Deferred shading graphics pipeline processor

A graphics rendering method generating a rendered image in a frame buffer, the image being generated from a plurality of graphics primitives, the method comprising the steps:

• sorting the graphics primitives into a plurality of tiles, each of the tiles being an area within the image, the tiles each being rendered separately;
• selecting one of the tiles;
• generating a first sequence of data comprising a first indicator followed by the graphics primitives that touch the selected tile, the first indicator designating a beginning of the rendering of the selected tile;
• generating a second indicator requesting image data corresponding to the selected tile from the frame buffer;
• reading the requested image data from the frame buffer and generating a third indicator when the reading is completed;
• generating a second sequence of data comprising the first indicator followed by generating image color values for the selected tile, the generating image color values being generated from the graphics primitives that touch the selected tile;
• combining, according to one or more programmatically specified fragment operations, the generated image color values and the read image data, the generated image color values for the selected tile and the read image data for the selected tile being synchronized by associating the first indicator and the third indicator.

A graphics pipeline generating a rendered image in a frame buffer, the image being generated from a plurality of graphics primitives, the graphics pipeline comprising:

• (1) logic sorting the graphics primitives into a plurality of tiles, each of the tiles being an area within the image, the tiles each being rendered separately;
• (2) shading logic generating image color values for the sorted graphics primitives in one of the separately rendered tiles;
• (3) logic generating a prefetch indicator for the one of the separately rendered tiles, causing image data to be read from the frame buffer in parallel with the shading logic generating image color values;
• and
• (4) pixel logic combining the generated image color values and the read image data.

A graphics rendering method generating a rendered image in a frame buffer, the image being generated from a plurality of graphics primitives, the method comprising the steps:

• (1) sorting the graphics primitives into a plurality of tiles, each of the tiles being an area within the image, the tiles each being rendered separately;
• (2) generating image color values for the sorted graphics primitives in one of the separately rendered tiles;
• (3) generating a prefetch indicator for the one of the separately rendered tiles, causing image data to be read from the frame buffer in parallel with the step of generating image color values;
• and
• (4) combining the generated image color values and the read image data.

A graphics rendering method generating a rendered image in a frame buffer, the image being generated from a plurality of graphics primitives, the frame buffer storing data comprising color values, z values, and stencil values, the method comprising the steps:

• (1) dividing the area of the image into a plurality of tiles, the tiles each being rendered separately;
• (2) detecting a condition of an application program specifying one or more buffer clear operations during an early stage of the generation of the rendered image, such that the rendered image can not be affected by the previous one or more of color values, z values, and color values stored in the frame buffer;
• (3) conditionally reading, for a selected tile, color values, z values, and stencil values from the frame buffer into a tile buffer, some of the reading being avoided if the condition is detected;
• and
• (4) rendering the image for the selected tile.