Hierarchy Builder

The Hierarchy Builder is a specialized sub-component of the optional Hierarchical Z/Stencil Culling Unit (HZCU) in graphics processing systems. Its primary function is to dynamically generate and maintain a hierarchical representation (often a tree or pyramid structure) of depth or stencil values from the scene geometry. This hierarchy enables efficient traversal and testing during the occlusion culling process, allowing the HZCU to quickly identify and discard objects or pixels that are not visible, thereby reducing the computational load on the rendering pipeline.

Operating as a hardware component, the Hierarchy Builder processes incoming depth or stencil data from the geometry pipeline. It aggregates this data into tiles or blocks at multiple levels of detail, from fine-grained pixel data to coarser region summaries. The constructed data structure has parent nodes that contain conservative depth bounds, such as the farthest depth, of their child regions. This structure is built and updated in real-time, often using parallel hardware logic, to provide the HZCU with an efficient map for hierarchical occlusion queries.

In terms of specifications, the Hierarchy Builder operates within a voltage range of 3.3–5.0 V DC, with a power consumption of 0.5–2.0 W. Its clock frequency ranges from 100–500 MHz, and processing latency is between 1–10 ns. The operating temperature range is -40 to 85 °C, while storage temperature is -55 to 125 °C. Relative humidity should be maintained between 5% and 95% (non-condensing). The ingress protection rating is IP40–IP65, and signal integrity is within ±0.05 dB. Data throughput ranges from 10–100 Gbps, with a weight of 50–200 g and dimensions of 30×30×10 to 50×50×20 mm. These values are reference ranges and must be verified for the specific model and application.

Standards referenced include IEC 62368-1 for operating voltage, IEC 60068-2-14 for operating temperature, IEC 60068-2-2 for storage temperature, IEC 60068-2-78 for relative humidity, and IEC 60529 for ingress protection. These standards serve as procurement and verification references, not as proof of certification or compliance. Always confirm model-specific values and standards with the legal manufacturer or supplier.

The Hierarchy Builder processes incoming depth or stencil data from the geometry pipeline. It aggregates this data into tiles or blocks at multiple levels of detail, from fine-grained pixel data to coarser region summaries. It constructs a data structure where parent nodes contain conservative depth bounds, such as the farthest depth, of their child regions. This structure is built and updated in real-time, often using parallel hardware logic, to provide the HZCU with an efficient map for hierarchical occlusion queries.