Editing Reyes rendering (section)

=== Pipeline ===

The basic Reyes [[Graphics pipeline|pipeline]] has the following steps:

# ''Bound.'' Calculate the [[bounding volume]] of each geometric primitive.
# ''Split.'' Split large primitives into smaller, diceable primitives.
# ''Dice.'' Convert the primitive into a grid of micropolygons, each approximately the size of a pixel.
# ''Shade.'' Calculate lighting and shading at each vertex of the micropolygon grid.
# ''Bust'' the grid into individual micropolygons, each of which is bounded and checked for visibility.
# ''Hide.'' Sample the micropolygons, producing the final 2D image.

In this design, the renderer must store the entire frame buffer in memory since the final image cannot be output until all primitives have been processed. A common memory optimization introduces a step called ''bucketing'' prior to the dicing step. The output image is divided into a coarse grid of "buckets," each typically 16 by 16 pixels in size. The objects are then split roughly along the bucket boundaries and placed into buckets based on their location. Each bucket is diced and drawn individually, and the data from the previous bucket is discarded before the next bucket is processed. In this way only a frame buffer for the current bucket and the high-level descriptions of all geometric primitives must be maintained in memory. For typical scenes, this leads to a significant reduction in memory usage compared to the unmodified Reyes algorithm.