Removed Batch Coverage

This page records which batch coverage was removed with the old generic shape batching prototype. It is historical and should not be treated as a feature roadmap.

Removed Coverage

The prototype attempted to cover:

• rounded boxes
• chamfer boxes
• simple fill/stroke shapes
• selected gradient fills
• selected inner effects
• selected widget shapes
• data-texture based parameter upload
• run discovery in the paint stream

Coverage kept shrinking as public style records grew. Each new field required more compatibility checks:

• style.backdrop
• innerGlow
• outerGlow
• pattern
• multi-stop gradients
• image masks
• transform
• per-shape fallbacks
• text/clip ordering barriers

The scheduler needed to prove that a shape could be batched without changing its output. That proof became the hot-path cost.

Why It Was Removed

The generic approach conflated two goals:

1. reduce draw calls
2. keep immediate UI behavior and visual parity

In GMod, the second goal dominated. UI often relies on explicit paint order, and the Lua/Source boundary makes classification and upload work expensive.

The prototype was removed because it was a net complexity increase without stable runtime wins on representative UI.

Current Coverage Strategy

MGFX now treats "coverage" as implemented render slots on immediate paths.

• Use GetCapabilities(target) for supported slots.
• Use Supports(target, key) for a specific slot.
• Add shader support to the target family that actually needs it.
• Keep fallback behavior explicit.

If a new optimization is needed, prefer a narrow fused shader or a specialized path with measured benefits over reviving a general-purpose scheduler.