Graphics processing

A graphics processor operable to execute a tile-based graphics processing pipeline to generate a render output, the graphics processor comprising one or more processing circuits configured to execute a graphics processing pipeline comprising:

• a sequence of one or more geometry processing stages to perform geometry processing;
• a binning stage that performs a binning process to generate data structures for identifying geometry to be processed for respective rendering tiles of a render output being generated;
• a rendering stage for rendering tiles of a render output being generated;
• wherein:
• the graphics processor further comprises a clipping processing circuit configured to, when the graphics processor is generating a render output in which primitives to be rendered can be clipped against a clip plane defined for the render output, for a primitive to be processed for the render output being generated and that is to undergo a clipping process as part of its processing for the render output:
• perform a clipping process for the primitive;
• and
• when the clipping process generates one or more new vertices for the primitive, generate position attributes for the new vertices that are generated as a result of the clipping process;
• and
• the rendering stage processing circuit is configured to use the position attributes generated by the clipping process for new vertices generated as a result of the clipping process for a primitive when determining the values of one or more non-position attributes when processing a primitive that underwent the clipping process for a render output.

A non-transitory computer readable storage medium storing software code which when executing on one or more processors performs a method of operating a graphics processor when executing a tile-based graphics processing pipeline to generate a render output, the graphics processing pipeline being executed comprising:

• a sequence of one or more geometry processing stages to perform geometry processing;
• a binning stage that performs a binning process to generate data structures for identifying geometry to be processed for respective rendering tiles of a render output being generated;
• a rendering stage for rendering tiles of a render output being generated;
• the method comprising, when generating a render output in which primitives to be rendered can be clipped against a clip plane defined for the render output, for a primitive to be processed for the render output being generated and that is to undergo a clipping process as part of its processing for the render output:
• performing a clipping process for the primitive;
• and
• when the clipping process generates one or more new vertices for the primitive, the clipping process generating position attributes for the new vertices that are generated as a result of the clipping process;
• and, thereafter:
• the rendering stage using the position attributes generated by the clipping process for the new vertices generated as a result of the clipping process for the primitive when determining the values of one or more non-position attributes when processing the primitive that underwent the clipping process for the render output.