simvx.graphics.renderer.hiz_pass

Hi-Z depth pyramid build pass (occlusion-culling phase O2).

Builds a hierarchical depth pyramid from the HDR target’s D32 depth buffer: mip0 is a 1:1 copy of the scene depth, and each successive mip is a conservative MIN reduction (farthest occluder: depth is reverse-Z, so the far plane is 0) over the previous mip’s 2x2 footprint. The pyramid is consumed later (O3) by a compute occlusion cull; this phase only builds and validates it.

The pass is fully gated by Renderer._occlusion_culling_enabled: it is lazily created on the first frame the toggle is on (mirroring VelocityPass), so with occlusion off nothing here is allocated or dispatched.

Resource/descriptor approach mirrors :class:SSAOPass: a compute pass that samples the samplable D32 depth target in DEPTH_STENCIL_READ_ONLY_OPTIMAL.

Module Contents

Classes

HiZPass

Builds a Hi-Z (hierarchical farthest-depth) pyramid via per-mip compute dispatches.

Functions

hiz_mip_count	Number of mip levels in the Hi-Z pyramid for the given base extent.
hiz_mip_sizes	Per-mip (w, h) dimensions, each (max(1, w>>i), max(1, h>>i)).

Data

__all__
log

API

simvx.graphics.renderer.hiz_pass.__all__

[‘HiZPass’, ‘hiz_mip_count’, ‘hiz_mip_sizes’]

simvx.graphics.renderer.hiz_pass.log

‘getLogger(…)’

simvx.graphics.renderer.hiz_pass.hiz_mip_count(width: int, height: int) → int

Number of mip levels in the Hi-Z pyramid for the given base extent.

floor(log2(max(w, h))) + 1 so the top mip is 1x1.

simvx.graphics.renderer.hiz_pass.hiz_mip_sizes(width: int, height: int) → list[tuple[int, int]]

Per-mip (w, h) dimensions, each (max(1, w>>i), max(1, h>>i)).

class simvx.graphics.renderer.hiz_pass.HiZPass(engine: Any)

Builds a Hi-Z (hierarchical farthest-depth) pyramid via per-mip compute dispatches.

Initialization

property mip_count: int

property image: Any

The Hi-Z R32F mip-chain image (for O3 readers / test readback).

property sampled_view: Any

Full-mip-chain sampled view (for the O3 occlusion cull’s textureLod).

property sampler: Any

The NEAREST/CLAMP sampler shared by the build and the O3 cull.

property base_extent: tuple[int, int]

Base (mip0) extent (width, height) of the pyramid.

setup(width: int, height: int, depth_view: Any, depth_image: Any, shader: str = 'hiz_build.comp') → None

Allocate the pyramid image, per-mip views, sampler, descriptors and pipeline.

shader selects the reduction compute shader; the default farthest-occluder pyramid serves occlusion culling, ssr_hiz.comp (nearest surface) serves the SSR trace.

render(cmd: Any) → None

Build the full pyramid: dispatch the reduction once per mip.

Call after the HDR pass has produced depth (depth in DEPTH_STENCIL_READ_ONLY_OPTIMAL). A pure depth reduction: no camera matrices.

resize(width: int, height: int, depth_view: Any, depth_image: Any) → None

Recreate the pyramid for a new extent and re-write descriptors.

cleanup() → None