Arm Limited

Sandeep Kakarlapudi

Andreas Due Engh-Halstvedt

Jorn Nystad

Frank Klaeboe Langtind

Peter William Harris

Tord Kvestad Øygard

Olof Henrik Uhrenholt

Edvard Fielding

Toni Viki Brkic

Arne Aas

Sean Tristram Ellis

Lars Oskar Flordal

Samuel Martin

Hakan Lars-Goran Persson

Mark Underwood

Philip Carlos Garcia

Andreas Engh Halstvedt

Robin Paul Fell

Robert John Rees

Marius Bjørge

Jan-Harald Fredriksen

Arne Bergene Fossaa

Michael Stokes

Saurav Arjun

Andreas Due-Engh Halstvedt

A method of operating a graphics processor to process sets of geometry to generate an output. Each set of geometry is associated with lower level geometry including vertex data to be used when rendering the geometry as well a separate higher level representation of the geometry. The higher level representations of the geometry can be obtained by the graphics processor independently of the other, lower level geometry and used to determine which sets of geometry should be processed for which regions of the output. Once this determination is made, the regions can be rendered by obtaining and processing the lower level geometry accordingly.

Graphics processing systems

When performing tile-based rendering a first, pre-pass operation in which primitives in a sequence of primitives for a tile are processed to determine visibility information for the sequence of primitives, the visibility information being usable to determine whether or not fragments for a primitive in the sequence of primitives should subsequently be processed further for the render output, is performed. Thereafter a second, main pass operation is performed in which the further processing of fragments for primitives that were processed during the first, pre-pass operation is controlled based on the determined visibility information for the sequence of primitives, such that for fragments for which the visibility information indicates that the fragments should not be processed further for the render output some or all of the processing during the second, main pass is omitted. The visibility information indicates which primitives should be rendered for which sampling positions of the render output.

Graphics processors

A method of operating a graphics processor that executes a graphics processing pipeline that includes an early culling tester that can access plural different culling test data buffers is disclosed. Information is maintained indicating which of the plural culling test data buffers is expected to be accessed, and the information is used to control the early culling tester. The information may be used to control the early culling tester such that processing delays associated with waiting for dependencies to resolve are reduced.

Graphics processing

A method of operating a graphics processor that comprises a renderer that can render primitives to generate a render output using different shading rates is disclosed. A shading rate for rendering a primitive is determined based on a depth value for the primitive. This can reduce processing effort required to render a render output while maintaining an acceptable image quality.

When performing foveated rendering, a graphics processor is controlled to render plural, e.g. three, different resolution versions from the same viewpoint for a scene. The rendered different resolution images are then appropriately combined (composited) to provide the output 'foveated' image (output frame) that is displayed. The geometry for the scene is processed and sorted into lists for respective rendering tiles of the images being rendered only once, to provide a single set of tile geometry lists that are then used in common when rendering each respective resolution image.

When a processing resource of a data processing system is to perform processing tasks for applications executing on a host processor, the host processor prepares a plurality of command streams to cause the processing resource to perform the processing tasks. When a processing task to be added to a command stream has a dependency on a processing task or tasks that will be included in another command stream, a wait command is added to the command stream that is to include the processing task that has a dependency on a processing task or tasks that will be included in the another command stream, to cause the processing resource to delay executing subsequent commands in the command stream after the wait command, until the processing resource has reached a particular position in the another command stream.

Preparing and executing command streams in data processing systems

A method of controlling a data processor to perform data processing operations is disclosed in which a host processor prepares one or more queue(s) of operations for execution by the data processor. When an error is encountered in the processing of an operation for one of the one or more queue(s), a queue can be set into an error state in which instructions that may have a data dependency on another operation are not executed. The host processor includes in the queues error barrier instructions that divide the respective queues into sets of operations between which there are no data processing dependencies. An error state for a queue can thus be cleared when its processing reaches the next error barrier instruction in the queue.

Control of instruction execution in a data processor

In a graphics processing system, an application executing on a host processor can request graphics processing operations that are to be performed by only subsets of the set of stages of a graphics processing pipeline implemented by a graphics processor. In response to such a request, the driver for the graphics processor causes the graphics processing operation that is to be performed using only a subset of the set of stages of the graphics processing pipeline to be performed. The driver can cause the graphics processing operation that is to be performed by the subset of stages of the graphics processing pipeline to be performed by the graphics processor, or on the host processor.

Graphics processing systems using a subset of pipeline stages

A graphics processing pipeline comprises vertex shading circuitry that operates to vertex shade position attributes of vertices of a set of vertices to be processed by the graphics processing pipeline, to generate, inter alia, a separate vertex shaded position attribute value for each view of the plural different views. Tiling circuitry then determines for the vertices that have been subjected to the first vertex shading operation, whether the vertices should be processed further. Vertex shading circuitry 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, to generate, inter alia, a single vertex shaded attribute value for the set of plural views.

Graphics processing systems using a vertex shader to render plural images

A graphics processing system includes a graphics processing pipeline, which includes a primitive generation stage and a pixel processing stage. The graphics processing system is arranged to process input data in the primitive generation stage to produce first primitive data associated with a first view of a scene and second primitive data associated with a second view of the scene. The graphics processing system is arranged to process the first primitive data in the pixel processing stage to produce first pixel-processed data associated with the first view. The graphics processing system is arranged to determine, for second pixel-processed data associated with the second view, whether to use the first pixel-processed data as the second pixel-processed data or whether to process the second primitive data in the pixel processing stage to produce the second pixel-processed data, and perform additional processing in the graphics processing pipeline based on the determining.

Graphics processing systems and graphics processors

A graphics processing pipeline includes position shading circuitry, a tiler, varying-only vertex shading circuitry and fragment (frontend) shading circuitry. The tiler reads a list of indices defining a set of vertices to be processed by the graphics processing pipeline and determines whether or not vertex shading is required for the positional attributes of the vertices. If vertex shading is required, the tiler sends a position shading request for the vertices to the position shading circuitry. The tiler uses the vertex shaded position data to identify primitives that should be processed further to generate the render output and that accordingly should be subjected to a second, varying shading, vertex shading operation. When the tiler determines that a vertex (or group of vertices) should be subjected to the second, varying shading, vertex shading operation, the tiler sends a varying shading request for the vertex (or vertices) to the varying shading circuitry.

In a graphics processing system, when rendering plural views of the same scene (step), such as for stereoscopic rendering, the vertex shading operation is configured so that rather than executing the vertex shader program separately for each view that is being rendered, a single vertex shading program is executed once for all the views. The vertex shader program that is executed is configured to, for view-dependent operations, perform the respective operation separately for each view (step), so as to derive an appropriate vertex shaded output attribute value for each view, and is configured to, for vertex shading operations that are not dependent upon the view being rendered, perform those vertex shading operations only once for the set of views and to provide only a single vertex shaded output value for each vertex attribute in question for the set of views (step).

In a graphics processing system, a driver for the graphics processing pipeline can include conditional graphics processing tasks in the graphics processing tasks that are to be executed by the graphics processing pipeline to generate a render output required by an application. Each such conditional task has associated with it a condition to be used by the graphics processing pipeline to determine whether to execute processing for the task or not and a region of the render output over which the processing for the task will be executed when the condition for the task is met. The graphics processing pipeline determines whether the condition associated with the task has been met, and only executes the processing for the task if the condition associated with the task has been met.

Executing conditional tasks in a graphics processing pipeline

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. The determination of whether or not the same result would be produced for each sampling point of the set of plural sampling points is facilitated by providing metadata which indicates whether or not fragment data and/or stored sample data for use when processing the sampling points is the same.

Method and apparatus for graphics processing of a graphics fragment

A graphics processing pipeline includes processing circuitry. The processing circuitry is configured to determine attribute information for an object to be rendered for a set of sampling points from a compressed representation of attribute information associated with the object, when the set of sampling points is being processed by the graphics processing pipeline to generate a render output. The processing circuitry is also configured to use the determined attribute information to control the processing of the set of sampling points by the graphics processing pipeline when generating the render output.

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Trondheim, Norway

Sandeep Kakarlapudi