester module receiving a packet of one or more rays to be tested for intersection with the volume. A first set of one or more testers performs intersection testing at a first level of precision to provide intersection testing results, wherein for a first type of the intersection testing result from the first set of one or more testers intersection testing does not need to be reperformed at a second level of precision greater than the first level of precision, and for a second type of the intersection testing result from the first set of one or more testers intersection testing is to be reperformed at the second level of precision; and a second set of one or more testers configured to perform intersection testing at the second level of precision.

Abstract: A system and method for coherency gathering for rays in a ray tracing system. The ray tracing system uses a hierarchical acceleration structure comprising a plurality of nodes including upper level nodes and lower level nodes. For each instance where one of the lower level nodes is a child of one of the upper level nodes, an instance transform is defined, specifying the relationship between a first coordinate system of the upper level node and the second coordinate system for that instance of the lower level node. The system provides an instance transform cache for storing a plurality of these instance transforms while conducting intersection testing.

Abstract: A method and an intersection testing module for performing intersection testing in a ray tracing system determines if a difference between an intersection distance at which a ray intersects a first primitive and an intersection distance at which the ray intersects a second primitive satisfies a comparison condition with respect to a threshold, and if the orientations of the first and second primitives are different. If so the intersection of the ray with the one of the first and second primitives which has a particular orientation is selected.

Abstract: A method and an intersection testing module for performing intersection testing in a ray tracing system determines a first offset intersection distance which is equal to a sum of an intersection distance at which a ray intersects a first primitive and a first offset which is dependent upon the orientation of the first primitive. A second offset intersection distance is determined which is equal to a sum of an intersection distance at which the ray intersects a second primitive and a second offset which is dependent upon the orientation of the second primitive. The determined first and second offset intersection distances are compared to select the intersection of the ray with one of the first and second primitives.

Abstract: A computer implemented method of building an acceleration structure for use in ray tracing includes (i) assigning, in a memory, a different one or more blocks of memory to each of a plurality of threads, each of the blocks of memory comprising one or more memory locations; (ii) for each element of a plurality of elements of a scene for which nodes of the acceleration structure are to be built, assigning that element of the scene to a block of memory so as to assign that element to a thread; and (iii) building one or more nodes of the acceleration structure by processing each of the plurality of threads in parallel.

Abstract: A computing system and method for processing data in which a forward transformation indication is received defining a transformation from a first space to a second space. A transformation is performed on input data from the second space to the first space to determine transformed data by performing a reverse translation operation on the input data, wherein the reverse translation operation is the reverse of a translation defined by the forward transformation indication. An inverse linear mapping operation is performed on the result of the reverse translation operation, wherein the inverse linear mapping operation is the inverse of a linear mapping defined by the forward transformation indication. The transformed data is processed in the computing system to render an image of a scene.

Abstract: A method of converting 10-bit pixel data (e.g. 10:10:10:2 data) into 8-bit pixel data involves converting the 10-bit values to 7-bits or 8-bits and generating error values for each of the converted values. Two of the 8-bit output channels comprise a combination of a converted 7-bit value and one of the bits from the fourth input channel. A third 8-bit output channel comprises the converted 8-bit value and the fourth 8-bit output channel comprises the error values. In various examples, the bits of the error values may be interleaved when they are packed into the fourth output channel.

Abstract: A method and an intersection testing module for performing intersection testing in a ray tracing system determines that a difference between an intersection distance at which a ray intersects a first primitive and an intersection distance at which the ray intersects a second primitive satisfies a comparison condition with respect to a threshold. It is determined that the orientations of the first and second primitives are different. The intersection of the ray with one of the first and second primitives is selected on the basis that the one of the first and second primitives has a particular orientation.

Abstract: A method of converting 10-bit pixel data (e.g. 10:10:10:2 data) into 8-bit pixel data involves converting the 10-bit values to 7-bits or 8-bits and generating error values for each of the converted values. Two of the 8-bit output channels comprise a combination of a converted 7-bit value and one of the bits from the fourth input channel. A third 8-bit output channel comprises the converted 8-bit value and the fourth 8-bit output channel comprises the error values. In various examples, the bits of the error values may be interleaved when they are packed into the fourth output channel.

Abstract: A system and method for coherency gathering for rays in a ray tracing system. The ray tracing system uses a hierarchical acceleration structure comprising a plurality of nodes including upper level nodes and lower level nodes. For each instance where one of the lower level nodes is a child of one of the upper level nodes, an instance transform is defined, specifying the relationship between a first coordinate system of the upper level node and the second coordinate system for that instance of the lower level node. The system provides an instance transform cache for storing a plurality of these instance transforms while conducting intersection testing.

Abstract: A method and an intersection testing module for performing intersection testing in a ray tracing system determines if a difference between an intersection distance at which a ray intersects a first primitive and an intersection distance at which the ray intersects a second primitive satisfies a comparison condition with respect to a threshold, and if the orientations of the first and second primitives are different. If so the intersection of the ray with the one of the first and second primitives which has a particular orientation is selected.

Abstract: A ray tracing system and method for processing data in which a forward transformation indication is received defining a transformation from a first space to a second space. A transformation is performed on input data from the second space to the first space to determine transformed data by performing a reverse translation operation on the input data, wherein the reverse translation operation is the reverse of a translation defined by the forward transformation indication. An inverse linear mapping operation is performed on the result of the reverse translation operation, wherein the inverse linear mapping operation is the inverse of a linear mapping defined by the forward transformation indication. The transformed data is processed in the ray tracing system.

Abstract: Methods and intersection testing modules are provided for determining, in a ray tracing system, whether a ray intersects a 3D axis-aligned box representing a volume defined by a front-facing plane and a back-facing plane for each dimension. The front-facing plane of the box which intersects the ray furthest along the ray is identified. It is determined whether the ray intersects the identified front-facing plane at a position that is no further along the ray than positions at which the ray intersects the back-facing planes in a subset of the dimensions, and this determination is used to determine whether the ray intersects the axis-aligned box. The subset of dimensions comprises the two dimensions for which the front-facing plane was not identified, but does not comprise the dimension for which the front-facing plane was identified.

Abstract: A hierarchical acceleration structure for use in a ray tracing system. When generating a node for the hierarchical acceleration structure, the primitives in a particular portion of the 3D scene may be alternatively bounded by different shaped volumes. These bounding volumes or ‘bounding regions’ can be Axis Aligned Bounding Boxes (AABBs), although other bounding volumes can be used. The ray tracing system may use sets of two or more bounding volumes in a 3D scene to bound all the primitives within that portion. The choice of how to create sets of multiple bounding volumes within a portion of the 3D scene may be done by using a binary space partition (BSP). Different sets of bounding regions may present different amounts of surface area for a hypothetical ray entering the portion of the 3D scene dependent upon the expected ray direction or angle.