GridPlacement 6.0 (formerly GridBuilding)

Targeting chain

This page is the canonical reference for the Targeting chain in GridPlacement 6.0.

The targeting chain is the coordinated sequence of systems that transforms raw pointer intent (mouse/touch/keyboard-driven cursor movement) into a stable target snapshot (snapped grid coordinate + resolved target node) that downstream chains can consume.

Boundary

  • Godot layer
    • Captures InputEvent and decides routing/priority.
    • Owns viewport/world coordinate sampling.
  • Core boundary (workflow readiness / ports)
    • Exposes narrow, engine-agnostic readiness/contracts (no Godot types).
    • Downstream chains (Placement/Manipulation) consume targeting through workflow ports.

6.0 targeting chain

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Godot InputEvent / viewport state
  ↓
GBInputService (routes intent)
  ↓
GBPositioningInputAdapter / Positioning adapter
  ↓
Positioner / targeting implementation
  - snaps to grid
  - runs shape cast / hit test
  - resolves logical target node
  ↓
Targeting state (readiness + current target snapshot)
  ↓
Consumers
  - Placement chain (validate / indicators / execute)
  - Manipulation chain (hover/active target, move/demolish/info)
  - UI (target informer)

What is “the target”

A target snapshot is treated as:

  • Grid coordinate
    • Snapped Vector2i (or Core equivalent) representing the current cell.
  • Resolved target node
    • A Node2D representing the logical target for manipulation/info.
    • May differ from the raw physics collider.

Target resolution (logical target vs collision object)

Targeting is allowed to detect collision shapes on child nodes while targeting a parent/root logical node.

Resolution priority:

  1. Direct metadata (e.g. a “root_node” meta pointing at the logical target)
  2. Manipulatable discovery (sibling/child lookup for a manipulatable component)
  3. Fallback: treat the collision node as the logical target

Output contract

What the targeting chain guarantees:

  • The latest target snapshot is stable (snapped) and updated when needed.
  • Downstream chains can treat targeting output as authoritative.

What it does NOT guarantee:

  • It does not apply indicators.
  • It does not validate placement rules.
  • It does not mutate grid occupancy.

Existing deep dives