agent_compositor_test/documents/session-logs/2026-07-05.md

Session Log — 2026-07-05

Completed

• DAG refactoring (scratchpad/dag.c): Decoupled PrGraph from PrNodeManager. Graph tracks its own active vertices (vertex_count, max_vertex_ever, b8 active). prGraphAddEdge, prGraphTopologicalSort no longer take PrNodeManager*. Kahn's algorithm integrated into prGraphAddEdge for cycle detection with rollback. Output verified matching baseline.
• RHI research document written to documents/research/rendering-hardware-interface.md. Covers 8 reference RHIs, architecture patterns, core API surface, Vulkan-specific considerations, Slang integration, and proposed directory layout / lifecycle design.
• Added NVRHI to documents/resources.md.
• RHI API surface (scratchpad/rhi/pr_rhi.h, pr_rhi_types.h): Full RHI API designed with compile-time alias dispatch, by-value desc structs, wapp array types for pointer+count replacement, PrRhiSwapchainResult enum, surface capabilities, compute pipeline support, all primitive topologies, and aligned function declarations grouped by subsystem section.
• Initial opencode setup (opencode.json, justfile, skills, trimmed AGENTS.md).

Key Decisions

• Graph API is self-contained — no graphics or node-manager dependencies.
• RHI will use compile-time alias dispatch (#define prRhiCreateDevice prRhiCreateDeviceVk) over vtbl — zero runtime overhead, dead-stripping, separate builds per backend.
• justfile (Just) as task runner.
• Object lifecycle: prRhiCreate* / prRhiDestroy* with explicit WpAllocator*.
• All GPU state explicit (no hidden pipeline state).
• Per-frame command pools and descriptor pools, arena-allocated scratch.
• #version-macro convention removed from Slang files; __slang define used instead.
• Desc structs passed by value (not const *) for simpler caller ergonomics.
• Array aliases grouped: opaque handles (**) first, value types (*) second, separated by blank line — element types before array aliases before desc structs.

Next Steps

• Begin Vulkan backend implementation starting with pr_rhi_vk_device.c (instance/device/surface/swapchain creation).
• Implement Slang shader compilation + reflection integration.
• Wire up per-frame lifecycle (command pool reset, descriptor pool reset, scratch reset).