prometeu-runtime/discussion/workflow/plans/PLN-0079-gfx2d-primitive-domain.md

id	ticket	title	status	created	ref_decisions	tags
PLN-0079	render-frame-packet-boundary	Gfx2D Primitive Domain	open	2026-05-25	DEC-0030	gfx renderer runtime frame-composer architecture ui pipeline

Briefing

Source decision: DEC-0030.

Replace primitive Game drawing paths with gfx2d.* command buffering while keeping gfx2d limited to primitives only.

Target

Game primitive drawing becomes a Game-mode ABI domain that records commands into a buffer consumed as part of Game 2D rendering.

Scope

• Add gfx2d.* syscall domain and command buffer.
• Migrate primitive Game drawing calls from old gfx.* behavior to gfx2d.*.
• Ensure gfx2d contains primitives only.
• Integrate gfx2d commands into the Game 2D packet/render path without taking ownership of scene, camera, sprites, HUD, or frame orchestration.

Out of Scope

• Shell UI primitive domain.
• composer.* high-level Game state.
• Widget/layout policy.
• Compatibility with old primitive gfx.* ABI names.

Execution Sequence

1. Inventory old primitive gfx.* syscalls and direct drawing callsites used by Game mode.
2. Define the gfx2d.* command enum and mutable command buffer.
3. Route Game primitive syscalls into the buffer.
4. Add app-mode and capability enforcement for Game-only access.
5. Integrate buffered primitives into Game 2D packet closure or renderer consumption at the DEC-0030-approved layer.
6. Remove or retire old primitive gfx.* ABI registrations.

Acceptance Criteria

• Game primitive commands are buffered as gfx2d.*.
• gfx2d does not own scene, camera, sprites, HUD, or frame orchestration.
• Shell mode cannot call gfx2d.*.
• No logical primitive path directly mutates framebuffer during production.

Tests / Validation

• Add syscall tests for each migrated primitive.
• Add command buffer ordering tests.
• Add capability rejection tests for Shell mode.
• Run pixel-equivalence tests for unchanged primitive output.

Risks

• The old gfx naming may appear in PBS wrappers; distinguish author API names from ABI domain names.
• Primitive ordering relative to composer output must be explicit.

Affected Artifacts

• Syscall registry and runtime render domain modules under crates/
• Game primitive tests