Abstract: A graphics processing pipeline (20) comprises first vertex shading circuitry (21) that operates to vertex shade position attributes of vertices of a set of vertices to be processed by the graphics processing pipeline. Tiling circuitry (22) then determines for the vertices that have been subjected to the first vertex shading operation, whether the vertices should be processed further. A second vertex shading circuitry (23) then performs a second vertex shading operation on the vertices that it has been determined should be processed further, to vertex shade the remaining vertex attributes for each vertex that it has been determined should be processed further.

Abstract: In a tile-based graphics processing system having plural rendering processors, the set of tiles 31 to be processed to generate an output frame 30 for display is partitioned among the different rendering processors by defining respective tile traversal paths 32, 33, 34, 35 for each rendering processor that start at a tile initially allocated to the processor and that, at least for the initial tiles along the path, traverse to spatially adjacent tiles in the output, and that will traverse every tile to be rendered if followed to their end. The next tile for a given rendering processor to process is then selected as being the next tile along its defined path, unless the next tile in the path has already been processed (or is already being processed) by another rendering processor, in which case the next tile to be allocated to the rendering processor is selected to be a free tile further on in the tile traversal path for that processor.

Abstract: A data processing system includes one or more processors 4, 5, 6, 7 operable to initiate atomic memory requests for execution threads and plural data caches 8, 9, 10, 11 that are used to store data needed to perform an atomic memory operation when an atomic memory operation is to be performed. When atomic operations are to be performed against a data cache, the results of atomic operations that are to access the same memory location are accumulated in a temporary cache line in the data cache pending the arrival in the cache of the “true” cache line from memory. The accumulated results of the atomic operations stored in the temporary cache line are then combined with the cache line from memory when the cache line arrives in the cache. Individual atomic values can also be reconstructed once the cache line arrives at the cache.

Abstract: A tile-based graphics processing system comprises a host processor 1 and a graphics processing pipeline 3. The graphics processing pipeline 3 includes a rasterizer, a renderer, a tile buffer comprising an allocated amount of memory for use as the tile buffer, and a write out stage configured to write data stored in the tile buffer to an external memory. The driver 4 for the graphics processing pipeline 3 on the host processor 1 determines the tile data storage requirements for each render target to be generated for a render output to be generated by the graphics processing system and allocates portions of the memory allocated for use as the tile buffer to respective ones of the render targets based on the determination.

Abstract: Operating a graphics processing pipeline that includes processing stages including a rasteriser that rasterises input primitives to generate graphics fragments to be processed, each graphics fragment having one or more sampling points associated with it, and a renderer that processes fragments generated by the rasteriser to generate output fragment data for output to a render output, comprising the following steps: (i) determining first information to test whether at least a part of a primitive should be processed further; (ii) using at least some of the first information to decide whether to process at least a part of the primitive further; and if it is decided that at least a part of the primitive is to be processed further: (iii) determining further information to be used in further processing of the primitive; and (iv) further processing at least a part of the primitive using the determined further information.

Abstract: When processing a set of tiles to generate an output in a tile based graphics processing pipeline, the pipeline, for one or more tiles of the set of tiles, renders one or more render targets containing data to be used in a processing operation (602), and stores the render targets in the tile buffer (604). It also stores some but not all of the sampling position values for a render target or targets for use when processing an adjacent tile of the set of tiles (606). It then performs a processing operation for the tile using the stored render target or targets (608) and one or more stored sampling position values from another, adjacent tile of the set of tiles (610), to generate an output for the tile (612).

Abstract: A data processing system includes one or more processors 4, 5, 6, 7 operable to initiate atomic memory requests for execution threads and plural data caches 8, 9, 10, 11 that are used to store data needed to perform an atomic memory operation when an atomic memory operation is to be performed. When atomic operations are to be performed against a data cache, the results of atomic operations that are to access the same memory location are accumulated in a temporary cache line in the data cache pending the arrival in the cache of the “true” cache line from memory. The accumulated results of the atomic operations stored in the temporary cache line are then combined with the cache line from memory when the cache line arrives in the cache. Individual atomic values can also be reconstructed once the cache line arrives at the cache.

Abstract: An apparatus for processing data 2 is provided including processing circuitry 24 controlled by an instruction decoder 20 in response to a stream of program instructions. There is also provided dedicated function hardware 12 configured to receive output data from the processing circuitry and to perform a dedicated processing operation. The instruction decoder 20 is responsive to an end instruction 54 and a software processing flag (blend_shade_enabled) to control the processing circuitry to end a current software routine, to generate output data and in dependence upon the software processing flag either trigger processing of the output data by the dedicated function hardware or trigger the processing circuitry to perform a further software routine upon the output data to generate software generated result data instead of hardware generated result data as generated by the dedicated hardware circuitry.

Abstract: The fragment processing pipeline 10 of a graphics processing core 2 has an associated occlusion query cache 19 that is used to maintain a set of local occlusion counters 21. The occlusion query cache 19 is maintained in a local memory 3 of the graphics processing system and can communicate via an interconnect 7 with a set of master occlusion counters 22 in a main memory 5 for the graphics processing system. When an occlusion query starts, a corresponding occlusion counter 22 is initialised in the main memory 5. A corresponding local occlusion counter 21 is also provided in the occlusion query cache 19 in the local memory 3 of the graphics processor, and is used to count the results of the occlusion query. The local occlusion counter value is written back to the occlusion counter 22 for the query in the main memory 5 at the appropriate time for further processing.

Abstract: A processing system comprises plural processing cores and a task allocator for allocating tasks to the processing cores. The processing cores perform the tasks that are allocated to them so as to produce results for the tasks, the results being stored by the processing cores in a buffer. The task allocator indicates to the processing cores memory portions within the buffer in which to store the results. When the processing cores determine that a given memory portion is becoming full, the processing cores request that the task allocator indicates a new memory portion in which to store its results. The processing system allows the task allocator to dynamically and efficiently allocate memory portions to plural processing cores without the task allocator 40 needing to know the sizes of the results being produced by the processing cores.

Abstract: A data processing system includes an execution pipeline that includes one or more programmable execution stages which execute execution threads to execute instructions to perform data processing operations. Instructions to be executed by a group of execution threads are first fetched into an instruction cache and then read from the instruction cache for execution by the thread group. When an instruction to be executed by a thread group is present in a cache line in the instruction cache, or is to be fetched into an allocated cache line in the instruction cache, a pointer to the location of the instruction in the instruction cache is stored for the thread group. This stored pointer is then used to retrieve the instruction for execution by the thread group from the instruction cache.

Abstract: A tile-based graphics processing system comprises a host processor 1 and a graphics processing pipeline 3. The graphics processing pipeline 3 includes a rasteriser, a renderer, a tile buffer comprising an allocated amount of memory for use as the tile buffer, and a write out stage configured to write data stored in the tile buffer to an external memory. The driver 4 for the graphics processing pipeline 3 on the host processor 1 determines the tile data storage requirements for each render target to be generated for a render output to be generated by the graphics processing system and allocates portions of the memory allocated for use as the tile buffer to respective ones of the render targets based on the determination.

Abstract: An apparatus for processing data 2 is provided including processing circuitry 24 controlled by an instruction decoder 20 in response to a stream of program instructions. There is also provided dedicated function hardware 12 configured to receive output data from the processing circuitry and to perform a dedicated processing operation. The instruction decoder 20 is responsive to an end instruction 54 and a software processing flag (blend_shade_enabled) to control the processing circuitry to end a current software routine, to generate output data and in dependence upon the software processing flag either trigger processing of the output data by the dedicated function hardware or trigger the processing circuitry to perform a further software routine upon the output data to generate software generated result data instead of hardware generated result data as generated by the dedicated hardware circuitry.

Abstract: A graphics processing pipeline determines whether respective graphics processing operations, such as respective blends, respective depth tests, etc., to be performed at a stage of the graphics processing pipeline would produce the same result for each sampling point of a set of plural sampling points represented by a fragment being processed by the graphics processing pipeline. If it is determined that respective graphics processing operations would produce the same result for each of the sampling points, then only a single instance of the graphics processing operation is performed and the result of that graphics processing operation is associated with each of the sampling points. The number of instances of the graphics processing operations needed to process the set of plural sampling points which the fragment represents is reduced in comparison to conventional multisampling graphics processing techniques which perform graphics processing operations for fragments on a “per sample” basis.

Abstract: A graphics virtual texturing system in which textures stored in a storage medium of a host system are divided into respective pages that are then loaded into a local memory of a graphics processing system for use. Each page of a graphics texture has an associated fade factor value that can be set by an application that is to use the texture to control the contribution that the page will be used to make to any texturing result that is generated using the texture page in question. The graphics processing system then controls the contribution of texture data from a texture page to texturing result data to be generated in accordance with the fade factor value associated with the texture page in question. This allows texture paging to be done in a more visually pleasing manner than just a binary “page-is-here”/“page-is-not-here” switch.

Abstract: A graphics virtual texturing system in which textures stored in a storage medium of a host system are divided into respective pages that are then loaded into a local memory of a graphics processing system for use. If the texture page that is required for performing a texturing operation at an originally desired level of detail (52) is not present in the local memory of the graphics processing system (53), the virtual texture lookup process loops back to try to sample the texture at an increased level of detail (55), and so on, until texture data that can be used is found in the local memory of the graphics processing system (53). This allows the texturing operation to proceed using texture data for the texel positions in question from a higher level (less detailed) mipmap in place of the originally desired texture data.

Abstract: A data processing apparatus comprises processing circuitry arranged to process processing threads using resources accessible to the processing circuitry. A pipeline is provided for handling at least two pending threads awaiting processing by the processing circuitry. The pipeline includes at least one resource-requesting pipeline stage for requesting access to resources for the pending threads. A priority controller controls priority levels of the pending threads. The priority levels define a priority with which pending threads are granted access to resources. When a pending thread reaches a final pipeline stage, if the request resources are not yet available then the priority level of that thread is raised selectively and the thread is returned to a first pipeline stage of the pipeline. If the requested resources are available then the thread is forwarded from the pipeline.

Abstract: In a tile-based graphics processing system, when an overlay image is to be rendered onto an existing image, the existing tile data for the existing image from the frame buffer in the main memory is pre-loaded into the local colour buffer of the graphics processor (step 41). The overlay content is then rendered and used to modify the tile data stored in the colour buffer (step 44). When the data for a given sampling position stored in the tile buffer is modified as a result of the overlay image, a corresponding dirty bit for the tile region that the sampling position falls within is set (step 45). Then, when all the rendering for the tile has been completed, the dirty bits are examined to determine which regions of the tile have been modified (step 46). The modified tile regions are written back to the output image in the frame buffer in the main memory (step 47), but any regions whose dirty bits have not been set are not written back to the frame buffer in the main memory.

Abstract: An apparatus for processing data 2 is provided including processing circuitry 24 controlled by an instruction decoder 20 in response to a stream of program instructions. There is also provided dedicated function hardware 12 configured to receive output data from the processing circuitry and to perform a dedicated processing operation. The instruction decoder 20 is responsive to an end instruction 54 and a software processing flag (blend_shade_enabled) to control the processing circuitry to end a current software routine, to generate output data and in dependence upon the software processing flag either trigger processing of the output data by the dedicated function hardware or trigger the processing circuitry to perform a further software routine upon the output data to generate software generated result data instead of hardware generated result data as generated by the dedicated hardware circuitry.

Abstract: A processing apparatus includes task manager circuitry 14 issuing task specifiers to processing circuitry 16, 18, 20, 22, 24 indicating processing tasks to be performed. The task specifier includes a relaxed dependency identifier to which the processing circuitry is responsive. The processing circuitry responds to the relaxed dependency identifier by starting the processing task concerned and then controlling the processing task concerned in dependency upon the status of the other processing task upon which there is a relaxed dependency. The task specifier may also indicate a strict dependency in which a processing task may not be started until the other processing task has completed as well as a no dependency indication in which the processing task may be started without reference to any other processing task.