Imagination Technologies Limited

Richard Broadhurst

John William Howson

Steven John Fishwick

Xile Yang

Isuru Herath

Lorenzo Belli

Panagiotis Velentzas

Robert Theed

Rudi Bonfiglioli

Roger Hernando Buch

A method of processing primitives within a tiling unit of a graphics processing system comprises determining whether a primitive falls within a tile based on positions of samples within each pixel. If it is determined that the primitive does fall within a tile based on the positions of samples within pixels in a tile, an association between the tile and the primitive is stored to indicate that the primitive is present in the tile. For example, an identifier for the primitive may be added to a control stream for the tile to indicate that the primitive is present in the tile. Various different methods are described to make the determination and these may be used separately or in any combination.

Generation of a control stream for a tile

Methods and graphics processing units for processing a plurality of fragments in a graphics processing system. A received first fragment is processed by performing an early depth test with hidden surface removal logic using a depth buffer; in response to the first fragment passing the early depth test, executing one or more instructions of a shader program for the first fragment on the processing logic to determine the property of the first fragment; and after the determination of the property of the first fragment, performing a late depth test on the first fragment with the hidden surface removal logic using the depth buffer. After said receiving a first fragment, a second fragment to be processed is received, wherein the second fragment does not have a shader-dependent property. The second fragment is processed by, before said late depth test is performed on the first fragment, performing an early depth test on the second fragment with the hidden surface removal logic.

Processing fragments which have a shader-dependent property in a graphics processing system

A method of managing resources in a graphics processing pipeline includes, in response to selecting a task for execution within a texture/shading unit, allocating to the task both a static allocation of temporary registers for the entire task and a dynamic allocation of temporary registers. The dynamic allocation comprises temporary registers used by a first phase of the task only and the static allocation of temporary registers comprises any temporary registers that are used by the program and are live at a boundary between two phases. When the task subsequently reaches a boundary between two phases, the dynamic allocation of temporary registers are freed and a new dynamic allocation of temporary registers for a next phase of the task is allocated to the task.

Allocation of resources to tasks

A graphics processing unit configured to process graphics data using a rendering space which is sub-divided into a plurality of tiles, the graphics processing unit comprising: a plurality of processing cores configured to render graphics data; cost indication logic configured to obtain a cost indication for each of a plurality of sets of one or more tiles of the rendering space, wherein the cost indication for a set of one or more tiles is suggestive of a cost of processing the set of one or more tiles; similarity indication logic configured to obtain similarity indications between sets of one or more tiles of the rendering space, wherein the similarity indication between two sets of one or more tiles is indicative of a level of similarity between the two sets of tiles according to at least one processing metric; and scheduling logic configured to assign the sets of one or more tiles to the processing cores for rendering in dependence on the cost indications and the similarity indications.

Tile assignment to processing cores within a graphics processing unit

A method of scheduling tasks in a processor comprises receiving a plurality of tasks that are ready to be executed, i.e. all their dependencies have been met and all the resources required to execute the task are available, and adding the received tasks to a task queue (or 'task pool'). The number of tasks that are executing is monitored and in response to determining that an additional task can be executed by the processor, a task is selected from the task pool based at least in part on a comparison of indications of resources used by tasks being executed and indications of resources used by individual tasks in the task pool and the selected task is then sent for execution.

Scheduling tasks in a processor

A graphics processing unit (GPU) processes graphics data using a rendering space which is sub-divided into a plurality of tiles. The GPU comprises cost indication logic configured to obtain a cost indication for each of a plurality of sets of one or more tiles of the rendering space. The cost indication for a set of tile(s) is suggestive of a cost of processing the set of one or more tiles. The GPU controls a rendering complexity with which primitives are rendered in tiles based on the cost indication for those tiles. This allows tiles to be rendered in a manner that is suitable based on the complexity of the graphics data within the tiles. In turn, this allows the rendering to satisfy constraints such as timing constraints even when the complexity of different tiles may vary significantly within an image.

Graphics processing units and methods for controlling rendering complexity using cost indications for sets of tiles of a rendering space

Methods and apparatus for merging tasks in a graphics pipeline in which, subsequent to a trigger to flush a tag buffer, one or more tasks from the flushed tag buffer are generated, each task comprising a reference to a program and plurality of fragments on which the program is to be executed, wherein a fragment is an element of a primitive at a sample position. It is then determined whether merging criteria are satisfied and if satisfied, one or more fragments from a next tag buffer flush are added to a last task of the one or more tasks generated from the flushed tag buffer.

Task merging

A computing system comprises graphics rendering logic and image processing logic. The graphics rendering logic processes graphics data to render an image using a rendering space which is sub-divided into a plurality of tiles. Cost indication logic obtains a cost indication for each of a plurality of sets of one or more tiles of the rendering space, wherein the cost indication for a set of one or more tiles is suggestive of a cost of processing rendered image values for a region of the rendered image corresponding to the set of one or more tiles. The image processing logic processes rendered image values for regions of the rendered image. The computing system causes the image processing logic to process rendered image values for regions of the rendered image in dependence on the cost indications for the corresponding sets of one or more tiles.

Computing systems and methods for processing graphics data using cost indications for sets of tiles of a rendering space

The graphics processing unit described herein is configured to process graphics data using a rendering space which is sub-divided into a plurality of tiles. The graphics processing unit comprises a tiling unit and rendering logic. The tiling unit is arranged to generate a tile control list for each tile, the tile control list identifying each graphics data item present in the tile. The rendering logic is arranged to render the tiles using the tile control lists generated by the tiling unit. The tiling unit comprises per-tile hash generation logic arranged to generate, for each tile, a per-tile hash value based on a set of textures that will be accessed when processing the tile in the rendering logic, and the tiling unit is further arranged to store the per-tile hash value for a tile within the tile control list for the tile.

Tile-based scheduling using per-tile hash values

Methods of memory allocation in which registers referenced by different groups of instances of the same task are mapped to individual logical memories. Other example methods describe the mapping of registers referenced by a task to different banks within a single logical memory and in various examples this mapping may take into consideration which bank is likely to be the dominant bank for the particular task and the allocation for one or more other tasks.

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Kings Langley, United Kingdom

Richard Broadhurst