Requirements

Requirements, specifications and tests are tracked with sphinx-needs. Each item has an ID, a status and links to the items it refines, implements or verifies.

Type	Prefix	Links
Requirement	REQ_
Specification	SPEC_	implements a requirement
Test	TEST_	verifies a specification or requirement; gtest names the GoogleTest case

Statuses: draft, open, implemented, verified.

Note

This section is at an early stage. The items below are a starting set that shows the structure; they are not a complete specification of the engine.

Overview

ID	Title	Type	Status	Implements	Verifies
REQ_GRAPH_PATHS	Multiple execution paths	req	implemented
REQ_GRAPH_PRERECORDED	Pre-recorded GPU work	req	implemented
REQ_GSPLAT_BACKENDS	Interchangeable splatting backends	req	implemented
SPEC_GRAPH_ORDER	Topological ordering with Kahn's algorithm	spec	implemented	REQ_GRAPH_PRERECORDED
TEST_GRAPH_HEADLESS_SUBMIT	Headless submit and wait	test	verified		REQ_GRAPH_PATHS; SPEC_GRAPH_ORDER
TEST_GSPLAT_BACKENDS_AGREE	Both backends agree on the raccoon scene	test	verified		REQ_GSPLAT_BACKENDS

Compute graph

Requirement: Pre-recorded GPU work REQ_GRAPH_PRERECORDED

status: implemented is implemented by: SPEC_GRAPH_ORDER

Running a compiled graph shall not record Vulkan command buffers; it shall only submit command buffers recorded at compile time.

Requirement: Multiple execution paths REQ_GRAPH_PATHS

status: implemented is verified by: TEST_GRAPH_HEADLESS_SUBMIT

A compiled graph shall support a fixed number of execution paths, each with its own command buffers, so that several frames can be in flight at once.

Specification: Topological ordering with Kahn's algorithm SPEC_GRAPH_ORDER

status: implemented implements: REQ_GRAPH_PRERECORDED is verified by: TEST_GRAPH_HEADLESS_SUBMIT

ComputeGraph::compileFrom() orders the elements with Kahn’s algorithm, sets them up and records one command buffer per element and path.

Test: Headless submit and wait TEST_GRAPH_HEADLESS_SUBMIT

status: verified gtest: ComputeGraph.headlessSubmitAndWait verifies: REQ_GRAPH_PATHS, SPEC_GRAPH_ORDER

Compiles a render graph over several headless paths and submits each path with submitAndWait.

Gaussian splatting

Requirement: Interchangeable splatting backends REQ_GSPLAT_BACKENDS

status: implemented is verified by: TEST_GSPLAT_BACKENDS_AGREE

The compute and the raster Gaussian splatting backends shall take the same inputs, so that switching the backend does not change the surrounding graph.

Test: Both backends agree on the raccoon scene TEST_GSPLAT_BACKENDS_AGREE

status: verified gtest: GaussianSplattingFactory.bothBackendsAgreeOnRaccoonScene verifies: REQ_GSPLAT_BACKENDS

Renders the raccoon scene with both backends and compares the images.