Doorway repulsion and corridor chokepoint yielding in Argus_ActEscort and Argus_AI

[saworbit]

Overview

One of the most frustrating classic co-op bot failure modes is door blocking: the human player enters a room, encounters heavy monster fire, attempts to backpedal through the doorway, and gets jammed against the companion standing squarely in the threshold.

Following established companion AI standards (such as Left 4 Dead and Half-Life survivor bots), companions must treat doorway volumes, narrow arches, and chokepoints with active avoidance.

Proposed Changes

1. Doorway Volume Repulsion

• Identify active and resting door trigger/portal volumes from the BSP/cartograph data.
• In \Argus_ActEscort, if the bot's candidate formation position sits within a door bounding box or immediate portal threshold, shift the target outside the doorway portal.
• Never choose a standstill hold point inside a door frame.

2. Backpedal Yielding & Chokepoint Clearance

• When the human teammate's velocity is directed toward the companion (\dotproduct(v_forward_teammate, self.origin - teammate.origin) < 0\ while distance < 96u):
  • Treat the player as actively retreating or kiting.
  • Companion immediately yields space, backpedaling or tucking into wall recesses to give the human an unobstructed escape corridor.

3. Combat Line of Movement Clearance

• In \Argus_BodyBlockCheck, if teammate is taking damage or firing while moving backwards, companion immediately widens lateral separation to avoid collisions.

Acceptance Criteria

• Verified on maps with narrow door thresholds (e.g. E1M1 opening corridor, slipgate door, E1M2 tech base doorways).
• Companion never wedges human in doorways during combat or exploration.