Methods of and apparatus for processing computer graphics

A computer implemented method of processing a graphics primitive of an image to be displayed, the computer implemented method comprising:

• generating, by a computer, a set of graphics fragments for rendering the primitive for display;
• rendering, by the computer, graphics fragments generated for the primitive to determine a set of rendered fragment data for each rendered graphics fragment;
• and
• performing, by the computer, an alpha test in respect of a fragment as part of the rendering process;
• wherein:
• the alpha test is performed by:
• generating an individual alpha value for a sampling point or sampling points for the fragment;
• and
• carrying out an alpha test individually for each sampling point for which an alpha value has been generated using the individual alpha value generated for the sampling point.

A method of processing a graphics primitive of an image to be displayed, the method comprising:

• generating, by a graphics processor, a set of graphics fragments for rendering the primitive for display;
• rendering, by the graphics processor, graphics fragments generated for the primitive to determine a set of rendered fragment data for each rendered graphics fragment;
• generating, by the graphics processor, an individual parameter value for a sampling point or sampling points for a fragment;
• and
• using the individual parameter value generated for a sampling point for subsequent processing in relation to the sampling point.

A system for processing a graphics primitive of an image to be displayed, the system comprising:

• means for generating a set of graphics fragments for rendering the primitive for display;
• means for rendering graphics fragments generated for the primitive to determine a set of rendered fragment data for each rendered graphics fragment;
• and
• means for performing an alpha test in respect of a fragment or fragments as part of the rendering process;
• wherein:
• the means for performing the alpha test comprises:
• means for generating an individual alpha value for a sampling point or sampling points for the fragment or fragments in question;
• and
• means for carrying out an alpha test for each sampling point individually using the individual alpha value generated for the sampling point.

A graphics processing system for processing a graphics primitive of an image to be displayed, the system comprising:

• processing logic circuitry configured to generate a set of graphics fragments for rendering the primitive for display;
• processing logic circuitry configured to render graphics fragments generated for the primitive to determine a set of rendered fragment data for each rendered graphics fragment;
• processing logic circuitry configured to generate an individual parameter value for a sampling point or sampling points for a fragment or fragments;
• and
• processing logic circuitry configured to use the individual parameter value generated for a sampling point for subsequent processing in relation to the sampling point.